INCREASE OF COPPER RECOVERY FROM POLYMETALLIC ORES

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1 Journal ofmining and Metallurgy, 36 (l-2)a (2000) J1-22. INCREASE OF COPPER RECOVERY FROM POLYMETALLIC ORES M. Adamovic, S. Radosavljevic" and M. Marinko Institute for Technology of Nuclear and Other Mineral Raw Materials Franche d'eperey 86s, Belgrade, Yugoslavia (Received 15 January 2000; accepted 20 March 2000) Abstract Selected concentrates minerals oflead with silver, copper and zinc with cadmium are produced from the polymetallic Pb-Zn-Cu-Ag ores from "Rudnik" mine in the plant for flotation concentration. Copper concentrate is characterized with relatively low recovery of copper with the significant presence of lead, zinc and iron minerals. Based on detailed chemical and mineralogical analysis ofproducts and middling of copper concentrates, module analysis is done, which pointed to further laboratory investigations ofthe concentration ofcopper minerals with the main goal ofincrease ofselectivity and recovery ofthe copper from copper concentrate. Characteristic results ofthe chemical and mineralogical investigations are shown, so as the investigations on flotation concentration of the copper minerals based on module analysis results. Investigation results showed recovery pointed that with the co-milling of the basic concentrate and with selective deprimation oflead, zinc and iron minerals, selective concentrates of copper minerals were got with the much higher recovery of copper from the concentrate. Keywords: polymetallic ore, selective flotation concentrate, flotation concentrate of copper, recovery, Rudnik mine * Corresponding author J.Min.Met. 36 (l-2)a

2 M. Adamovic et al. 1. Introduction Polymetallic ore with the variable content of lead, zinc and copper and relatively high content of silver, bismuth and cadmium is treated in the feed flotation plant "Rudnik". Among mentioned sulfide minerals of iron (pyrrhotine, pyrite) are presented also. Their content is significantly increasing with the deeper mining works, while the content of lead, zinc and copper is decreasing. With applying of selective flotation concentration technologic from the mentioned ore the following selective concentrates are produced [3, 4]: Lead concentrate with the lead content of 72-75%, and silver of glt, with of lead recovery the concentrate is 90-93%, silver is %. Copper concentrate with the copper content of 14-17%, and silver of glt, with of copper recovery in the concentrate is 35-50%, silver is 7-9% Zinc concentrate with the zinc content of 47-49%, and Cd of glt, with of zinc recovery in the concentrate is 80-83%. High technological effects in the production of lead concentrates and the satisfying in the production of zinc concentrates significantly reduce the produced copper concentrate. This is especially emphasized in the cases when the copper content in the ore feed is below 0.25%, which causes the concentrate production below metallurgy standards. Low-quality bulk concentrates with the 10-14% copper, 8-10% lead, and 10-12% zinc content are produced in those cases, while the iron content is around 25%. Due to constant lowering metal content in the ore it happened that during the longer periods low-quality copper concentrate is produced. For the determining of possibility of improving the technological results (increasing the quality of copper concentrate and of copper recovery) large laboratory investigations on flotation concentration were performed which were followed by the product and semi-product concentration detailed chemical and mineralogical analysis. 12 I. Min.Met. 36 (I-2)A 2000

3 Increase of Copper Recovery from Polymetallic Ores 2. Technology Detailed chemical and mineralogical analysis were performed for the defining basic technology parameters for the following products: Polymetallic ore feed flotation; Copper rough concentrate; Copper mineral drain slurry flotation Copper concentrate; Refining semi-product. It has to be emphasized that in the technology process of the copper mineral flotation in the "Rudnik" flotation plant, is done after the flotation of lead minerals and before zinc minerals flotation. Influence of the mentioned technology processes was not studied, but parameters in the part of the process of copper mineral flotation concentration were analyzed [1, 2]. 3. Mineralogy 3.1. Methods The methods for determination in investigated ore and concentrate sample are: Mineralogical investigation, quantitative and qualitative microscopic analysis (for automatic image analyze is used the program OZARIA 2.5 [6]; Determination of copper, lead, zinc and sulphur content (for correction quantitative analyze) Mineralogical composition ofthe ore and the copper concentrate According to the basic mineralogy analysis in the polymetallic ore specimen, next minerals are determined: pyrrhotine, pyrite, marcasite, galena, sphalerite, chalcopyrite, covelline, chalcocite, bornite, tetrahedrite, i.min.met. 36 (l-2)a

