An Integrated Process for Innovative Extraction of Metals from Black Shale hosted Copper Mine Dumps

Transcription

1 From Illusion 3 to Reality An Integrated Process for Innovative Extraction of Metals from Black Shale hosted Copper Mine Dumps Gregor Borg, Michael Du Bois, Ralph Gorny, Bernd Friedrich, Hermann Wotruba, Henning Morgenroth From Illusion 3 to Reality Project Aims and initial Partners Assessment and utilisation of metals contained in Mansfeld Mine dumps Mineralogical and geochemical characterisation and improvement of insitu analytics Development of optimised sorting and hydrometallurgical recovery methods for metals from black shale hosted ores Product design, market analysis, marketing networks Halle (Saale): Martin Luther Universität Halle Wittenberg EPRU Economic Geology and Petrology Research Unit Gregor Borg Helbra (Mansfelder Land): NMB GmbH & Co.KG Neue Mansfelder Bergwerkschaft Michael du Bois Projectpartners Aachen: RWTH Aachen AMR Institut Aufbereitung Mineralischer Rohstoffe Hermann Wotruba IME Institut für Metallurgische Prozesstechnik und Metallrecycling Bernd Friedrich CONMET GmbH Ralph Gorny Freiberg: UVR FIA GmbH Verfahrensentwicklung Umweltschutztechnik Recycling Henning Morgenroth Martin Luther Universität Halle Wittenberg

2 The European Copperbelt in Germany a mining heritage Barren waste dumps and low grade ore dumps from copper mining, Mansfeld, Germany % Cu % Pb % Zn ppm Ag Mo < 930 ppm Co < 640 ppm Se < 77 ppm Ni < 198 ppm (sweeteners) mio t of lowgrade ore dumps The past high cost underground mining and high energy pyrometallurgical recovery Pouring slag from August- Bebel-Smelter, Helbra (Hebestedt & Eisenächer, 2002)

3 Large fragments of low grade ore today a typical economically viable ore grade 100 years of weathering with minimal oxidation only % Cu % Pb % Zn ppm Ag Global ore grades are in decline we better get used to low grade ores after Mudd (2009)

4 Low grade ores Technological advances to compensate for dropping ore grades Black shale hosted Cu districts with un used low grade mine dumps Global demand for innovative recovery from black shale hosted Cu ore White Pine, Michigan, USA Mansfeld District Germany pilot study Lubin District Poland Zairian/Zambian Copperbelt Dzhezkazgan Central Kazakhstan Zunyi District Guizhou Province Southern China Kalahari Copperbelt Botswana/Namibia

5 Mansfeld district distribution and size of dumps 19 dumps with 5-6 Mio t low grade ore 9 dumps under investigation Jung (1965) Inhomogeneous dump material a challenge for sampling and resource estimation Percentage of ore types Average grades [%] of different ore types Cu Pb Zn black shale 0,83 1,02 1,39 limestone 0,59 0,32 0,34 gypsum 0,75 0,13 0,16 Low grade black shale hosted ore with crust of secondary copper minerals

6 Kupferschiefer ore a challenge low grade Cu, Ag, Zn, Pb ore very fine grained ore particles (20 40 microns) C org. content 10 15% sulphide flotation severly hindered tailings cannot be disposed in new dumps entire material needs to be utilised Mapping, drilling, sampling and quick analyses

7 Hand held xrf on rough and cut samples From no quality to low quality not advisable Mn Mn pulps versus rough sample surface Element N R 2 Value Slope Cu 38 0,94 0,73 Fe 38 0,51 0,73 Mn 38 0,07 0,68 Mo 38 0,86 1,02 Ni 31 0,36 0,80 Pb 38 0,79 0,72 Se 19 0,41 1,10 Zn 38 0,71 0,71 fp xrf NITON XL3t900 data pulps versus rock surface black shale pulps versus cut samples Element N R 2 Value Slope Cu 31 0,88 0,84 Fe 31 0,89 0,88 Mn 31 0,93 1,04 Mo 30 0,97 0,96 Ni 22 0,26 0,74 Pb 31 0,92 0,79 Se 10 0,57 0,82 Zn 31 0,58 0,61 Hand held xrf on pulverised samples Reliable cost and time efficient grade determination Cu Pb Zn Element N R 2 Value Slope Co 11 0,95 1,63 Cu 32 0,98 0,89 Fe 46 0,92 1,15 Mn 46 0,94 1,20 Mo 46 0,99 0,92 Ni 30 0,87 2,73 Pb 26 0,99 2,04 Se 27 0,52 0,79 V 37 0,75 2,75 Zn 16 0,98 0,90 ICP MS versus fp xrf Niton XL3t900 powder data Laboratory analyses performed by ICP MS after Aqua Regia digestion (sample split 15 g) good correlation of fp xrf analyzer with ICP MS data data quality level after US EPA (1998): R 2 = Definitive value R 2 = Quantitative screening R 2 < 0.70 Qualitative screening

