Study on Foaming Behaviour of Molten Slag during Smelting Reduction with Iron Bath

The molten slag in smelting reduction with iron bath has peculiar behaviour for its high FeO concentration. Slag foaming is effected by the concentration and reduction rate of FeO, basicity of slag and temperature. Addition of granulated coke can greatly decrease slag foaming extent in the process of smelting reduction with iron bath. The anti-foaming capacity of granulated coke is the best when the ratio of coke used for coke layer to total coke used in smelting reduction is controlled at about 20%.

Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w（CaO）/w（SiO_2） ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al_2O_3 grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100：16.17：59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recovery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca_2 SiO_4 and Ca_（12）Al_（14）O_（33）, with small amounts of Fe Al_2O_4, CaAl_2O_4, and Ca_2Al_2SiO_7.

Smelting chlorination method applied to removal of copper from copper slags

In order to reasonably utilize the iron resources of copper slags, the smelting chlorination process was used to remove copper from copper slags. Higher holding temperature and O2 flow rate are beneficial to increasing copper removal rate. However,the Cu2O mode is formed by the reaction of surplus O2 and CuCl with O2 flow rate increasing over 0.4 L/min, causing CuCl volatilization rate and copper removal rate to decrease. The resulting copper removal rate of 84.34% is obtained under the optimum conditions of holding temperature of 1573 K, residence time of 10 min, Ca Cl2 addition amount of 0.1(mass ratio of CaCl2 and the copper slag) and oxygen flow rate of 0.4 L/min. The efficient removal of copper from copper slags through chlorination is feasible.

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.

Extraction of metals from a zinc smelting slag using two-step procedure combining acid and ethylene diaminetetraacetic acid disodium

A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium (EDTA-Na2) was applied to extract metals such as Cd,Cu,Fe,Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd,Cu,Fe and Zn in slag reach 88.3%,54.1%,69.6% and 54.7%,respectively,while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L,65 °C and 120 r/min for 2 h. However,Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd,Cu,Fe,Pb and Zn from zinc smelting slag.

Preparation and Microstructural Analysis of Smelting Waste Non-ferrous Metal Slag Geopolymer

The geopolymer samples were prepared with smelting waste slag of non-ferrous metal as the raw material and water glass as the activator. The effect of modulus of water glass and water binder ratio on the compressive strength was studied. The results show that the strength of the geopolymer activated by water glass with modulus of 1.1 and water binder ratio of 0.28 can maintain an increasing trend in the 90 curing days. Through the analyses with XRD, SEM（EDS）, and FTIR, the main reaction products are found to be geopolymer gels, which bond the crystalline minerals to provide strength. The molecular chains of amorphous phase in slag become shorter after depolymerization-polycondensation.

Corrosion of Magnesia-chrome Brick by Smelting Reduction Slag with Iron Bath

Effects of FeO content （0, 5%, 10%, and 15% in mass, respectively ） in lab-synthesized smelting redttc- tion slag with iron bath and test temperature （1 450, 1 500, 1550, anti 1 600 ℃ ） on corrosion am,amount and microstructure of fused rebonded magnesia - chrome brick with 26.02 massqc of Cr2O3 were researched by rotary cylinder method. The results show that ： （ 1 ） the corro- sion amolult of magnesia -chrome brick by slag without FeO is higher than that by the slag with 5% FeO, and the vorrosion amount increases when FeO content increa- ses from 5% to 15% ; （2） the test temperature is one of the important factors affecting the slag corrosion resist- ance of magnesia - chrome brick, and the corrosion of smelting reduction slag to brick increases with the temperature rising.

Influence of Anthracite-to-Ilmenite-Ratio on Element Distribution in Titanium Slag Smelting in Large DC Furnaces

The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicomponent systems,and verified through comparison with production results.In particular,using the coexistence theory for titanium slag structures,the influence of the AIR(anthracite to ilmenite ratio)on the distribution of such elements is analyzed.The results show that the AIR can be adjusted to achieve a selective reduction of oxides in the melt.

