高温还原性气氛下TiOx-SiO2-MgO系结晶过程的研究

实验通过定组成的H2/CO2混合气控制氧分压,在温度为1873 K、1673 K、1473 K,氧分压为1.22×10-8~2.18×10-12 Pa、4.92×10-8~8.79×10-12 Pa的范围内,研究了TiOx-SiO2-MgO 系的析出相.结合XRD和EDS分析并对比汪大亚等人的研究可知,当氧分压较高（PCO∶PCO2=5∶1）时,对于初始成分TiO2∶MgO∶SiO2摩尔比为60∶25∶15的试样,在1873 K 和1673 K 时的析出相为TiO2,在1473 K 时其析出相为MgTi2O5;对于初始成分TiO2∶MgO∶SiO2摩尔比为60∶15∶25的试样,在1873 K时其析出相为TiO2,在1673 K和1473 K时析出相为MgTi2O5.而当氧分压较低（PH2∶PCO2=600∶1、300∶1、150∶1）时,2种不同成分的试样在不同温度下的析出相均为黑钛石,并且随着氧分压的降低,黑钛石中的Mg 含量逐渐减少.     

复吹转炉补炉技术的改进实践

介绍了济钢炼钢厂"铁块补炉法"技术的改进情况,包括护炉前的炉渣调整、渣补护炉的操作步骤及要点等。采用优化后的"铁块补炉法"技术后,转炉护炉时间缩短至50 min,节约了30%的补炉料,吨钢成本降低0.65元。     

260 t转炉留渣双渣法冶炼低磷IF钢的半钢控制实践

针对260 t转炉冶炼低磷IF钢时存在温度、磷和氧含量很难同时命中的问题,采用了留渣双渣的冶炼工艺,通过合理控制留渣量、一次倒渣温度和一次倒渣时间等措施后,冶炼低磷IF钢转炉终点磷含量低于0.012%,终点氧值降低了0.011 2%,提高了钢水质量。     

锌冶炼转窑渣用于水泥混凝土胶凝材料的研究

研究了锌冶炼转窑渣用于水泥混凝土辅助胶凝材料时不同掺入量对混凝土的抗压强度和重金属离子浸出性的影响。结果表明,随转窑渣用量的增加,混凝土固化块的抗压强度呈先增强后减弱的趋势;当掺入比为胶凝材料的11%时,固化块的28天抗压强度达到36.5 MPa的最大值;当掺入比超过13%后固化块抗压强度迅速下降。水泥混凝土对转窑渣中的镉、铅等重金属离子具有很强的固化稳定能力,其中对镉的固化能力大于铅。试验条件下,固化块的镉、铅离子的毒性浸出浓度分别为0.258~0.276μg/mL和1.541~1.835μg/mL,远低于国家标准中危险废物浸出毒性鉴别标准的浓度限值。     

某铜冶炼渣铜选矿试验研究

针对甘肃某公司所属的铜冶炼渣成分复杂、嵌布粒度不均匀的性质特点采用优先快速浮选出一部分易浮铜矿物得到合格的铜精矿1,优先浮选尾矿经一次粗选、三次精选、一次扫选获得合格的铜精矿2,一次精选中矿及扫选中矿返回球磨机再磨的工艺流程,铜粗选二采用针对该铜冶炼渣性质研制的新型捕收起泡剂酯-11,闭路试验获得了铜品位为29.69%,铜回收率为85.62%的总铜精矿,试验指标良好,为现场工艺改进提供了技术依据。     

GOR冶炼不锈钢深脱硫工艺

以70 t EAF-GOR-LF-CC工艺生产304不锈钢为背景,分别对GOR冶炼过程初始钢液、终点钢液以及还原渣取样分析,重点考察了还原渣碱度、渣中残余Cr2O3质量分数(w((Cr2O3)))以及钢液初始硫质量分数(w([Ss]))对钢液深脱硫效果的影响规律,得出了以下结论：还原渣碱度对脱硫有较大影响,高炉渣碱度有利于钢液脱硫,但当炉渣碱度达到1.75以上时,炉渣碱度对终点硫质量分数(w([Sf]))的影响逐步变小。还原渣中残余Cr2O3对脱硫有阻碍作用,尽可能降低渣中w((Cr2O3))有利于提高GOR脱硫效果,当w((Cr2O3))降低到0.3%以下时,表观渣-钢间硫分配比(LS°=w((S))/w([S]))明显升高。GOR初始钢液硫质量分数越低,越容易获得最终低硫钢液,当w([Ss])＜0.07%时,钢液中最低w([Sf])更容易降低到0.004%以下。根据GOR工业试验结果得出了冶炼终点时优化的表观渣-钢间硫分配比( LS°)随还原渣碱度、w((Cr2O3))和w([Ss])的变化关系。     

