Factors affecting lead jarosite formation

The importance of lead jarosite in hydrometallurgical processing and the factors affecting its formation in both the slow addition and autoclave synthesis techniques are discussed. In the slow addition method the principal factors are the amount and rate of delivery of soluble lead to the hot ferric sulphate solution; high temperatures and good agitation are also essential to avoid the formation of PbSO₄. The key step in the autoclave synthesis process is the selective removal of residual PbSO⁴ from the reaction product and methods of accomplishing this are described. The major factors affecting the autoclave synthesis of lead jarosite are the ratio of $\text{PbSO}{}_4\text{Fe}{}^{\mathrm{3+}}$, acid concentration and the ionic strength of the solution. Time, temperature, degree of agitation and seeding all affect the reaction but to a lesser degree. The principal techniques identified to suppress lead jarosite formation were high acidity (> 0.3 M H₂SO₄ or the presence of substantial quantities (> 0.3 M) of other jarosite formers such as K₂SO₄. Lead jarosites containing more than 16% Pb were produced and X-ray diffraction data for such material are presented.     

黄钾铁矾法炼锌工艺在青海高海拔地区的可行性

黄钾铁矾法炼锌工艺在20世纪80年代已开始应用于我国炼锌行业,但由于高海拔地区特殊的地理环境和条件,该工艺一直未被推广和应用。本文结合小型试验和工业试验,以大量试验数据充分论证了黄钾铁矾法炼锌工艺在高海拔地区的可行性。     

Gangue mineral dissolution and jarosite formation in copper solution mining

The formation of solid reaction products has been recognized as a potential problem in solution mining operations, but little evidence has been reported on the extent of precipitation or on gangue mineral degradation. The present study is particularly concerned with the reactions of gangue minerals during the acid dissolution of non-sulphide copper minerals. Jarosite and gypsum are the major precipitates that form and evidence is presented that potassium- and calcium-bearing minerals provide the cations for precipitate formation. Reaction is most pronounced with weathered and/or hydrothermally altered rock types and can lead to extensive physical degradation of the rock. In a confined environment these reactions could have a deleterious effect on permeability, and thus on process liquor flowrate and contact with ore minerals. The loss of permeability could be such that the production rate becomes uneconomical.     

Cupric chloride leaching of a complex copper/zinc/lead ore

A complex Cu/Zn/Pb ore from Cayeli, Turkey, was reacted with cupric chloride solutions under different conditions. Energies of activation were calculated for dissolution of copper (37 kJ mol^?1), iron (33 kJ mol^?1, zinc (26 kJ mol^?1) and lead (7.5 kJ mol^?1, values which indicate diffusion control of the reaction, probably through the sulphur layer formed round each particle. Particle size/leaching relationships corroborated microscopic assessments and indicated that chalcopyrite dissolved at a very low rate. Calculation of Fe:Cu ratios of metal leached showed considerable dissolution of pyrite from finely-ground ($\text{d}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{≈ 3?5 μ}\text{m}$) ore. Examination of residues using SEM X-ray fluorescence line scan techniques revealed little attack of large pyrite crystals, suggesting that fine pyrite particles in complex relationship with the sphalerite and chalcopyrite were dissolving.     

The copper chaperone CCS directly interacts with copper/zinc superoxide dismutase

Dominantly inherited mutations in the gene encoding copper/zinc superoxide dismutase (SOD1) result in the fatal motor neuron disease familial amyotrophic lateral sclerosis (FALS). These mutations confer a gain-of-function to SOD1 with neuronal degeneration resulting from enhanced free radical generating activity of the copper present in the mutant enzyme. The delivery of copper to SOD1 is mediated through a soluble factor identified as the copper chaperone for SOD1 (CCS). Amino acid sequence alignment of SOD1 and CCS reveals a striking homology with conservation of the amino acids essential for mediating SOD1 homodimerization. Here we demonstrate that CCS and SOD1 directly interact in vitro and in vivo and that this interaction is mediated via the homologous domains in each protein. Importantly, CCS interacts not only with wild-type SOD1 but also with SOD1 containing the common missense mutations resulting in FALS. Our findings therefore reveal a common mechanism whereby different SOD1 FALS mutants may result in neuronal injury and suggest a novel therapeutic approach in patients affected by this fatal disease.     

