铜钴伴生硫化矿火法冶炼过程钴的分配计算

针对铜钴伴生硫化矿冶炼的难题,提出了氧化造锍熔炼—还原造锍熔炼—氧化吹炼的工艺流程,以提高钴回收率、缩短钴回收流程。对氧化造锍熔炼—还原造锍熔炼过程中钴的分配比进行了计算。结果表明,在氧化造锍阶段,低操作温度和低冰铜品位可大幅提高钴在锍和渣中的分配比;在还原造锍阶段,低的还原温度和造高含铁冰铜都有利于钴的富集和回收。在典型的闪速熔炼—还原贫化工艺过程中钴的最大回收率为65%,可通过改变操作工艺条件来提高钴回收率。     

铜钴冶炼渣还原造锍熔炼回收铜和钴

从试验上验证了铜钴硫化矿冶炼新工艺的可行性,并着重研究了新工艺中铜钴冶炼渣还原造锍熔炼阶段还原剂焦炭用量、硫化剂黄铁矿用量、熔炼温度和保温时间对铜钴回收率的影响。结果表明,加入铜钴冶炼渣质量分数6%的焦炭和20%的黄铁矿,在1 350℃熔炼3h,弃渣含铜、钴可分别降至0.12%和0.074%,产品铜钴锍中铜、钴回收率分别达到92.95%和89.95%。贫化渣主要物相为铁橄榄石(Fe2SiO4)和磁铁矿(Fe3O4),铜钴锍主要物相为硫化亚铁(FeS)、钴铁硫化物(Fe0.92Co0.08S)、吉硫铜矿(Cu8S5)。     

Distribution equilibria and slag chemistry of DON smelting

Equilibrium fluxing chemistry and metal value distributions of nickel matte smelting in the one-step direct nickel matte technology have been determined experimentally at 1350–1450°C in MgO-bearing iron silicate slags at silica saturation. The aim was to approach the detailed smelting chemistry at typical concentrations 2.5–10?wt-% iron in MgO-bearing iron silicate slags at silica saturation by quenching and X-ray microanalysis. The results obtained under controlled P(O₂) and P(S₂) as well as constant P(SO₂)?=?0.1?atm show that copper and nickel solubilities in the slag as well as matte-to-slag distributions favour matte when the slag is modified by magnesia. At the same time, along with increasing magnesia content of the slag, its iron activity is affected by the dissolution of MgO in the slag, and iron concentration of the formed nickel matte is lowered considerably, and its sulphur concentration increased at constant oxygen and sulphur pressures of the gas phase.     

Phase equilibrium and minor-element distribution between Ni3S2-FeS matte and calcium ferrite slag under high partial pressures of SO2

Calcium ferrite slag has been successfully used in the copper smelting process, but no attempt has been made to use it in the nickel smelting process. The phase equilibrium and the distribution of minor elements between the Ni₃S₂-FeS matte and the CaO-FeO_x-based slag (containing about 2 wt pct MgO) in a magnesia crucible were investigated at 1523 K under controlled partial pressures of S₂, O₂, and SO₂ of 10.1, 50.7, and 101.3 kPa, respectively. The results were compared with those for the iron-silicate-based slag, and the following conclusions were obtained: (1) there is no significant difference in the solubility of nickel between both slags in the high-matte-grade range, (2) the dissolution of cobalt in the calcium ferrite slag is clearly smaller than that in the iron silicate slag, (3) detrimental arsenic, antimony, and bismuth are preferentially collected and fixed in the calcium ferrite slag rather than in the iron silicate slag, and (4) it is considered, with regard to technical feasibility, that the use of the calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel converting stage.     

Incorporation of matte-slag thermochemistry into sulphide smelter discrete event simulation

Discrete event simulation (DES) is a suitable framework to evaluate and optimise the dynamics of sulphide smelters. In particular, iron–nickel–copper–cobalt sulphides undergo continual oxidation within a roasting or smelting operation, followed by batch oxidation within the converting operation, thus producing iron-free Bessemer matte (or blister copper, in the case of copper smelters); this semi-finished product undergoes further processing to produce nickel, copper and cobalt products, and to recover precious metals. The juncture between continuous smelting and batch converting is often an appropriate focus for the earliest phases of DES development, since it is typically a major bottleneck within nickel and copper smelters; later phases may include increasing levels of detail for auxiliary unit operations, as well as plant logistics. Moreover, DES can support matte-slag chemistry, including Gibbs free energy balances to determine the iron speciation within the slag. DES is therefore capable of linking the fundamentals of oxidation reactions to the intricacies of plant dynamics.     

