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NNadir

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Upgrading Low Quality Iron Ores With Biomass Gasification/Coal Tars.

I have no use whatsoever for the ethically vacuous "free marketeer" philosophy, since it posits that some human beings have the right to destroy arbitrarily the lives of other human beings solely for their self interest.

This said, there are two kinds of appeals to "free market" nonsense, the puerile and the sophisticated.

The puerile type consists of the destructive nonsense put out by that vicious and despicable muddled self declared "thinker" Ayn Rand, who unfortunately lived at all - never mind too long - and is embraced by middle aged eternally intellectually teen aged muddle heads like, say, Paul Ryan, whose life experience should have been limited to playing video games in their parents bedrooms, but nevertheless have ended up defending overt racists in, of all places, the House of Representatives.

The sophisticated type is the one that points out that most of us - at least in the so called "First World" - are culpable in the amoral destruction of other human lives - the lives I personally rail about, spitting in the wind, are the lives of all future generations - and that we are by definition hypocrites if we object to the outcome and implication of our lifestyles with respect to other human beings, current and future.

I admire and often study the thinking of the great technological philosopher and scientist Vaclav Smil, whose rhetoric is often of the second type. Note that this is decidedly not of the discipleship type characterized by the Ayn Rand/Paul Ryan Bozo cartoon type, and their "Objectivist" pseudoathesim in which they nonetheless grovel at the foot of a clay goddess who authored holy books for the mindless. No, by contrast, when I read Smil it is often (but not always) to be challenged to find ways to argue that he might be made wrong, even if he is right now.

One of Smil's writings that has challenged me concerns iron - hence the title of this post - this one: The Iron Age & Coal-based Coke: A Neglected Case of Fossil-fuel Dependence.

I never tire of saying that I feel that it is a moral imperative to entirely end dependence on fossil fuels, since they are clearly not sustainable, and yet, as Smil points out, we live and have lived for well more than a millennium, in an age of iron, in modern times, complex steel alloys, all of which rely on the use of carbon, carbon almost always obtained from coal.

Our generation has consumed the best ores for pretty much all of the essential elements in the periodic table, and what remains for the future generations is our table scraps, our garbage and the poor pickings of future generations. This is true to some extent even for very common elements like aluminum and iron. (In the former case, cryolite mines in Greenland were completely depleted by the 1980's and all modern cryolite - the flux intermediate for the Hall electrolysis process by which all aluminum is made is now synthetic.)

It is thus with some interest that I came across this paper in the scientific journal Energy and Fuels that discusses a process for upgrading the low quality iron ore Goethite by combining tars that derive not only from coal, but from biomass gasification. The paper is this one: Integrated Pyrolysis–Tar Decomposition over Low-Grade Iron Ore for Ironmaking Applications: Effects of Coal–Biomass Fuel Blending (Akiyama et al, Energy Fuels, 2018, 32 (1), pp 396–405)

Biomass gasification is one of a few technologically feasible paths for removing the dangerous fossil fuel waste carbon dioxide from the atmosphere - but only if the heat is provided by nuclear energy, and not by combustion. However, in the case of many of these processes, most of them in fact, a side product remains, "tars" and/or "asphaltenes."

From the introductory text:

Presently, ironmaking industries face problems related to the depletion and shortage of both high-grade iron ores as raw materials as well as carbonaceous material as a primary reduction agent. The effective utilization of low-grade ores, such as goethite (FeOOH), in the modern ironmaking industry is highly attractive to solve problems related to the depletion of high-grade iron ores. Goethite, however, cannot be directly charged into a blast furnace as a result of its high combined water content.(1-6) Previous researchers proposed a new process called the integrated biomass or coal pyrolysis–tar decomposition process that solves these problems simultaneously. This process aims to reduce tar by decomposing it as deposited carbon over low-grade iron ore as well as using chemical vapor infiltration (CVI) to produce carbonized ore.(7) The report described fundamental experiments of an ironmaking process that used low-grade iron ore and woody biomass. The decomposition of biomass tar produced carbon that deposited within the iron ore pores, resulting in partial reduction of the iron. Furthermore, nanocracks suitable for carbon deposition were initiated and propagated during this dehydration. Carbon tar completely filled the nanocracks and increased the carbon content, which could be used as a potential reduction agent.(8) A similar method was applied using steelmaking slag as supplementary fuel in a sinter machine.(9) The CVI ore can then be used for ironmaking applications because it has a higher reduction reactivity as a result of the nanoscale contact between iron oxide and carbon.(10) Investigations have been performed on the carbon deposition of various solid fuels, including high-grade bituminous coal, low-grade lignite coal, and biomass palm kernel shells.(11) However, a new challenge was introduced: to produce a CVI ore with a higher carbon content as a reduction agent.

In modern blast furnace operation (typical case in Japan), 385 kg of coke per ton of hot metal is needed, while 112 kg of pulverized coal per ton of hot metal is injected.(12) For every ton of coke produced, around 1.6 tons of coking coal is used.(13) However, because high-grade coal (coking coal) tends to be expensive with limited availability, the utilization of biomass (mainly wood) as a substitution for coal (which is a non-renewable carbonaceous material) also gained much attention in an attempt to reduce greenhouse gas emissions. Furthermore, utilization of any individual biomass material normally faces several problems, such as seasonal harvesting, which limits year-round availability, higher transportation costs, and lower fuel qualification properties.(14)...


The chemistry of biomass is extremely complex, especially since practical sources of it involves hundreds if not thousands of species grown under variable conditions. Further adding to this complexity, a plethora of strategies for processing it into gaseous compounds exist. The authors offer a brief description of a current highly sophisticated effort to rationalize some of these parameters by referring to what is called the "Distribution Activation Energy Model" or DAEM, which evokes a beautiful looking equation.

The authors write:

The basic assumption of the DAEM is that many solid fuel decomposition reactions take place during pyrolysis. It can be simply approached as a sum of an unlimited number of parallel first-order decomposition reactions. When multiple Gaussian distributions of activation energy are applied, the DAEM equation can be written as



(1)
where Xcalc is the calculated residual volatile fraction of solid fuel at a given time, n is the number of activation energy distributions, β is the heating rate (K s–1), k0i is the pre-exponential factor of constituent i (s–1), σi is the activation energy variance of constituent i (kJ mol–1), E0i is the mean activation energy of constituent i (kJ mol–1), R is the gas constant (J mol–1 K–1), and T is the absolute temperature (K).


