Phase equilibria relations in the V_(2)O_(5)-rich part of the Fe_(2)O_(3-)TiO_(2)-V_(2)O_(5) system at 1200℃ related to converter vanadium-bearing slag

The efficient recycling of vanadium from converter vanadium-bearing slag is highly significant for sustainable development and circular economy.The key to developing novel processes and improving traditional routes lies in the thermodynamic data.In this study,the equilibrium phase relations for the Fe_(2)O_(3)-TiO_(2)-V_(2)O_(5)system at 1200℃in air were investigated using a high-temperature equilibrium-quenching technique,followed by analysis using scanning electron microscopy-energy dispersive X-ray spectrometer and X-ray photoelectron spectroscopy.One liquid-phase region,two two-phase regions(liquid-rutile and liquid-ferropseudobrookite),and one three-phase region(liquid-rutile-ferropseudobrookite)were determined.The variation in the TiO_(2)and V_(2)O_(5)contents with the Fe_(2)O_(3)content was examined for rutile and ferropseudobrookite solid solutions.However,on further comparison with the predictions of FactSage 8.1,significant discrepancies were identified,highlighting that greater attention must be paid to updating the current thermodynamic database related to vanadium-bearing slag systems.

Chemical and mineralogical characterizations of a copper converter slag

A copper converter slag was examined chemically and mineralogically to determine its existing phases, in particular those containing Co and Cu. The slag consists predominantly of fayalite and magnetite, together with some glass, chalcocite, and metallic copper. Copper is entrapped in the slag mostly as chalcocite and metallic copper, as well as trace copper oxide. There was no indication of any independent Co mineral in the slag, but Co was found to be enriched in fayalite and megnetite as solid solution, although Co was detected in all the phases of the slag by SEM-EDX (scanning electron microscopy equipped with model EDAX-9100 energy dispersive spectrometer) and WDS (model WDX-2A X-ray wave-length dispersive spectrometer).

Enhancement of the nickel converter slag-cleaning operation with the addition of spent potlining

The slag cleaning(or matte settling) process was experimentally investigated at 1573 K using a fayalitic nickel converter slag containing spinel and matte/alloy particles.The addition of various amounts of spent potlining(SPL) was studied in terms of its influence on matte settling and the overall metal recoveries.The slags produced were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and wet chemical analysis using inductively coupled plasma optical emission spectrometry.The presence of solid spinel particles in the molten slag hindered coalescence and settling of matte/alloy droplets.Matte settling was effectively promoted with the addition of as little as 2 wt% SPL because of the reduction of spinel by the carbonaceous component of the SPL.The reduced viscosity of the molten slag in the presence of SPL also contributed to the accelerated matte settling.Greater metal recoveries were achieved with larger amounts of added SPL.Fast reduction of the molten slag at 1573 K promoted the formation of highly dispersed metal particles/clusters via accelerated nucleation in the molten slag,which increased the overall slag viscosity.This increase in viscosity,when combined with rapid gas evolution from accelerated reduction reactions,led to slag foaming.

Hydrophobic-surface of copper from converter slag in the flotation system

The converter slag from a smeltery in Daye contains 2.01% copper.The floatability of copper has a significant influence on the flotation of converter slag.Flotation tests,contact angle tests and FTIR were conducted to assess the influences of pH and different flotation concentrators on its hydrophobic process,mechanism and flotation.The results show that since chemisorptions are formed on the surface,hydrophobicity of copper is highly enhanced by xanthate,butylamine dithiophosphate and Z-200.The hydrophobic-surface of copper becomes worse with low recovery in strong acid and alkali situation.When pH value is 10,butylamine dithiophosphate and butyl xanthate are used as the mixed-collector,the grade of copper is 40.01%and that of tailings is 0.37%.

Investigation on the Copper Content of Matte Smelting Slag in Peirce-Smith Converter

The copper contents and its existing forms in the slags during the slag-making stage of Peirce-Smith converters in Guixi Smelter, Jiangxi Province, China have been investigated. The investigation was based on plant trials with the corresponding thermodynamic calculations and kinetic considerations. From the plant data, the total copper content in the slags was in the range of 2% to 8% (mass fraction). The mechanical entrainment of matte drops has been found to be the main cause of the copper loss. The suspension index, defined as the ratio of the mass fraction of copper in suspended matte drops in the slag to that in bulk of the matte phase, has been adopted to quantify the matte entrainment. The values of this parameter estimated in this work have been found mainly within a range of 2.5%-8.0%. The Fe3O4 content in the slag has been estimated to be the most important factor, among others, influencing the separation of slag with matte and, consequently, the copper loss from the slag.

