Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1909. / The entire thesis text is included in file. Typescript. Illustrated by authors. Ralph W. Watson determined to Ralph Wilheim Watson from "Thirty-Eighth Annual Catalogue. School of Mines and Metallurgy, University of Missouri". Ralph W. Watson is not listed in "University of Missouri, School of Mines and Metallurgy, Thirty-Eighth Annual Commencement" program. Title from title screen of thesis/dissertation PDF file (viewed February 23, 2009)

Thesis (M.S.)--Ohio State University, 1963. / Available online via OhioLINK's ETD Center

Thesis (M.S.)--Ohio State University, 1965. / Available online via OhioLINK's ETD Center

The amount of reaction between pyrite and vapor state nitric acid-has been analytically determined at 130°, 145°, 160° and 175° C. for one hour reaction time, and for one-half, one and two hour reaction times at 160°C. The variation of pressure with time for constant-boiling (68.2 per cent) nitric acid was studied at 130° and 160°C The reaction observed between pyrite and vapor state nitric acid followed the possible chain of reactions given below: (formula omitted) with the possible reaction: Fe₂(S0₄)₃ + H₂S0₄⇄Fe₂(S0₄)₃ . H₂SO₄. At 160°C the overall reaction was found to be of an apparent zero-order as was also that for the formation of ferric sulfate and ferric oxide, over the range of almost 100 per cent decomposition of the nitric acid. The maximum amount of pyrite used was about 11 per cent. Experimental results show that reactions (3), (4),(5) and (6) must all be surface reactions. A decrease in the rates of the reactions was noted between 145° and 160°C. This was most probably caused by the change in the physical and chemical properties of sulfur in this range, and indicates that elemental sulfur has a significant retarding effect on the rate of the overall reaction / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

This study was undertaken to determine minor element geochemistry of pyrite and the applicability of pyrite minor-element research to exploration for mineral deposits. Previous studies show that Co, Ni, and Cu are the most prevalent cations substituting for Fe in the pyrite lattice; significant amounts of As and Se can substitute for S. Other elements substitute less commonly and in smaller amounts within the lattice, in interstitial sites, or within discrete mechanically-admixed phases. Mode of substitution is determined most effectively with the electron microprobe. Cation substitution for Fe²⁺ is favored by transition elements with non-bonding "d" electrons .in low-spin configurations, an octahedral covalent radius similar to that of Fe (1.23 [symbol omitted] and high electronegativity. Anion substitution for S is favored by chalcogeri and pnigogen elements with a tetrahedral coordination radius close to 1.04 [symbol omitted] and high electronegativity. Statistical tests performed on several hundred pyrite analyses compiled from the literature and stored on computer cards support: (l) log-normal frequency distributions of minor elements in hydrothermal pyrite; (2) redistribution of minor elements in pyrite by metamorphism; (3) statistical differentiation of hydro-thermal, volcanic-exhalative, and syngenetic pyrites on the basis of Co and Ni concentrations and ratios; (4) relationship of minor element "spectra" and concentrations in disseminated pyrite to those in adjacent rocks; and (5) relationship of minor-element concentrations in hydrothermal pyrites to major ore-forming elements present. Forty pyrite samples from several distinct types of mineral deposits in the Smithers area, B.C. were analyzed for Co, Ni, Mn, Cu, Pb, and Zn using atomic-absorption spectrophotometry. Co concentrations are highest in pyrites from volcanic rocks, massive sulphide deposits and a breccia pipe. Ni and Mn concentrations are uniformly low. High contents of Cu, Fb, and Zn are caused by inclusions of common sulphides. Calculation of correlation coefficients for minor elements revealed that contamination does not significantly affect Co or Ni concentrations. Minor element data from the Smithers pyrites provides evidence for genetic relationships between several different mineral deposits, the presence of "metallogenetic" sub-provinces, and minor-element zonation in mineral deposits. Research into minor-element geochemistry of pyrite can be useful in exploration for mineral deposits; most effective use is during secondary stages of exploration. Most useful elements for exploration applications are Co, Ni, Cu, Au, Ag, Hg, Tl, Sn, As, and Se. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The oxygen pressure leaching of pyrite has been studied in sulfuric and perchloric acid using an oxygen-18 tracer technique. The results are consistent with an entirely electrochemical mechanism. The leaching potential of a pyrite pulp has been measured as 0.699V SHET*(110°C, 1M H2S04, 176 psi 02) and potentiostatic experiments at that potential have yielded the same reaction product ratios as observed in oxygen pressure leaching. The ratio of sulfate to elemental sulfur produced during pyrite leaching has been found to be a function of the leaching mixed potential. The yield of sulfate is increased with increasing potential until all the mineral sulfur is converted to the sulfate form at potentials above 1.0V. A mechanistic model of pyrite leaching has been advanced, which includes the electrochemical formation of a protective sulfur film as its basis. The theory has been supported by polarization studies in combination with Eh-pH diagrams. Chalcopyrite leaching has been studied using the same 0¹⁸ technique. Again the results are consistent with an electrochemical mechanism. The ratio of the sulfate to elemental sulfur in the reaction products has been observed to increase with higher oxygen pressures. The mixed potential of leaching is also increased at higher pressure indicating that the same type of mechanism observed in the pyrite work is operational for chalcopyrite. Molybdenite leaching has also been discussed in terms of the electrochemical model derived for pyrite with good results, and the mechanism therefore appears to have applications in many, if not most, sulfide systems. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Experiments were conducted to study the rate of oxidation of pyrite under conditions of varying pH, temperature and oxygen concentration. The rate of oxidation appears to be slightly increased below pH 3.00. In the basic range the oxidation is retarded as pH 9.00 is approached. Increases in temperatures cause increases in the rate of oxidation of pyrites. Corresponding decreases in the pH values are also noted. The rate of oxidation is increased by increaseing the concentration of oxygen. From these results, the possible use of pyrite in alkaline soils in the prevention of chlorosis caused by iron deficiency seems feasible.