The authors walk us through a few iterations of this equation to get an even more beautiful looking equation, this one:



At this point, I plainly confess that the actual use of this equation if over my head, despite the obvious appeal to the Arrhenius law in the integral in the exponent of another integrated exponential, but that's OK, because this is the first time in my life I ever heard about DAEM related work with respect to biomass gasification. Playing with that equation has to be fun. I do hope to find the time to get to the references some day and learn about this beautiful thermodynamics.

You learn something every day...if you're lucky, and I am lucky, bourgeois piece of crap that I am.

Anyway, the authors get down to performing some experiments with biotars and coal tars.

Here's a schematic of their apparatus:



The caption:

Figure 1. Apparatus configuration for integrated pyrolysis–tar decomposition–carbon deposition over iron ore.


It looks like a mini-retort.

They study their process by the use of thermogravimetric analysis, (TGA), a TGA being a device that measures the loss of mass as a substance is heated. This is plotted along with the DTG, the "Differential Thermogravimentric" curve, which represents the rate of decomposition, in essence the derivative of the TGA output as a function of temperature.



The caption:

Figure 2. TG/DTG profiles and the highest decomposition rate temperatures for coal–biomass blending with different BBRs during pyrolysis. Coal and biomass particle size = 125–355 μm.


Here "BBR" refers to the biomass blending ratios, the ratio of biomass to coal.

It is useful to stop here to speak about the coal component of this system, since many of my writings on the internet are adamant that coal mining and use should be phased out rapidly. With due deference to the exceptional mind of Vaclav Smil, I do believe that synthetic coal that will be superior to mined coal is in the realm of possibility and further, with input of energy, and I also believe it is technically feasible to make synthetic coal from, um, carbon dioxide. The path for doing this would involve (besides procuring the carbon dioxide) a metal based carbon dioxide splitting thermochemical system driven by nuclear heat or by reformation of either waste plastic or biomass with carbon dioxide as an oxidant. The resultant carbon monoxide could then be disproportionated into pure carbon and carbon dioxide using a chemical equilibrium - also a function of temperature - known as the Boudouard equilibrium, CO2 <-> CO + C.

All that is required is energy, which at least in theory is available in unlimited supply since uranium is available in unlimited supply, since there is so much uranium on this planet that humanity could never consume all of it without vaporizing the planet, something that is obviously to be avoided, even if it is possible.

With appropriately Rube Goldbergish heat flows, this need not be all that expensive for future generations, who couldn't possibly be more stupid than our generation, a generation that has allowed an orange baboon with a poor intellect and a non-existent ethical matrix that is Ayn Randian in dimension into the White House.

In any case, coal that finds its way into steel making is at least partially sequestered more or less permanently, at least in high carbon steels.

On this score, it is popular on the American left - and I say this criticizing my own demographic - to pretend that "coal is dead," because the orange baboon has represented that he was going to restore allegedly "dead" coal in the United States. The American left also likes to pretend that the "fastest growing source of energy" on this planet is so called "renewable energy," one component of which, wind energy, is highly reliant on access to steel.

Neither of these pretensions are even remotely true, as I repeatedly point out by reference to the International Energy Agency's World Energy Outlook 2017 report:

IEA 2017 World Energy Outlook, Table 2.2 page 79

Converted MTOE in the original cited table table in the report to the SI unit exajoules in this text one can learn that allegedly "dead" coal has been for the entire 21st century the fastest growing source of energy on this planet, having increased by 60.1 exajoules in the period between 2000 and 2016, 2016 being the last year for which data has been fully compiled. Overall the consumption of coal has risen to 157.2 exajoules out of 576 exajoules the report says was being consumed as of 2016. This makes coal only second to dangerous petroleum as a source of energy on the planet, which grew by "only" 30.1 exajoules to a total of 183.7 exajoules.

The entire so called "renewable energy" scheme, after sucking trillions of dollars out of the world economy does not produce even 10 exajoules of energy, 9.4 to be more precise, having grown by only 6.9 exajoules in the 21st century, or a little more than 11% as fast as coal, never mind dangerous petroleum and dangerous natural gas.

Anyway, back to steel making with biomass cut with a little dangerous coal:

The authors work to explore the parameters in the DAEM equations evoked above and, then, continuing to look at the pictures as a way of understanding this work they produce the following bar graph:



The caption:

Figure 4. Carbon yield product distribution of integrated pyrolysis–tar decomposition in a N2 atmosphere at a pyrolysis temperature of 1073 K and a tar decomposition temperature of 873 K for 40 min. Case A, co-pyrolysis only; case B, co-pyrolysis with tar decomposition over porous iron ore (3 g).


Here's a blurb from the text discussing the bar graph:

The integrated coal–biomass co-pyrolysis–tar decomposition over low-grade iron ore was designed to reduce the tar product while simultaneously converting it to carbon deposited into the iron ore. Moreover, production of high carbon content carbonized ore is desired. Figure 4 shows the product distribution carbon yields from integrated coal–biomass pyrolysis, for both pyrolysis only (case A) and pyrolysis–tar decomposition over porous iron ore (3 g) (case B). The observed pyrolysis products were the carbon yield of char, heavy tar, light tar, deposited carbon in iron ore (case B only), and gas at any BBR. Heavy tar and light tar in this experiment were separated by the boiling point according to the International Energy Agency (IEA) tar protocol, in which the components with the boiling point higher than 378 K could be categorized as the heavy tar fraction.(35) The deposited carbon in iron ore is the carbon amount of solid fuel that deposited in the iron ore bed during the CVI process, which was evaluated from mass balance. In contrast, the carbon content in iron ore was measured by the CHN/O/S elemental analyzer. The term of the deposited carbon and the carbon content in CVI ore were introduced to distinguish the different points of view. It was obvious that the total carbon yield of the biomass pyrolysis product is lower than the coal product because biomass has a lower carbon content than coal. Total carbon yields of the coal–biomass blends gradually decreased at elevated BBRs.


Note that the main product here in terms of mass is gas. It is important to consider what these gases are, since coal is involved and the potential for dumping gases into the planetary atmosphere as fossil fuel waste is not acceptable, even if almost universally practiced.

Another figure from the text, showing gas compositions:



The caption:

Figure 7. Effect of co-pyrolysis at different BBRs on gas H2, CH4, CO, and CO2 product distribution of integrated pyrolysis–tar decomposition in a N2 atmosphere for 40 min at a pyrolysis temperature of 1073 K and tar decomposition temperature of 873 K. Case A, co-pyrolysis; case B, co-pyrolysis with tar decomposition over porous iron ore (3 g).