Replacement of bentonite in hematite ore pelletisation using a combination of sodium lignosulphonate and copper smelting slag

Bentonite is the most common binder used in iron ore pelletisation owing to its good bonding properties in green and dry pellets at both ambient and elevated temperatures. However, due to its high alumina and silica content, it increases the slag volume and energy consumption in downstream processes. Organic binders may be used to replace bentonite; however, they fail to provide strength at a high temperature (700–900°C) due to poor thermal stability during pellet induration. In the present study, an organic binder Na lignosulphonate (NLS) has been used along with copper smelting slag (Cu-SS). FeO in Cu-SS provides diffusion bonding at high temperature and maintains the strength of pellets even after evaporation/burning of NLS. It also enhances recrystallisation bonding at relatively lower temperature to provide good strength. The study has been carried out with hematite ore and varying amounts of NLS and Cu-SS. Copper smelting slag (1.0%) addition with 0.5%NLS has been found to be optimum to provide very good green properties and ～300?kg/pellet cold crushing strength (CCS) at 1250°C induration temperature. However, hematite pellets of similar basicity with 0.5% bentonite requires higher induration temperature (1300°C) to achieve a similar CCS. The developed pellet also shows better reducibility (80%), similar reduction degradation index (18%) and swelling index (10%) to the usual bentonite pellet. Thus, the induration temperature of hematite pellet has been lowered by 50°C using a combination of NLS and Cu-SS eliminating bentonite completely, which can provide a considerable energy and cost saving.     

Numerical simulation of copper recovery from converter slags by the utilisation of spent potlining (SPL) from aluminium electrolytic cells

An innovative method was devised to improve copper recovery and operational efficiency of the Cu converter slag-cleaning furnace, by utilising both carbon and fluoride values of an otherwise environmental hazardous material (i.e. spent potlining (SPL)) produced from the aluminium industry. Results based on numerical modelling show that 90% Cu recovery could be achieved by adding as little as 3–4?wt-% of SPL to the molten converter slag. The fluorides and sodium-containing compounds in the SPL reduced the slag viscosity, resulting in a much faster settling rate of matte droplets. In this process, the SPL could be detoxified by destroying the cyanides to form harmless N₂ gas, and inertising the fluorides in a much diluted form in the ferro-silicate slag, ensuring a safe disposal to the environment.     

Effect on cleanliness of molten steel with different refining slag systems for low alloy ship plate

To study the effect of refining slag on the compositions of molten steel and inclusions, the reaction between ship plate steel and different slag systems (slag A-CaO/Al₂O₃: 1.0, SiO₂: 5 mass-% and slag B-CaO/Al₂O₃: 1.5, SiO₂: 9 mass-%) was investigated by laboratory-scale high-temperature equilibrium experiments. Results showed that the desulphurisation capacity of the two slags was very similar, and the average sulphur content for both was 0.002?mass-% in steel, but the deoxidation capacity of slag B was slightly higher than slag A. The amount of inclusions <5?μm was more in steel balanced with slag B than in that balanced with slag A. To generate inclusions smaller than 5?μm, and spherical liquid CaO–MgO–Al₂O₃–SiO₂ inclusions, and to decrease the T[O] (total oxygen) content in steel, refining slag composition should be: CaO/Al₂O₃ ～ 1.5, and SiO₂ ～ 9?mass-%. Slag system optimisation can reduce or even eliminate calcium treatment during production. T[O] content in the slab could be controlled to 15–21?ppm, with typical micro-inclusions of ≤10?μm, and CaO–Al₂O₃–MgO and CaO–Al₂O₃–CaS systems in molten steel.