Thermodynamic Modeling of Arsenic in Copper Smelting Processes

Published data on the activity coefficients of arsenic in liquid copper, matte and, slag have been reviewed, assessed, and used in the development of thermodynamic databases for solution models of melts. The databases were validated against the literature data on the equilibrium distribution of arsenic between the matte and the slag. The models and databases were used in investigating the effects of matte grade, slag chemistry, SO₂ partial pressure, arsenic loading, and temperature on the equilibrium distribution of arsenic between the melts and gas phase during copper smelting and converting. The results obtained show that the continuous smelting processes operates close to equilibrium between condensed phases with most arsenic reporting to the gas phase. A comparison of the batch and continuous converting processes showed a considerable difference with respect to the elimination of the arsenic from condensed phases. These results indicate batch processes to be more efficient in the removal of arsenic through the gas stream.     

Thermodynamic prediction of melting of copper-electrolyte slime

Balance calculations of multicomponent equilibrium compositions in the gas–liquid–solid system under oxidizing smelting of the copper-free copper-electrolyte slime, during which sulfur, selenium, and tellurium dioxides transfer into the gas phase, while compounds of lead, copper, antimony, iron, and aluminum are concentrated in the composition of the silicate slag, are performed with the help of the Outotec’s Chemical Reaction and Equilibrium Software HSC Chemistry program. It is established that, under optimal conditions of oxidizing smelting of the charge (100 kg) of the electrolyte slime (O₂ ≈ 0.9 kg, SiO₂ ≥ 6%, CaO ~ 3%, t = 1200°C), lead, antimony, and arsenic almost completely transfer into the silicate slag, while copper and silver (above 91%) transfer into the matte. Selenium is distributed between the gas phase (49.8%), matte (24.1%), and metallic phase (26.1%), while tellurium is distributed between sublimates (14.4%), silicate slag (8.4%), and matte (77.2%).     

Activities of CoS and FeS in copper mattes and the behavior of cobalt in copper smelting

The distributions of cobalt and iron between metallic copper and high copper mattes were measured at 1400 and 1500 K. A value of 0.40 ±0.02 was found as the Raoultian activity coefficient of CoS at infinite dilution in the Cu₂S-FeS-CoS mattes. The present activities of FeS in the Cu-saturated Cu₂S-FeS mattes were found to deviate more positively than those reported by Krivsky and Schuhmann at 1623 K, and the positive deviation from the Temkin’s ideality was greater at 1400 K than at 1500 K. Using the activity coefficient of CoS, the partitions of cobalt between copper mattes and fayalitic slags were calculated for various conditions of copper smelting. It was found that cobalt exhibits, in the matte-slag equilibria, chemical properties intermediate between nickel and iron, but much closer to iron than to nickel. The overall recovery of cobalt in blister copper depends on matte grade, and is as low as 3 pct at best. When a high cobalt recovery is desired, therefore, a copper concentrate rich in cobalt must not be processed by conventional pyrometallurgical technology in view of the inevitably high loss to slag. M. NAGAMORI, formerly Associate Professor, Department of Metallurgical Engineering, University of Utah, Salt Lake City, Utah.     

铜精矿及其冶炼过程中相关固体废物的综合表征

采用X射线荧光光谱(XRF)、红外光谱(IR)以及偏光显微(PM)分析联用技术对进口铜精矿及其冶炼过程中产生的相关固体废物冰铜渣和阳极炉渣进行鉴别。XRF对元素组成及其大致含量进行表征,IR对其中的脉石矿物物相进行识别,PM对其中的非脉石矿物物相进行识别。3种表征手段的联用,可以对其中的物相进行全面的识别。结果表明,铜精矿、冰铜渣和阳极炉渣的的物相组成基本无交叉。通过物相分析可以准确判定其物相归属,从而实现对铜精矿及其冶炼过程中产生的相关固体废物进行有效鉴别。     

A thermodynamic database for copper smelting and converting

The thermodynamic properties of the slag, matte, and liquid copper phases in the Cu-Ca-Fe-Si-O-S system have been critically assessed and optimized over the ranges of compositions of importance to copper smelting/converting based on thermodynamic and phase equilibria information available in the literature and using the modified quasichemical model. A thermodynamic database has been developed, which can be used for the calculation of matte-slag-copper-gas phase equilibria of interest for the production of copper. The model reproduces within experimental error limits all available experimental data on phase diagrams, matte-alloy miscibility gap and tie-lines, enthalpies of mixing, and activities of Cu and S in the matte and liquid alloy. The calculated solubilities of Cu in both S-free slag and slag equilibrated with matte are also in good agreement with experiment under all studied conditions, such as at SiO₂ saturation, in equilibrium with Fe, Cu, or Cu-Au alloys, at fixed oxygen or SO₂ partial pressures and at different contents of CaO in the slag. Sulfide contents (sulfide capacities) of the slags are predicted within experimental error limits from the modified Reddy-Blander model, with no adjustable parameters. As an example of the application of the database, the stability field of matte/slag equilibrium is calculated, and the matte and slag compositions are plotted vs iron to silica ratio in the slag at various SO₂ pressures over this field. The matte-slag two-phase field is limited by the calculated lines corresponding to precipitation of copper, silica, and magnetite.     