The point here was to convert a low grade iron ore, goethite, the table scraps we leave for future generations as an expression of our generalized contempt for our children and their decedents - our contempt for humanity as a whole - into an ore of a quality that we enjoyed but squandered on quixotic enterprises like cars and idiotic wind turbines, magnetite. This has been achieved by this process.

By reference to the immediate figure above, a note is in order about the composition of the gas component.

Here is the chemical equation for the pyrolysis reactions:



The authors write:

The significant increase of H2 and CO2 at higher BBRs could be correlated to the presence of water from biomass pyrolytic tar-promoting steam reforming, as in eq 8, and water-gas shift reaction (WGSR), as in eq 9.


The "water gas shift reactions" are these:





The gases above, as mixtures of carbon oxides and hydrogen are forms of what are known as "synthesis gas" or "syn gas" for short, from which pretty much any modern commodity carbon compound may be formed. (Such practices may require hydrogen from thermochemical or biomass reforming based water or carbon dioxide splitting.) To the extent that such practices result in polymers, or engineered carbon products such as carbon fibers, graphene or carbon based ceramics such as metal carbides and MAX phases, they represent economically valuable carbon sequestration.

They need not be dumped in the atmosphere as waste, despite our current practice.

A better world is possible, even if it is less and less likely.

Enjoy the weekend, and if you come from a Christian cultural background, have a happy Easter.




I had a Freundlich exponent when I was a kid, but I went away for a weekend and my Mom...

...forgot to feed and it and died.

I've been absorbed in grief ever since.

I don't know why I had to say that, but I just did.

Go back to your normal lives...

Forensic Analysis of One of the Earliest Weapons Grade Plutonium Samples Ever Prepared.

Recently I've been studying - because some excellent articles on the topic have been showing up in the scientific journals I routinely scan and or read - the interesting chemistry of the clean up of one of the most radioactively contaminated sites in the world, the Hanford Reservation near Richland, Washington.

Here for instance, is one such paper on this topic, on which I may comment in the future in this space: Review of the Scientific Understanding of Radioactive Waste at the U.S. DOE Hanford Site (Peterson et al, Environ. Sci. Technol., 2018, 52 (2), pp 381–396)

I am always interested in radiochemistry, since I believe understanding it represents the last best hope of the human race.

Coincidentally, I've been going through old papers that I collected years ago but never read to sort them into appropriate directories, and I came across an interesting paper relating to one of the earliest known samples of plutonium ever prepared, prepared in the early days of the Manhattan project. The paper is here: Nuclear Archeology in a Bottle: Evidence of Pre-Trinity U.S. Weapons Activities from a Waste Burial Site (Schwantes et al., Anal. Chem., 2009, 81 (4), pp 1297–1306)

The Hanford site, which is where most of the plutonium for America's nuclear weapons was made, for most of its history as a production plant, operated on what its operators considered to be "emergency" conditions, extreme conditions of races against real and putative enemies, in both hot and cold war. The mentality was not focused at all on the long term other than potential post apocalyptic scenarios in which our enemies nuked us before we could nuke them. In such a mentality, so far as radioactive fission products as well as toxic chemicals were concerned, they were handled in a way that in our more distant time we would regard as extremely cavalier. In the earliest years, nuclear by products, often referred to as "nuclear waste," were often disposed of in open trenches, to be replaced later by single shell tanks, some of which famously leaked, and then in double shell tanks. Poor records and inventories were kept, but again, the remediation of this site has some fascinating chemistry and the clean up shows as much ingenuity as the creation of these materials did.

By the way, the existence of the Hanford Site has not lead to a death toll that even remotely approximates the number of people who have been killed by the by products of combustion of dangerous fossil fuels and biomass, which approximates about 7 million people a year, every year, which is roughly the equivalent of nuking and completely wiping out a city the size of Hong Kong every year, without stop. There are people, not very bright people, who wish to represent Hanford as the worst environmental problem that has ever existed, scientifically illiterate journalists for example. The 55,000 citizens of Richland, Washington are leading useful lives - many are scientists at Pacific Northwest National Laboratories - and are not dropping dead in the streets.

But no matter.

Anyway...Nuclear Forensics and the earliest plutonium samples:

From the opening text of the paper:

The frequency of smuggling events involving radioactive materials is supply driven and is on the rise world-wide.(1, 2) While special nuclear materials from the nuclear fuel cycle have not significantly contributed to this increasing trend to date, it is likely that with the current nuclear renaissance and greater access to these materials by the public, smuggling events involving fissionable materials may rise in the near future. Perhaps the most effective tool investigators have against this type of smuggling is the successful application of nuclear forensic science.(3) Nuclear forensics is defined as the science of identifying the source, point-of-origin, and/or routes of transit of nuclear and radiological materials associated with illegal activities for ultimately contributing to the prosecution of persons responsible for those activities.(4) In many respects, the goals of nuclear archeology are identical to those of nuclear forensics, without the added constraints specifically associated with legal prosecution. As such, studies of nuclear archeology serve as an excellent means for advancing the science and demonstrating the capabilities of the nuclear forensics community. Moreover, depending upon the pedigree of the artifacts studied, fully characterized finds representing specific end members of various processes or reactors may be of direct use to forensics experts for comparative purposes against real interdicted sample materials of unknown origin.(5-7) This work provides the public a rare glimpse at a real-world example of the science behind modern-day nuclear forensics and, in doing so, uncovers a sample of historical significance.

Background

The Hanford Site in Washington became the location for U.S. plutonium production during World War II. The Pu produced at this site was used in the first Pu nuclear weapon dropped on Nagasaki, Japan, on August 10, 1945, and in Trinity, the name given to the world’s first test of a nuclear weapon on July 16, 1945. In December 2004, a safe containing several hundred milligrams of extremely low burnup Pu (a term typically associated with Pu produced as part of a weapons program) in a one gallon glass jug was unearthed by Washington Closure Hanford (WCH) personnel while excavating the 618-2 burial ground in the 300-area of Department of Energy’s Hanford site.(8, 9) The jug contained ∼400 mL of slurry characterized as a white precipitate in a clear liquid. Pictures in Figure 1 document this find. In-field γ analysis conducted on the container detected the presence of only 239Pu. The minimum 239,240Pu/238Pu and 239Pu/241Am ratios were estimated to be at least 320:1, and 1000:1, respectively, based upon the detection limits of this analytical technique, indicating the Pu was produced from extremely low exposure fuel, consistent with early military reactor operations at Hanford. The absence of γ-emitting U or fission product isotopes in the spectra also suggested the Pu had been separated and purified prior to its disposal. Considering the potential historical significance of the find, WCH personnel coordinated with staff at Pacific Northwest National Laboratory (PNNL) to conduct further analysis of the sample. All of the liquid and ∼2% of the solid from the container were repackaged into two 1 L polypropylene bottles on May 10, 2006, with one of the two bottles being transferred to PNNL. The majority of the solid material remained, caked to the walls of the original glass jug and was earmarked for disposal. We have coined the process of characterizing this sample as nuclear archeology.


