CFD modeling of gas−liquid flow phenomenon in lead smelting oxygen-enriched side-blown furnace

A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effect.Its modeling results were verified with theoretical correlations and experiments,and the nozzle-eroded states in practice were also involved in the analysis.Through comparison,it is confirmed that the thermal expansion effect influences the flow pattern significantly,which may lead to the backward motion of airflow and create a potential risk to production safety.Consequently,the influences of air injection velocity and furnace width on airflow behavior were investigated to provide operating and design guidance.It is found that the thin layer melt,which avoids high-rate oxygen airflow eroding nozzles,shrinks as the injection velocity increases,but safety can be guaranteed when the velocity ranges from 175 to 275 m/s.Moreover,the isoline patterns and heights of thin layers change slightly when the furnace width increases from 2.2 to 2.8 m,indicating that the furnace width shows a limited influence on production safety.

Effect of Fe/SiO2 and CaO/SiO2 mass ratios on metal recovery rate and metal content in slag in oxygen-enriched direct smelting of jamesonite concentrate

The oxygen-enriched direct smelting of jamesonite concentrate was carried out at 1250℃by changing the slag composition.The effects of Fe/SiO2 and Ca O/SiO2 mass ratios on the metal recovery rate as well as metal content in slag were investigated.Experimental results indicated that the metal(Pb+Sb)recovery rate was up to 88.30%,and metal(Pb+Sb)content in slag was below 1 wt.%under the condition of slag composition of 21-22 wt.%Fe,19-20 wt.%SiO2 and 17-18 wt.%Ca O with Fe/SiO2 mass ratio of 1.1:1 and Ca O/SiO2 mass ratio of 0.9:1.The microanalysis of the alloy and slag demonstrated that the main phases in the alloy contained metallic Pb,metallic Sb and a small amount of Cu2 Sb and Fe Sb2 intermetallic compounds.The slag was mainly composed of kirschsteinite and fayalite.Zinc in the raw material was mainly oxidized into the slag phase in the form of zinc oxide.

Reductive smelting of spent lead–acid battery colloid sludge in a molten Na_2CO_3 salt

Lead extraction from spent lead–acid battery paste in a molten Na2CO3 salt containing Zn O as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, Zn O and salt dosages, were investigated in detail using single-factor experiments. The optimum conditions were determined as follows: T = 880°C; t = 60 min; Na2CO3/paste mass ratio = 2.8:1; and the Zn O dosage is equal to the stoichiometric requirement. Under the optimum conditions, the direct recovery rate of lead reached 98.14%. The results suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic calculations indicated that the reaction approaches of lead and sulfur were Pb SO4→Pb and Pb SO4→Zn S, respectively. Sulfur was fixed in the form of Zn S, whereas the molten salt did not react with other components, serving only as a reaction medium.

Iron extraction from lead slag by bath smelting

A new bath smelting process was proposed to recover iron for solid wastes reduction.99.79%of iron metallization,99.61%of iron recovery,pig iron with93.58%Fe,0.021%S,0.11%P,1.38%C,0.22%Si,0.01%Pb and0.031%Zn were achievedafter the wastes were smelted at1575°C for20min under C/Fe molar ratio of1.6and basicity of1.2.The produced pig iron could beused in steel-making.This study provides a way for recycling iron from smelting slag and hydrometallurgical residue.

A pre-warning system of abnormal energy consumption in lead smelting based on LSSVR-RP-CI

The pre-warning of abnormal energy consumption is important for energy conservation of industrial engineering. However, related studies on the lead smelting industries which usually have a huge energy consumption are rarely reported. Therefore, a pre-warning system was established in this study based on the intelligent prediction of energy consumption and the identification of abnormal energy consumption. A least square support vector regression (LSSVR) model optimized by the adaptive genetic algorithm was developed to predict the energy consumption in the process of lead smelting. A recurrence plots (RP) analysis and a confidence intervals (CI) analysis were conducted to quantitatively confirm the stationary degree of energy consumption and the normal range of energy consumption, respectively, to realize the identification of abnormal energy consumption. It is found the prediction accuracy of LSSVR model can exceed 90% based on the comparison between the actual and predicted data. The energy consumption is considered to be non-stationary if the correlation coefficient between the time series of periodicity and energy consumption is larger than that between the time series of periodicity and Lorenz. Additionally, the lower limit and upper limit of normal energy consumption are obtained.

