Enrichment of platinum group metals (PGMs) by two-stage selective pressure leaching cementation from low-grade Pt-Pd sulfide concentrates

A hydrometallurgical process was developed for producing Pt-Pd enriched concentrates from low-grade sulfide concentrates on-site at Jinbaoshan mine in an isolated area in China. The developed process (pressure acidic leaching-pressure cyanidation leaching) includes the following two steps. (1) The flotation concentrates are treated by acidic pressure leaching to selectively dissolve all the base metals (Cu, Ni, Co) while leaving most (85 to 94 pct) of the precious metals in the iron residues. The leaching solution is then processed by copper cementation and solvent extraction (SX) to recover PGMs and CuNiCo, respectively. (2) The iron residues are treated by pressure cyanidation leaching to selectively dissolve precious metals. The cyanidation solution is then cemented by zinc power reduction to produce Pt-Pd concentrates. Testing results from both lab and pilot (5 kg/batch, 50 L autoclave) scale tests show that Pt+Pd content has been increased from 86 g/t (flotation concentrate) to 56 to 59 wt pct (zinc cementation residue) with an extraction recovery of 95.8 pct. The Pt-Pd enriched cementation residues can be sold as Platinum Group Metal (PGM) concentrates to refineries for further refining.     

Hot rolling and heat treatment of Ni−Cu−Cb(Nb) steel

Copper-containing steels can be susceptible to hot shortness and the properties of columbium (Nb) grain-refined steels are sensitive to processing conditions. Ni?Cu?Cb steel embodies both copper age-hardening and columbium grain refining; therefore, the effect of nickel on hot shortness and the effects of hot rolling and heat treatment on mechanical properties were examined with the 0.85 pct Ni-1.2 pct Cu-0.03 pct Cb, age hardenable steel. The nickel level of 0.7 to 1.0 pct in Ni?Cu?Cb steel is sufficient to prevent hot shortness due to copper. A suitable aging treatment is 1 hr at 1050°F while comparable properties can be obtained by aging for 4 hr at 975°F. Laboratory processing has shown that lower hot rolling finishing temperatures and greater reductions at the finishing temperature improve laboratory-made heats of this steel by lowering the ductile-to-brittle transition temperature and raising the yield strength. Lower soaking temperatures also result in lower impact transition temperatures but have no effect on strength.     

Physicochemical laws of the atmospheric sulfuric acid leaching of the copper—nickel concentrates from the beneficiation of disseminated ores

A physicochemical substantiation is performed for the organization of a combined flotation hydrometallurgical technology for the processing of the copper??nickel concentrates from the beneficiation of disseminated ores. This technology is used instead of the traditional pyrometallurgical technology providing the production of a sulfide concentrate with a total nickel, copper, and cobalt content of 14.64% for the through extraction of (wt %) 92.2 Ni, 74.0 Cu, 95.3 Co, 91.9 Pt, 95.9 Pd, and 96 Rh to the concentrate.     

多金属结核氨浸液中镍钴铜的萃取分离

采用LIX84从氨性溶液中萃取分离镍、钴、铜。首先采用 5级逆流共萃铜、镍 ,钴留在萃余液中 ,含铜、镍的负载有机相经二级洗涤氨 ;用镍电解废液进行 7级逆流选择性反萃镍 ,实现镍与铜的初步分离 ;然后从含铜有机相中反萃铜得到纯净的硫酸铜溶液 ,选择性反萃镍得到含有少量铜的粗镍液 ,该液仍采用LIX84萃取脱铜 ,并回收铜 ,从而将铜、镍彻底分离 ,实现了用一种萃取剂分离氨浸液中的镍、钴、铜。联动连续运转试验结果表明 ,采用本研究确定的萃取工艺流程和萃取设备处理氨浸液 ,萃取分离效果好 ,试验结果稳定、可靠。金属回收率高 ,萃取回收率分别为 ( %) :Ni 99 0 ,Co 99 7,Cu 99 9。     

