DOCSLIB.ORG

The Extraction of Zinc from Secondary Zinc Minerals

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Extraction of Zinc from Secondary Zinc Minerals THE EXTRACTION OF ZINC FROM SECONDARY ZINC MINERALS WITH AQUEOUS SODIUM CYANIDE SOLUTIONS by Steve Bogdan Kesler, B. Sc(Eng), Ä. R. S. M. April, 1976 A thesis submitted for the degree of Doctor of Philosophy of the University of London and for the Diploma of Imperial College. Department of Mining and Mineral Technology, Imperial College, London S. W. 7. Dvý`- -1- ACKNOWLEDGEMENTS I should like to thank Professor E. Cohen, all the staff and research students of the Department for their helpful discussions and the technical staff for their patience in building and repairing apparatus. In particular, I thank my colleagues Mr. R. F. Dougill for all his valuable time spent on my computing problems and Mr. J. R. J. Burley for his advice on mineralogy. The willingness of Mr. A. Read of Warren Spring and the Institute of Geological Sciences to spare me some of their time was also much appreciated. Above all I thank Dr. H. L. Shergold, my supervisor, for his constant advice, tact and understanding and without whom this work could not have been accomplished. I should also like to thank the Science Research Council for providing the financial assistance to enable me to carry out this research and last, but not least, Miss Christine Ball, for volunteering to type this thesis even after she had'seen my appalling handwriting. -2- ABSTRACT The possibility of recovering zinc from zinc oxide material with a sodium cyanide leaching stage has been investigated. Zinc oxide and the secondary zinc minerals all dissolve stoichiometrically in cyanide solutions. The predominant species in cyanide solutions saturated with smithsonite or hemimorphite is the Zn(CN)42 complex, and a cyanide to zinc molar ratio close to 4/1 is obtained. A lower ratio results from cyanide solutions saturated with zinc oxide or hydrozincite because of the formation of zinc hydroxy complexes. The dissolution of smithsonite and hemimorphite is mass transfer controlled, the former by transfer either of cyanide ion to or, more probably, Zn(CN)42 away from the reaction interface whilst the latter is controlled by the diffusion of zinc cyanide complexes through a thin silica surface layer. The dissolution reactions follow heterogeneous reaction theory and empirical reaction models have been derived. Dissolution of smithsonite and hemimorphite is very anisotropic the reactions being initiated at high energy surface sites. Preferential dissolution at sub-grain boundaries results in the disintegration of the smithsonite particles. -3- The addition of sodium hydroxide to the cyanide solution increases the rate of dissolution of hemimorphite by thinning or removing the surface silica film. Roasting the hemimorphite removed compositional water from channels in the crystal structure and produced an increased reaction surface area. Zinc and free cyanide can be recovered from cyanide solutions containing dissolved zinc oxide by electrolysis but part of the cyanide is oxidised to cyanate at the anode. The recovery of zinc from cyanide solutions containing dissolved smithsonite, hemimorphite or hydrozincite is possible by precipitation as the cyanide. The precipitate can be dissolved in spent electrolyte from zinc sulphate electrolysis allowing cyanide recovery and electrodeposition of zinc from the electrolyte. Reagent losses as cyanide or sodium hydroxide are substantial but a cyanide leaching process might be economically viable if cyanide oxidation during electrolysis can be minimised and if cheap supplies of sodium hydroxide are available. -4- CONTENTS Page Acknowledgements. 1 Abstract. 2 Contents. 4 Chapter INTRODUCTION 6 1.1. Occurrence of zinc oxide minerals 6 1.2. Conventional zinc mineral processing. 8 1.3. Alkaline leaching of zinc oxide material. 11 1.4. Reactions between cyanide and the zinc minerals. 