8 Who is who and who does what Initial partners and additional partners analytical algorithmens for portable analytics limestone and sandstone (high-quality aggregate) Building industry Characterisation of dumps and ores (sampling, geochemistry, mineralogy) Sensor-aided Sorting (optical, IR, spektrometrical) black shale NMB AMR EPRU barren black shale as silicates and energy source, <12% C org.!) Cement industry improved vertical roller mill Barren slimes Cement industry mixed waste acids Bio leaching mineralised black shale crushing and milling gravity separation, floatation hydrometallurgy I (SX) Acid Leach hydrometallurgy II (EW) Electrolysis Base metals (Cu, Zn, Pb, Ag) UVR-FIA IME future research r4? Marketing CONMET (Product design, Market Analysis, Forecasting)

9 Heap leaching of mixed chunky ore quick and easy? Kupferschiefer, Mansfeld Lisbon Valley, Utah Heap leaching of mixed chunky ore Mixed limestone conglomerate black shale aggregate No sorting or flotation Pb (HCL) Cu (HCL) Cu (H 2 SO 4 ) Cu (NH 3 )

10 Heap leaching of chunky limestone ore Limestone ore only (subordinate component) No sorting or flotation (hand separated) Zn (H 2 SO 4 ) Ag (HCL) Cu (HCL) Cu (H 2 SO 4 ) Cu (NH 3 ) Heap leaching of chunky conglomerate ore Conglomerate and sandstone ore only (very subordinate component) No sorting or flotation (hand separated) Cu (HCL) Pb (HCL) Ag (HCL) Cu (H 2 SO 4 ) Zn (HCL) Zn (H 2 SO 4 ) Pb (H 2 SO 4 ) Cu (NH 3 ) Zn (NH 3 )

11 Sensor based sorting Tested on lowest grade ore (worst case scenario) concentrates ore in lower volume increases grade avoids crushing/milling of waste avoids crushing of harder rocks Upgrading and Cu recovery by optical sorting Waste Concentrate Total Cu Recovery 24,71% 75,29% 100% Cu Grade 0,32% 1,87% Improved milling Possible mill feed < 150 mm avoids pre crushing Ball mill versus vertical roller mill (Bond Work-Index) images: Loesche material kwh/t black shale (ball mill) 12,8 limestone (ball mill) 13,8 conglomerate (ball mill) 17,0 black shale (vertical roller mill) 7,1 58% energy reduction

12 Froth flotation problems from high carbon content Solvent extraction inorganic leach Effects of traditional roasting of sulphide ore concentrates Mass balance of Cu in different solvents with varying pretreatment of the material. sulphuric and hydrochloric acid give relatively high recovery rates roasting is required (additional process step and energy costs)

13 Solvent extraction inorganic leach Without roasting but alternative solvents (waste acids) optically sorted only flotation concentrate optically sorted only flotation concentrate optically sorted only flotation concentrate Nitric acid gives excellent recovery rates Best on sorted material without roasting Nitric acid from separated waste acids from solar industry (generates income) The alternative bioleaching* crushed/milled ore, no flotation pre treatment by acid for carbonate removal recovery [%] ,0 Zn Kontr 1,0 phbac phthy 0 0, phkontr days Data: A. Schippers *pre grown mixed culture of acidophilic Fe(II), sulfur and organic carbon oxidizing bacteria Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Acidiphilium spp. Image: Schippers Cu Zn Image: Schippers/BRGM 8,0 7,0 6,0 5,0 4,0 3,0 ph Cu Bac Cu Thy Cu Kontr Fe Bac FeThy Fe Kontr Zn Bac Zn Thy

14 Two possible scenarios Economics are currently being evaluated and compared analytical algorithmens for portable analytics limestone and sandstone (high-quality aggregate) Building industry barren black shale as silicates and energy source, <12% C org.!) Cement industry improved vertical roller mill Barren slimes Cement industry Characterisation of dumps and ores (mapping, drilling, sampling, hand held assays) optical sorting black shale mineralised black shale milling (VRM) gravity separation, flotation hydrometallurgy I (SX) (waste) acid leach Scenario I Sorting, milling, flotation, inorganic leaching of sulphide concentrate with recycled waste acid, electro winning hydrometallurgy II (EW) Electrolysis base metals (Cu, Zn, Pb) Ag marketing (product design, market analysis, forecasting)

15 Scenario II Sorting, milling, acid pre treatment, bioleaching, electrowinning Characterisation of dumps and ores (mapping, drilling, sampling, hand held assays) optical sorting black shale mineralised black shale milling (VRM) acid treatment for carbonate removal analytical algorithmens for portable analytics limestone and sandstone (high-quality aggregate) Building industry barren black shale as silicates and energy source, <12% C org.!) Cement industry improved vertical roller mill hydrometallurgy I (SX) bioleaching hydrometallurgy II (EW) Electrolysis base metals (Cu, Zn, Pb) Ag Barren slimes Cement industry Bio leaching marketing (product design, market analysis, forecasting) Successful research includes finding what you were never looking for! An integrated process for innovative extraction of metals from mine dumps Gregor Borg, Michael Du Bois, Ralph Gorny, Bernd Friedrich, Hermann Wotruba, Henning Morgenroth