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EN
Bentonite is the traditionally used binder in iron ore pelletization. However, it consists of up to 85% silica and alumina which are undesired acidic gangue in iron-making. In this study, carboxymethyl cellulose, sodium lignosulfonate and cornstarch were used as acidic gangue-free organic alternatives to bentonite in synthesizing iron pellets. Iron ore, water and the corresponding binder were mixed and rolled in a pelletizing disk to form green pellets. The green pellets were dried and subsequently indurated in a furnace at 1200 ℃ to form indurated pellets. To evaluate the effectiveness of the organic binders, the pellets produced were tested on various pellet properties. Known industrial pellet property standards and the bentonite binder were used as references. Carboxymethyl cellulose, sodium lignosulfonate and corn starch produced green pellets with average drop numbers of 7.20 ± 0.84, 5.60 ± 0.89 and 6.00 ± 1.00 respectively, compared to bentonite’s 5.00 ± 0.71. Dry pellets of average compressive strength 5.93 ± 0.09, 5.86 ± 0.03 and 11.52 ± 0.18 kg/pellet were produced by carboxymethyl cellulose, sodium lignosulfonate and corn starch respectively while bentonite’s averaged 5.60 ± 0.08 kg/pellet. For indurated pellets, carboxymethyl cellulose (210.2 ± 1.88 kg/pellet) and sodium lignosulfonate (198.1 ± 2.49 kg/pellet) pellets were weaker than those of bentonite (250.4 ± 2.06 kg/pellet) but satisfied the industrial requirement of 181.4 kg/pellet. A boron oxide additive (0.1 wt. %) was used to boost the strength of carboxymethyl cellulose indurated pellets to 252.6 ± 1.32 kg/pellet, rendering them superior to those of bentonite.
EN
This study was undertaken to improve gold and silver extraction from a pyritic gold flotation concentrate, which assayed 11 g/t Au, 42 g/t Ag, 0.21% Cu, 3.57% Zn, and 31% Fe. Direct cyanide leaching of the concentrate at 1.5 g/L NaCN yielded a low gold extraction (37%), confirming its refractory nature. Effects of lead nitrate (200-500 g/t Pb(NO3)2) and pre-aeration (24 h) before cyanide leaching at 1.5-3.5 g/L NaCN were investigated. Earlier studies have focused on the impact of these parameters on gold leaching. Besides gold, this study demonstrated the behaviour of silver and base metals (copper and zinc) from the pyritic gold concentrate. Adding lead nitrate had a negligible effect on gold extraction whilst improving silver extraction. Dissolution of copper was substantially suppressed by adding lead nitrate, i.e., from 23% (no Pb(NO3)2) to 4% (500 g/t Pb(NO3)2) over 24 h. Zinc dissolution was negligible (≤0.01%). Pre-aeration of the concentrate improved the gold and silver extractions by 4-14% and 23-44% at the subsequent cyanide leaching (1.5-3.5 g/L NaCN). However, it did not affect the leaching of copper. Only negligible leaching of zinc (≤0.6%) occurred during cyanide leaching. Pre-aeration also reduced cyanide consumption in subsequent cyanide leaching (1.5 g/L NaCN), i.e., from 2.83 kg/t to 2.03 kg/t NaCN per solids. These results suggested that lead nitrate can improve silver extraction while suppressing copper dissolution, which would be advantageous in the leaching-adsorption circuit (CIP), mitigating the dissolved copper-associated problems. Pre-aeration can also be suitable for improved gold/silver extractions and reduced reagent consumption.
EN
The Cerattepe (Artvin) mine contains volcanogenic massive sulfide (VMS) deposits in northeastern Turkey. This is a kuroko type deposit located in Late Cretaceous volcanic, intrusive and sedimentary rocks, and has a structure with dense alteration stages. In this study, batch flotation tests were carried out to determine the flotation behavior of a new sample (mix ore), that was the combination of two different ores with different flotation behaviors. The mixed ore contains 2.18% Cu, 1.46% Zn, (Cu/Zn ratio 1.49) 38.35% Fe, and 41.6% S content. An efficient separation of copper minerals from zinc minerals using the conventional selective flotation method could not be achieved due to complex mineralogy and very low liberation degree. Therefore, sequential selective flotation resulted in poor Cu recovery. The effects of flotation parameters such as collector type, collector amount, particle size, and pH conditions, were investigated to obtain a bulk copper-zinc concentrate. The best results were obtained using thionocarbamate (Aero 3894) and dithiophosphine (Aerophine 3418A) collector reagents at d80=40 μm particle size. Under optimal conditions (grain size, d80=40 μm, pH=11, amount of collector reagent 60 g/t (Aero 3894), frother (MIBC)=50 g/t, solid ratio=32%, flotation time=8 min.), a bulk copper-zinc concentrate containing 13% Cu and 9.5% Zn was obtained with a copper yield of 84.4% and a zinc yield of 88.9%. The concentrate mass pull was 13%. After rougher and two-stage scavenger flotation, a concentrate (rougher concentrate + scavenger products) was obtained with a mass pull of 22%. Copper and zinc recoveries of this concentrate were 91.8% and 92.5%, respectively.
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