4 M. Adamovic et al. arsenopyrite, nature silver, nature bismuth, lead-bismuth sulphosalts, magnetite, hematite, limonite, cuprite, smithsonite, cerussite, quartz, carbonates and contact silicates. The content of sulphide minerals was 16.9%, and from that amount, the 70.9% were free grain (grinding condition 65% 74/-lm). Copper minerals were rarely present. A major copper mineral - chalcopyrite (0.75%) was founded, while covelline, chalcocite, and bornite were present in trace amounts. Oxide copper mineral determined was cuprite «0.01 %). Chalcopyrite appears as a free aggregates with 73.2 %. The rest of chalcopyrite grains are mostly like simple and complex intergrowth and as disseminated in other minerals. The predominantly presents sulphide mineral is pyrrhotine (9.3%) and, from that amount, 64.4% are free aggregates. The rest of grains are located in all other determinate appearing ways. On the Fig. 1, detailed structure construction of mineral aggregates main sulphide minerals is described [5]. According to the basic mineralogy analysis in the copper concentrate sample, next minerals are determined: pyrrhotine, pyrite, marcasite, galena, sphalerite, chalcopyrite, covelline, tetrahedrite, arsenopyrite, nature silver, nature bismuth, lead-bismuth sulphosalts, limonite, cuprite, gangue minerals. The content of sulphide minerals was 85.5%, and from that amount, the 79.2% were free grain. o Free grain Disseminated III Simple intergrowth t!i Complex intergrowth Pirrhotine"''::=====:C====::J::::====f.~~~~ Galena_iI======:C====::J::::=======~ Sphalerite.'::=====:C====::J::::======::::::iii': Chalcopyrite k:===:::::;;;:~===:;z:===:::::;2:::=:::::::=:2==~~ 0% 20% 40% 60% 80% 100% Fig. 1. The structure aggregates ratio of chalcopyrite, sphalerite, galena, and pyrrhotine in polymetallic feed flotation "Rudnik". 14 r Min.Met. 36 (l-2)a 2000

5 Increase of Copper Recovery from Polymetallic Ores DFree grain Disseminated II Simple intergrowth III Complex intergrowth Pirrhotine _li=====:=t:::::::iiiiiiiiiiiiiiiiiiriiiiiiiiiiij;iiiliiiiiiiiiiiiiiiii: Galena_lI======:!!!!!!!!!!!!!!!!!~!!!!!!!!!!!!!!!!!!!!li!!!!!!!!!!!!!!!!!!!!~~ Sphalerite_lI=======C=======:=::!!~!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!~~ ==------" Chalcopyrite k:======~2:::======:;z=======:z=======::::z======~ 0% 20% 40% 60% 80% 100% Fig. 2. The structure aggregates ratio of chalcopyrite, sphalerite, galena, and pyrrhotine in copper concentrate. Copper minerals are present. A major copper mineral - chalcopyrite (25.62%) was founded, while covelline are present in trace amounts. Oxide copper mineral determined was cuprite «0.01%). Chalcopyrite appears as a free aggregates with 88.3%. The rest of chalcopyrite grains are mostly like simple and as disseminated in other minerals The predominantly presents sulphide mineral is pyrrhotine (15.7%) and, from that amount, 51.6% are free aggregates. The rest of grains are located in all other determinate appearing ways. On the Fig. 2, detailed structure construction of mineral aggregates main sulphide minerals is described. In Table 1 quantitative mineral composite of the ore feed in flotation plant, "Rudnik" and the copper concentrate are presented. Gangue minerals are mostly like carbonates, and quartz-silicates. The following composition was determined by the chemical analysis (in %): of lead; of copper; 7.15 of zinc; of iron; of sulphur; 0.66 of manganese; of antimony; of bismuth; 571 glt of silver and 0.52 glt of gold. Chemical and mineralogical analysis was performed on the monthly composite production sample for the determination of the present elements content and they're interconnection in the low-quality copper concentrate. J.Min.Met. 36 (1-2)A

