混合黄药与硫化矿作用对其降解规律的影响

对几种不同的单一/混合黄药在自然条件下及与硫化矿作用后的降解规律进行了分析研究,考察了黄药浓度、不同比例的混合黄药及其与硫化矿作用对黄药降解的影响,并建立了相应的降解动力学方程。结果表明,在自然降解条件下,混合黄药中不论提高乙黄还是戊黄的比例,与单一黄药的自然降解相比,其更难降解;提高混合黄药中戊基黄药的比例,能加快其与硫化矿作用后的自然降解速率。与硫化矿作用后的混合黄药,都明显大于在自然条件下黄药的降解速率,与含硫低的硫化矿作用后的降解速率高于与含硫高的硫化矿作用后的。不同浓度的单一黄药、不同比例的混合黄药自然条件下及与硫化矿作用后的降解过程基本符合一级动力学方程。

黄药与硫化矿作用对其降解规律的影响研究

对几种不同的黄药在自然条件下及与硫化矿作用后的上清液中的降解规律进行了分析研究,考察了黄药结构与硫化矿作用对黄药降解的影响,并建立了相应的降解动力学方程。结果表明,不同结构的黄药在自然条件下降解速率和降解率不同。对于直链黄药,随着碳链长度的增加,黄药的降解速率降低,对于同分异构体,含支链黄药比直链黄药降解速率快。与硫化矿作用后的上清液中的黄药,降解速率与矿石性质有关,降解速率都明显大于在自然条件下降解速率。黄药自然条件下及与硫化矿作用后的降解过程基本符合一级动力学方程。

Interaction effects of flotation reagents for SAG mill reject of copper sulphide ore using response surface methodology

Flotation reagents have a complex behaviour in the beneficiation of base minerals in clayey ores.Interaction effects of reagents on the efficiency of copper flotation for a highly clayey low-grade sulphide ore were investigated using a central composite design.Preliminary results showed that sodium-isopropyl-xanthate(SIPX)and O-isopropyl-N-ethyl-thionocarbamate(IPETC)were found to be the most efficient collectors in the presence of lime as the pH regulator.The effects of dosage of collectors(SIPX and IPETC)and the dosage of methyl-isobutyl-carbonyl(MIBC)as frother on the separation efficiency were evaluated at different pH levels.Based on the analysis of variance(ANOVA),the interaction effects of the collector−pH and collector−frother were significant for the separation efficiency.At the low level of collector dosage,increasing pH from 9 to 11 enhanced copper separation efficiency from 81%to 86%for IPETC and from 77%to 86%for SIPX.Results of ANOVA showed that the maximum copper separation efficiency(88.7%)was obtained at the dosages of 8.6 g/t SIPX,7 g/t IPETC and 20 g/t MIBC at pH 11.Finally,it was concluded that a mixture of SIPX and IPETC collectors was more suitable to treat highly clayey sulphide ores.

Impact of silver sulphides on gold cyanidation with polymetal sulphides

Gold leaching was influenced in association with silver and polymetal sulphide minerals.A packed bed was adopted to single out the galvanic and passivation effects with four sets of minerals:pyrite?silica,chalcopyrite?silica,sphalerite?silica and stibnite?silica.Pyrargyrite enhanced Au recovery to 77.3%and 51.2%under galvanic and passivation effects from pyrite(vs 74.6%and 15.8%).Pyrargyrite in association with sphalerite also enhanced Au recovery to 6.6%and 51.9%(vs 1.6%and 15.6%)under galvanic and passivation effects from sphalerite.Pyrargyrite associated with chalcopyrite retarded gold recovery to 38.0%and 12.1%(vs 57%and 14.1%)under galvanic and passivation effects.Accumulative silver minerals enhanced Au recovery to 90.6%and 81.1%(vs 74.6%and 15.8%)under galvanic and passivation impacts from pyrite.Silver minerals with sphalerite under galvanic and passivation effects enhanced Au recovery to 71.1%and 80.5%(vs 1.6%and 15.6%).Silver minerals associated with chalcopyrite retarded Au recovery to 10.2%and 4.5%under galvanic and passivation impacts(vs 57%and 14.1%).Stibnite retarded Au dissolution with pyrargyrite and accumulative silver minerals.Pyrargyrite and accumulative silver enhanced gold dissolution for free gold and gold associated with pyrite and sphalerite.Gold dissolution was retarded for gold and silver minerals associated with chalcopyrite and stibnite.

Iron Monosulfide Distribution in Three Coastal Floodplain Acid Sulfate Soils, Eastern Australia

The distribution of iron monosulfide (quantified as acid volatile sulfur: SAV) was compared with geo- chemical properties that are known to affect its formation and accumulation in three coastal Holocene acid sulfate soils (ASS) at Tuckean Swamp, McLeods Creek and Bungawalbyn Swamp respectively. These properties included PH, reactive iron (FeR), pore-water sulfate (SO:42-) and organic carbon (OC). Iron monosulfide was concentrated at the oxic/anoxic boundary. The Tuckean Swamp and McLeods Creek sites are Holocene sediments, whereas the Bungawalbyn Swamp is a Holocene peat. The concentration of SAV averaged 0.2 g kg-l in a 0.5 m thick soil layer at the Tuckean Swamp, but was an order of magnitude lower in the oxic/anoxic transition layers at McLeods Creek and Bungawalbyn Swamp. The SAV mineral greigite (Fe3S4) was identified in the Tuckean Swamp by X-ray diffraction and scanning electron microscopy with quantitative energy dispersive X-ray analysis (SEM-EDX). Very small concentrations of greigite were also observed in the McLeods Creek, based on crystal morphology and elemental composition. The concentration of SAV was a small fraction of the total reduced sulfur, representing at most 3% of the Pyrite sulfur. However, the presence of this highly reactive sulfide mineral, distributed within pores where oxygen diffusion is most rapid, has important implications to the potential rate of acid production from these sediments.