Thermodynamic modeling of selenide matte converting

A by-product of the electrorefining of anode copper is a slime that contains significant amounts of silver, as well as selenium, copper, and other minor elements such as gold. Slimes are usually smelted to recover silver and gold. The thermodynamics of the smelting of such selenium-rich materials have received scant attention, and the little that has been done leads to erroneous predictions. In this work, a chemical potential diagram is developed that successfully explains previously published observations. The smelting of slimes was also modeled with a computational thermodynamics package. Despite the simplicity of the model, which assumed that the activity coefficients of all species remained constant throughout oxidation, it gave good agreement with experimental results published elsewhere for the compositions of all phases during smelting. The model was used to demonstrate that using air rather than pure oxygen significantly affected only the selenium content of the slag, reducing it to low levels. Smelting temperature in the range tested was shown not to be an important process variable.     

碲渣综合回收工艺研究

简述了碲渣综合回收金银等的工艺试验碲渣经磨矿水浸碲产出粗二氧化碲,用离子沉淀和络合净化法提纯;浸碲渣用氯盐浸出铜铋,中和水解回收氯氧铋,置换回收海绵铜;残留渣中的金银可返回金银冶炼系统回收。对该工艺综合回收碲、铋、铜、金、银的经济效益进行了估算。     

顶吹炉处理铅阳极泥的工业试验

应用顶吹炉吹炼铅阳极泥提取阳极泥中有价金属,工艺包括混合料制备、一次还原熔炼、还原捕金、二次吹炼、回收砷锑等工序。经过大量工业试验表明,该工艺方法产出的贵铅含银不低于70.0%,银直收率95%~98%、回收率99.0%~99.7%,工艺具有流程短、渣含贵金属金银量低、处理量大、能耗低等优势。     

Cobalt distribution during copper matte smelting

Many smelter operators subscribe to the “precautionary principle” and wish to understand the behavior of the metals and impurities during smelting, especially how they distribute between product and waste phases and whether these phases lead to environmental, health, or safety issues. In copper smelting, copper and other elements are partitioned between copper matte, iron silicate slag, and possibly the waste gas. Many copper concentrates contain small amounts of cobalt, a metal of considerable value but also of some environmental interest. In this work, the matte/slag distribution ratio (weight percent) of cobalt between copper matte (55 wt pct) and iron silicate slag was thermodynamically modeled and predicted to be approximately 5. Experiments were performed using synthetic matte and slag at 1250 °C under a low oxygen partial pressure and the distribution ratio was found to be 4.3, while between industrial matte and slag, the ratio was found to be 1.8. Both values are acceptably close to each other and to the predicted value, given the errors inherent in such measurements. The implications of these results for increasingly sustainable copper production are discussed.     

提高铅阳极泥金银直收率新工艺

在铅阳泥火法熔炼阶段会产出大量富含金银的一次灰、一次渣,该阶段指标控制的好坏对金银直收率有很大影响。文章阐述了氧气底吹熔炼新技术在铅阳极泥提金银过程中的应用,有效地降低了金银在一次灰、一次渣中的损失,提高了阳极泥中金银的直收率,同时,新工艺为铅阳极泥处理向大型化发展提供了强有力的技术支持,有很高的推广价值。     

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。     

H2-C熔融还原条件下渣金间磷的分配比的试验研究

 通过300kg级氢-碳熔融还原热模拟试验,从热力学角度分析了氢-碳混合熔融还原条件下磷的分配比,运用熔渣规则溶液模型计算了氧化钙、二氧化硅、氧化镁、氧化铝、氧化亚铁、五氧化二磷六元熔渣组分的活度、活度系数,进而计算出一定温度条件下熔渣的磷容量以及渣金平衡时磷分配比的理论值。通过比较理论计算得出的磷分配比与试验中磷的分配比的差异,解析产生差异的原因,进而为氢-碳混合熔融还原炼铁新工艺冶炼高磷铁矿提供参数。试验结果表明：用熔渣规则溶液模型计算渣金间的磷的分配比是合适的,氢-碳熔融还原工艺可以利用高磷铁矿。     