6 M. Adamovic et al. Table J. Quantitative mineral composition (in %). Minerals Polymetallic ore Copper concentrate Galena Sphalerite Chalcopyrite Pyrrhotine Pyrite 1.30 <0.01 Marcasite Covelline Tetrahedrite Arsenopyrite Bornite 0.02 <0.01 Nature silver <0.01 <0.01 Nature bismuth < Pb-Bi sulphosalts Magnetite 0.51 <0.01 Limonite Cerussite 0.04 <0.01 Cuprite <0.01 <0.01 Gangue minerals Total: The most significant elements which reduces the copper concentrate quality were 16.8% iron sulfides, about 28% the other major sulfide minerals (galena and sphalerite) and 29.6% gangue minerals. By the method of standard modal analysis the estimation of the liberation degree is evaluated, and the relatively low liberation degree for the most present mineral species in the concentrate was founded. During modal analysis the liberation of minerals for all grain-size distribution classes were estimated. Modal analysis results emphasized the following recommendations: copper sulfide minerals were liberated with the grinding fineness of 80% 53 urn with the around of 90%. Copper sulphides formed three classes of binary composites: with sphalerite, pyrrhotine and gangue minerals where copper sulphides were predominant. Around 40% of galena with the opening fineness of 80% -53 urn is free, while the rest was forming binary composites with the pyrrhotine and 16 I. Min. Met. 36 (J-2)A 2000

7 Increase of Copper Recovery from Polymetallic Ores gangue minerals, and around 20% of galena is included in the structure of multiphase mineral associations. Sphalerite was with the mentioned grinding fineness free to the level of 80%. Prevailing quantity of unelaborated sphalerite was in the structural, simple composites and the minor quantity was in the multiphase. Pyrrhotine was with the fineness of 80% -53 um liberated with approximately 90% while remaining was included in multiphase composites with galena and gangue minerals, mostly. 4. Copper mineral flotation According to detailed mineralogical analysis and to other investigations it is found that the main reason of low quality and usability of copper in the concentrate was: Insufficient liberation of sulfide minerals among each other and between minerals in the waste; Recovery technological process of flotation and purification of copper minerals; Inadequate reagent regime; Insufficient deprimating of following sulfide minerals. Considering those facts it is found that the investigations should be directed to the following: Evaluation of the optimal conditions for the rough flotation of copper minerals (flotation time, flotation reagent regime); Additional grinding of the concentrate of copper minerals to the fineness 80% -53 urn (according to the data from the modal analysis) for the optimal liberation of mineral species; Evaluation of the optimal conditions of the raw concentrates refining; Deprimating of iron and zinc sulphide minerals. J.Min.Met. 36 (1-2)A

8 M. Adamovic et at Copper minerals rough flotation Flotation tests were performed on the ore samples and drain slurry lead mineral flotation from the production in the feed flotation plant "Rudnik". Flotation tests were performed in the laboratory Denver cell D-12, and the grinding test and additional grinding tests in the laboratory mill with the volume of Ore grinding tests were performed to the fineness of 65% 74 urn (following the plant conditions, and the additional grinding of the basic concentrate to the fineness of 80% -53 urn (according to the conditions of modal analysis). Lead flotation on the ore tests was performed according to the production conditions, while the conditions for the copper mineral flotation were changed. With the plant pulp tests (drain slurry lead flotation) conditions were changed in the flotation concentration of the copper minerals. Those investigations showed that the higher usability of copper minerals could be obtained by the significant increase of the quantity of collector in the flotation process, which resulted, with the lowering of copper content in the basic concentrate. The influence of the collector quantity on the usability of copper in the basic concentrate is given on the Fig. 3, and the influence of the usability on the copper content in the basic concentrate on the Fig ~ ==-+-===*==~ R% ,' f ,------,----_ The collector consumption in 9ft Fig. 3. Influence ofthe collector consumption on recovery of copper. 18 i.min.met. 36 (l-2)a 2000