18 2 EXPERIMENTAL 32 2.1. Materials. 32 2.2. Analytical techniques. 44 2.2.1. Zinc analysis. 44 2.2.2. Cyanide analysis. 45 2.2.3. Cyanide ion-selective electrode. 47 2.2.4. Potentiometric titrations. 55 2.2.5. Ultra-violet absorption spectrophotometry. 70 2.2.6. Conclusion. 75 2.2.7. Determination of the free cyanide concentration of leach liquors. 76 3 THE SOLUBILITY OF THE SECONDARY ZINC MINERALS IN AQUEOUS CYANIDE SOLUTIONS 82 3.1. Experimental procedure. 82 3.2. Results. 86 3.2.1. Influence of cyanide concentration. 86 3.2.2. Influence of temperature. 92 3.2.3. Influence of sodium hydroxide addition. 93 3.3. Discussion. 98 4 KINETIC STUDIES 112 4.1. Introduction. 112 4.2. Agitation system. 118 4.3. Experimental technique and data analysis. 120 4.4. The influence of agitation rate on the rate of dissolution of the secondary zinc minerals. 122 4.5. The influence of particle size on the rate of dissolution of smithsonite and hemimorphite in cyanide solutions. 132 -5- Chapter Page 4.6. The influence of cyanide concentration on the rate of dissolution of the secondary zinc minerals. 139 4.7. The influence of temperature on the rate of dissolution of smithsonite and hemimorphite. 148 4.8. General rate equations for the dissolution of smithsonite and hemimorphite in cyanide. 154 4.9. Scanning electron microscope examination of smithsonite and hemimorphite after leaching in sodium cyanide. 156 4.10. Surface area changes during smithsonite dissolution. 179 4.11. Further dissolution studies on hemimorphite. 182 4.12. Addition of sodium hydroxide to the cyanide leach solvent. 185 4.13. Roasting of hemimorphite. 194 5 DISCUSSION OF KINETIC RESULTS. 204 5.1. Comparison of rate equations with the experimental results. 224 6 METAL AND SOLVENT RECOVERY 228 6.1. Introduction 228 6.2. Solution purification. 235 6.2.1. Experimental. 240 6.2.2. Results. 241 6.2.3. Conclusions. 242 6.3. Electrodeposition of zinc from cyanide solutions. 244 6.3.1. Experimental. 251 6.3.2. Results. 254 6.3.3. Discussion. 275 6.4. Zinc cyanide precipitation. 283 6.4.1. Experimental. 283 6.4.2. Results. 285 6.4.3. Discussion. 292 6.4.4. Conclusions. 295 7 PROCESS EVALUATION. 297 7.1. Direct electrolysis of zinc cyanide solution. 297 7.2. Precipitation of zinc as zinc cyanide. 302 8 FINAL CONCLUSIONS. 307 REFERENCES 312 -6- 1. INTRODUCTION 1.1. Occurrence of zinc oxide minerals The major source of zinc is the sulphide minerals sphalerite and wurtzite, however, significant amounts have and are being recovered from zinc carbonate and zinc silicate minerals. These latter minerals, known as calamine ores, originated through the weathering and oxidation of the primary sulphide deposits resulting in the formation of a zinc sulphate solution which precipitated on encountering carbonate rocks or available silica. Many primary zinc deposits are, therefore, capped by oxidised zinc ores containing smithsonite (zinc carbonate), hydrozincite (basic zinc carbonate) and hemimorphite (zinc silicate). In some cases, oxidised. zinc deposits occur alone either as a result of the complete oxidation of the sulphide minerals or the transport of the zinc sulphate solution some distance from the original primary ore body before precipitating. The zinc minerals of commercial interest are shown in Table 1.1. -? - Table 1.1. Zinc minerals of commercial interest I--- - T Composition Mineral Formula rTn(%)_ I Si(%) Sphalerite ZnS 67.1 ý - Wurtzite ZnS 67.1 - Smithsonite ZnCO3 52.1 - H d i i te I 2Z 3 Z 59.6 y roz nc nC(ý . n(OH) 2 - H em i morp hi te Zn Si Cý (OH) H 54.3 11.7 62722 .O 180.3 ý Zincite* Zn - Willemite Zn SiO 58.7 12.6 (Fe, Franklinite* Mn Zn)(Fe, Mn)204 15-20 - m Zincite and franklinite only occur in quantity at Franklin, New Jersey(, ). The zinc sulphide minerals are generally associated with lead minerals such as galena and cerussite, other sulphides like pyrite and chalcopyrite, silver minerals and less commonly gold, the latter two greatly adding to the value of the ore. The most common gangue