Process for enrichment of a ferronickel alloy to 90 Pct Ni

The nickel of most lateritic ores is extracted as a FeNi alloy containing a certain amount of cobalt. The utilization of this ferroalloy is effectively limited to the fabrication of stainless steels, which absorbs about 40 pct of the total nickel consumption. The production of electrolytic nickel from ferronickel is feasible, but it requires anodes made of alloy enriched to at least 80 pct Ni. Such enrichment is complicated by the simultaneous oxidation of nickel during the slagging of iron, which accelerates as the iron is depleted and becomes prohibitive for an alloy with more than 60 pct Ni. A simple and economical upgrading of ferronickel up to 90 pct Ni is proposed by a two-stage converting with oxygen, under simultaneous addition of nickeliferous laterite. Nickel losses are effectively restricted by the two-stage operation. The rich slags of the second stage, produced in contact with an alloy of more than 60 pct Ni, are recycled in liquid state into the empty first stage converter. The subsequent addition of the low grade liquid metal into the first stage converter “washes” the rich slags and reduces their nickel content. The slags of the first stage, produced in contact with low grade alloys, contain little nickel and are discarded. The overall nickel loss is considerably reduced by blowing in short blows with intermediate slag skimmings. The addition of the lateritic ore, during converting, achieves a very satisfactory and inexpensive temperature control, substitutes as a flux, and introduces nickel and oxygen to the process at a very minimal cost. The heat evolved during the oxidation of the iron in the molten alloy is effectively utilized for the smelting of the laterite added.     

Differential precipitation of copper and nickel from acidic polymetallic aqueous solutions

During the pyrometallurgical treatment of copper concentrates several wastes (gaseous, solid and liquid) are generated. Wastewaters produced in a primary copper smelter are acidic polymetallic solutions characterized by intermediate to high sulphuric acid concentration. Additionally, they usually contain large quantities of valuable metals, such as Cu and Ni, as well as impurities, such as Pb, Zn, Fe, As, Sb, Bi, etc. Therefore, recovery of valuable metals from acidic polymetallic aqueous solutions is of great importance for every plant. This paper is dealing with the recovery of copper and nickel from the acidic polymetallic solutions generated in the copper smelter at Bor, Serbia. The process of differential precipitation of metals through neutralization with caustic soda was selected as the treatment alternative that combines simplicity, efficiency and reliability with low capital and maintenance costs. The concept was based on the development of a simple and efficient process that could be more attractive for industries located in countries suffering from economic recession. Theoretical analysis and experimental results showed that copper and nickel can be differentially removed from the acidic polymetallic solutions at pH = 7 and pH = 10, respectively, mainly contaminated by arsenic, which occurs at high concentrations in acidic polymetallic solutions. Both metals were precipitated as hydroxides, although a small portion of copper was removed also as copper sulfate salt. The resulted precipitates are rich in copper and nickel and can be recycled in copper, as well as in nickel smelters.     

Fluidized Bed Selective Oxidation-Sulfation Roasting of Nickel Sulfide Concentrate: Part II. Sulfation Roasting

The fluidized bed sulfation roasting process followed by water leaching was investigated as an alternative process to treat nickel sulfide concentrate for nickel production. The effects of several roasting parameters, such as the sulfation gas flow rate, roasting temperature, the addition of Na₂SO₄, and the roasting time, were studied. 79 pct Ni, 91 pct Cu, and 95 pct Co could be recovered with minimal dissolution of Fe of 4 pct by water leaching after two-stage oxidation-sulfation roasting under optimized conditions. The sulfation roasting mechanism was investigated, showing that the outermost layer of sulfate melt and the porous iron oxide layer create a favorable sulfation environment with high partial pressure of SO₃. Sulfation of the sulfide core was accompanied by the conversion of the sulfide from Ni_1?x S to Ni₇S₆ as well as inward diffusion of the sulfation gas.     