Here's a photograph of the safe and the bottle in it in which the plutonium was found:



The caption:

Figure 1. Pictures of (a) excavated safe and contents and (b) glass bottle containing several hundred milligrams of Pu.


Apparently the process utilized to isolate the plutonium used a lanthanum fluoride carrier. It must have been the case that there was very little plutonium available at the time of the isolation, which is not surprising. In 1944, a chemist named Don Mastick broke a test tube in such a way as to end up eating what was then the world supply of the element; and many years later, as an old man was interviewed on the subject before dying in 2007 at the age of 87.

The scheme for analyzing the contents of the bottle is shown in the following graphic, also from the paper:



One of the interesting things about this paper which surprised me - this after more than 3 decades of reading about nuclear science - was that there was enough Na-22, a radioactive isotope of sodium in the sample to use it as a kind of tracer of the history of the bottle. As it is a radioactive isotope that is neutron deficient, as opposed to neutron rich, it's not an isotope I ever bothered thinking much about. It arises from the interaction of fluorine, a monoisotopic element with a mass number of 19, with alpha particles:

GEA revealed the presence of the relatively short-lived 22Na isotope within the sample. The mechanism for the formation of 22Na (t1/2 = 2.6 years) within fluoride matrixes in the presence of α-emitting actinides has been well documented in the literature(18-23) following the reaction pathway of 19F(α,n)22Na. The production rate for this reaction is a function of the physical characteristics of the fluoride matrix, the production rate and energy of the α particles, and the proximity of the α particles to the 19F atoms. Equation 5 provides a mathematical model for the production of 22Na within simple actinide fluoride solids.




You learn something every day. This might be of interest to all those people working on MSRs (Molten Salt Reactors) utilizing the "FLIBE" or "FLINAK" salts. It's probably not a serious drawback, but one probably requiring some attention.

Some additional comment from the authors on the role of Na-22 in their analysis:

Isotopes like 22Na that are produced from secondary nuclear reactions involving radioactive material may be useful to investigators when a sample of unknown history containing such material is discovered. With the use of the Pu jug as an example, the 22Na activity becomes an easy to detect (γ energy, 1275 keV; branching ratio, 99.4%) signature for 239Pu under steady-state conditions (regions 2 and 4 of Figure 4). In addition, with the assistance of an accurate production model for 22Na, the total Pu within the sample prior to repackaging can be estimated prior to reaching steady-state conditions (i.e., within region 1) if it is known a priori when 22Na production began. Alternatively, the time since 22Na production began may be estimated during the in-growth period (region 1) if the amount of Pu within the sample (prior to repackaging) is known. However, it is region 3 of Figure 4 that is of most interest to the nuclear forensics community. Here the Pu jug after repackaging (2006) resembles what might be expected from an interdicted sample that, unknown to the investigator, had been separated from the majority of the Pu prior to confiscation. In such a case, a decrease in the 22Na activity with time would suggest the confiscated sample may have been portioned off from a greater amount of Pu that had escaped interdiction


Figure 4:



The caption:

Figure 4. Predicted and measured 22Na content with time within the Pu sample from 1945−2038.


Further elaboration is in the text of the original paper about how to use isotopes like 22Na (or similar secondary nuclear reactions) to determine whether the same contains all of the plutonium originally available from its source, or only a fraction of it.

By the way, the plutonium in this sample was almost pure Pu-239, a grade of plutonium that today would be considered an extreme weapons grade material. This is unsurprising, since the Manhattan project had no way of knowing the effect of plutonium-240 would have on their weapons, and probably went to great lengths to avoid its accumulation. This requirement, regrettably greatly increased the volume of waste in order to isolate it, and this remained an issue, even after it was understood that weapons grade plutonium could tolerate more Pu-240 than was realized. Weapons grade plutonium is still not at all like reactor grade plutonium.



The caption:

Figure 7. Comparison of measured Pu isotopic ratios from the sample (solid red squares) with predicted ratios within spent fuel from X-10 reactor at 3.6 and 3.7 MWd/MTU (solid and dashed blue lines, respectively) and B-reactor operations (dashed grey line) in the 1940s. The model line for the B-reactor represents ratios that would have been produced at the lowest recorded power level (17.2 MWd/MTU) for that reactor. The area above the B-reactor model line represents the possible range of isotopic ratios that could have been produced at power levels above the lowest recorded value. The value of the 242/239 ratio for the sample was found to be below the limit of detection (identified by the open red square) of the analytical technique used.


Using the ratio, the authors determined that the source of the plutonium was not Hanford's more famous B-reactor, but rather the X-reactor, which was not located at Hanford, but rather at Oak Ridge.

This is explicated in the full text.

Interesting stuff, I think.

I wish you a pleasant rest of the weekend.





Copernecium forms a mercury like amalgam with gold.

I'm going through old papers I collected 10 years ago but never read, and I came across this oldie but goodie from 2007, which somehow found its way into a directory about the environmental and climate impact of large dams, along with an obituary of John Wheeler:

Chemical characterization of element 112 (R. Eichler, N. V. Aksenov, A. V. Belozerov, G. A. Bozhikov, V. I. Chepigin, S. N. Dmitriev, R. Dressler, H. W. Gäggeler, V. A. Gorshkov, F. Haenssler, M. G. Itkis, A. Laube, V. Ya. Lebedev, O. N. Malyshev, Yu. Ts. Oganessian, O. V. Petrushkin, D. Piguet, P. Rasmussen, S. V. Shishkin, A. V. Shutov, A. I. Svirikhin, E. E. Tereshatov, G. K. Vostokin, M. Wegrzecki & A. V. Yeremin, Nature volume 447, pages 72–75 (03 May 2007))

One of the most dubious mining practices in the world is the extraction of gold from ores using liquid mercury, because mercury readily dissolves gold, which historically was the most problematic element to dissolve, at least until the discovery of a mixture of acids, hydrochloric and nitric acid, known as "aqua regia" because it dissolves "the king of metals." Aqua regia however is somewhat less effective when recovering gold from ores than mercury, and therefore mercury is still utilized for this purpose, particularly in wild cat mining of the type utilized to recover not only gold but many diffuse elements such as tantalum and the lanthanides, leading to distributed pollution that is difficult to address.