Thermodynamics of Arsenic in FeOx-CaO-SiO<Subscript>2</Subscript> Slags

The distribution of arsenic between calcium ferrite slag and liquid silver (wt pct As in slag/ wt pct As in liquid silver) with 22 wt pct CaO and between iron silicate slag with 24 wt pct SiO₂ and calcium iron silicate slags was measured at 1573 K (1300 °C) under a controlled CO-CO₂-Ar atmosphere. For the calcium ferrite slags, a broad range of oxygen partial pressure (10^–11 to 0.21 atm) was covered, whereas for the silicate slags, the oxygen partial pressure was varied from 10^–9 to 3.1 × 10^–7 atm. The measured relations between the distribution ratio of As and the oxygen partial pressure indicates that the oxidation state of arsenic in these slags is predominantly As³⁺ or AsO_1.5. The measured distribution ratio of arsenic between the calcium ferrite slag and the liquid silver was about an order of magnitude higher than that of the iron silicate slag. In addition, an increasing concentration of SiO₂ in the calcium-ferrite-based melts resulted in decreases in the distribution of arsenic into the slag. Through the use of measured equilibrium data on the arsenic content of the metal and slag in conjunction with the composition dependent on the activity of arsenic in the metal, the activity of AsO_1.5 in the slags was deduced. These activity data on AsO_1.5 show a negative deviation from the ideal behavior in these slags.     

富氧底吹炼铅氧化熔炼元素分配热力学模拟

基于最小吉布斯自由能原理,模拟计算了铅精矿富氧底吹炼铅工艺氧化熔炼段的元素分配行为,并与半工业试验数据进行对比。在典型工业富氧底吹炼铅工艺参数条件下,重点考察了氧料比对Pb、Cu、As、Sb、Bi等元素分配行为的影响。计算结果表明,Pb、Cu、As、Sb和Bi在渣相中的分配率随氧料比的提高而增加。当氧料比为175kg/t时,Pb、Cu、Sb和Bi在金属相、渣相和气相中的分配比例基本符合半工业试验统计数据,但As计算结果与半工业数据存在一定偏差,原因可能是由于缺乏精确的活度系数。     

The behavior of selenium and tellurium in metal-matte systems

The distribution of selenium and tellurium between molten metal and matte was determined at temperatures of 1100° to 1250°C. The experimental technique permitted separate sampling of each phase while at temperature. Partition coefficients (ratio of weight percent selenium or tellurium in the matte to weight percent selenium or tellurium in the metal) varied from 10.5 to 16.9 for selenium and 5.5 to 8.1 for tellurium. The coefficients decreased with increasing temperature but were essentially independent of impurity concentration, iron content and oxygen and SO₂ partial pressures over the ranges studied. Application of these results to actual operations is discussed. The similarities in the chemical behavior of S, Se, and Te during smelting are also considered.     

两步三段式厚渣层铁浴熔融还原炼铁工艺

针对目前熔融还原设备无法将煤气二次燃烧氧化区与铁氧化物还原区隔离而导致能耗偏高的问题,提出了一种两步三段式厚渣层铁浴熔融还原炼铁工艺,以期利用厚渣层冶炼的方法使得氧化区与还原区的梯度隔离。设计了主反应器铁浴炉尺寸与产能,并建立了工艺的整体静态模型,考察了球团金属化率与铁浴炉炉顶煤气氧化度对工艺煤耗、氧耗以及能耗的影响。在选定的适宜操作参数,即煤气氧化度55%,球团金属化率80%条件下,冶炼1t铁水,消耗球团矿1 869.83kg,煤粉674.07kg,同时得到还原度71%的改质煤气898.44kg。结合反应器的设计产能,反应器可处理球团矿3 793.66kg/(h·m2)。     

Influence of gold content on copper oxidation from silver-gold-copper alloys

In the final stages of the smelting of copper anode slimes, a silver alloy, known as “doré,” is produced. Oxidation refining is used to remove copper since this element interferes with subsequent electroparting of the small amounts of gold and platinum group metals in the doré. The gold content of doré can be greatly increased by gold scrap additions and this may affect the minimum achievable copper content of doré. In this work, silver-gold-copper alloys were oxidized by injecting pure oxygen at 1100 °C in the absence of any slag cover. For the gold contents expected in practice, the equilibrium copper content of the doré did not increase significantly as the gold content increased. However, at the other extreme of composition, the equilibrium copper content was a very strong function of the silver content of the gold bullion. The activity coefficient of copper in silver-gold alloys was calculated and compared to those predicted from a ternary subregular solution model of the system Ag-Au-Cu. Satisfactory agreement was found.     