Traditional Chinese Technology of Crucible Lead Smelting: A Comprehensive Study Based on Historical Records and Archaeological Findings

Crucible lead smelting, a traditional technology unique to China, refers to the production of lead by reducing lead sulfide with iron metal in crucibles. In recent years, a number of crucible lead production sites of the Liao-Jin-Yuan periods(tenth–fourteenth centuries CE) have been found in northern China, providing opportunities for the study of the technology. This paper provides a comprehensive overview of this technology based on the historical and archaeological evidence, with particular emphasis on the crucibles used. Firstly, it reviews the historical records on crucible lead smelting, and introduces, in detail, the technology used in Gansu during the Qing period(1644–1911) as well as indigenous methods used in the twentieth century;secondly, it summarizes the discoveries of crucible lead smelting sites in recent years, and reconstructs the manufacturing of crucibles and the iron reduction method by analysis of the crucible and slag;finally, it expounds the technical characteristics of crucible lead smelting, and explores the origin and development of the technology.

Relationship between copper content of slag and matte in the SKS copper smelting process

In the newly developed oxygen-enriched bottom-blowing copper smelting process(also known as the SKS copper smelting process), Cu loss in slag is one of the most concerning issues. This paper presents our research results concerning the relationship between the Cu content of the matte and slag in the SKS process; the results are based on actual industrial production in the Dongying Fangyuan copper smelter. The results show that the matte grade strongly influences Cu losses in slag. The dissolved and entrained losses account for 10%–20% and 80%–90% of the total SKS industrial Cu losses in slag, respectively. With increasing matte grade, the dissolved and entrained Cu losses in the SKS slag both increase continuously. When the matte grade is greater than 68%, the content of Cu in the smelting slag increases much more dramatically. To obtain a high direct recovery of copper, the matte grade should be less than 75% in industrial SKS copper production.

Thermodynamic modeling of antimony removal from complex resources in copper smelting process

This work investigated the reaction mechanism of Sb in copper smelting process. The difference of multi-phase distribution of Sb in four typical copper smelting processes was analyzed. A multi-phase equilibrium model of the oxygen-enriched bottom-blow copper smelting process was developed. The impacts of Cu, S, and Sb concentrations in raw materials on Sb distribution in multiphases were researched. This model was also used to investigate the effect of process factors such as copper matte grade, oxygen-enriched concentration, smelting temperature, and oxygen/ore ratio(ratio of oxygen flow rate under standard conditions to concentrate charge rate) on Sb distribution behavior. The results showed that calculation data were in good agreement with the actual production results and literature data. Increasing the Cu content and decreasing the S and Sb contents in the concentrate, increasing the copper matte grade, oxygen/enriched concentration, and oxygen-ore ratio, and at the same time appropriately reducing the smelting temperature are conducive to the targeted enrichment of Sb into the slag. Modeling results can provide theoretical guidance for the clean and efficient treatment of complex resources and the comprehensive recycling of associated elements.

Life cycle inventory analysis of CO_2 and SO_2 emission of imperial smelting process for Pb-Zn smelter

Based on the principle of life cycle assessment, CO2 and SO2 emission of Imperial Smelting Process in a certain zinc-lead smelter was analyzed by life cycle inventory method. According to the system expansion and substitution method, the environmental impacts of co-products were allocated among the main products of zinc, lead and sulfuric acid. The related impacts were assessed by use of Global Warming Potential （GWP） and Acidification Potential （ACP）. The results show that the GWP index from 1998 to 2000 is 11.53, 11.65, 10.93 tCO2-eq/tZn respectively, the ACP index decreases from 14.88 kgSO2-eq/tZn in 1998 to 10.99 kgSO2-eq/tZn in 2000. Power and electricity generation, followed by smelting and zinc distillation, are mainly responsible for GWP. Sintering individually affects ACP. Reduction in greenhouse gas emissions of the ISP may come from energy conservation measures rather than from technological developments. And recycling more secondary Pb and Zn materials effectively treated by ISP, and reducing the amount of primary metal are the main ways to put SO2 emission under control.