香格里拉铜硫矿选矿工艺研究

针对香格里拉铜硫矿的矿石性质,进行了先铜后硫的优先浮选工艺流程和铜硫混选一分离工艺流程及这两种工艺的粗精矿再磨试验研究,通过对三种工艺流程浮选指标的对比,最终确定了原矿磨矿（80％．74μm）人选的优先浮选工艺流程,在其小型闭路试验中可以获得铜品位19．80％,铜回收率83．06％的铜精矿;硫品位40．35％、硫回收率66．32％的硫精矿。有价元素铜、硫得到了有效回收。     

热处理工艺对高强度含铜9Ni钢组织和性能的影晌

随着液化天然气（LNG）储罐朝着大型化发展,在不增加容器壁厚的情况下,必须提高钢板强度。在传统9Ni钢中添加Cu,通过析出强化,使其强度水平得到显著提高。提出一种新型含1．25％Cu（质量分数）9Ni钢。试验钢经过控轧直接淬火（DQ）;研究了DO材料分别经过1）QLT（奥氏体（γ）单相区淬火（Q）＋两相区（α＋γ）淬火...     

High strength copper alloys by thermomechanical treatments

A thermomechanical processing technique for in creasing the strength of copper alloys is described. Alloys studied include phosphor bronze (5 pct Sn), nickel silver (12 pct Ni-28 pct Zn), tin-modified cupronickel (9 pct Ni-2 pctSn), and Cu?Be (2 pct Be). In this technique, the material is cold-rolled to about 95 pct reduction in thickness followed by heat treatment below the recrystallization temperature. The severe cold work results in increased strenght through strain hardening and texture strengthening, but at the expense of decreased ductility. The terminal heat treatment recovers the ductility while maintaining or increasing the strength imparted by cold work alone. Preliminary results indicate that cold work-accelerated precipitation is chiefly responsible for the strength increase during heat treatment. As a result of the present processing, the copper alloys exhibit higher yield strengths for given amounts of ductility than have heretofore been attained.     

An application of acetonitrile leaching and disproportionation.: Refining segregated copper from roasted concentrates and ores

Pure copper with > 99% recovery has been obtained on a laboratory scale from a variety of copper sulfide concentrates by the following steps. An oxidative roast at 800–900°C to remove sulfur; reduction of the calcine, preferably but not necessarily under segregation roasting conditions at 650–750°C, to generate particulate copper; screening, in the case of segregation roasting, to partially separate from magnetite the over-size carbon which is coated with copper, gold and silver; selective dissolution in acetonitrile-water of the copper from both fractions; then thermal disproportionation of the copper(I) sulfate solution to remover pure copper powder. At least 80% of the silver and > 98% of the copper is recovered by this new concept. Cyanidation of leach residues recovers > 99% of the copper, > 90% of the silver and 80% of the gold, without interference from the iron in the residue. The method has been applied to the product of a segregation roast of refractory copper ores (TORCO process), to the product of a double roast of copper concentrates (Opie-Coffin process) and to the product of a non-segregation reductive roast of a dead roasted concentrate (USBM process). It is also applicable to calcines reduced in a blast furnace.Successful scale up could result in a low cost process for producing copper from copper concentrates. The energy requirements promise to be less than 6000 kJ as 25 psig steam per kg copper, if effective use of steam from the exothermic roasts can be achieved.     

Cu（II）、Ni（II）离子在蛇纹石表面的吸附及对其浮选的影响

通过吸附量测试、纯矿物浮选和红外光谱分析,研究Cu2+和Ni2+离子在蛇纹石表面的吸附过程及对蛇纹石浮选的活化机理.Cu2+和Ni2+离子在蛇纹石表面的吸附符合二级动力学模型,等温吸附过程符合Langmuir等温吸附模型,吸附能够自发进行,为物理吸附和化学吸附的共同作用,Cu2+和Ni2+离子在蛇纹石表面的吸附量随p H值升高而增大.Cu2+和Ni2+离子在弱碱性条件下对蛇纹石具有活化作用,活化机理为铜镍的氢氧化物沉淀和羟基络合物作用于蛇纹石表面,形成活性位点,黄药在活性位点上吸附生成黄原酸铜或黄原酸镍,从而使蛇纹石表面疏水性增大,浮选受到活化.      

Structure and properties of the slags of continuous converting of copper nickel-containing mattes and concentrates: III. Influence of the slag composition on the surface tension and density of slag melts

The surface tension and density of the slags that form during the continuous converting of copper mattes and concentrates into blister copper are determined. The slag melt compositions are varied over a wide range of (Fe + Ni) concentrations and SiO₂/CaO and (Fe)/(Cu + Ni) ratios. The surface tension and density are measured by the bubble pressure technique. The concentration of iron and nickel in a slag and the (Fe)/(Cu + Ni) and SiO₂/CaO ratios affect the density and surface tension.     