Reduction smelting on bismuth oxide residue in FeO-SiO2-CaO ternary slag system

Reduction smelting of the bismuth oxide residue from pressure leaching of bismuth sulfide was investigated in the FeO-SiO_2-CaO ternary slag system.The results show that all the recovery ratios of Bi,Ag,Cu and Pb increase with the increase of reductive coal proportion,reaction temperature and time,while too much reductive coal would help Fe enter metal phase;CaO/SiO_2and Fe O/SiO_2 of the chosen slag system should be 0.5-0.75 and 1.25-1.75,respectively,for the reason that the slag system has the optimum mobility and is beneficial for the recovery of metals.The corresponding optimum conditions are determined as follows:the added coal proportion is 7%of the leaching residue,CaO/SiO_2 mass ratio in the chosen slag system is 0.5 and FeO-SiO_2 is 1.5,the reaction temperature is 1300°C and the reaction time is 40 min.Under the above conditions,the recovery ratios of Bi,Ag,Cu and Pb are 99.6%,99.8%,97.0%and 97.3%,respectively.

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。

含铜污泥搭配发热危废协同处理及综合利用技术

本文介绍了富氧侧吹熔池熔炼炉协同处理含铜污泥和发热危废的技术,该工艺具有金属回收率高、熔炼强度大、一次能源消耗低,实现了含铜污泥的有价金属的综合回收和发热危废的无害化处理。生产实践表明:处理量10万吨/a含铜污泥和发热危废,可降低煤率约10%,节约成本770万/a,产出约4000t/a的多金属合金(其中含铜55%、含镍11.9%),为企业提质增效打开了的突破口。

陕西韩城芝川古代冶铁遗址初步考察

韩城芝川古代冶铁遗址位于陕西省渭南市韩城芝川镇芝西村,遗存面积超4000 m^(2),考古年代为西汉。科研团队对该遗址开展冶金考古田野调查并采集到炉渣、陶片等遗物,使用扫描电镜及能谱(SEM-EDS)、金(矿)相显微观察等手段对采集到的18个冶炼遗物进行成分分析和显微结构观察。结果表明,16个炉渣为硅钙铝系高钙低铁炉渣,基体主要为玻璃相、偶见铁橄榄石,其产品是生铁,应为生铁冶炼炉渣。1个炉渣为高铁渣,以浮氏体为主、间有铁橄榄石和极少量玻璃相;1个样品的块状金属为熟铁,很可能为生铁炒钢的遗物。该遗址主要是生铁冶炼遗址,同时进行炒钢冶金活动,是迄今发现陕西渭南地区最早的生铁炒钢遗址。

侧吹熔炼处置锌冶炼渣炉渣组成对导热性及析出物相的影响

侧吹熔炼炉采用水冷挂渣炉壁时,高导热系数炉渣可在炉衬表面形成稳定渣皮,保护并延长炉衬的使用寿命。针对铁矾渣和铅银渣处理用FeO-CaO-SiO_(2)-PbO-ZnO五元渣系,采用稳态平板法对炉渣渣皮的导热系数进行了测定,并通过扫描电镜对固态渣皮进行微观结构分析,以探究炉渣组分改变对渣皮导热系数及结晶矿相的影响。结果表明,增加CaO和SiO_(2)都会使渣皮导热系数增大,其中添加CaO对渣型影响最显著。优化渣型的导热系数从原渣的7.62 W/(m·K)增大到了17.94 W/(m·K),提高了135%。在冷凝过程中,高温析出的物相为黄长石,其熔点、黏度相较于原渣也有显著降低。调整后的渣型更容易形成稳定的渣皮,有利于水冷挂渣护炉。

基于风险管控的历史遗留硫磺冶炼废渣综合治理效果

为解决赤水河源头流域(云南段)历史遗留硫磺冶炼废渣40多年无序堆积导致流域水体持续酸化的污染问题,通过对“自然衰减”“异位修复”“风险管控”等治理途径分析,提出“风险管控+生态修复”模式开展了该区域内酸性废渣和废水的示范工程治理。在查明治理区域污染因子的基础上,采取“废渣防流失、复合阻隔控制、适生植物配比、污水收集处理和运行监测管理”的集成风险管控技术,分析工程实施前、实施中和实施后的固废属性,以及地表水、地下水和废渣渗滤液中污染因子的变化。结果表明:在投加0.35%~0.65%比例生石灰条件下,固废属性从第Ⅱ类一般工业固废改性为第Ⅰ类一般工业固废;工程完工时,地下水pH即可达标,硫酸盐超标倍数从最大5.3倍削减至1.2倍;工程实施3个月后,渗滤液pH稳定达标,硫酸盐超标倍数从最大3.2倍削减至1.7倍;工程实施7个月后地表水pH达标。基于风险管控的历史遗留硫磺冶炼废渣综合治理,能够满足管控目标,并初步完成了技术推广和应用。