Selenium partitioning between slag and matte during smelting

Copper concentrates usually contain a number of minor as well as precious elements, the control of which in copper smelting processes is often a key to the quality of the anode copper produced and may also have a bearing on the overall economics of the process. During copper smelting, the copper concentrates are partially oxidized to form slag and matte. The molten slag and matte are separated from each other in the settler. The matte being heavier in density settles at the bottom of the furnace and slag being lighter in density floats over the matte and is eventually discarded off. During the separation, selenium is distributed between slag and matte. Selenium is a value added by-product of copper process. The lower recovery of selenium from the copper process is attributed to the high loss of selenium to the discarded slag. Knowledge of the distribution and form of selenium in slag and matte is very important in the control of the selenium loss, although to date very little is known regarding their distribution. The samples of slag and matte were collected from the smelter exit before their separation. Selenium was added in different proportions in the sample. The experiments involving slag-matte separation were performed at 1250°C for 4 hours of soaking time under inert atmosphere in a vertical tubular furnace. The distribution of selenium and the mechanism by which selenium is dissolved in matte and slag have been established by this study.     

Slags and mattes in vanyukov’s process for the extraction of copper

Slags and matte in Vanyukov’s process, an autogeneous method of processing sulfide concentrates of nonferrous metals used in a specially designed furnace at the Balkhash copper-smelting plant (Kazakstan), have been characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The liquid matte was shown to have contained 3.6 wt pct of slag inclusions and about 4 wt pct of magnetite. The solid matte is a mixture of sulfide phases. The liquid-waste slag was shown to have contained 0.6 wt pct of matte inclusions and about 3 wt pct of magnetite. The silicate field of the solid slag consists of two phases, identified as iron orthosilicate and iron metasilicate. It was shown that most slag formation occurred before the emulsion reached the settling tank of the furnace. Thermodynamic calculation of the exchange reactions for the oxide and sulfide components of the slag showed that zinc and lead dissolved in the slag are present mainly as oxides, but with only a small part (10 to 20 pct) in the form of sulfides. By contrast, copper is present in the slag as dissolved sulfides and also as matte reguli. The results of these thermodynamic calculations are supported by the experimental data.     

电解铝废槽衬还原提取铜转炉渣中铜钴的试验

研究了用铝电解槽废槽衬(包括废阴极炭块和废碳化硅侧块)替代工业煤作还原剂,提取含钴转炉渣中铜、钴的可行性。研究发现,在相同条件下,采用废阴极炭块和废碳化硅侧块均可实现对含钴转炉渣的还原熔炼。工业煤还原剂铜和钴回收率分别达到了91.4%和94.8%;废阴极炭块作还原剂,其中含有的氟可改善渣型,促进渣与冰铜分离,铜和钴回收率分别达到97.3%和99.3%;废碳化硅作还原剂,铜和钴回收率分别为95.4%和90.0%。碳化硅比炭质还原剂密度大,更容易进入渣相参与熔池反应,更有利于应用在工业电炉中。     

Thermodynamic modeling of lead distribution among matte, slag, and liquid copper

Recently, a thermodynamic database was developed for the calculation of equilibria involved in the production of copper. The present study is concerned with the further development of the thermodynamic models and the database of model parameters for the matte, slag, and blister copper phases with a view to including Pb in the database and permitting calculations in the seven-component system Pb-Cu-Ca-Fe-Si-O-S. Thermodynamic and phase equilibrium data available in the literature are reviewed, critically assessed, and optimized with the modified quasi-chemical model. When used with the Gibbs energy minimization software and other databases of the FACT thermodynamic computing system, the database developed in the present study can be used for the calculation of matte-slag-copper-gas phase equilibria during copper smelting and converting. The distribution of lead among these phases can be computed. For example, the distribution of lead among matte, silica-saturated slag, and copper has been calculated at metal saturation, or under fixed partial pressure of SO₂, and has been compared with the available experimental data. The Pb distributions among the equilibrium phases have been calculated under various conditions, which are difficult to study experimentally, such as at magnetite saturation or under various oxygen partial pressures and iron to silica ratios in the slag.     