minerals associated with zinc deposits are calcite and dolomite with fluorite, quartz and limonite. A number of metals are commonly found substituted for zinc in the oxide zinc minerals and these include copper, cobalt, cadmium, manganese, lead, magnesium and iron, although usually only to a small extent (less than 1%). The most important of these substituted metals is cadmium which rarely -8- occurs as a natural cadmium mineral and, indeed, most of the world's production of this metal comes as a by-product from the processing of zinc ores. 1,2, Conventional zinc mineral processin The zinc sulphide minerals are conveniently concentrated by normal sulphide flotation methods and the zinc oxide minerals are often recovered by flotation with a dodecylamine/fuel oil emulsion(2) a fatty acid(3) Flotation the or after sulphidisation(4) . of zinc oxide minerals, however, generally results in a poor concentrate grade and recovery because the reagents are not selective enough. More recently work has been conducted whereby the zinc oxide minerals are floated by the use ofchelating agents(5) which enable more selective flotation. However, flotation is made difficult by the similarity in the surface properties of the zinc oxide minerals and the gangue and by the presence of hydrated iron oxide slimes which coat both gangue and zinc minerals alike. Zinc has a low boiling point (9030 C) and is often recovered from oxidised zinc deposits of sufficiently high grade by fuming in retorts after roasting or calcining. This process, however, has many disadvantages not least being the requirement -9- of a cheap source of fuel. The reduction can be summarised by the following two gas-solid reactions. Zn0(s) + CO(g) -s Zn(g) + C02(g) (1, la) C02(g) C(s) 2CO(g) (1. lb) + r- Zinc oxide is relatively stable, however, and the reduction reaction is only thermospontaneous at 950°C. On condensing the zinc, therefore, the reaction given by Equation 1.1 tends to reverse and large amounts of the zinc revert to zinc oxide.
Load more

Recommended publications
  • C:\Documents and Settings\Alan Smithee\My Documents\MOTM\Smithsonite.Wpd
    @oqhk1//0Lhmdq`knesgdLnmsg9Rlhsgrnmhsd We are delighted to present another mineral, beautiful in appearance, significant to modern man and to our ancestors, and whose name honors a man who never saw America, but made a most significant contribution to its national education! OGXRHB@K OQNODQSHDR Chemistry: ZnCo3 Zinc Carbonate Class: Carbonates Dana’s: Anhydrous Carbonates Crystal System: Hexagonal-Trigonal Crystal Habits: Crystals are rare, usually as rhombohedrons, often curved and rough, or more rarely, as scalenohedrons; Usually as crusts; Botryoidal, stalactitic, reniform; Massive, granular, earthy Color: Grayish white to dark gray, greenish or brownish white, also green to apple-green, blue, green- blue, yellow, pink, brown, or white; rarely, colorless and transparent Luster: Greasy to vitreous Transparency: Transparent to translucent Streak: White Refractive Index: 1.848, 1.621 Cleavage: Perfect in one direction Fracture: Uneven to conchoidal; brittle Hardness: 4.5 Specific Gravity: 4.2 Luminescence: Often fluoresces white, vivid blue, pink, red, yellow, and orange under shortwave and longwave ultraviolet light Distinctive Features and Tests: Specific gravity and hardness higher than other carbonates; Infusible Dana Classification Number: 14.1.1.6 M @L D Our featured mineral is pronounced smith!-sun-t, and was named in 1832 in honor of British mineralogist and chemist James Smithson (1765-1829), whose legacy provided for the foundation of the Smithsonian Institute, and who did much research into zinc and zinc minerals. See History and Lore for more information on the man and the institution. BNL ONRHSHNM Smithsonite is the sixth member of the carbonates class to be our featured mineral, after azurite (September 1996), calcite (November 1996), rhodochrosite (October 1997), aragonite (June 2000) and dolomite (January 2001).
