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NASA NTRS1987

The evaporation path of seawater and the coprecipitation of Br- and K+ with halite

Brines and salt were sampled at the Morton Bahamas solar salt production facility on Great Inagua Island in the Bahamas. The brines were analyzed by ion chromatography to define more precisely than heretofore the evaporation path of seawater to the end of the halite facies. At Inagua, calcium carbonate begins to precipitate at a brine concentration factor of 1.8 times that of seawater. Gypsum begins to precipitate at a brine concentration of 3.8 times seawater, and halite at a concentration factor of 10.6. Three of the most concentrated brines from Inagua (40 times seawater) were evaporated further in the laboratory. Magnesium sulfate first precipitated at brine concentrations about 70 times those of seawater, and potassium-bearing phases began to precipitate for these brines at concentrations greater than 90 times those of seawater. The distribution of coefficients of Br- and K+ between brines and halite were determined by combining analytical data for the Inagua brines with measurements of the Br- and K+ content of halites from Inagua and of halite which had precipitated from Inagua brines during storage. The observed average value of DBr- is 0.032, in good agreement with some of the previous measurements. The measured values of DK+ are highly variable (0.001 to 0.021); DK+ for halite precipitated early in the halite facies is in the vicinity of 0.015.

NASA Discipline Exobiology↗

NASA NTRS1981

Combustion system processes leading to corrosive deposits

Degradation of turbine engine hot gas path components by high temperature corrosion can usually be associated with deposits even though other factors may also play a significant role. The origins of the corrosive deposits are traceable to chemical reactions which take place during the combustion process. In the case of hot corrosion/sulfidation, sodium sulfate was established as the deposited corrosive agent even when none of this salt enters the engine directly. The sodium sulfate is formed during the combustion and deposition processes from compounds of sulfur contained in the fuel as low level impurities and sodium compounds, such as sodium chloride, ingested with intake air. In other turbine and power generation situations, corrosive and/or fouling deposits can result from such metals as potassium, iron, calcium, vanadium, magnesium, and silicon.

Stearns, C. A.↗

NASA NTRS1983

Combustion system processes leading to corrosive deposits

Stearns, C. A.↗

NASA NTRS1992

Reduced vertebral bone density in hypercalciuric nephrolithiasis

Dual-energy x-ray absorptiometry and single-photon absorptiometry were used to determine bone density at the lumbar spine and radial shaft in 62 patients with absorptive hypercalciuria, 27 patients with fasting hypercalciuria, and 31 nonhypercalciuric stone formers. Lumbar bone density was significantly lower in patients with absorptive (-10%) as well as in those with fasting hypercalciuria (-12%), with 74 and 92% of patients displaying values below the normal mean, whereas only 48% of the nonhypercalciuric stone formers had bone density values below the normal mean. In contrast, radial bone density was similar in all three groups of renal stone formers investigated. The comparison of urinary chemistry in patients with absorptive hypercalciuria and low normal bone density compared to those with high normal bone density showed a significantly increased 24 h urinary calcium excretion on random diet and a trend toward a higher 24 h urinary uric acid excretion and a higher body mass index in patients with low normal bone density. Moreover, among the patients with absorptive hypercalciuria we found a statistically significant correlation between the spinal bone density and the 24 h sodium and sulfate excretion and the urinary pH. These results gave evidence for an additional role of environmental factors (sodium and animal proteins) in the pathogenesis of bone loss in absorptive hypercalciuria. In conclusion, our data suggest an osteopenia of trabecular-rich bone tissues in patients with fasting and absorptive hypercalciurias.

Non-NASA Center↗

NASA NTRS1976

Preliminary results from the Viking X-ray fluorescence experiment - The first sample from Chryse Planitia, Mars

Iron, calcium, aluminum, silicon, and sulfur are major elements in the first surface sample of Mars that has been analyzed by the Viking X-ray fluorescence spectrometer. Titanium is present in minor quantities. This is consistent with the sample's being a mixture of fine silicate and oxide mineral grains, with a significant proportion of sulfates, possibly hydrated. Ferric oxide is regarded as the red pigmenting agent on the Martian surface, but if it coats silicate grains, the coatings must be very thin or discontinuous. A high abundance of Fe, relatively low abundances of Al, Rb, Sr, and Zr, and a high Ca/K ratio are distinctive features of the spectra. Preliminary determinations indicate the following abundances (as percentages by weight): Fe, 14 plus or minus 2; Ti, less than 1; S, 2 to 5; the Ca/K ratio by weight is greater than 5.