难选低品位铜铅锌多金属矿选矿试验研究

新疆某铜铅锌矿属于难选低品位多金属硫化矿,原矿铜品位0.15%、铅品位3.52%、锌品位1.24%。针对该矿石性质,试验采用铜铅混合浮选—铜铅分离—铜铅尾矿选锌—锌尾矿再磁选铁的浮选流程,可获得铜品位22.30%、铜回收率68.63%的铜精矿,铅品位58.67%、铅回收率86.83%的铅精矿,锌品位42.85%、锌回收率65.32%的锌精矿,及品位67.0%的铁精矿,全铁回收率62.97%(对磁性铁的回收率为97.52%),闭路产品全部达到国家质量标准要求。     

低污染黄铁矾工艺实践应用分析

本文阐述了低污染黄铁矾法沉矾工艺的机理,并计算出低污染黄铁矾法沉矾母液铁浓度的理论最大限值为10.62g/L.低污染黄铁矾工艺应用实践的特点是:有效提高了高铁原料对锌冶炼工艺的适应性.但增大了冶炼渣综合回收利用的难度.针对工艺特征提出了改进低污染黄铁矾沉矾工艺的几条建议.     

某铜铅混合精矿铜铅分离试验研究

针对某铜铅混合精矿的矿石性质,确定了采用混合精矿浓缩脱药后,以重铬酸钾和JY405作为铅的抑制剂进行抑铅选铜。经一次粗选、四次精选、一次扫选浮选工艺流程,获得了铜品位23.06%、含铅4.69%、铜回收率92.27%的铜精矿,铅品位71.36%、含铜0.42%、铅回收率98.59%的铅精矿。     

The concentrations, distribution and sources of cadmium, copper, lead and zinc in the atmosphere of an urban environment

The four metals Cd, Cu, Pb and Zn have been measured in residential city air in a relatively small urban environment. The atmospheric concentrations are Cd, 0.516, 0.305; Cu, 12.5, 8.22; Pb, 155, 70.2; and Zn 47.4, 22.4 ng m-3 at two different sites. Except for lead the concentrations are low and more typical of rural areas in more industrialised centres. The concentrations were found to be higher in the colder and more stable air conditions existing during the winter season. Also concentrations on the flat were higher than those on a hillside probably reflecting the influence of thermal inversions. Wind direction influences the concentrations, they being greater when the wind flow comes across the industrial areas of the city. Some of the major sources of the elements are coal, soil, tyre wear and automobile emissions.     

The corrosion of lead anodes in copper electrowinning

The steady-state corrosion rate of 0.4 pct As-10 pct Sb-Pb anodes in H₂SO₄ copper electro-winning electrolytes was studied. The corrosion rate increases markedly with increasing acid strength and current density, although the corrosion per pound of copper electrowon is affected only slightly by current density. Several ions such as Cu⁺², Mg⁺², Al⁺³, SiO₃ ^-2 and Na+ have no effect on the corrosion while Fe+S and Ni+2 ions have moderate inhibiting effects. Strong corrosion inhibition is brought about by introducing small amounts of Co*2 into the solution or by substituting a Ca-Pb alloy for the conventional antimonial lead anodes.     

原子吸收光谱法连续测定金精矿中的银铜铅锌

针对金精矿日常化验中银、铜、铅、锌需分别溶样测定,浪费人力、时间,采用火焰原子吸收法一次溶样连续测定样品中的银、铜、铅、锌。金精矿采用盐酸-硝酸-氢氟酸-高氯酸混酸完全消解,盐酸(1+9)溶液定容,原子吸收光谱法进行测定。该方法加入标准物质回收率为96.9%~107.7%,相对标准偏差RSD(n=7)为1.17%~7.07%,检出限分别为Cu 0.001 5μg/m L、Pb 0.029 9μg/m L、Zn 0.011 2μg/m L、Ag 0.001 9μg/m L。该方法对金精矿中银、铜、铅、锌的测定结果与国家标准方法测定值相符。     

The effect of dietary copper and zinc on cholesterol metabolism

The effects of different amounts of dietary zinc and copper on cholesterol metabolism in the rat were investigated. The levels of the minerals used were comparable to those likely to occur in a normal mixed North American diet. Although the different levels affected the serum, liver, and femur concentrations of the minerals, they had no effect on the levels of serum and liver, total, esterified or free cholesterol, or on high density lipoprotein cholesterol. It was concluded that dietary copper and zinc, at levels likely to occur in a normal mixed diet, are not significant factors in cholesterol metabolism.     

Decomposition of jarosite

Precipitation of iron as a jarosite is used in various hydrometallurgical processes. There are several advantages to this route, for example excellent liquid-solid separation characteristics, selective precipitation of iron in environmentally more stable form, recovery of sulfur as sulfuric acid and higher zinc extraction. However, jarosite precipitation also has disadvantages, the major being the high cost of reagents. A laboratory study was therefore carried out on the conversion of ammonium jarosite to iron oxide with recovery of reagents as byproducts. The investigation resulted in the development of three process possibilities: 1) thermal decomposition with separate recovery of hematite, ammonia and sulfur dioxide, 2) decomposition of jarosite in an aqueous slurry to hematite and ammonium sulfate, or 3) decomposition in an aqueous slurry to magnetite and ammonium sulfate. The conditions affecting the decomposition of jarosite by all three methods have been defined and the chemical, mineralogical and physical characteristics of the iron products are identified.     