    [Show full text]
  • Download PDF About Minerals Sorted by Mineral Name
    MINERALS SORTED BY NAME Here is an alphabetical list of minerals discussed on this site. More information on and photographs of these minerals in Kentucky is available in the book “Rocks and Minerals of Kentucky” (Anderson, 1994). APATITE Crystal system: hexagonal. Fracture: conchoidal. Color: red, brown, white. Hardness: 5.0. Luster: opaque or semitransparent. Specific gravity: 3.1. Apatite, also called cellophane, occurs in peridotites in eastern and western Kentucky. A microcrystalline variety of collophane found in northern Woodford County is dark reddish brown, porous, and occurs in phosphatic beds, lenses, and nodules in the Tanglewood Member of the Lexington Limestone. Some fossils in the Tanglewood Member are coated with phosphate. Beds are generally very thin, but occasionally several feet thick. The Woodford County phosphate beds were mined during the early 1900s near Wallace, Ky. BARITE Crystal system: orthorhombic. Cleavage: often in groups of platy or tabular crystals. Color: usually white, but may be light shades of blue, brown, yellow, or red. Hardness: 3.0 to 3.5. Streak: white. Luster: vitreous to pearly. Specific gravity: 4.5. Tenacity: brittle. Uses: in heavy muds in oil-well drilling, to increase brilliance in the glass-making industry, as filler for paper, cosmetics, textiles, linoleum, rubber goods, paints. Barite generally occurs in a white massive variety (often appearing earthy when weathered), although some clear to bluish, bladed barite crystals have been observed in several vein deposits in central Kentucky, and commonly occurs as a solid solution series with celestite where barium and strontium can substitute for each other. Various nodular zones have been observed in Silurian–Devonian rocks in east-central Kentucky.
    [Show full text]
  • Washington State Minerals Checklist
    Division of Geology and Earth Resources MS 47007; Olympia, WA 98504-7007 Washington State 360-902-1450; 360-902-1785 fax E-mail: [email protected] Website: http://www.dnr.wa.gov/geology Minerals Checklist Note: Mineral names in parentheses are the preferred species names. Compiled by Raymond Lasmanis o Acanthite o Arsenopalladinite o Bustamite o Clinohumite o Enstatite o Harmotome o Actinolite o Arsenopyrite o Bytownite o Clinoptilolite o Epidesmine (Stilbite) o Hastingsite o Adularia o Arsenosulvanite (Plagioclase) o Clinozoisite o Epidote o Hausmannite (Orthoclase) o Arsenpolybasite o Cairngorm (Quartz) o Cobaltite o Epistilbite o Hedenbergite o Aegirine o Astrophyllite o Calamine o Cochromite o Epsomite o Hedleyite o Aenigmatite o Atacamite (Hemimorphite) o Coffinite o Erionite o Hematite o Aeschynite o Atokite o Calaverite o Columbite o Erythrite o Hemimorphite o Agardite-Y o Augite o Calciohilairite (Ferrocolumbite) o Euchroite o Hercynite o Agate (Quartz) o Aurostibite o Calcite, see also o Conichalcite o Euxenite o Hessite o Aguilarite o Austinite Manganocalcite o Connellite o Euxenite-Y o Heulandite o Aktashite o Onyx o Copiapite o o Autunite o Fairchildite Hexahydrite o Alabandite o Caledonite o Copper o o Awaruite o Famatinite Hibschite o Albite o Cancrinite o Copper-zinc o o Axinite group o Fayalite Hillebrandite o Algodonite o Carnelian (Quartz) o Coquandite o o Azurite o Feldspar group Hisingerite o Allanite o Cassiterite o Cordierite o o Barite o Ferberite Hongshiite o Allanite-Ce o Catapleiite o Corrensite o o Bastnäsite
    [Show full text]
  • Revision 1 New Insights Into the Crystal Chemistry of Sauconite (Zn
    This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America. The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press. DOI: https://doi.org/10.2138/am-2020-7460. http://www.minsocam.org/ Revision 1 New insights into the crystal chemistry of sauconite (Zn-smectite) from the Skorpion zinc deposit (Namibia) via a multi-methodological approach Emanuela Schingaro1*, Gennaro Ventruti1, Doriana Vinci1, Giuseppina Balassone2, Nicola Mondillo2, Fernando Nieto3, Maria Lacalamita1, Matteo Leoni4,5 1Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari Aldo Moro, Via Orabona 4, I-70125, Bari, Italy 2Dipartimento di Scienze