Toulmin, P., III↗

DOE OSTI2024

Speciation and Aqueous Dissolution of Macronutrients in Fire Ash: Variation across Ecosystems and the Effects on Nutrient Cycling

This study investigated the speciation and aqueous dissolution of macronutrients in fire ash from diverse ecosystems and speciation of ash and smoke from laboratory burning, exploring the variations and their causes. The speciation of phosphorus (P), calcium (Ca), and potassium (K) in fire ash from five globally distributed ecosystems was characterized by using X-ray absorption spectroscopy and sequential fractionation. Aqueous dissolution of the macronutrients was measured by batch experiments at acidic and alkaline pHs. The results showed that P existed mainly as Ca phosphates, Ca as double carbonates, calcite, and sulfates, and most K was associated with Ca carbonates. Mineralogy and the relative abundance of the species were primarily controlled by elemental stoichiometry and fire temperature. Differences in Ca and P speciation existed between ash and smoke from laboratory burning, possibly caused by the temperature difference and/or mass fractionation during burning. The rates, extents, and pH dependencies of macronutrient dissolution differed among macronutrients and depended on their speciation, with K being highly soluble and the P and Ca regulated by solution pH. The variability in ash macronutrient chemistry and ecosystemspecific fire ash loads resulted in varying loads and availability of individual macronutrient from fire among ecosystems. This study provides a mechanistic understanding of how fires transform the chemistry of macronutrients and affect macronutrient returns to soils across different ecosystems, which is essential for evaluating the disturbance to ecosystem nutrient cycling by fires.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1979

Heterogeneous phase reactions of Martian volatiles with putative regolith minerals

The chemical reactivity of several minerals thought to be present in Martian fines is tested with respect to gases known in the Martian atmosphere. In these experiments, liquid water is excluded from the system, environmental temperatures are maintained below 0 C, and the solar illumination spectrum is stimulated in the visible and UV using a xenon arc lamp. Reactions are detected by mass spectrometric analysis of the gas phase over solid samples. No reactions were detected for Mars nominal gas over sulfates, nitrates, chloride, nontronite clay, or magnetite. Oxidation was not observed for basaltic glass, nontronite, and magnetite. However, experiments incorporating SO2 gas an expected product of volcanism and intrusive volatile release - gave positive results. Displacement of CO2 by SO2 occurred in all four carbonates tested. These reactions are catalyzed by irradiation with the solar simulator. A calcium nitrate hydrate released NO2 in the presence of SO2. These results have implications for the cycling of atmospheric CO2, H2O, and N2 through the regolith.

Clark, B. C.↗

NASA NTRS1976

Mineralogic and petrologic implications of Viking geochemical results from Mars - Interim report

Chemical results from four samples of Martian fines delivered to Viking landers 1 and 2 are remarkably similar in that they all have high iron; moderate magnesium, calcium, and sulfur; low aluminum; and apparently very low alkalies and trace elements. This composition is best interpreted as representing the weathering products of mafic igneous rocks. A mineralogic model, derived from computer mixing studies and laboratory analog preparations, suggests that Mars fines could be an intimate mixture of about 80% iron-rich clay, about 10% magnesium sulfate (kieserite), about 5% carbonate (calcite), and about 5% iron oxides (hematite, magnetite, maghemite, goethite). The mafic nature of the present fines (distributed globally) and their probable source rocks seems to preclude large-scale planetary differentiation of a terrestrial nature.

Baird, A. K.↗

NASA NTRS1986

Statolith formation in Cnidaria: effects of cadmium on Aurelia statoliths

Statolith formation in Cnidaria was reviewed with an emphasis on Aurelia statoliths. The review provides information on the chemical composition, mechanisms of initiation of mineralization, and effects of environmental factors on Cnidarian statolith formation. Environmental factors discussed included modified sea water ingredients, X-irradiation, clinostat rotation, and petroleum oil ingredients. A detailed account of the effects of cadmium on mineralization and demineralization of Aurelia statoliths is given. Cadmium at dosages of 2 to 4 micromoles significantly reduces statolith numbers in developing ephyrae. At a dosage of 3 micromoles, cadmium accelerates statolith loss in unfed ephyrae studied at 4 and 8 days following ephyrae release from strobilae. Cadmium, therefore, is shown to reduce statolith numbers in developing ephyrae and to cause greater reduction of statolith numbers in unfed ephyrae after 4 and 8 days than occurred in controls. Supplementation of Cd(2+)-containing artificial sea water (ASW) with calcium (3X and 5X ASW calcium content) results in higher numbers of statoliths at day 4 as compared with cadmium-treated ephyrae. At 8 days only the 5X calcium supplemented ASW is effective in enhancing statolith numbers in Cd(2+)-treated ephyrae. These results suggest that cadmium competes in some manner with calcium at the mineralizing sites of Aurelia.