富氧双侧吹铜熔池熔炼炉上升烟道结渣的矿物学分析

富氧双侧吹铜熔池熔炼炉上升烟道烟尘结渣严重,阻塞烟道,是制约熔炼炉长周期高负荷高作业率生产的关键因素。分别利用X射线荧光光谱仪、X射线衍射仪、扫描电子显微镜和电子探针显微分析仪,研究富氧双侧吹铜熔池熔炼炉上升烟道结渣烟尘的化学成分、物相组成及微观形貌。结果表明,上升烟道烟尘的主要元素为Fe、Cu、Pb、Zn和O,主要物相是(Cu, Zn, Fe)Fe_(2)O_(4)和Fe_(3)O_(4),表面微观形貌呈致密无孔洞。结合生产过程工况条件,对烟道结渣原因进行分析,认为富氧双侧吹铜熔池熔炼炉生产过程中,富氧空气通过喷嘴鼓入炉内,强烈搅动熔体,熔体中的气泡破裂逸出,喷溅形成的小颗粒熔渣与冰铜被热气流带入上升烟道,熔渣与冰铜被氧化为高熔点的(Cu, Zn, Fe)Fe_(2)O_(4)和Fe_(3)O_(4),在烟道壁面遇冷凝结形成结渣;同时,熔炼炉负压运行,入炉原料水分低,铜精矿等未反应的粉料被烟气带入到上升烟道高温段,在氧化气氛下反应生成黏结结渣;此外,原料中Pb、Zn、As等易挥发性物质进入烟道,被氧化为低熔点化合物后与高熔点的(Cu, Zn, Fe)Fe_(2)O_(4)和Fe_(3)O_(4)黏结在一起,形成致密的结渣烟尘。因此,在冶炼生产中,建议通过控制入炉原料水分和杂质含量,减少粉料入炉;控制渣型和熔炼温度,减少熔体喷溅;使用喷嘴燃烧重油,烧熔结渣烟尘,保证生产正常稳定运行。

钒钛磁铁矿冶炼渣场周边土壤-鱼塘-河流系统中钒铬分布特征及生态风险评价

为探究冶炼废渣中钒(V)和铬(Cr)对周边环境的影响,采集渣场周边土壤、沉积物、鱼塘底泥、鱼塘水和河水样品,分析V和Cr的浓度、赋存形态,并采用富集因子法、地质累积指数法和潜在生态风险指数法对V和Cr的污染状况和生态风险进行评价。结果表明,研究区土壤中V和Cr平均含量分别约为四川省背景值的2.6和4.0倍,富集程度分别为轻微和中度富集;沉积物中V、Cr平均含量分别约为对照沉积物的5.0和3.2倍,底泥中V、Cr平均含量分别约为对照沉积物的5.5和1.4倍,V和Cr富集程度均为中度和轻微富集;水样表现为V污染,鱼塘水和河水V平均浓度分别约为金沙江水样的17.6和1.8倍。研究区V和Cr主要以残渣态形式存在于土壤中,其占比分别为57.1%和89.4%,沉积物和底泥中V和Cr残渣态占比分别为20.1%和74.9%,各环境介质中V的生物可利用率及迁移率要远高于Cr;结合V和Cr地球化学性质分析,研究区环境介质中V和Cr可能主要以V 5+和Cr 3+形式存在。污染评价结果表明,土壤中V、Cr污染程度分别为轻微和中度污染,沉积物与底泥中V、Cr污染程度分别为中度和轻微污染,V和Cr均对生态系统构成轻微风险。因此,为保护研究区域生态系统和公共健康,应尽快修复受污染土壤和沉积物。