della Terra dell’Ambiente e delle Risorse, Università “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126, Napoli, Italy 3Departamento de Mineralogía y Petrología, IACT, Universidad de Granada-CSIC, Av. Fuentenueva s/n, 18002, Granada, Spain 4Saudi Aramco Research and Development Center, P.O. Box 5000, 31311, Dhahran, Saudi Arabia 5Dipartimento di Ingegneria Civile, Ambientale e Meccanica, Università di Trento, Via Mesiano, 77, Trento, 38123, Italy *Corresponding author: Emanuela Schingaro, e-mail: [email protected] RUNNING TITLE: New insights into the crystal chemistry of sauconite 1 Always consult and cite the final, published document. See http:/www.minsocam.org or GeoscienceWorld This is the peer-reviewed, final accepted version for American Mineralogist,
    [Show full text]
  • The Geochemistry and Mobility of Zinc in the Regolith. Advances in Regolith 2003 289
    Advances in Regolith 2003 287 THE GEOCHEMISTRY AND MOBILITY OF ZINC IN THE REGOLITH D. C. McPhail1, Edward Summerhayes1, Susan Welch1 & Joël Brugger2 CRC LEME, Department of Geology, Australian National University, Canberra, ACT, 0200 1South Australian Museum and Adelaide University, Adelaide, SA 5000 INTRODUCTION The mobility of zinc in the regolith is important for several reasons, including the weathering of zinc deposits, formation of non-sulphide zinc deposits and contamination of soils and waters from human impact. The mobility of zinc is also important more generally to geologists and geochemists, both exploration and otherwise, because of the need to understand the formation of zinc ore deposits, such as Mississippi Valley Type (MVT), volcanic-hosted massive sulphide (VHMS), zinc oxide and others in which zinc occurs. This means that exploration geochemists, economic geologists and environmental scientists need to understand how zinc exists in the regolith, different lithologies and water, how it is mobilized or trapped, how far it can be transported and whether it is bioavailable and acts as either a micronutrient or a toxin to plant and animal life. In economic geology, there is presently an increasing interest in the formation of zinc oxide, or non- sulphide zinc deposits, and this is reflected in a recent special issue in the journal Economic Geology (Sangster 2003). Although the mobility of zinc in the regolith depends on the transporting process (e.g., groundwater advection or convection, sediment or airborne physical transport, biotic), it depends substantially on the geochemistry of zinc, i.e., how does zinc exist in groundwater and the regolith materials and what are the important geochemical reactions between water and solid.
    [Show full text]
  • Aurichalcite (Zn, Cu)5(CO3)2(OH)6 C 2001-2005 Mineral Data Publishing, Version 1
    Aurichalcite (Zn, Cu)5(CO3)2(OH)6 c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Monoclinic, pseudo-orthorhombic by twinning. Point Group: 2/m. As acicular to lathlike crystals with prominent {010}, commonly striated k [001], with wedgelike terminations, to 3 cm. Typically in tufted divergent sprays or spherical aggregates, may be in thick crusts; rarely columnar, laminated or granular. Twinning: Observed in X-ray patterns. Physical Properties: Cleavage: On {010} and {100}, perfect. Tenacity: “Fragile”. Hardness = 1–2 D(meas.) = 3.96 D(calc.) = 3.93–3.94 Optical Properties: Transparent to translucent. Color: Pale green, greenish blue, sky-blue; colorless to pale blue, pale green in transmitted light. Luster: Silky to pearly. Optical Class: Biaxial (–). Pleochroism: Weak; X = colorless; Y = Z = blue-green. Orientation: X = b; Y ' a; Z ' c. Dispersion: r< v; strong. α = 1.654–1.661 β = 1.740–1.749 γ = 1.743–1.756 2V(meas.) = Very small. Cell Data: Space Group: P 21/m. a = 13.82(2) b = 6.419(3) c = 5.29(3) β = 101.04(2)◦ Z=2 X-ray Powder Pattern: Mapim´ı,Mexico. 6.78 (10), 2.61 (8), 3.68 (7), 2.89 (4), 2.72 (4), 1.827 (4), 1.656 (4) Chemistry: (1) CO2 16.22 CuO 19.87 ZnO 54.01 CaO 0.36 H2O 9.93 Total 100.39 (1) Utah; corresponds to (Zn3.63Cu1.37)Σ=5.00(CO3)2(OH)6. Occurrence: In the oxidized zones of copper and zinc deposits. Association: Rosasite, smithsonite, hemimorphite, hydrozincite, malachite, azurite.