The effect of silicon and nickel additions on the sulfide spacing and fracture toughness of a 0.4 carbon low alloy steel

This paper discusses the effects of silicon and nickel additions on the mechanical properties of a 0.4 carbon low alloy steel. The four experimental steels used in the study were obtained by making additions of 1.5 wt pct nickel and 2 wt pct silicon, both separately and in combination, to a 0.4C/1.5Ni/1.0Cr/0.5Mn base steel. The base + Ni + Si steel, resulting from combined nickel and silicon additions, has a yield strength of 1682 MN/m² and impact and fracture toughnesses of 65 J and 115 MN/m^3/2, respectively. The other three steels have comparable strength levels but more typical impact and fracture toughnesses of about 30 J and 75 MN/m^3/2, respectively. The microstructures of the four steels are almost identical. The only significant observed difference among the four steels is that the sulfides in the base + Ni + Si steel are almost three times as large as those in the other three steels. As the four steels have similar sulfide volume fractions, there is a similar difference in sulfide spacings. The improved toughness of the base + Ni + Si steel is attributed to the increased sulfide spacing due to the influence of combined nickel and silicon additions on the average sulfide size.     

Diffusional breakdown of nickel protective coatings on copper substrate in silver-copper eutectic melts

Diffusion couples with electrolessly plated nickel diffusion barriers between copper substrates and silver-copper eutectic alloys were tested at 800 °C and 850 °C, respectively. Growth of (Cu, Ni, Ag) ternary solid solution into the melt was observed at both temperatures. The growth pattern changed from cellular to dendritic as the temperature was increased from 800 °C to 850 °C. The nonplanar growth morphology can be explained in terms of constitutional supercooling in the melt. Kinetics of (Cu, Ni, Ag) solid solution growth were found to be controlled by interdiffusion at the interface of the nickel barrier and the growing solid-state phase. Local breakdown of the nickel diffusion barrier started once the (Cu, Ni, Ag) solid solution reached the copper substrate. Silver diffused from the silver-copper melt, through the ternary solid solution, dissolving copper and forming silver-copper liquid along copper grain boundaries. Ultimately, the nickel barrier was totally converted to the ternary solid solution, broke up, and floated into the liquid. Dissolution of the copper substrate occurred subsequently. A thin layer of chromium undercoating proved to be very effective in extending the protection time of the nickel diffusion barrier, due to the extremely low solubility of both copper and silver in chromium at these test temperatures.     

The effect of hot-rolling on chill-cast AI-AI3Ni,chill-cast AI-AI2Cu,and Unidirectionally Solidified AI-AI3Ni Eutectic Alloys

The effect of hot-rolling on the mechanical properties and microstructures of chill-cast Al-Al₃Ni, chill-cast Al-Al₂Cu, and unidirectionally solidified Al-Al₃Ni eutectic alloys has been studied. The chill-cast eutectic alloys were produced by casting into preheated mild steel molds placed on copper chills. This system promoted growth along the length of the ingot and not radially from the mold wall. Cellular microstructures resulted with good alignment of Al₃Ni fibers or Al₂Cu lamellae within the cells and an interfiber/lamellar spacing of ~ 1 /urn. In contrast, the Al-Al₃Ni eutectic alloy was also unidirectionally solidified at a growth rate of 3 x 10^-1 m s^-1 in a conventional horizontal crystal grower. This produced well-aligned Al₃Ni fibers with an interfiber spacing of 1.2 ώm. Both the unidirectionally solidified and chill-cast Al-Al₃Ni eutectic alloy can be hot-rolled at 773 K to reductions in area of greater than 95 pct. Deformation was achieved by Al₃Ni fiber fracturing followed by separation of the broken fiber fragments in the rolling direction. Additionally, for the chill-cast eutectic the cellular microstructure disappeared and the Al₃Ni fibers were homogeneously distributed throughout the matrix, after area reductions of 60 to 70 pct. In both cases, the eutectic microstructure was deformed with a constant volume fraction of Al₃Ni/unit volume being maintained during rolling. The chill-cast Al-Al₂Cu eutectic alloy can be hot-rolled at 773 K to an area reduction of ~50 pct, after the continuous brittle Al₂Cu phase within the cells has been ‘broken up’ by coarsening at high temperature. The variations of room temperature tensile properties for the chill-cast and unidirectionally solidified eutectic alloys were measured as a function of reduction of thickness during hot-rolling and the results were compared with predicted strengths from discontinuous fiber reinforcement theory. Formerly with the Department of Engineering and Applied Sciences, Sussex University, Falmer, Brighton, BNl 9QT, Sussex, United Kingdom,     