To recover gold from solution in liquid mercury, the mercury is distilled off.

Wonderful.

Anyway...

Element 112, now known as the element Copernicium, is a cogener of the toxic metals mercury and cadmium, the toxicity of which is largely an effect related to their displacing another cogener, zinc, in metalloenzymes, thus inactivating them.

The ten year old paper linked above refers to its chemistry, which has been the subject of some interest owing to relativistic corrections to its electronic structure, a topic to which the wonderful host of this group, directed my attention recently. It has not been clear whether or not Copernicium would be an inert gas rather like radon or a liquid. From the text:

The heaviest elements to have been chemically characterized are seaborgium1 (element 106), bohrium2 (element 107) and hassium3 (element 108). All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost electrons and hence their chemical properties. However, the chemical characterization results are not trivial: relativistic effects on the electronic structure of the heaviest elements can strongly influence chemical properties4–6. The next heavy element targeted for chemical characterization is element 112; its closed-shell electronic structure with a filled outer s orbital suggests that it may be particularly susceptible to strong deviations from the chemical property trends expected within group 12. Indeed, first experiments concluded that element 112 does not behave like its lighter homologue mercury7–9. However, the production and identification methods 10,11 used cast doubt on the validity of this result...

The systematic order of the periodic table places element 112 in group 12, which also includes zinc, cadmium and mercury. It should thus have the closed-shell electronic ground state configuration Rn: 5f 146d107s 2, which implies noble metal characteristics16. However, relativistic calculations of atomic properties of superheavy elements suggest4–6 contraction of the spherical s- and p1/2-electron orbitals. The effect may increase the chemical stability of the elemental atomic state of element 112 beyond that of a noble metal and endow it with inertness more similar to that of the noble gas radon17, although recent relativistic calculations on element 112 predicted18 that it should form a semiconductor-like solid with clear chemical bonds. It was suggested19 that the questions of the bonding characteristics of element 112 and whether it more strongly resembles a noble metal or a noble gas might be addressed experimentally, by determining its gas adsorption properties on a noble metal surface such as gold. In fact, relativistic calculations indicate that the spin-orbit splitting of the 6d orbitals results in element 112 having a ground-state configuration with a 6d5/2 outermost valence orbital, which would make it behave like a noble transition metal20,21. Moreover, relativistic density functional calculations of its interaction with noble metals predict metallic interactions similar to those of the lighter homologue mercury22–24...

... By directly comparing the adsorption characteristics of 283(Cn) to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface...


Some interesting details about this elegant experiment requiring significant teamwork:

Thermochromatography allows very efficient probing of the interaction potential of volatile gas-phase species with stationary surfaces over a broad range of interaction enthalpies.We used the in situ volatilization and on-line detection method28 for thermochromatography measurements at temperatures between135 uC and 2186 uC, with the original system modified and significantly improved11,29 to enable gas adsorption investigations of element 112 on gold surfaces. Figure 1 depicts schematically the experimental set-up. A target of 242PuO2 (1.4mg cm22 242Pu) with an admixture of nat.Nd2O3 (15 mg cm22 of Nd of natural isotopic composition) was deposited on a thin (0.7mg cm22) Ti backing foil and irradiated for about three weeks at the U-400 cyclotron at FLNR with 3.131018 48Ca particles at a primary energy of 27063MeV. The beam energy in themiddle of the target was 23663MeV, corresponding to the maximum of the production cross-section of 287Fl in the 242Pu(48Ca, 3n) reaction channel12. The irradiation generated not only 287Fl, but also the partially alphadecaying nuclide 185Hg with a half-life of 49 s. This nuclide is produced in the reaction 142Nd(48Ca, 5n) and serves in our experiment as a monitor for the production and separation process. Various isotopes of radon (for example, 219Rn, with a half-life of 4 s) were also produced in multi-nucleon transfer reactions between 48Ca and 242Pu. Thus, radon and mercury were studied simultaneously with element 112 throughout the experiment.


Cool, I think.

The conclusion:

The statistical Monte Carlo approach to modelling the gas chromatography results17,30 uses adsorption enthalpy values to mimic the observed deposition patterns, which provides upper and lower limits for the adsorption enthalpy of element 112 on gold2DHads Au(E112) of 98 kJ mol21 and 45 kJ mol21 (68% confidence interval), respectively; it also yields a most probable value of 2DHads Au(E112) 552 kJ mol21, which has a large associated uncertainty due to the small number of observed events (see also Supplementary Information section 2). Still, the range of likely adsorption enthalpies inferred from this study indicates an interaction between element 112 and gold that is significantly stronger than the purely dispersive van der Waals interactions of noble-gas like elements27. We therefore conclude that the stronger adsorption interaction of element 112 with gold involves formation of a metal bond, which is behaviour typical of group 12 elements.


The added bold is mine.


(Cn substituted for 112 and Fl for 114 in the original text where needed to distinguish the mass number from the atomic number, owing to the inability to utilize superscripts here.)

The host here recently directed me to a wonderful paper on the effects of relativity on the chemistry of heavy elements, which by the way, is evoked to account for the fact that mercury is a liquid rather than a solid.

It is here: Relativistic Effects in Chemistry: More Common Than You Thought (Pyykkö, Annual Review of Physical Chemistry, Vol. 63:45-64 (Volume publication date May 2012)

Have a nice Daylight Savings Time Sunday afternoon.








Uranium catalyzed electrolysis of water to produce hydrogen.

The paper I will discuss in this post is this one:
Uranium-mediated electrocatalytic dihydrogen production from water (Meyer et al Nature volume 530, pages 317–321 (18 February 2016))

First some bitter background:

I don't have much use for the anti-nuke ersatz "climate activist" Joe Romm, who I consider an appalling fool, but despite my general contempt for almost all of his rhetoric, there is one thing about it with which I agree: Hydrogen will never be a useful consumer fuel, useful for powering cars and other dubious artifacts of our modern "screw the planet and the future be damned" culture.

On this, he disagreed with his pal, fellow anti-nuke Moron Amory Lovins, who once promised us Hydrogen Hypercars in Showrooms by 2005 adding to his long list of stupid Ouija board quality prognostications about energy.

The referenced National Geographic puff piece on Lovins was published on October 16, 2001.

At Mauna Loa the weekly average for concentrations of the dangerous fossil fuel waste carbon dioxide in the planetary atmosphere posted on October 14, 2001 was 368.16 ppm.

On October 15, 2017, the posted figure from the same source was 403.97 ppm.