    [Show full text]
  • Nickeloan Hydrozincite" a New Variety
    MINERALOGICAL MAGAZINE, SEPTEMBER I979, VOL. 43, PP. 397-8 Nickeloan hydrozincite" a new variety A. K. ALWAN AND P. A. WILLIAMS Department of Inorganic Chemistry, University College, PO Box 78, Cardiff CFI IXL, Wales SU M M A R Y. Extensive substitution of Ni for Zn in hydro- specimen are of the order of I mm in thickness and zincite from the Parc Mine, North Wales, has been have a pure white streak. No difficulty was ex- observed. This is the first time that a substantial concen- perienced in obtaining specimens suitable for ana- tration of another transition metal in this mineral has lysis which were free from limonite, which is also been reported. The average composition of the nickeloan present in large quantities in the workings as a hydrozincite is Zn4.63Nio.37(CO3h(OH)6. The relation- ship of this new variety to other secondary carbonate- result of oxidation of the sulphide orebody (Alwan containing nickel minerals is discussed, as is the and Williams, i979). The material obtained was possibility of substitution of other transition metal ions analysed by atomic absorption spectrophotometry, into the hydrozincite lattice. using a Varian AA6 instrument fitted with a carbon rod analyser, after dissolution in Analar| 0.05 mol dm-3HNO3. A summary of the analytical results are given in Table I. Very minor amounts of Cu and DURING the course of a study (Alwan and Fe were found to be present. Concentrations of Co, Williams, I979) on the formation of hydrozincite, Ca, and Mg are less than the detection limit, and A1 Zns(CO3)2(OH)6, from aqueous solution in the was not detected.
    [Show full text]
  • Optical Properties of Common Rock-Forming Minerals
    AppendixA __________ Optical Properties of Common Rock-Forming Minerals 325 Optical Properties of Common Rock-Forming Minerals J. B. Lyons, S. A. Morse, and R. E. Stoiber Distinguishing Characteristics Chemical XI. System and Indices Birefringence "Characteristically parallel, but Mineral Composition Best Cleavage Sign,2V and Relief and Color see Fig. 13-3. A. High Positive Relief Zircon ZrSiO. Tet. (+) 111=1.940 High biref. Small euhedral grains show (.055) parallel" extinction; may cause pleochroic haloes if enclosed in other minerals Sphene CaTiSiOs Mon. (110) (+) 30-50 13=1.895 High biref. Wedge-shaped grains; may (Titanite) to 1.935 (0.108-.135) show (110) cleavage or (100) Often or (221) parting; ZI\c=51 0; brownish in very high relief; r>v extreme. color CtJI\) 0) Gamet AsB2(SiO.la where Iso. High Grandite often Very pale pink commonest A = R2+ and B = RS + 1.7-1.9 weakly color; inclusions common. birefracting. Indices vary widely with composition. Crystals often euhedraL Uvarovite green, very rare. Staurolite H2FeAI.Si2O'2 Orth. (010) (+) 2V = 87 13=1.750 Low biref. Pleochroic colorless to golden (approximately) (.012) yellow; one good cleavage; twins cruciform or oblique; metamorphic. Olivine Series Mg2SiO. Orth. (+) 2V=85 13=1.651 High biref. Colorless (Fo) to yellow or pale to to (.035) brown (Fa); high relief. Fe2SiO. Orth. (-) 2V=47 13=1.865 High biref. Shagreen (mottled) surface; (.051) often cracked and altered to %II - serpentine. Poor (010) and (100) cleavages. Extinction par- ~ ~ alleL" l~4~ Tourmaline Na(Mg,Fe,Mn,Li,Alk Hex. (-) 111=1.636 Mod. biref.