富氧底吹造锍捕金工艺研究

采用富氧底吹造锍捕金工艺处理复杂含铜、高砷金精矿,以提高金、银的回收率,减少废水、废渣的排放。研究影响造锍熔炼过程中金、银走向和在冰铜中富集程度的因素,并调整造锍熔炼工艺指标,降低炉渣中有价元素的损失。     

Effect of Iron Phase Evolution on Copper Separation from Slag <Emphasis Type="Italic">Via</Emphasis> Coal-Based Reduction

Copper slag, a by-product of copper pyrometallurgy, inevitably contains a certain amount of copper. Oxygen-enriched smelting technologies increase the copper content in slag indirectly because of the production of higher-grade matte. The effect of iron phase evolution on the copper content in slag during the slag cleaning process in an electric furnace was investigated using the method of combining theory with experiments. Based on the analysis, the main factors that impede the separation of slag and copper/matte were determined. Subsequently, the properties of slag were analyzed after decreasing the magnetite content within the slag. The experimental results showed that decreases in magnetite content were beneficial for the separation of copper and slag because of the decrease of slag viscosity. Nevertheless, Cu-Fe alloys formed when magnetite was completely reduced to metallic iron, and the foaming slag was formed at 1250 °C. Furthermore, the distribution of copper in the reduced slags was studied in detail.     

还原气氛下渣-锍两相平衡反应

通过考察还原气氛下熔渣与锍相之间的平衡情况,研究了渣-锍两相反应的影响因素及机理,探讨了还原产物的分配规律。结果表明,熔渣碱度提高有利于锍相还原反应的进行,添加CaS抑制锍相的还原。由于锍相成分及密度不同出现分层现象,造成锍相在熔渣中的夹杂损失。CaS与金属铁具有互斥性,当熔渣中CaS质量分数超过0.9%之后,渣相中几乎没有金属铁的存在;在选取的实验条件下,CaS在渣、锍两相的平衡分配比维持在0.5左右。     

Entrainment behavior of copper and copper matte in copper smelting operations

In copper smelting, the loss of copper to the slag due to entrainment is largely influenced by the flotation of copper metal and/or matte in the slag phase. To evaluate this behavior, the surface tension of copper as a function of temperature and oxygen pressure and the interfacial tension of the copper-iron matte-slag system as a function of matte grade were measured. From the surface and interfacial tension values, the spreading and flotation coefficients of the copper, matte, and slag system were calculated. Ternary interfacial energy diagrams were also con-structed using these data. It is shown that matte droplets containing higher than 32 mass pct Cu will not form a film on rising gas bubbles when they collide in the slag phase. However, matte droplets will attach to gas bubbles upon collision and thus can be floated over the entire range of matte composition. Spreading of copper on bubbles is not possible at oxygen pressures between 10⁻¹² and 10⁻⁸ atm. Flotation of copper by gas bubble in slag is possible at oxygen pressure higher than 10⁻⁹ atm. However, it is feasible for rising matte droplets (attached to rising bubble) to trap and float copper irrespective of the matte grade.     

Tellurium distribution in copper anode slimes smelting

Tellurium is a common minor constituent of copper anode slimes. The distribution of tellurium between the phases during slimes smelting is an important consideration, both in terms of metal quality and the capture of the oxidized tellurium. In this work, the oxidation by oxygen at 1100 °C of a silver-copper selenide matte containing 2 pct tellurium has been examined. The distribution of tellurium between the phases was determined as the extent of oxidation increased, and the system was modeled using a computational thermodynamics package. Oxidized tellurium was found to report to the slag, with none being removed with the gas. The thermodynamic model predicted, to an acceptable level, the tellurium content of all phases as oxidation progressed. It was used to show that oxidation by air rather than oxygen results in higher residual tellurium levels in silver metal and that the lower the smelting temperature, the greater the extent of tellurium elimination from silver to the slag.     

当今最先进的镍冶炼技术——奥托昆普直接镍熔炼工艺

对近十几年的奥托昆普直接镍熔炼（DON-Direct Outokumpu Nickel）方法的作业经验（包括对环境的显著影响）进行了回顾。在DON工艺中,闪速熔炼炉中直接产出含铁低的高品位冰镍,不需要进一步吹炼。熔炼炉渣中的有价金属在电炉中以含铁冰镍回收。DON炉中产出的低熔点高品位冰镍（尤其是那些含铜低的）,对炉子设计提出了挑战,特别是对炉膛和热工的设计。参考产出的冰镍,对DON工艺、电炉冰镍及高氧化镁炉渣的热力学模型的选择结果进行了总结,对闪速炉和电炉的设计原则也进行讨论。