Stabilisation of Pb in Pb Smelting Slag-Contaminated Soil by Compost-Modified Biochars and Their Effects on Maize Plant Growth

Compost has been used to stabilise lead (Pb) in soil. However, compost contains a high level of dissolved organic matter (DOM) which may make Pb bioavailable in plant and thereby limiting its effectiveness and application. Addition of biochar to compost can reduce this effect. Rice husk (RH) and Cashew nut shell (CNS) biochars and compost-modified biochars were used in comparison to compost for stabilizing Pb in lead smelting slag (LSS)-contaminated soil (Pb = 18,300 mg/kg) in Nigeria. Efficiency of Pb stabilisation in control and amended soils was assessed using CaCl2 batch leaching experiment and plant performance. In pot experiments, maize plant was grown on the contaminated soil and on soil treated with minimum and optimum doses of the amendments singly and in combination for 6 weeks. Agronomical and chemical parameters of the plants were measured. CaCl2-extractable Pb in the untreated soil was reduced from 60 mg/kg to 0.55 mg/kg in RHB amended soils and non-detectable in other amended soils. RH-biochar/compost increased plant height, number of leaf and leaf area more than the others. Similarly, at minimum rate, it reduced root and shoot Pb by 91% and 86.0% respectively. Compost-modified rice husk biocharstabilised Pb in lead smelting slag contaminated soil reduced Pb plant uptake and improved plant growth. Lead stabilisation through the use of rice husk biochar with compost may be a green method for remediation of lead smelting slag-contaminated soil.

Analysis of Oxygen Consumption in Lead and Zinc Metallurgy

This article analyzes the role of oxygen in lead zinc metallurgy,including shortening the metallurgical process,promoting energy conservation and environmental protection,improving metallurgical strength,enhancing raw material adaptability,and enhancing comprehensive recovery efficiency.This article introduces different lead zinc metallurgical processes and their oxygen consumption characteristics,including oxygen enriched side blowing lead smelting,oxygen bottom blowing lead smelting,oxygen enriched top blowing lead smelting,flash smelting lead,oxygen pressure leaching zinc smelting,and atmospheric pressure oxygen leaching zinc smelting.It is pointed out that oxygen enhanced metallurgy is the direction for the transformation and upgrading of lead zinc metallurgy.

Vapor pressure measurement of lead and lead chlorides in FeO_T-CaO-SiO_2-Al_2O_3 system

Vapor pressure of lead and lead chlorides from FeOT？CaO？SiO2？Al2O3 slag system was measured by using Knudsen effusion method. The results suggest that the vapor pressures of lead and lead chlorides increase with increasing temperature. For the slag systems without chlorine, the logarithm of vapor pressure （lnp） shows highly linear dependency on the reciprocal of temperature （1/T）, and higher vapor pressure is observed in the condition where more metallic lead vapor is formed. In this case, the vapor pressure of lead increases with increasing slag basicity （w（CaO）/w（SiO2））, increasing FeO content andw（Fe2＋）/w（Fe3＋） ratio. For the case of slag system with chlorine addition, the total pressures of PbCl2 and PbCl increase with decreasing basicity and FeO content of slag.

Vaporization behavior of lead from the FeO-CaO-SiO_2-Al_2O_3 slag system

Vaporization behavior （1163-1463 K） of lead in the slag system of FeO-CaO-SiO2-Al2O3 with CaC% was examined. A thermodynamic estimation with the principle of Gibbs free energy minimization showed that the major vapor species from the sample of the FeO-CaO-SiO2-Al2O3 system＋PbO＋CaCl2 were metallic Pb, PbCl, PbCl2, and FeCl2, at the experimental temperature range. The experimental results show that the mole ratio of vaporized Cl in lead chlorides to vaporized Pb, simply expressed as Cl/Pb decreases with increasing temperature. The larger Cl/Pb means a larger ratio of gaseous PbCl2, since metallic Pb and PbCl vapors are formed in a similar reduction atmosphere. The evaporation is initially rapid and becomes steady after holding for 10 min. Gaseous PbCl2 is mainly formed during the heating period, and at the holding stage, it reacts with FeO to produce gaseous FeCl2 With regard to slag composition, FeO content and basicity significantly affect the evaporation of lead. High FeO content and high basicity promotes the formation of metallic Pb and PbCI, whereas, it prohibits PbCl2 evaporation.