NASA Discipline Number 40-10↗

DOE OSTI2022

High-Resolution Transmission Electron Microscopy Study of a Powder River Basin Coal-Derived Fly Ash

Examination of a fly ash derived from the combustion of a low-S, subbituminous Powder River Basin coal by Scanning Electron Microscopy (SEM) and High-resolution Transmission Electron Microscopy (HRTEM), both supplemented by Energy-dispersive X-ray spectroscopy (EDS), showed that the fly ashes were dominated by amorphous phases, Ca-rich plagioclase feldspars, Mg-rich phases, complex Ca-Mg-Al-Si-Ti-Fe grains, and trace amounts of REE-rich particles. Many of the particles were rimmed by a Ca-S, possibly a sulfate. HRTEM-EDS examination of a REE-rich particle proved it to be a mix of light- and heavy-rare earth minerals mixed with amorphous phases.

58 GEOSCIENCES↗

NASA NTRS2001

Carbonate Biogenic Structures in Storrs Lake, Bahamas

Storr's Lake, an inland hypersaline lake on San Salvador Island, Bahamas, contains calcium carbonate-rich lithified mats of filamentous microorganisms, diatoms, associated photosynthetic and chemotrophic bacteria, and trapped sediment. In addition, 16S rRNA analysis indicates the presence of five sulfur-reducing genera of bacteria. These microbes are potential modern-day analogs to some ancient stromatolitic structures. The goals of this study are to identify unique compositional and biogenic features, possibly correlating some of these with some of the sulfate-reducing bacteria. Additional information is contained in the original extended abstract.

Byrne, Monica↗

DOE OSTI2021

Stochastic simulations of temporally and spatially variable Fe cycling within a floodplain aquifer

This data package contains model input and output files for local and global sensitivity analysis (SA) of a reactive transport model simulating redox cycling within a floodplain aquifer. The reaction network is implemented in CrunchFlow and focuses on spatially and temporally heterogeneous Fe cycling, though it contains several other species and redox pathways (37 aqueous species and 7 minerals in total). The package contains data from 600 Monte Carlo simulations (for global SA) and 104 one-at-a-time simulations (for local SA). It includes all input files required to run the CrunchFlow model, as well as limited model output – .csv files containing time series of primary species concentrations at 21 grid cells within the domain. These time series files contain the following species: H+, CO32-, SO42-, Cl-, Ca2+, Mg2+, Na+, K+, Fe(II), Fe(III), HS-, CH3COO-, O2(aq), S(aq), and Br-.These data were used to demonstrate the application of a novel form of global SA, distance-based generalized sensitivity analysis (DGSA) to a reactive transport model. The 2D model simulates the export of reduced species from pockets of fine-grained, organic-rich sediments embedded in a coarse sand aquifer. Stochastic simulations jointly varied 17 key model input parameters across several orders of magnitude, including the spatial variability of each parameter. DGSA on the model results reveal that the amplitude and variability of exported Fe(II) are most sensitive to the interaction between sand permeability and individual reaction rates. By contrast, the propagation of reducing conditions downgradient from the fine-grained lenses depends most heavily on the rate of dissolved organic carbon and sulfate release from the fines.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2025

Mine Tailings Valorization by Electrochemically Stimulated Mineralization from Mildly Acidic Conditions

This study presents a high-efficiency electrochemical process for the mineralization of calcium carbonate (CaCO 3 ) from mildly acidic mine tailing supernatant water. Electrochemical pH control was used to promote carbonate speciation and precipitation from CO 2 -saturated solutions, achieving >1 mol CaCO 3 precipitated per mol e - at applied potentials between -1.4 and -1.6 V vs Ag/AgCl. Product morphology and polymorph selectivity were tunable via applied potential, yielding calcite and vaterite phases. Experiments using real mine tailings water confirmed selective calcite precipitation, despite the presence of sulfate and other trace elements. These results highlight a viable route for coupling CO 2 utilization with mine tailings valorization.