Recovery of Copper and Cobalt from Converter Slag with a New Flotation Method Using H_(2）S

In this study,two different samples were obtained from Küre Copper factory.It was determined that the samples contain:the sample of K.C.F.(Küre Copper Factory),0.70%Cu and 0.5%Co.This sample was firstly grounded at-100 mesh dimension.Flotation was done according to previously obtained optimum flotation conditions.The flotation yield of Cu and Co in concentrate phase was found to be low by collective flotation.Even when the samples were grounded at-160 mesh,no change was observed in the flotation result.Especially,Co could not float under the flotation conditions of the non-sulfurized samples.There,a new flotation method was applied which was not applied until now.For this aim,the samples were firstly sulphurised under the steam of H2S+H2O.By this method,the amount of Cu and Co in the samples get rich.According to the obtained results,the optimum reactions for flotation and sulphurization were determined.In the first sulphurization conditions for the sample of K.C.F.,the yield of flotation for the Co and Co were found to be 98.27%and 68.07%,respectively.The results indicate that Cu can be floated at low yield in the original samples.On the other hand,Co cannot float under these conditions.

Thermodynamic Study on Process in Copper Converters(The slag-making stage)

The so-called Goto's model was modified by introducing a parameter of the oxygen efficiency from industrial trials, as well as the selected and newly re-assessed thermodynamic data. The application of the model to copper converters in Guixi Smelter has been carried out by the combination of thermodynamic calculations with the mass and heat balance using the plant data obtained in industrial trials for many heats. For the slag-making stage, good agreements have been reached betWeen the calculated and measured temperature, blowing time as well as the contents for main elements in the matte and the slag. Relativel}'' large deviations for contents of Zn and Pb in the slag may be caused by the complex chemical composition of the real molten slag, which ma}; result in a large difference of γzn. and γPb,adopted with their real values. It is noted that the model can simulate the slag-making stage of copper converting process in industrial Pierce-Smith converters well.

Simulation on Slag Splashing for LD Converter

SeveraL parameters affecting slag splashing in LD converter have been discussed. Using parffin and starch model, a simulated test about 30 t converter has been made in laboratory and the modified Frode numberwas chosen as the main similar basis of the system. It was results that the optimized slag splashing parameters wasobtained through data treatment The nitrogen gas flow rate is about 8 500 m3/h, the splashing time is of 3 min,and the lance height is of 0.8 m. It is necessary to add MgO or carbon into the slag to adjusting slag composition.Also, it is difficult for the splashed slag condensing on the line when the slag temperature is much higher

Brief of the technology using sliding gate for slag stopping during converter tapping in the steelmaking plant of Baoshan Iron & Steel Co.,Ltd.

The sliding gate used to stop slag during converter tapping is similar to the control of slide gate in ladle,with the sliding gate device installed outside the BOF tapping hole tip.Owing to the quick opening and closing(in 0.5 s) of the sliding gate,it can not only effectively stop the pre - slag and post - slag during converter tapping but also automatically judge and stop slag with the help of AMEPA slag detecting and PLC control technology.Currently it is regarded as the best process to stop slag during converter tapping.

The study of microstructure and phosphorus distribution in converter slag

An efficient slagging is a key process to improve the dephosphorization ability in converter operation. The microstructure analyses can provide the information of phosphorus distribution in various mineral phases to feature completely the dephosphorization process.Two kinds of converter slags were investigated in this study, including conventional slag with high basicity and dephosphorization slag with low basicity.The characteristics of high basicity converter slag have been reported widely.However,the investigations on the low basicity slag properties for dephosphorization in converter are less discussed in steelmaking slag system.This study focused on the microstructure and phosphorus-containing phases in converter slag.The slag composition and mineral phase were examined by the usual XRF chemical analysis and EPMA,XRD studies.The results indicated that the phosphorus-containing phase in high basicity slag was the dicalcium silicate(2CaO·SiO_2 or C_2S) phase,while phosphorus in low basicity slag was incorporated in CaFeSiO_4 structure.

Design and experiment on concentration of phosphorus in factory converter slags

The phosphorus-concentrating phase in the converter slags was designed and simulated by synthetic converter slag.The distribution of phosphorus in factory converter slags was also analyzed by scanning electron microscope(SEM) and X-ray diffraction(XRD).Then factory converter slags were modified by addition of SiO_2 and heated to 1540℃and then cooled to room temperature.The results showed that the phosphorus in the factory converter slags was mostly distributed in two phases:dicalcium silicate (C_2S) and tricalcium silicate(C_3S) by formation of solid solution,and with a little in matrix.Whereas,in the synthetic slags with the basicity close to 3,phosphorus was almost concentrated in phase of C_2S(Pconcentrating phase) in which the contents of P_2O_5 reach to 7.74%.This lays a good foundation for grinding and separation of P- concentrating phase.