从冶炼铜渣中进一步提取金银的湿法工艺研究

湿法冶炼中氰化金泥杂质元素含量的波动,容易造成冶炼副产品铜渣中的贵金属含量过高,从而影响到黄金精炼的回收率,直接关系到企业的经济效益。为了更有效地回收贵金属,提高企业经济效益,利用金银与其他贱金属的电位差异,通过加入氧化剂调整体系电位,以此达到金银与贱金属分离的目的。从铜渣中进一步提取贵金属工艺采用控电位氯化技术分离出杂质铜-废液置换铜-含金银渣进一步除杂分出金-剩下含银渣铸阳极板银电解回收银,来处理含金品位高的铜渣能够最终实现金、银、铜的分离,提高黄金冶炼回收率。     

烟化法处理铅锌冶炼渣的生产实践与探讨

铅锌冶炼渣含有锌、铅、银、锗等有价金属,且属重金属危废物。根据锌浸出渣和铅还原渣的特性,将固态锌浸出渣与液态铅还原渣按配比混合烟化处理。该技术应用实践表明：铅锌冶炼渣通过烟化炉搭配处理,具有生产效率高、资源利用率高、节能环保等优点。既能有效回收铅锌冶炼渣中的有价金属,又实现了铅锌冶炼渣的无害化处理。     

A thermodynamic model of nickel smelting and direct high-grade nickel matte smelting processes: Part II. distribution behaviors of Ni, Cu, Co, Fe, As, Sb, and Bi

A thermodynamic model has been developed to predict the distribution behavior of Ni, Cu, Co, Fe, S, As, Sb, and Bi in nickel smelting and direct high-grade nickel matte smelting processes. The model has been validated by numerous experimental data and industrial data with a wide range of operating conditions. The effect of operating conditions on the distributions of Ni, Cu, Co, As, Sb, and Bi among the gas, matte, and slag phases has been investigated. It was found that the distribution behavior of Ni, Co, Cu, As, Sb, and Bi in the nickel smelting furnace depends on process parameters such as the smelting temperature, matte grade, oxygen enrichment, Fe/SiO₂ ratio in the slag, Cu/Ni ratio in charge, and oil/air ratio. The parameters also have an influence on the behavior of Fe₃O₄ in the slag.     

辉锑矿富氧熔池熔炼的工艺研究

采用富氧顶吹装置模拟辉锑矿挥发熔池熔炼的行为,考察了氧气系数、初始渣Fe/SiO_2、CaO含量对熔炼渣中锑含量的影响。在氧气系数为1.04、初始渣Fe/SiO_2=0.94、CaO 15%的最优条件下,熔炼后渣含锑为1.8%。采用SEM-EDS对渣中锑的物相及分布行为进行了表征,发现熔渣中锑以微小的金属粒子形式存在。通过加入一定量的锑锍作为捕集剂,并在高温下对锑渣进行贫化,使渣中的锑含量由沉降前的2.36%降低至0.86%。辉锑矿可以采用富氧挥发熔池熔炼—熔炼渣高温贫化工艺进行处理。     