加压氰化全湿法处理低品位铂钯浮选精矿工艺研究

针对前期研究提出的浮选精矿先经湿法预处理而后再加压氰化浸出铂族金属的全湿法新工艺，变动预处理反应过程各种工艺参数，考察了预处理对铜、镍氧化浸出以及对后续铂、钯氰化浸出指标的影响。试验结果表明，浮选精矿经预处理后不仅可有效回收浮选精矿中的铜等有价值有色金属，而且有利于后续加压氰化提取铂钯等贵金属。新工艺实现了全湿法直接处理低品位铂钯硫化浮选精矿的创新。     

Mechanical and Thermal Properties of Pulsed Electric Current Sintered (PECS) Cu-Diamond Compacts

In this work, dispersion strengthening of copper by diamonds is explored. In particular, the influence of 50- and 250-nm diamonds at contents of 3 and 6 vol. pct on the mechanical and thermal properties of pulsed electric current sintered (PECS) Cu composites is studied. The composite powders were prepared by mechanical alloying in argon atmosphere using a high-energy vibratory ball mill. The PECS compacts prepared had high density (>97 pct of T.D.) with quite evenly distributed diamonds. The effectiveness of dispersoids in increasing the microhardness was more pronounced at a smaller particle size and larger volume fraction, explained by Hall–Petch and Orowan strengthening models. The microhardness of Cu with 6 and 3 vol. pct nanodiamonds and pure sm-Cu (submicron-sized Cu) was 1.77, 1.46, and 1.02 GPa, respectively. In annealing experiments at 623 K to 873 K (350 °C to 600 °C), the composites with 6 vol. pct dispersoids retained their hardness better than those with less dispersoids or sm-Cu. The coefficient of thermal expansion was lowered when diamonds were added, being the lowest at about 14 × 10^?6 K^?1 between 473 K and 573 K (200 °C and 300 °C). Good bonding between the copper and diamond was qualitatively demonstrated by nanoindentation. In conclusion, high-quality Cu-diamond composites can be produced by PECS with improved strength and better thermal stability than for sm-Cu.     

High temperature embrittlement of NI and Ni-Cr alloys by trace elements

The effects of Sb, Sn, and Zr additions on the creep properties of Ni and Ni + 20 pct Cr are reported. Antimony and tin additions (~1 wt pct) induce extensive grain boundary cavitation in nickel, while smaller antimony additions had little effect on Ni + 20 pct Cr. Addition of 0.11 pct Zr to Ni + 20 pct Cr greatly inhibited grain boundary cavitation and reduced its Coble creep rate. Auger electron spectroscopy of cavitated specimens provided direct evidence of impurity segregation to cavity surfaces. Residual sulfur segregated most strongly, and was observed on cavity surfaces in all cavitated specimens. Tin segregated somewhat less intensely than sulfur, and antimony segregated only slightly. Segregation of antimony and sulfur to uncavitated portions of Ni + 1 pct Sb grain boundaries was also observed. These results are discussed in terms of segregation effects on energetic and transport properties of the grain boundaries and cavity surfaces. This paper is based on a presentation made at the symposium “The Role of Trace Elements and Interfaces in Creep Failure” held at the annual meeting of The Metallurgical Society of AIME, Dallas, Texas, February 14-18, 1982, under the sponsorship of The Mechanical Metallurgy Committee of TMS-AIME.