Nevertheless, irrespective of what a fool Amory Lovins is, hydrogen is, and for as long as an industrial society exists, will always be an important captive intermediate for a variety of products, the most important being ammonia, but for many other products as well, including fuels. Hydrogen can be used to reduce ("hydrogenate" ) carbon dioxide or carbon monoxide to make dirty fuels like gasoline (the Fischer-Tropsch process into which the Carter administration put lots of research effort) or clean fuels like dimethyl ether, and less attractively, methanol. This potential for a closed carbon cycle was enthusiastically advanced by the late great Nobel Laureate George Olah in his widely cited 2011 paper Anthropogenic Chemical Carbon Cycle for a Sustainable Future (Olah et al J. Am. Chem. Soc., 2011, 133 (33), pp 12881–12898)

Olah's dead, and despite his noble efforts during his magnificent life, the planet is still dying.

What Lovins, a poorly educated ignoramus who is nevertheless thought by some, including himself, to be a "real stable genius," was too stupid to understand, or simply deliberately avoided since he makes a lot of money "consulting" for huge and very dirty dangerous fossil fuel companies, is that 99% of the hydrogen on this planet is generated by the energy wasting process of reforming dangerous natural gas, and less commonly these days, coal.

Lovins liked to pretend, or at least convince his acolytes, that hydrogen could be industrially made by what he called "soft" technologies - they are actually environmentally egregious nightmares of unsustainable industrial chemistry - the solar driven electrolysis of water.

This is pretty funny, since Lovins, who made his name hyping "energy conservation," while apparently knowing zero about the laws of thermodynamics, never bothered to account for the fact that electrolysis of water is one of the most thermodynamically inefficient processes known for producing hydrogen. About 1% of the hydrogen on the planet is so produced, and of this 1%, almost all of it is produced as a side product in the production of chlorine gas utilized to make bleach, polyvinyl chloride and historically interesting molecules like DDT and CFC's. Until very recently and for most of the period of Lovins' awful career, the main electrode for undertaking these electrolysis efforts was a mercury electrode. Bleach produced still produced this way - and there is some - usually contains small amounts of mercury, making it the third largest contributor to mercury in the environment after coal burning and medical waste.

(By the way, despite all Lovins’ hype about energy conservation, the strategy has failed as badly as the solar and wind industries have failed. In 1973, world energy demand was estimated to be 256 exajoules. As of 2016, world energy consumption is 576 exajoules.

IEA 2017 World Energy Outlook, Table 2.2 page 79 (MTOE converted to exajoules.)
For the 1973 figure see Current Energy Demand; Ethical Energy Demand; Depleted Uranium and the Centuries to Come and references therein)



All the above said, the production of hydrogen via electrolysis also results in the isolation of heavy water which is useful in the production of stable labeled isotopes useful for chemical, biochemical, medical and environmental research. What should be equally important – or would be in a sane world – deuterium is a key component of a potentially extremely mass efficient type (particularly in thorium based cycles) of nuclear reactor, commonly called a CANDU reactor, a result of having been developed in Canada, but otherwise known more generally as a heavy water reactor. The main national nuclear energy program investing in this approach is India’s, although heavy water reactors do still operate in Canada.

Thus there is a role for electrolysis and for improving its efficiency.

This brings me to the paper cited at the outset of this post. The complexity of the electronic structures of the light actinide uranium and the multiple oxidation states suggests - as do other elements with this property of having multiple oxidation states . (This fact, the complexity of the electronic structure of uranium, was the subject of a recent post of mine in this space, Highly sensitive, uranium based UV detectors.)


As an “actinide,” uranium is expected to exhibit a +3 oxidation state, and it does. However the shielding of the 5f orbitals is less effective than it is for the corresponding lanthanides, where the filling of 4f orbitals results in lanthanide chemistry being being dominated by this +3 oxidation state, so much so, that the separation of the lanthanide elements from one another was long problematic.


Because of this ineffective shielding in uranium however, f orbitals are available for chemistry, and this is why, until the Seaborg actinide concept was developed and accepted, uranium was thought to be a cogener of tungsten, rather than a cogener of neodymium, with which it shares only limited chemistry.


Like uranium hexafluoride, a +6 compound, for example, a gaseous compound at moderate temperatures that plays a huge role in isotope separation both for nuclear power and for nuclear weapons, tungsten hexafluoride is a gas, and both tungsten and uranium form, for another example oxocations.

(However for reasons having more to do with quantum chemical formalism than actual chemistry, uranium is -rightly I think - considered an actinide, as is thorium, which effectively exhibits no f related chemistry at all, and in fact, doesn’t really possess a 3+ oxidation state of any significance.)

The availability of multiple oxidation states can be used to reduce water and this brings me (finally!) to a discussion of the paper cited in the opening paragraph of this post.

From the introductory text:

Depleted uranium is a mildly radioactive waste product that is stockpiled worldwide. The chemical reactivity of uranium complexes is well documented, including the stoichiometric activation of small molecules of biological and industrial interest such as H2O, CO2, CO, or N2 (refs 1–11), but catalytic transformations with actinides remain underexplored in comparison to transition-metal catalysis12–14. For reduction of water to H2, complexes of low-valent uranium show the highest potential, but are known to react violently and uncontrollably forming stable bridging oxo or uranyl species15. As a result, only a few oxidations of uranium with water have been reported so far; all stoichiometric2,3,16,17. Catalytic H2 production, however, requires the reductive recovery of the catalyst via a challenging cleavage of the uranium-bound oxygen-containing ligand. Here we report the electrocatalytic water reduction observed with a trisaryloxide U(iii) complex [((Ad,MeArO)3mes)U] (refs 18 and 19)—the first homogeneous uranium catalyst for H2 production from H2O. The catalytic cycle involves rare terminal U(iv)–OH and U(v)=O complexes, which have been isolated, characterized, and proven to be integral parts of the catalytic mechanism. The recognition of uranium compounds as potentially useful catalysts suggests new applications for such light actinides.


Here, from the paper, is the structure of the complex:



The caption:

Figure 2 | Independent synthesis and characterization of the uranium(IV) hydroxo complex [((Ad,MeArO)3mes)U–OH] (2–OH). a, Synthesis of 2–OH with concomitant H2 evolution. b, Molecular structure of the crystallographically characterized complex 2–OH in crystals of C67H84O5U ・ 3(C4H8O), with thermal ellipsoids at 50% probability. All hydrogen atoms except for the hydroxo H were omitted for clarity. c, Infrared vibrational spectra of 2–OH (black) and its isotopomer 2–OD (blue), showing the expected isotopic shift for the O–H stretching vibration ν. The inset is a close-up of the 2–OH spectrum, showing the two OH stretching frequencies at ν = 3,659 cm−1 and ν = 3,630 cm−1.