9 Increase of Copper Recovery from Polymetallic Ores ~== R ~~---- % , , ,-----,------,-----, CU% Fig. 4. Copper content in the rough concentrate. Based on the tests results it is concluded that the following investigation cycle (additional grinding and purification of the copper basic concentrate) should be performed with the lower quality rough concentrate ( % of copper) what enables higher total copper recovery. Based on the tests results it is concluded that the following investigation cycle (additional grinding and cleaning of the copper rough concentrate) should be performed with the lower quality rough concentrate ( % of copper) what enables higher total copper recovery Additional grinding ofthe Cu rough concentrate and the depression ofthe lead, zinc and iron minerals Additional grinding of the copper rough mineral concentrate was performed to the fineness of 80% -53 urn with the depression addition. Depressions of lead minerals were performed with the K 2Cr2 0 7 and the sulfide minerals of iron and zinc with the NaCN. Influence of the deprimators of lead on the lead content in the copper concentrate is given on the Fig. 5, and the deprimators influence of the sulfides of iron and zinc on the Fig Laboratory tests results Metal balance of the flotation concentration sum in the plant conditions was given in the Table 2 and in the Table 3 sum in the laboratory conditions. J.Min.Met. 36 (1-2)A

10 M. Adamovic et al ~---~~----; 4 +~~---~~ ' Pb% ~~"""'"=~;::::::==:.. O-t r-----, i K2Cr207 consumption in 9ft Fig. 5. Influence ofthe K ZCrZ07 on the depression oflead minerals. ~Fe.. a.,zn Fe% 10 and 8 Zn% II NaCN consumption in 9ft Fig. 6. Influence ofthe NaCN on depression of iron and zinc minerals. Table 2. Metal balance at flotation plant "Rudnik". Products M,% Content in % Recovery in % Pb Cu Zn Fe Pb Cu Zn Fe Input C/Cu Tailing J.Min.Met. 36 (l-2)a 2000

11 Increase of Copper Recovery from Polymetallic Ores Table 3. Metal balance obtained through research presented in this paper. Products M,% Content in % Recovery in % Pb Cu Zn Fe Pb Cu Zn Fe Input C/Cu Tailing Analysis of the results Flotation of copper minerals in the technology process in the flotation plant "Rudnik" is after the concentration of lead minerals and before the concentration of zinc minerals. Since concentrations of those minerals are sufficient, scope of the investigations for the improving of technology parameters in the flotation of copper minerals was directed only to this part of the process with the aim not to change anything in the lead cycle and not to change anything in the concentration process for zinc minerals. Investigations, although limited with the mentioned facts, gave significant improvements of the technology parameters in the process of flotation concentration of copper minerals (compare Table 2 and 3). Additional grinding of the rough concentrate of copper minerals lead to positive liberation of mineral species, so it was enabled the successful deprecating of lead, zinc and iron sulfide minerals. Mentioned processes enabled significant improvement of selectivity, and furthermore in the increasing of the copper content in the concentrate. Minor rounding of the intergrow grains in the process of the basic flotation and clearing enabled significant increase of the recovery of copper in the copper concentrate. J.Min. Met. 36 (1-2)A

12 M. Adamovic et al. References 1. M. Adamovic, Z. Konc, Years of Processing Institute of Mining, 1995, Belgrade, p (in Serbian). 2. M. Adamovic, 1. Stanojev, B. Brankovic, S. Golubovic, XXIX October Conference, Bor, 1997, Proceedings p (in Serbian). 3. K. Misic, Proc. of Institute of Mining, No 2, Belgrade, 1984, p (in Serbian). 4. K. Misic, Proc. ofinstitute of Mining, No 1, Belgrade, 1985, p (in Serbian). 5. S. Radosavljevic, Mineralogy analysis of copper concentrates from Rudnik flotation, Report Institute for Technology of Nuclear and Other Mineral Raw Materials, Belgrade, 1996, pp. 12. (in Serbian). 6. R. Tomanec, S. Radosavljevic, and P. Jovanic, V Colloquium of Mineral Processing, Belgrade, 1996, Proceedings p (in Serbian). 22 J.Min.Met. 36 (J-2)A 2000

THE EFFECT OF DIFFERENT COLLECTORS ON THE QUALITY OF BASIC COPPER CONCENTRATE OF THE ORE BODY TENKA ***

THE EFFECT OF DIFFERENT COLLECTORS ON THE QUALITY OF BASIC COPPER CONCENTRATE OF THE ORE BODY TENKA *** MINING AND METALLURGY INSTITUTE BOR UDK: 622 ISSN: 2334-8836 (Štampano izdanje) ISSN: 2406-1395 (Online) UDK: 622.765.061(045)=111 doi:10.5937/mmeb1602025j Abstract Ivana Jovanović *, Milenko Ljubojev