Effect of the composition of some sulphide minerals on cyanidation and use of lead nitrate and oxygen to alleviate their impact

An investigation was carried out on synthetic ores containing high purity pyrite, pyrrhotite and chalcopyrite and on two gold ores currently processed to evaluate the impact of cyanicides on cyanidation and to improve the leaching performance by using a pre-leaching, injecting oxygen and adding lead nitrate. With regard to the synthetic ores, it was found that pyrrhotite did not generate a high cyanide consumption while pyrite and chalcopyrite were detrimental. Pre-leaching was deleterious for the ore containing chalcopyrite while pre-leaching with lead nitrate was very efficient to decrease the reactivity of the ore containing pyrite. The two gold ores studied had very different compositions. The low sulphide ore had a low sulphide content (1.36% S), present as pyrrhotite while the second had a very high sulphide content (20.2% S), in the form of pyrite, pyrrhotite and chalcopyrite. The efficiency of the process conditions was peculiar to the ores. The high sulphide ore required a stronger, longer pre-leaching period (12 h) with greater amounts of lime (7.0 kg/t) and lead nitrate (600 g/t) than the low-sulphide ore. The ore with a low sulphide content required a pre-leaching of only 1 h with a small quantity of Pb(NO₃)₂ (50 g/t) and leaching can be performed at 360 ppm NaCN to allow a recovery of 96.4% Au and a low cyanide consumption at 0.18 kg/t. As for the high sulphide ore, cyanidation had to be conducted at 560 ppm NaCN to recover 88.4% Au with a cyanide consumption of 0.80 kg/t. An increase in the amount of lime enhanced oxidation of soluble sulphides. Lead nitrate stabilized copper and iron dissolution by forming a passivation layer at the surface of sulphide minerals. Lead nitrate also prevented the formation of a passive layer at the surface of gold.     

用短锥旋流器分选黄铁矿的试验研究

黄铁矿通常用浮选的方法回收 ,本文通过对黄铁矿、脉石物理性能的研究 ,用重选使黄铁矿和脉石实现分离 ,对主要分离设备———短锥旋流器的工作原理及效果进行了探讨。试验表明 ,短锥旋流器是黄铁矿分离的有效设备。     

Oxidative desulphurisation of sulphur-rich coal

Process of oxidative desulphurisation of sulphur-rich containing Ukrainian coal was carried out in the temperature range of 623-723 K by air/steam mixture in the fluidised bed reactor. Mössbauer spectroscopy was applied to study the reaction products in form of iron compounds after every step of thermal treatment. The pyritic sulphur that constitutes most of total sulphur oxidises selectively at these conditions. At lower temperature (623 K) the ferrous sulphates and pyrite oxidised mainly to the ferric sulphate. At 673 K and higher temperatures α-Fe₂O₃ and SO₂ were basic products of FeS₂ oxidation. The transformation of FeS₂ into pyrrhotite as the first stage of desulphurisation was observed at 698 K independently of the partial pressure of oxygen. The iron monosulphide (FeS) was not found at any stage of desulphurisation suggesting the pyrrhotite Fe_1−xS oxidation before the sequential FeS₂→Fe_1−xS→FeS transformation.     

氯化亚锡-甲基橙容量法测定硫铁矿和硫精矿中全铁含量

确定了用氯化亚锡一甲基橙容量法测定硫铁矿和硫精矿中全铁含量的最佳测定条件，操作简便，条件易控制，对环境无汞污染。RSD为0．65％，结果稳定可靠。经大量试验证明，采用此法测定，方便快速，结果令人满意。     

ELECTROSTATIC BENEFICIATION OF EASTERN OIL SHALES

A dry electrostatic process for beneficiating Eastern oil shales was investigated. Scanning electron microscope analysis showed a need to grind the shale to an average particle size of less than 5 μm for nearly complete liberation of mineral inclusions from the organic matrix. The carbonaceous and noncarbonaceous components of shale were imparted positive and negative surface charges, respectively, with a copper tribocharger. Tests in a batch electrostatic separator showed kerogen enrichments from 12 percent in feed up to a value of 34 percent in the product stream. The efficacy of beneficiation was found to be strongly dependent on hydrodynamic conditions, such as particle velocity, particle concentration in the carrier gas, electric field strength, geometry of the separator, etc. Furthermore, the extent of separation was found to be limited by a strong cohesive force acting between the finely ground shale particles which results in the formation of agglomerates.     

机械活化黄铁矿的储能研究

采用自行研制的机械化学热量仪在303.15 K下对机械活化黄铁矿进行了在线储能研究。结果表明:湿磨时黄铁矿最大储能为361.5 J/g,活化效率为20.5%;干磨时黄铁矿最大储能为338.3 J/g,活化效率为16.1%。粒度和X射线衍射分析表明,活化后黄铁矿粒度减小,晶格发生畸变。     

某硫铁矿尾矿再选试验研究

采用摇床重选工艺和浮选工艺对某硫铁矿尾矿进行了再选试验研究。结果表明：摇床重选可以获得硫品位为46.41%的硫精矿,但硫回收率较低,为47.62%;而以BS为捕收剂、2^#油为起泡剂进行浮选,则可以获得硫品位为45.45%,硫回收率达到83.17%的硫精矿。     

不同晶型氧化铁在硫酸中溶出率的研究

从氧化铁的晶型角度对α-Fe2O3和γ-Fe2O3两种氧化铁在硫酸中的溶出率进行研究,探讨了硫酸浓度、溶解温度、氧化铁粒径2个不同因素对溶出率影响规律,并从微观角度分析了两种氧化铁溶出率差异的根本原因。从而推断出利用工业硫酸溶解处理硫铁矿烧渣的不可行性,为工业脱硫和硫铁矿烧渣提纯等工艺设计和开发提供理论依据和技术指导。     

云浮硫铁矿爆破漏斗试验研究

根据利文斯顿爆破漏斗理论,在云浮硫铁矿采场进行了单孔系列爆破漏斗试验,绘出爆破漏斗体积与药包埋深关系曲线图。采用MATLAB软件对试验数据进行三次项回归,计算出爆破漏斗的最佳埋深、临界埋深和最佳炸药单耗等。同时进行了宽孔距多孔同段爆破漏斗试验,确定了药包的炮孔排距和炸药单耗的参数范围。     

硫铁矿浮选中的活化研究进展

从可浮性、活化机理、活化应用三个方面分别概述和分析了黄铁矿和磁黄铁矿的活化研究进展,并认为在今后浮选仍然是硫铁矿选矿的主要发展趋势;现代选矿测试技术的发展,将推动硫铁矿的活化机理研究;目前需要开发环保、来源广和低廉的硫铁矿活化剂。