I very much doubt that this complex - and here I'm referring to the organic ligands and not the final synthesis shown in the graphic - is trivial to synthesize, but then again, it's a catalyst not a reagent, and depending on its stability and turn over rate, it might be viable to make it.

The authors propose the following mechanism for the hydrogen reduction reaction:



The caption:

Figure 3 | Postulated mechanism for the reduction of H2O by the U(iii) complex 1, based on EPR results. The addition of H2O to 1 probably yields a U(iii) aquo species, which forms a fleeting U(v) hydroxo–hydrido intermediate, [((Ad,MeArO)3mes)U(OH)(H)], by intramolecular insertion; this hydroxo–hydrido species then decays to a U(v) oxo species by elimination of H2 (reaction (1)). Subsequently, the U(iv) hydroxo complex 2–OH is formed in a comproportionation reaction between the U(v) oxo and the U(iii) aquo species (reaction (2)). In the net reaction, two U(iii) aquo complexes form two molecules of 2–OH and one equivalent H2.


Their experiments to confirm this mechanism sound like incredible fun:

To elucidate this mechanism, we performed time- and temperature- dependent EPR experiments with a reaction mixture of 1 and H2O in a frozen toluene solution at 7.5 K (Fig. 4). Initially, a spectrum of the neat U(iii) f 3 starting material (10 mM) in toluene was recorded, yielding an almost axial signal with g values centred at 1.56, 1.48, and 1.20 (see Supplementary Information), as expected for [((Ad,MeArO)3mes)U] (1)19. In the following measurement, a mixture of 1 (10 mM) in toluene with a sub-stoichiometric amount of H2O (0.375 equiv.) was prepared. Under these dilute conditions the reaction takes about 2 h at room temperature for completion...


Frozen toluene at 7.5K, I'd guess is made by dipping toluene in liquid helium; that my friends has to be fun.

And then...

Hence, the sample was allowed to equilibrate for 5 min at room temperature and then flash-frozen in liquid nitrogen to trap potential intermediate species in a frozen solvent matrix. Indeed, we obtained a convoluted spectrum of at least two species: the U(iii) starting material and another, welldefined rhombic species with simulated g values at 2.73, 1.83, and 1.35, consistent with an intermediate U(v) f 1 species (Fig. 4)


Here's the EPR spectrum:



And its caption:

Figure 4 | X-band EPR spectrum of a frozen 10 mM toluene solution of 1 with a sub-stoichiometric amount of H2O. The EPR data show a convoluted spectrum of two species: the U(iii) starting material and a well-defined rhombic species, tentatively assigned to the fleeting U(v) hydroxo–hydrido species. Experimental conditions are as follows: temperature T = 7.5 K, frequency ν = 8.96286 GHz, power P = 1 mW, modulation width of 1.0 mT. The experimental spectrum (black) and simulation (red) under these conditions are shown. The best fit for the experimental spectrum is a convolution of the signal of 1 in toluene (simulated, green; g values at g1 = 1.56, g2 = 1.48, g3 = 1.20, with line widths of W1 = 21.4 mT, W2 = 30.5 mT, W3 = 14.4 mT; relative weight of 1.0) and the signal of an additional, rhombic transient U(v) species (simulated, blue; g values at g1 = 2.73, g2 = 1.83, g3 = 1.35, with line widths of W1 = 18.9 mT, W2 = 25.5 mT, W3 = 26.5 mT; relative weight of 0.70). The spectra are offset for ease of viewing.


And finally the full cyclic mechanism of the electrolysis, wherein the oxidized uranium is reduced to U(III):



And its caption:

Figure 5 | Postulated electrocatalytic cycle for H2 generation from H2O in the presence of the homogeneous U(iii) catalyst [((Ad,MeArO)3mes)U] (1). Step 1 (top to bottom-right), H2 evolution and formation of [((Ad,MeArO)3mes)U(OH)(THF)] (2–OH) through oxidation of 1 with H2O. Step 2 (bottom-right to bottom-left), electrochemical reduction of 2–OH, forming the transient anion 2–OH−. Step 3 (bottom-left to top), elimination of OH– from 2–OH− to regenerate catalyst 1.


This device is a battery, and like all batteries, it wastes energy, however it wastes less energy than other electrolysis devices.

Regrettably the world has chosen, much to the detriment of the environment to choose to explore so called "renewable energy" to address climate change, surrounding this choice with all kinds of delusional statements designed to obscure the complete and total failure of this choice to address the expanding use of dangerous fossil fuels.

By their very nature, these systems are wasteful, since they necessarily require redundant systems, usually systems involving gas turbines. To the extent that the excess rotational energy of a spinning turbine being shut for a few hours so we can all make excited, if nonsensical, demonstrations of how great solar energy is, can be recovered, a battery is not a bad idea as a brake, as is the case in hybrid cars. At least some of the energy can be recovered and not wasted.

I actually think that this system, the uranium catalyzed electrolysis system might make sense in very limited circumstances, for example in remote systems, such as on space craft powered by RTG's, where the waste heat of the RTG might serve to provide operating temperatures for fuel cells operating on hydrogen.

Large scale energy storage should be a non-starter on environmental grounds but this is not culturally accepted yet, given the general contempt for science and the inexplicable pop enthusiasm for so called "renewable energy."

A better use for depleted uranium in my view, would be to convert it to plutonium and fission it, but that's just my view.

Have a nice evening, and if you're in this Nor'easter, as I am, by all means be safe.



Sexual Harassment in Science.

As a culture, it is a good thing from my perspective on which to reflect.

This video on this interesting question is from the American Chemical Society.

Especially for senior people, it's worth reflecting on the type of environment provided in your work place.

https://www.acs.org/content/acs/en/acs-webinars/popular-chemistry/harassment/video.html



Understanding the Relationship Between Chemical Feedstocks and Dangerous Fossil Fuels.

Recently in this space, I posted a very esoteric piece - so esoteric that it understandably provoked no comment - on the preparation of p-xylene from dimethylfuran, a chemical that is accessible from biomass such as straw.

The Conversion of Cellulosic Biomass Into Aromatic Compounds.

In so doing, I failed to apply a lesson I often - albeit with very limited success - try to evoke whenever one hears these "feel good/sound good" bits of environmental wishful thinking - which is to think about scale. For instance, the scale of world energy consumption as of 2016 was 576 exajoules per year - fraction of which that is derived from dangerous fossil fuels has been rising not falling throughout the 21st century - and all of the endless hype about the solar industry's "percent" growth is merely an attempt to bury the issue of scale. Wind and solar energy combined, despite all the cheering, did not produce 10 exajoules of energy in 2016 and thus has been insignificant, is insignificant, and always will be insignificant.