36 MATERIALS SCIENCE↗

NASA NTRS1987

Correlation between calmodulin activity and gravitropic sensitivity in primary roots of maize

Recent evidence indicates a role for calcium and calmodulin in the gravitropic response of primary roots of maize (Zea mays, L.). We examined this possibility by testing the relationship between calmodulin activity and gravitropic sensitivity in roots of the maize cultivars Merit and B73 x Missouri 17. Roots of the Merit cultivar require light to the gravitropically competent. The gravitropic response of the Missouri cultivar is independent of light. The occurrence of calmodulin in primary roots of these maize cultivars was tested by affinity gel chromatography followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with bovine brain calmodulin as standard. The distribution of calmodulin activity was measured using both the phosphodiesterase and NAD kinase assays for calmodulin. These assays were performed on whole tissue segments, crude extracts, and purified extracts. In light-grown seedlings of the Merit cultivar or in either dark- or light-grown seedlings of the Missouri cultivar, calmodulin activity per millimeter of root tissue was about 4-fold higher in the apical millimeter than in the subtending 3 millimeters. Calmodulin activity was very low in the apical millimeter of roots of dark-grown (gravitropically nonresponsive) seedlings of the Merit cultivar. Upon illumination, the calmodulin activity in the apical millimeter increased to a level comparable to that of light-grown seedlings and the roots became gravitropically competent. The time course of the development of gravitropic sensitivity following illumination paralleled the time course of the increase in calmodulin activity in the apical millimeter of the root. The results are consistent with the suggestion that calmodulin plays an important role in the gravitropic response of roots.

NASA Program Space Biology↗

NASA NTRS2002

Galacturonomannan and Golgi-derived membrane linked to growth and shaping of biogenic calcite

The coccolithophores are valuable models for the design and synthesis of composite materials, because the cellular machinery controlling the nucleation, growth, and patterning of their calcitic scales (coccoliths) can be examined genetically. The coccoliths are formed within the Golgi complex and are the major CaCO(3) component in limestone sediments-particularly those of the Cretaceous period. In this study, we describe mutants lacking a sulfated galacturonomannan and show that this polysaccharide in conjunction with the Golgi-derived membrane is directly linked to the growth and shaping of coccolith calcite but not to the initial orientated nucleation of the mineral phase.

NASA Discipline Cell Biology↗

NASA NTRS1978

Elemental characteristics of aerosols emitted from a coal-fired heating plant

Size differentiated aerosols were collected downstream from a heating plant fueled with eastern coal and analyzed using particle induced X-ray emission technique. Based on aerosol masses collected in various size ranges, the aerosol size distribution is determined to be trimodal, with the three peaks centered at 0.54 microns, 4.0 microns, and 11.0 microns, respectively. Of the various trace elements present in the aerosols, sulphur is the only element that shows very strong concentration in the smallest size group. Iron is strongly concentrated in the 4.0 micron group. Potassium, calcium, and titanium also exhibit stronger concentration in the 4.0 micron group than any other group. Other trace elements - vanadium, chromium, manganese, nickel, copper, and barium - are equally divided between the 0.54 microns and the 4.0 microns groups. Apparently, all of the trace elements - except S - enter aerosols during the initial formation and subsequent condensation phases in the combustion process. Excess concentration of sulphur in the 0.54 microns group can only be accounted for by recondensation of sulphur vapors on the combustion aerosols and gas-to-particle phase conversion of sulfate vapors at the stack top.

Singh, J. J.↗

DOE OSTI2020

Low-Temperature Plasma Treatment for Enhanced Recovery of Highly Valued Critical REEs from Coal (Final Report)