Thermodynamic modeling of lead blast furnace

A thermodynamic model was developed to predict the distribution behavior of Cu, Fe, S, O, Pb, Zn, As, and the heat balance in a lead blast furnace. The modeling results are validated by the plant data of a lead smelter in Kazakhstan. The model can be used to predict any set of controllable process parameters such as feed composition, smelting temperature, degree of oxygen enrichment and volume of oxygen-enriched air. The effects of the blast air, industrial oxygen, and coke charge on the distribution of Cu, Fe, S, O, Pb, Zn, As, the heat balance, and the lead loss in slag, were presented and discussed.

铅冶炼渣基生态胶凝材料的研发及重金属固化

铅冶炼渣(LSS)是一种含有重金属(Cr、Ni、Cu、Zn、As和Pb)的危险废物,其不当处置会对生态系统造成不可挽回的危害。本工作采用化灰渣(LAS)、水氯镁石(BF)、矿粉(SP)及适量水泥(CM)协同激发铅冶炼渣制备生态胶凝材料。通过正交试验得到胶凝材料的最优配比,阐述了不同因素对生态胶凝材料抗压强度的影响;采用XRD、SEM、FTIR、硫酸和硝酸法等方法分析了胶凝材料水化产物的特性及重金属浸出规律。研究结果表明:当铅冶炼渣和水泥的质量比为3∶1,化灰渣、水氯镁石、矿粉的外掺量分别为铅冶炼渣和水泥质量总量的20%、10%、10%时,制备出的生态胶凝材料抗压强度最优,28 d抗压强度达到40.9 MPa,且矿粉掺量为影响其抗压强度的第一要素。微观分析表明,胶凝材料的水化产物主要为弗里德尔盐、方解石、C-S-H和C-A-S-H,它们相互连接形成致密的空间网络结构,这不但有助于提高胶凝材料的力学性能,还能实现对重金属元素的物理固封和离子交换吸附固化。胶凝材料对主要重金属的胶结固化率大于83%,重金属浸出液浓度符合生活饮用水卫生标准(GB5749-2006)的要求。

利用含铅冶炼渣合成纳米硫化铅的工艺研究

以含铅冶炼渣为原料,采用HCl-NaCl体系湿法浸出回收金属铅制备纳米硫化铅,重点介绍了冶炼废渣中的铅回收工艺条件。结果表明,含铅冶炼渣浸出液冷却后过滤得到粗PbCl_(2),经精制、转化后可得到纳米硫化铅。该工艺为含铅渣的处理和纳米硫化铅的湿法制备提供了新的途径。

铅锌冶炼重金属重污染土壤稳定化研究

针对部分铅锌冶炼场地遭受严重重金属污染的问题,采用基于铁的稳定化材料FeCl_(3)+CaCl_(2)+NaOH+Ca(OH)_(2),FeCl_(3)+CaCl_(2)+NaOH+Ca(OH)_(2)+Na_(2)S及FeCl_(3)+Na_(2)HPO_(4)进行修复。根据TCLP浸出法评估效果,选出最佳组合为FeCl_(3)+Na_(2)HP0_(4),该组合在3个场地中使Pd浸出浓度分别下降96%,63%,61%,显著减少重金属迁移。研究突显了合适材料的选择对有效土壤稳定化的重要性。