    [Show full text]
  • (Mnco3-Znco3) Solid-Solutions at 5~
    The formation of rhodochrosite-smithsonite (MnCO3-ZnCO3) solid-solutions at 5~ MICHAEL E. BOTTCHER* Geochemical Institute, Georg-August-University, Goldschmidtstr.1, D-37077 G6ttingen, Germany Abstract MnxZn(l_x)CO3 solid-solutions were prepared at 5~ by precipitation from metal-beating bicarbonate solutions. The solids were identified by X-ray powder diffraction and infrared spectroscopy. Zn2+ ions substitute extensively for Mn2+ ions in the crystal lattice of anhydrous rhombohedral carbonates. Throughout the 24 h during which the experiments were conducted, the aqueous solutions remained undersaturated with respect to pure oxides, sulphates, hydroxides and hydroxysulphates. The solutions, however, were supersaturated with MnxZno_x)CO3 of any given composition. Besides the anhydrous rhombohedral carbonates, Zn4(OH)2(CO3)3.4H20 was precipitated from an aqueous solution with initially high Zn2+ concentration. The negative logarithm of the solubility product of Zn4(OH)2(CO3)3.4H20 was estimated theoretically to be 43.9 (25~ Remaining saturation with respect to Zn4(OH)z(CO3)3-4H20 was calculated accordingly. The suggestion is made that hydrated zinc hydroxycarbonate is metastable under the experimental conditions used here, but that it should transform into anhydrous carbonates. KEYwoems: rhodochrosite, smithsonite, solid-solutions, zinc hydroxycarbonate, synthesis. Introduction quantitative significance has probably previously been underestimated. However, although B6ttcher A nearly complete natural rhodochrosite-smithsonite et al. (1993) applied a tentative thermodynamic (MnCO3-ZnCO3) solid-solution series has been model to estimate the metal-activity ratios of the found in the oxidized zone of the ore body at aqueous solutions from which the Broken Hill Broken Hill, N.S.W., Australia (Birch, 1986; carbonates were precipitated, less is known on the B6ttcher et al., 1993; B6ttcher et al., in prep.).
    [Show full text]
  • Geology and Mineralogy of the Ape.X Washington County, Utah
    Geology and Mineralogy of the Ape.x Germanium-Gallium Mine, Washington County, Utah Geology and Mineralogy of the Apex Germanium-Gallium Mine, Washington County, Utah By LAWRENCE R. BERNSTEIN U.S. GEOLOGICAL SURVEY BULLETIN 1577 DEPARTMENT OF THE INTERIOR DONALD PAUL HODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1986 For sale by the Distribution Branch, Text Products Section U.S. Geological Survey 604 South Pickett St. Alexandria, VA 22304 Library of Congress Cataloging-in-Publication Data Bernstein, Lawrence R. Geology and mineralogy of the Apex Germanium­ Gallium mine, Washington County, Utah (U.S. Geological Survey Bulletin 1577) Bibliography: p. 9 Supt. of Docs. no.: I 19.3:1577 1. Mines and mineral resources-Utah-Washington County. 2. Mineralogy-Utah-Washington County. 3. Geology-Utah-Wasington County. I. Title. II. Series: United States. Geological Survey. Bulletin 1577. QE75.B9 no. 1577 557.3 s 85-600355 [TN24. U8] [553' .09792'48] CONTENTS Abstract 1 Introduction 1 Germanium and gallium 1 Apex Mine 1 Acknowledgments 3 Methods 3 Geologic setting 3 Regional geology 3 Local geology 3 Ore geology 4 Mineralogy 5 Primary ore 5 Supergene ore 5 Discussion and conclusions 7 Primary ore deposition 7. Supergene alteration 8 Implications 8 References 8 FIGURES 1. Map showing location of Apex Mine and generalized geology of surrounding region 2 2. Photograph showing main adit of Apex Mine and gently dipping beds of the Callville Limestone 3 3. Geologic map showing locations of Apex and Paymaster mines and Apex fault zone 4 4. Scanning electron photomicrograph showing plumbian jarosite crystals from the 1,601-m level, Apex Mine 6 TABLES 1.
