Andrzej Luszczkiewicz, Tomasz hmielewski Wroclaw University of Technology, Wroclaw, Poland Andrzej Konieczny KGHM Polish opper, Lubin, Poland
Main copper producers Highland Valley (Teck/ominco/Billiton) Aitik (Bolinden) Norilsk Kidd k. (Falconbridge) KGHM (Poland) Erdenet Bingham (Rio) Morenci (Phelps D) aridad (Grupo M.) Neves orvo (ex Rio) Sharcheshmeh Dexing Grasberg (Rio/F port) OK Tedi (BHP) huquicamata (odelco) Escondida (BHP/Rio) Los Pelambres (Antofagasta) El Teniente (odelco) ollahuasi (Anglo/F bridge) Nchanga (ZM/Anglo) Palabora (Rio/Anglo) Batu Hijau (Newmont) Olympic Dam (WM) u mine production (2011) 16.0 mln t KGHM Polish opper (2011) 571 kt Mt Isa (MIM)
KGHM deposit s location
KGHM Lubin-Glogow Mining Area Deposit UK D PL KGHM F I
Geology of the Lubin- -Glogow Basin Generalized lithostratigraphic section of the basal Zechstein and the position of the Kupferschiefer ore series
ross section of sandstone - shale - dolomite Dolomite ore Shale ore Sandstone ore Typical u-ag section containing grey sandstone (A), boundary dolomite (B), dolomitic shale (), black shale (D) and dolomite (E).
urrent limiting conditions in Polish copper industry
Difficulties in the flotation processes caused by the presence of the black shale in the processing plant
urrent flotation parameters How to elevate both the metals recovery and the concentrate grade? enhance mechanical comminution as a method of liberation intensify froth flotation as a method of beneficiation limit of features has been reached
New approach required superior chemical alteration of the ore, by-product or concentrate by means of inexpensive and environmentally safe medium sulphuric acid
General concept of hybrid FLF process of ore beneficiation FEED (middlings from cleaning flotation) LEAHING WITH H 2 SO 4 (~70%) H 2 SO 4 from smelter LEANING FLOTATION Final tailings Final concentrate
Leaching of carbonate intergrowths in H 2 SO 4 Leaching time
hemistry of acidic carbonate leaching Decomposition of acid-consuming components Liberation of disseminated sulphide particles Principle: hemical reaction of H 2 SO 4 with carbonates of calcium (ao 3 ) and magnesium (MgO 3 ) - major components of intergrowth with metals bearing minerals: ao 3 + H 2 SO 4 + H 2 O = aso 4 2H 2 O + O 2 MgO 3 + H 2 SO 4 = MgSO 4 + O 2
Beneficial role of O 2 in non-oxidative leaching O 2 creates the non-oxidative atmosphere in the leaching slurry and prevents the digestion of sulphide minerals. The redox potential is to low to leach out copper and other metals in sulphidic form
Reference experiments Flowsheet of laboratory procedure (both unleached and leached with H 2 SO 4 ) Sample of commercial product from the plant Slurry mixing and batch test samples preparation Determination of maximum H 2 SO 4 consumption for carbonates decomposition Leaching with H 2 SO 4 with 70% carbonate decomposition tailings Flotation for gypsum removing midlings Fractional flotation -3-2 -1
Flowsheet of pilot plant tests of chemical modification and subsequent flotation of the feed in a continuous system with indicated points of sampling Feed (middlings - by-product from 1 st cleaning operation) Feed to comparative experiment (without leaching) Feed to leaching De-gypsing flotation Feed to flotation after leaching H 2 SO 4 Reactor 1 leaning flotation Scavenger K flot. Reactor 2 oncentrate Tailing Reactor 3 Repulpator
Pilot plant tests - setup FEED (middlings from cleaning flotation) O 2 To the atmosphere H 2 SO 4, from smelter LEAHING LEANING FLOTATION tailings aso 4 2H 2 O, MgSO 4 concentrate Δβ u = +3.5%, Δε u = +4.0% Δβ Ag = +250 g/t, Δε Ag = +3.5%
ommercial application Flowsheet of the Polkowice oncentrator Feed from grinding circuit 85% - 45mm Rougher flotation regrind BM H Rougher-scavenger 1st cleaning M T Hard-to-tread middlings was selected to leaching and flotation operation H Middlings cleaning M M 2nd cleaning Final concentrate Final tailings
Analysis of industrial process at the Polkowice oncentrator. Flowsheet of the 1 st and 2 nd technological line Feed from grinding circuit 85% - 45mm - concentrate M - middlings T - tailing BM - ball mill H - hydrocyclone Feed from grinding circuit 85% - 45mm Rougher flotation regrind BM H Rougher-scavenger T Rougher flotation regrind BM H Rougher-scavenger T 1st cleaning M1 1st cleaning M Leaching H M 2nd cleaning 1 Final concentrate De-gypsing flotation T 2 Scavenger de-gypsing T1 M2 3 Final tailings M 2nd cleaning Middlings cleaning Final concentrate M Final tailings flotation-leaching-flotation (FLF) node