铜底吹熔炼过程中Pb、Zn、As分布影响机理分析

探究底吹熔炼过程中Pb、Zn、As等杂质元素在产物中的分布特征,以及熔炼参数与杂质元素分布规律的关系,对低品位、高杂质复杂铜精矿的冶炼具有重要意义。本文采用热力学计算软件Factsage理论分析与实际生产数据分析相结合的方法,探讨了Pb、Zn、As在产物中的分布特征及其影响机理,得到以下主要结论。温度升高,有利于Pb、Zn挥发进入烟尘降低其在渣和铜锍中的占比,也有利于促进渣中As向烟尘中转化脱除,但会导致As在铜锍中占比增加;渣铁硅比增加,会使得Pb、Zn在渣中分布占比逐渐降低,在铜锍和渣中占比逐渐升高,而As在渣中的占比会增加;渣中CaO含量升高,会使得Pb、Zn在渣中分布占比降低,在烟尘和铜锍中增加,As在渣中的占比会增加,在烟尘中占比降低;实际生产操作中,可通过提高冶炼温度促进部分杂质元素挥发,在适当降低渣铁硅比提高Pb、Zn脱除率的同时,可配合添加CaO促进As向渣中迁移。实际生产数据统计表明,Pb在铜锍、渣、烟尘中的分布占比分别为23.86%、33.12%、43.02%,Zn分别为4.47%、88.54%、6.99%,As分别为16.58%、15.34%、68.08%。

内蒙古某铜冶炼炉渣选矿厂流程确定、设计与生产实践

内蒙古赤峰某铜冶炼炉渣主要为侧吹-连续吹炼炉渣,缓冷后铜主要以硫化铜的形式存在,铁主要以磁铁矿和铁橄榄石的形式存在。为了确定选矿厂的流程、设备、产品指标等关键工艺技术及设备信息,通过对比粗碎—半自磨—球磨方案与三段一闭路破碎—球磨方案的优劣,最终确定了包含半自磨的碎磨工艺;通过参考类似选矿厂的实践和技术的先进性、稳定性、可操作性,确定了选矿厂全流程及设备规格型号和数量,并设计了产品指标。生产实践表明,铜冶炼炉渣选矿系统的铜精矿铜品位、回收率及尾矿品位等关键指标均优于设计值,实现了全面达产、达标。

四川某铜矿选冶渣综合理化特性及环境污染特性评价

针对铜矿选冶渣组成复杂、环境特性不清和治理修复难度大等问题,采用矿物解离分析仪(MLA)、X射线光电子能谱仪(XPS)和同步热分析仪-傅里叶变换红外气相色谱质谱联用仪(STA-FTIR-GCMS)等分析测试仪器研究铜矿选冶渣的综合理化特性;运用毒性浸出程序(TCLP)、改进的三步提取(BCR)、风险评估编码(RAC)和次生相与原生相比值(RSP)等方法研究铜矿选冶渣的环境污染特性.结果表明,铜矿选冶渣多呈团聚状,体积平均粒径为54.18μm,主要含铁橄榄石(75.33%)、磁铁矿(12.15%)、黑云母等物相.硫酸硝酸法测得的铜矿选冶渣Cr、Cu、Zn和Pb浓度未超过《危险废物鉴别标准浸出毒性鉴别》规定的危废限值,该铜矿选冶渣为一类一般工业固体废物.RAC法和RSP法评价结果表明,Cu是铜矿选冶渣的主要防治对象,Fe、Zn、Pb是铜矿选冶渣的次要防治对象.研究结果为铜矿选冶渣的安全处理和处置提供了基础数据.

山西翼城冶南汉代冶铁遗址初步调查

冶南遗址位于山西省临汾市翼城县冶南村,面积约1.2 km^(2),考古年代为西汉。采用X射线荧光分析仪(EDX)、扫描电镜及能谱分析仪(SEM-EDS)、金(矿)相显微镜等对冶南遗址采集的6个炉渣和2个金属铁块进行了基体成分和显微组织检测分析。结果表明,6个炉渣样品为硅钙铝系低铁渣;2个铁块样品为熟铁,可能是生铁炒钢产品。判断该遗址为生铁冶炼遗址,同时也是生铁炒钢遗址。该遗址是目前山西地区确认的第一处大型生铁冶炼及炒钢的汉代官铁遗址。