This work represents the study of the biological oxidation of iron pyrite, FeS_2. The chief objective of the study was to investigate the possibility of biological oxidation of iron pyrite and to determine, if possible, the physical and chemical conditions under which the oxidative process occurs. The apparatus used to study the problem consisted of an air-lift percolator containing Ottawa sand as a dispersing medium for the finely divided pyrite. A nutrient solution which would support bacterial growth was the lixiviant. The microorganisms used in the study were autotrophic, iron-oxidizing bacteria obtained from the mine waters of Bingham Canyon, Utah. Studies were made by inoculating the solutions in the percolators with actively growing bacteria and comparing the amount of iron oxidized in the inoculated percolators with the amount of iron oxidized in a sterile, control sample. The effect of autoclaving, mercuric chloride, temperature, light, and carbon dioxide on the oxidative process was studied. The acidity produced in the oxidation of the pyrite was measured. The effect on the activity of the bacteria of ammonium ion and cupric ion was studied. The results of the above studies showed that iron-oxidizing autotrophic bacteria do oxidize iron pyrite. Sterile control samples contained only five percent of the amount of iron in solution that appeared in inoculated solutions. Autoclaving and mecuric chloride killed the micro-organisms and therefore stopped the oxidative process. A reduction in temperature to 0° C. decreased the bacterial activity by an average of eighty-seven per cent. The bacterial activity was increased when the reaction vessels were placed in total darkness. The absence of carbon dioxide or oxygen in the atmosphere of the bacteria slows down the oxidative rate. Results showed that the ammonium ion or the nitrate ion is necessary for the normal growth and activity of the microorganisms. The bacteria in the problem have a tolerance for high concentration of cupric ion. They grew and were active in 500 ppm Cu^++. The possibilities in converting discarded pyrite waste to useful ferric sulfate by biological oxidation should prove to be valuable throughout the Intermountain area.

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