Analysis of industrial process at the Polkowice oncentrator. Flowsheet of the 1 st technological line with chemical treatment of middlings (by-product from I cleaning) with sampling points indicated Feed from grinding circuit 85% - 45mm Rougher flotation regrind BM 1st cleaning - concentrate BM - ball mill M - middlings H - hydrocyclone T - tailing sampling points H Rougher-scavenger T Feed to leaching Product samples selected from technological FLF node M1 Leaching Fractional flotation M 2nd cleaning 1 De-gypsing flotation M2 2 T Scavenger de-gypsing... -1-2 -3 - n. Tailing Fractions of concentrate Final concentrate T1 3 Final tailings
Analysis of industrial process at the Polkowice oncentrator. Flowsheet of the 1 st technological line with chemical treatment of middlings (by-product from I cleaning) with sampling points indicated Feed from grinding circuit 85% - 45mm Rougher flotation regrind BM 1st cleaning - concentrate BM - ball mill M - middlings H - hydrocyclone T - tailing sampling points H Rougher-scavenger T Leached products Product samples selected from technological FLF node M1 Leaching Fractional flotation M 2nd cleaning 1 De-gypsing flotation M2 2 T Scavenger de-gypsing... -1-2 -3 - n. Tailing Fractions of concentrate Final concentrate T1 3 Final tailings
opper content in concentrate, % Grade-recovery curves of flotation analysis of industrial products samples selected from flotation-leaching-flotation (FLF) node 35 30 25 20 15 Flot. feed to leaching Rw=26% Flot. feed to leaching Rw=86% Flot. leached products Rw=26% Flot. leached products Rw=86% Rw degree of carbonates decomposition 10 5 0 0 20 40 60 80 100 opper recovery, %
Fuerstenau recovery-recovery curves of flotation analysis of industrial products samples selected from FLF node 100 Recovery of barren part of ore in tailing, % 80 60 40 20 0 Lack of upgrading Flot. feed to leaching Rw=26% Flot. feed to leaching Rw=86% Flot. leached products Rw=26% Flot. leached products Rw=86% 0 20 40 60 80 100 opper recovery in concentrate, %
omparison of industrial process on 1 st and 2 nd technological line at the Polkowice oncentrator Feed from grinding circuit 85% - 45mm - concentrate M - middlings T - tailing BM - ball mill H - hydrocyclone Feed from grinding circuit 85% - 45mm Rougher flotation regrind BM H Rougher-scavenger T Rougher flotation regrind BM H Rougher-scavenger T 1st cleaning M1 1st cleaning M Leaching H M 2nd cleaning 1 Final concentrate De-gypsing flotation T 2 Scavenger de-gypsing T1 M2 3 Final tailings M 2nd cleaning Middlings cleaning Final concentrate M Final tailings
opper recovery, % omparison of industrial process on 1 st and 2 nd technological line at the Polkowice oncentrator 95 94 93 Line 2 (standard process) Line 1 (process with middlings leaching) 92 91 90 89 88 87 86 85 84 4 5 6 7 8 9 Weight percent concentrate Δβ u =+0.6%, Δε u =+3.4% Δβ Ag =+150 g/t, Δε Ag =+2.9%
SUMMARY The application of non-oxidative leaching of carbonates from copper concentrate and middlings with sulfuric acid in the flotation circuit system enables a significant increase of recovery and concentrate grade to the level which can not be achieved by introduction of new grinding and flotation equipment or by modification of existing flotation circuits.
SUMMARY Remarkable increase in flotation recovery and concentrate grade was observed for u and Ag, No need to change the existing flotation circuits, Effective utilization of H 2 SO 4, No hazardous effect of leaching products.
ONLUSIONS A new hybrid FLF process involving sulphuric acid treatment of flotation middlings combined with a subsequent flotation in the commercial scale resulted in a significant increase of process selectivity. Originally designed methodology, referred as flotation analysis, was elaborated for evaluation of sampled material in laboratory experiments. A beneficial effect of the chemical pre-treatment of the flotation middlings on flotation selectivity was shown by means of floatability curves for unleached and leached feeds. It was found that the application of the FLF process on the industrial scale resulted in an increase of copper recovery by 3.4%.