Selective oxidation of copper from liquid copper-silver alloys

In this work, the oxygen refining of liquid copper-silver alloys with a borosilicate slag was studied. First, a comprehensive thermodynamic analysis was performed using the data available in the literature. The results indicate that since silver oxide is relatively unstable in silicate-based slags, then it should be thermodynamically feasible to oxidize copper from copper-silver alloys with a very low silver loss to the silicate slag. In actual practice, although relatively low copper levels can be achieved in the metal phase, the silver losses to the slag are excessive. Therefore, in the present work, both kinetic and equilibrium experiments were performed on a molten copper-silver alloy containing 12.68 mass pct silver in order to elucidate the mechanism of silver loss to the slag. The kinetic experimental results indicated that copper levels of less than 2 mass pct could be achieved with silver recoveries of about 95 pct after relatively short refining times of 15 minutes. In the equilibrium experiments, the copper contents of the metal were less than 1 mass pct, and these values were in good agreement with those which were calculated from the data of previous researchers. In order to explain the relatively high silver losses to the slag, a model was developed which is based on the transport of silver from the metal phase to the slag phase both in metallic form and as silver oxide in the copper oxide oxidation product. The copper and silver oxides and the metallic copper-silver alloy are all transported into the slag by the oxidizing gas bubbles. It is proposed that once in the slag, the silver oxide is unstable and decomposes into metallic silver which is not easily recovered in the metal phase. Also, the transfer of the copper-silver alloy into the slag, by the gas bubbles, promotes the slag-metal exchange reaction, which again results in the generation of silver particles in the slag.     

转炉高钛铁水冶炼工艺优化

由于高炉采用钛矿护炉,使得铁水中的钛质量分数明显增高,已远远超出转炉正常冶炼要求。为了减轻高钛铁水对120 t转炉冶炼带来的不利影响,如过程喷溅、“炉渣返干”、炉口黏渣等情况,通过改变铁水消化模式、供氧制度、枪位制度、造渣制度和终点控制制度等方面进行冶炼工艺优化,成功解决了这一系列问题。结果表明,优化后的冶炼工艺不仅缩短了废钢入炉的时间,稳定了过程控制,而且加快了生产节奏,吨钢钢铁料消耗降低2.5 kg,取得了较好的实践效果和经济效益。     

Distribution behavior of cobalt, selenium, and tellurium between nickel-copper-iron matte and silica-saturated iron silicate slag

The distribution coefficients (D _X) of cobalt, selenium, and tellurium between nickel-copper-iron matte and silica-saturated iron silicate slag were determined as a function of matte and slag compositions, temperature, and the partial pressure of oxygen. The effect of slag additives, such as CaO, MgO, and Al₂O₃, on the distribution behavior of the minor elements was also investigated. Analysis of the data indicated that D _Co, D _Se, and D _Te were strongly dependent on the matte grade and slag additives. The effect of slag additives on the solubility of Co, Se, and Te in slag was discussed in terms of various experimental conditions. Cobalt distribution coefficients were found to decrease with increasing oxygen partial pressure, indicating the oxidic dissolution of cobalt in the slag. Based on the experimental results and available thermodynamic data, the activity coefficients of CoS in the nickel-copper-iron matte were estimated as a function of mole fraction of FeS in the matte at 1250 °C. Meanwhile, the distribution coefficients of both selenium and tellurium increased when raising the partial pressure of oxygen, implying that there was molecular dissolution of selenium and tellurium in the slag within the oxygen partial-pressure range investigated in this study.     

Analysis of titanium distribution behaviour in vanadium-containing titanomagnetite smelting blast furnace

The operating data of a commercial vanadium-containing titanomagnetite smelting blast furnace (BF) have been examined over a period of one year. The liquidus temperatures and viscosities of a large number of slags were calculated by using the software Multi-Phase Equilibrium. The results show that both the slag liquidus temperature and hot metal temperature of the BF were 60 K lower than that of conventional BF operation, while both slags had similar viscosity. The correlations between the Ti distribution of hot metal and slag and the operating temperature, and hot metal and slag chemistry were analysed. Ti distribution ratio increases with increasing temperature and carbon content in hot metal. The Ti distribution calculated based on a slag/hot metal equilibrium model gave reasonably good agreement with plant measurements. This suggests that the slag and hot metal phases were close to equilibrium in the furnace hearth. A sensitivity analysis showed that temperature and C content has a significant influence on the Ti distribution ratio. The effect of slag chemistry on the Ti distribution is insignificant. Lowering of the operating temperature and carbon in hot metal can help reducing the Ti distribution into the hot metal, hence reducing the formation of Ti(C,N).