铜熔炼渣的火法回收工艺与铅锌锑富集规律

铜精矿火法冶金后产生的熔炼渣经浮选回收铜后,尾渣含Pb、Zn和Sb,仍具有一定回收经济价值。浮选法对铜熔炼渣中Pb、Zn和Sb的回收率低,而火法熔炼通过高温和碳热还原可以有效分离这些元素。对直接还原熔炼、造锍还原熔炼和氧化-还原熔炼3种典型的火法回收工艺进行了对比中试试验。结果表明:火法回收工艺可达到理想的铜回收率,但不同工艺对Pb、Zn和Sb的回收效果不同;直接还原熔炼提高了Pb的回收率;造锍还原熔炼提高了Zn的回收率;熔炼法需消耗大量还原剂和能源,经济性需慎重考虑。火法熔炼适合作为铜回收的备用工艺进行研究。

黄河流域典型铅锌冶炼企业重金属废水管控与碳排放协同研究

黄河流域作为国家生态安全的重要屏障,重金属污染一直以来备受关注.为提升重金属重点排放源铅锌冶炼行业废水排放管控水平,本文聚焦黄河流域中上游典型地区某铅锌冶炼企业,研究了不同产污环节排放废水中重点重金属排放特征及达标情况,并从行业绿色低碳发展方面测算了不同冶炼工艺流程碳排放强度、不同产污环节排放废水处理过程碳排放强度.结果表明:(1)采用氧化法+硫化钠除汞+石灰中和+生物制剂法+除铊稳定剂的组合处理工艺,污酸废水中总铅、总镉、总汞和总砷的排放浓度均可稳定达到《铅、锌工业污染物排放标准》(GB 25466-2010)特别排放限值要求,以处理后各重金属日最大检出浓度的90%分位数作为参比浓度,该处理工艺对总铅、总镉、总汞的去除率分别为98.2%、99.8%、99.9%.(2)铅锌冶炼企业污酸车间地面冲洗水应全部纳入污酸车间污水处理系统进行集中处理,避免铅、镉、汞、铊等重金属废水稀释排放,长期汇入黄河干流富集造成潜在环境风险.(3)锌冶炼过程重金属主要富存于固相颗粒和液相颗粒中,污酸废水(废气洗涤制酸废水)中总铅、总镉、总汞、总砷产污系数分别为4.83、4.33、7.02、0.01 g/t(以产品计),较实际流向废气中相应重金属产污系数低10^(3)量级.(4)鉴于污酸废水处理碳排放强度约为一般性生产废水的7.93倍,建议加强评估并推广应用2022年《国家先进污染防治技术目录(水污染防治领域)》提出的有色冶炼烟气洗涤污酸废水治理与资源化利用技术,研究提出基于资源化利用途径的污酸废水排放控制要求.(5)湿法炼锌工艺碳排放强度为3.08 t/t(冶炼1 t锌的CO_(2)排放量),相对属于绿色低碳冶炼工艺.研究显示,黄河流域中上游部分典型铅锌冶炼企业已采用相对绿色低碳冶炼工艺,鉴于黄河流域的国家战略定位,需进一步提升末端重金属废水风险管控和减污降碳协同治理力度,引领沿黄冶炼产业高质量发展.

铅基物料冶炼技术发展趋势

我国铅矿资源“贫矿多、富矿少”,海外铅精矿供应过剩量减少。铅冶炼过程存在多元素资源共生、原料品质波动大、冶炼工艺复杂等特点,目前我国有色金属冶炼行业处于机械化、电气化、自动化、信息化并存,不同企业之间呈现发展不平衡的状态。基于以上,本文介绍了铅矿资源(铅精矿和含铅废料)分布情况及铅主要用途,铅冶炼技术发展历程,并概述了当前主要铅基物料冶炼技术,如氧气底吹熔炼-熔融还原-富氧挥发炼铅技术、富氧浸没顶吹炼铅技术、硫酸铅渣湿法炼铅技术、侧吹浸没燃烧熔池熔炼处理再生铅资源技术、脆硫铅锑矿处理技术、铅阳极泥处理技术、铜浮渣及铅精渣处理技术、铅电解技术等,结合铅冶炼的工业生产场景,采用深度学习方法,建立熔炼炉的数据驱动模型,可实现对系统关键运行指标的实时预测与评估,推动铅冶炼技术的智能化、数字化,以迎接铅行业发展机遇与挑战。