    [Show full text]
  • The Structure of Hemimorphite
    Zeitschrift fUr Kristallographie, Bd. 113, S. 23-29 (1960) The structure of hemimorphite By G. A. BAHCLAY and E. G. Cox Department of Inorganic and Structural Chemistry University of Leeds With 1 figure (Received June 16, 1959) Auszug Die Struktur von Kieselzinkerz, Zn4Si207(OH)2. H20, wurde auf Grund von hkO- und Okl-Projektionen der Elektronendichte neu bestimmt. Das SiP7-Ion besteht aus zwei Si04-Tetraedern mit einem gemeinsamen Sauerstoff- atom; der Si-O-Si-Winkel ist 133°, der Si-O-Abstand vom gemeinsamen O-Atom 1,72 A; die ubrigen Si-O-Abstande sind 1,60 und 1,62 A. Nach vorlaufigen Ergebnissen einer gemeinsam mit H. LYNTON angestellten Untersuchung hat der Thortveitit, Sc2Si207, nicht die Symmetrie 21m und ist cler Winkel Si-O-Si entgegen fruheren Annahmen kein rechter. Abstract The structure of hemimorphite, Zn4(OH)2Si207 . H20, has been redetermined by means of hkO and Okl electron-density projections. The Si207 ion consists of two Si04 tetrahedra with a shared corner; the Si-O-Si angle is 133° and the Si-O distances are 1.72 A (central) and 1.60, 1.62 A (peripheral). Preliminary results for thortveitite, Sc2Si207, (with H. LYNTON) show that the crystals do not have 21m symmetry and that the Si-O-Si angle is not 1800 as formerly supposed. Introduction Earlier investigations of hemimorphite, Zn4(OH)2Si207. H20 (ITo and WEST, 1932), and thortveitite, Sc2Si207 (ZACHARIASEN, 1930), in- dicated linear Si-O-Si bonds in the pyrosilicate groups. On the other hand in the melilites (WARREN, 1930; WARREN and TRAUTZ, 1931), lawsonite (WICKMAN, 1947), tilleyite (SMITH, 1953) and epidote (ITO, MORIMOTOand SADANAGA,1954) the reported Si-O-Si angles range from 131 ° to 165 0; moreover in X207 groups of other kinds the X-O-X angle is usually considerably less than 180°.
    [Show full text]
  • The Mineralogy of Warsaw Formation Geodes
    Proceedings of the Iowa Academy of Science Volume 66 Annual Issue Article 47 1959 The Mineralogy of Warsaw Formation Geodes Richard B. Tripp U.S. Geological Survey Let us know how access to this document benefits ouy Copyright ©1959 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Tripp, Richard B. (1959) "The Mineralogy of Warsaw Formation Geodes," Proceedings of the Iowa Academy of Science, 66(1), 350-356. Available at: https://scholarworks.uni.edu/pias/vol66/iss1/47 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact [email protected]. Tripp: The Mineralogy of Warsaw Formation Geodes The Mineralogy of Warsaw Formation Geodes By RICHARD B. TRIPP Abstract. Mineral inclusions found in geodes from the Warsaw formation of southeastern Iowa are described. The following are reported as present: quartz, chalcedony, calcite, dolomite, ankerite, barite, aragonite, smithsonite, iron pyrite, marcasite, chalcopyrite, sphalerite, sulfur, goethite, hematite, pyrolusite, kaolinite, malachite, selenite, and limonite. Tenorite and chalcocite have been tentatively identified. The geodes found in the Warsaw formation of southeastern Iowa and adjacent areas present a number of interesting mineralogical in­ clusions, many not previously described in the literature. For the past ten years an intensive study has been made of the mineral inclu­ sions found in geodes collected from thirty-two different exposures in the Keokuk, Iowa, area.
    [Show full text]