The principle objective of this project was to develop a novel process flowsheet using low-temperature plasma treatment (LTP) integrated with conventional hydrometallurgical processes to recover rare earth elements (REEs), especially highly valued REEs (i.e. scandium and critical REEs), from coal and coal byproducts. LTP treatment was used to pretreat the solid feed material prior to leaching in an effort to improve the leaching characteristics of the REEs and potentially reduce acid consumption. Initially, a detailed experimental program was performed on a laboratory LTP furnace to identify a set of process parameter values to be used for assessing the enhanced leaching performance achieved on four specific gravity fractions of West Kentucky No. 13 and Fire Clay coarse coal refuse materials. High-temperature oxidation (HTO)) was also evaluated as a means for improving REE leachability on the same fractions of both coal sources. The lixiviants used to assess leachability improvements included: i) untreated water, ii) 0.1 M ammonium sulfate solution and iii) 1.2 M sulfuric acid solution at a temperature of 75°C. The laboratory data was used to develop multiple process flow sheets using HTO only to produce a rare earth oxide mix concentrate or utilizing both LTP and HTO treatment processes to generate a high purity heavy REO mix concentrate and a light REO mix concentrate. A techno-economic analysis was performed on each circuit. Low-temperature plasma oxidation was found to enhance REE leaching characteristics for all specific gravity (SG) fractions of the West Kentucky No. 13 coarse refuse material. The leaching recovery improvement was preferentially achieved for the heavy REEs with higher values obtained when treating the lower density fraction material. For example, the leaching recovery for the heavy REEs in the untreated 1.6 SG Float fraction material was 8% in a 0.1 M ammonium sulfate solution. After LTP treatment for 32 hours, heavy REE recovery increased to 33%. The corresponding recovery value for the light REEs was 10%. These findings indicate a strong affinity of the heavy REEs with the organic material, which is the component being reduced in content during the LTP treatment. Scanning electron micrographs showed the development of a honeycomb structure with increased LTP treatment with higher surface area as confirmed from BET measurements. Higher surface area promotes improved leaching efficiency due to enhance chemical interactions. When using 1.2 M sulfuric acid, the LTP treatment was found to provide a heavy REE recovery increase from 23% to 53% for the 1.6 SG Float fraction which corresponded to an ash content increase from around 20% to 35%. However, LTP treatment provided no improvement in leaching characteristic for the 2.2 SG sink material in the acid solution, which was likely due to the low organic content. The LTP treatment of the Fire Clay SG fractions provided no improvement in REE leaching characteristic, which may be due to the association with REE minerals such as monazite and REE-associated mineral matter such as clays. High temperature oxidation using temperatures in the range of 600-750OC was found to significantly enhance the leaching characteristics of both the light and heavy REEs for all density fractions in both coarse coal refuse materials. Generally, the increase in light REE recovery for the West Kentucky material was from 15% for the untreated material to 90% for the HTO treated material at 600°C. Recovery values dropped significantly when using temperatures below 600°C and above 750°C. The impact of the excessive temperatures was most likely a result of sintering. For the heavy REEs, HTO significantly improved recovery in the lighter SG fractions, which may be due to an affinity with the organic content. Only limited heavy REE recovery improvement was obtained for the denser SG fractions. Another benefit of HTO is the conversion of calcium-based minerals to a very soluble calcium oxide, which is removable using a mild acid solution, and the conversion of Fe minerals to relatively insoluble minerals such as hematite and magnetite. The pregnant leaching solution produced from the leaching of all SG fractions obtained from both coal sources was treated using two stages of solvent extraction procedurally modeling a rougher-cleaner circuit followed by oxalic acid precipitation. Rare earth oxide products having a purity greater than 97% was produced from nearly all of the SG fractions. A novel process flowsheet was developed based on the selective leaching of heavy REEs that was made possible through LTP treatment of West Kentucky No. 13 coarse refuse followed by salt leaching. In the flowsheet, coal refuse material is ground to a top size of 1mm and then treated by LTP. The treated material is mixed into a 0.1 M ammonium sulfate solution and then filtered to produce a heavy REE enriched pregnant leach solution. The heavy REEs are concentrated by two stages of selective precipitation to produce a heavy REE mix oxalate and then roasted to obtain a heavy REO mix concentrate. The solid residues remaining after salt leaching is dried and then subjected to HTO treatment followed by concentration using selective precipitation and roasting to produce a light REO mix concentrate. An alternative circuit was developed using HTO treatment only to treat 100% of the coarse refuse material followed by selective precipitation and roasting to generate a high purity REO mix product. A techno-economic analysis performed for the treatment of West Kentucky No. 13 and Fire Clay coarse refuse based on a hypothetical 500-tph plant revealed that the net present value for all scenarios was significantly negative. Primary reasons include: i) a substantial decrease in the basket value of the final product relative to the feed and ii) high chemical costs relative to the amount of product generated. The basket value reduction was primarily due to little to no scandium recovery due to poor leaching characteristics when using low acid concentrations as necessitated by the low feed grades. Operating costs were primarily influenced by the chemical costs relative to the kilograms of concentrate produced and feed grade. For the Fire Clay coarse refuse material, the total operating cost was estimated to be $354 per kg of REO produced which was higher than the basket value of the REO product ($276/kg). Approximately 37% of the total cost was the sulfuric acid used during the leaching process. A comparative analysis performed to assess the economic viability of using low-temperature plasma furnaces found that market value enhancement for the generation of both heavy REO and light REO concentrates will be needed in addition to significant technology advancements to reduce the cost of plasma furnaces.

01 COAL, LIGNITE, AND PEAT↗

NASA NTRS2012

Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines can be achieved using alternate pretreatment formulations under laboratory conditions. Additional testing and hazard assessments will be required to determine the feasibility of utilizing the proposed urine pretreatment formulations on ISS.

Muirhead, Dean↗