A recent publication in one of my favorite journals Environmental Science and Technology has served for my inattention to issues of scale in referencing a lab scale process as significant; there's a long way between "there" - "there" being significance - and "here," "here" being a world in which the collapse of the planetary atmosphere is accelerating and not as popularly imagined, even remotely being addressed. The paper is this one, about the role that dangerous fossil fuels play in the chemical industry, the chemical industry being at the very core of and essential to our way of life, pretty much involved in everything a modern bourgeois person - such as I am - does. Here is the paper: Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products (Levi and Cullen, Environ. Sci. Technol., 2018, 52 (4), pp 1725–1734)

This graphic from the paper shows pretty much everything you need to know about it:



(Similar types of flow diagrams for energy are widely available from the Lawrence Livermore Laboratory and other places. I sometimes post a particular version here and there showing the energy flow diagram for Denmark, that offshore oil and gas hellhole showing how trivial its much ballyhooed and hyped wind industry is.)

Anyway.

From this diagram, one can discern the world requirement for "BTX" (Benzene, Toluene and Xylenes) is on the order of 80 million tons, of which roughly 70 million tons is carbon. This compares to the average annual average amount of carbon dioxide that is routinely dumped into the atmosphere while we wait for the grand super duper renewable energy nirvana that never comes, roughly 35 billion tons of CO2, corresponding to about 15 billion tons of carbon.

70 million tons may be accessible via "waste" biomass. Over on another website where I was banned for telling the truth, I roughly calculated from available references that the total carbon content of all the straw in China is roughly 267 million tons.

This of course does not account for transporting and processing all the straw in China, of course, just so I'm not encouraging false optimism.

According to the cited paper, the world chemical industry's contribution to climate change from direct by products of the chemicals themselves as carbon dioxide, is relatively small, 267 million tons, or less than 1%. More serious is the release of methane, and probably less serious, but significant all the same, is the contribution to climate change from nitrous oxide, a side product of the ammonia industry on which our food supply depends:



However this ignores the energy input of chemical processing, which is far more significant.

From the opening text of the paper we have these remarks from the authors:

Industrial chemicals and their derivatives pervade modern society. Although often diffuse in their application (e.g., pharmaceuticals), the bulk outputs of the chemical and petrochemical sector, (also referred to here as "the chemical sector" ), are deployed in huge volumes to make millions of tonnes per year (Mt yr–1) of chemical products, such as fertilizers and plastics. Our industrialized economy is dependent on chemicals.

In performing this pivotal role, the chemical sector exerts a large environmental burden. It is responsible for approximately 7% of global anthropogenic global greenhouse gas (GHG) emissions, and 5.5% when only counting CO2 emissions.(1) The sector’s final energy consumption is the largest among industrial sectors: 42.5 EJ in 2014, of which 25 EJ is feedstock energy.(2) Other sources of emissions include those stemming directly from the chemical transformations mobilized in reactors (process emissions), and from energy conversion in the transformation sector (indirect emissions). In addition to these gaseous emissions, chemical products can spawn pernicious aqueous discharges. The oft-publicised problem of fertilizer runoff contributing to hypertrophication,(3) and the more recent exposition of plastic waste ending up in the world’s oceans(4, 5) and organisms(6) are notable examples.


Returning to the issue of the ammonia industry, it is worth noting that 55 million tons, graphically it seems to be on the order of 1/3 of the total, comes from coal, the most dangerous of the three dangerous fossil fuels. Coal is often reported as being "dead," which is nonsense; reports of its death are greatly exaggerated, to steal a Twainism. Between 2000 and 2016 coal was the fastest growing source of primary energy on this planet, increasing by 2/3 of the amount used in 2000 (roughly 90 exajoules worth) by 60 additional exajoules. The contribution that coal makes to ammonia synthesis may be trivial in comparison to its use in the energy and steel industry, but it is real and significant.

I found this paper thought provoking, and it served for a useful refocusing on the realities of our increasingly dire environmental situation.

If we want to be serious - and there's no way that we are even remotely so in any country or even in any political party in any country - scale is the most important thing of which we can think.

I hope you're having a pleasant weekend.

Nature Climate and Atmospheric Science: Dramatic declines in snowpack in the western US

According to this open sourced paper in Nature Climate and Atmospheric Sci, the Western US Mountains Can't Hold Snow; the West Can't Get Water: Dramatic declines in snowpack in the western US (Mote, et al npj Climate and Atmospheric Sciencevolume 1, Article number: 2 (2018)

This is not a short term event. It's a trend.

California’s recent multi-year drought (2011–16) and its extension into Oregon and Washington has shown that warming can create drought simply by preventing the accumulation of mountain snowpack. The year 2015, for instance, set the record low 1 April snow water equivalent (SWE) at over 80% of sites west of 117° longitude,1 a result of high winter temperatures rather than low precipitation.2,3,4

More than a decade ago, we showed that spring snowpack had declined at a large majority of locations in the mountainous western US, and corroborated the observations with hydrologic modeling that reached broadly similar conclusions.5 We also noted that computing an area-averaged snowpack value from observations is challenging because the locations of long-term monitoring sites are usually chosen to favor a certain type of terrain and elevational range, with temperature-sensitive locations undersampled early in the record in some states.6 Methodological choices (e.g., about record length) can therefore strongly influence results and must be carefully evaluated. In contrast, model-based estimates provide a basis for estimating long-term SWE changes across the entire Western U.S. domain.

Since our earlier work, several papers have further explored the relationships between mountain snowpack, variability and trends in precipitation and temperature, and geographically important factors. Stoelinga et al. (ref. 7) derived a snowpack index for the Cascades from streamflow measurements, from which they estimated that the spring snowpack declined 23% between 1930 and 2007. Pierce et al. (ref. 8) using a hydrologic model forced by observations and by two 1600-year climate model runs to estimate natural internal climate variability, attributed declines in snowpack (specifically SWE divided by accumulation-season precipitation) across the western US to anthropogenic warming...


The article is, again, open sourced and there's not a whole lot of need to go over or quote the rest of it. It's pretty clear.

It seems to be involved with something called "climate change." A lot of whiny people have been carrying on about it, but fortunately we've successfully been able to completely and totally ignore them.

Don't worry; be happy.

California has lots of wind turbines and lots of solar cells and therefore all of our problems will shortly be solved, because they, and the natural gas on which they depend most of the time, are clean and green.

Have a nice Friday.
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