The domestic lead and zinc market development in recent months

LeadThe domestic lead market,as usual,reacts onemonth behind the price changes taking place inconnection with the LME.Compared withAugust the September price on the domesticmarket increased to an average of 4,766yuan/ton at the various local cash markets,upby 2.03 per cent and it was 3.11 per cent highercompared to the same period of last year.     

铅烟化炉次氧化锌搭配锌系统生产电锌的工艺研究

将铅烟化炉次氧化锌配入常规的锌系统生产电锌,铅、锌两系统次氧化锌搭配比接近1∶1,锌总回收率91.77％,阴极锌100％达0#品级,平均品位99.9984％.该方法铅、铟等富集于渣中利于综合回收,并且取消了加铁和锰,完全利用锌焙砂自身的铁鼓风氧化除砷锑.     

一些铅锌矿山的关闭对铅锌市场的影响

按犦此文是CHRMetapsLtd.公司ClaireHassall女士在2001年12月5～7日于珠海召开的“第四届中国铅锌市场报告会”上所作的报告,经作者本人同意,本刊整理后予以刊载,以飨读者。摘要自2001年4月中国有色金属工业信息中心,北京安泰科信息开发公司召开第三届铅锌市场报告会以来,铅锌市场已发生了很多事件,对铅市场的看法或许没有什么变化,但对锌市场的展望则须考虑到基本面发生的一些重大变化,本文重点讨论由于矿山关闭对锌市场变化的影响,同时,也对由此带来的对铅市场的影响作简要评述。     

The behavior of thallium during jarosite precipitation

Jarosite precipitation provides an effective means of eliminating thallium from zinc processing circuits, and a systematic study of the extent and mechanism of thallium removal during the precipitation of ammonium, sodium, and potassium jarosites was carried out. Thallium (as Tl⁺) substitutes for the “alkali” ion in the jarosite structure. Nearly ideal jarosite solid solutions are formed with potassium, but thallium is preferentially precipitated relative to either ammonium or sodium. Approximately 80 pct of the dissolved thallium precipitates during the formation of ammonium jarosite; the extent of thallium removal is virtually independent of thallium concentrations in the 0 to 3000 mg/L Tl range and of the presence of 75 g/L of dissolved Zn. Although the deportment of thallium is nearly independent of (NH₄)₂SO₄ or Na₂SO₄ concentrations >0.1 M, the precipitates made from more dilute media are relatively enriched in thallium. Likewise, the precipitates made from dilute ferric ion media are also Tl-rich. Low solution pH values or low temperatures both significantly reduce the amount of jarosite formed, but the precipitates made under these conditions are enriched in thallium. Furthermore, because thallium jarosite is more stable than the ammonium or sodium analogues, the initially formed precipitates are consistently Tl rich. The presence of jarosite seed accelerates the precipitation reaction, but dilutes the thallium content of the product. The results suggest that most of the thallium in a hydrometallurgical zinc circuit could be selectively precipitated in a small amount of jarosite, by carrying out the precipitation reaction for a short time in the absence of seed and from solutions having low alkali concentrations.     

高铜铅银阳极板的电解

介绍含高铜铅银阳极板电解生产情况,讨论各主要工艺参数电解时对电银质量的影响,批阳了由含杂同奶阳极板电解生产国际１号银的工艺条件。     

Rubidium jarosite and thallium jarosite — new synthetic jarosite-type compounds and their structures

Rubidium jarosite (RbFe₃(SO₄)₂(OH)₆) and thallium jarosite (TlFe₃(SO₄)₂(OH)₆) were synthesized as single phase products by precipitation from aqueous solution. Hydronium ion (H₃O⁺) substitutes for part of the “alkali” metal in these compounds. Both jarosites are hexagonal (R3m) and have similar unit cell dimensions. During heating rubidium jarosite undergoes two major decompositions; initially water is evolved and subsequently sulphur oxides are emitted. Thallium jarosite decomposes in three principal stages during programmed heating. The first two stages are similar to the decomposition of rubidium jarosite; the third decomposition involves the breakdown of thallium sulphate and the subsequent sublimation of thallous oxide.     

Foreign trade areas for lead and zinc

China's exports in the past few yearswere mainly to the neighbouring countriesor regions in Asia.According to ChinaCustoms statistics,in 1997 China exported175,200 tons of refined lead,in which 91per cent or 162,400 tons were traded withJapan,Korea Rp.,Indonesia,Hong Kong,Taiwan,Malaysia and Singapore.As forzinc,the situation was quite similar with