Chemical Corrosion Mechanisms of Magnesite-chrome Bricks by Converter Slag

The corrosion resistance of four kinds magnesitechrome bricks against converter salg was investigated by static crucible slag tests. The microstructures of the asdelivered and tested refractories were analyzed by means of SEM and EDS. The results showed that： Different magnesite-chrome bricks have different slag resistances. Generally, the slag resiantance sequence is as follows： rebounded fused magnesite-chrome brick 〉 semi-reboun- ded magnesite-chrome brick 〉 direct-bonded magnesitechrome brick 〉 silicate bonded magnesite-chrome brick. Slag reacts with the periclase of magnesite-chrome refractories, which results in the dissoving of periclase in fayalite slag. However, the complex spinels have superior slag resistance.

Comprehensive Utilization and Control Measures of Iron and Steel Slag

With the increase of steel production,the amount of steel slag piled up is on the rise.The article analyzes the current situation of blast furnace slag utilization,elaborates on the current treatment technology of blast furnace slag,and points out that in the future,the utilization of blast furnace slag will develop towards the direction of developing high value-added products,and the sensible heat recovery rate of blast furnace slag is expected to increase.Analyze the current application status and treatment process of converter slag.The comprehensive treat-ment technology of converter slag is limited by multiple factors,and it is proposed to control converter slag from the production source through"slag recycling".

High Efficient Technology of Steelmaking With Low Silicon Hot Metal on Large Converter

To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Synthetic slag was added to adjust the slag composition. The problems such as difficulty in dephosphorization and slag adhesion to oxygen lance and hood were settled. Steel production and metal yield were increased and the nozzle life was prolonged through these techniques.

基于ICP-MS研究转炉钢渣微粉吸附镍和铅的动力学机理

随着工业化的发展,水体和土壤中的重金属污染日益严重。其中,重金属镍是一种常见的致敏性金属,会引起人体过敏发炎,甚至会引发癌症;血液中铅浓度的超标会危害人的神经系统、心血管系统和生殖系统,造成终身性的危害。因此,治理镍和铅重金属污染具有十分重要的意义。钢渣是炼钢过程中产生的一种副产物,其存在难以利用与附加值低的问题。同时加之管理制度的不健全,导致大量钢渣露天堆放,对土地资源、地下水源,以及空气质量造成严重影响。钢渣微粉具有比表面积大、多孔、化学活性高等特性,被广泛利用,可以成为吸附材料。本文以转炉钢渣微粉为研究对象,利用激光粒度仪、电感耦合等离子体质谱仪、比表面积与孔隙度吸附仪、X射线荧光光谱仪等测试转炉钢渣微粉的基本性质,重点研究转炉钢渣微粉添加量、重金属初始浓度、溶液pH和吸附时间对转炉钢渣微粉吸附Ni^(2+)、Pb^(2+)的效果,结合吸附动力学与吸附等温线理论揭示转炉钢渣微粉对Ni^(2+)、Pb^(2+)的吸附作用机理,为处理镍、铅重金属污染和工业废水处理提供技术支持与理论依据。结果表明:当转炉钢渣微粉添加量大于12.5 g·L^(-1)、重金属初始浓度小于100 mg·L^(-1)、溶液pH大于3和吸附时间大于120 min时,转炉钢渣微粉对Ni^(2+)、Pb^(2+)的吸附效果良好,即基本达到90%。转炉钢渣微粉对Ni^(2+)、Pb^(2+)的吸附符合准二级动力学模型,吸附速率由边界扩散和颗粒内扩散共同控制,吸附过程以化学吸附为主。转炉钢渣微粉的结构具有多孔性为物理吸附Ni^(2+)、Pb^(2+)提供吸附空间,转炉钢渣微粉的化学成分不仅具有碱性与Ni^(2+)、Pb^(2+)形成络合产物,而且水化过程中CaO与SiO_(2)生成C—S—H凝胶,对Ni^(2+)、Pb^(2+)形成络合吸附与硅酸盐体系包裹。转炉钢渣微粉对Ni^(2+)、Pb^(2+)吸附可能存在多层吸附。吸附Ni^(2+)、Pb^(2+)的过程为优惠吸附,吸附容易进行,其理论最大吸附量分别为18.785和17.002 mg·g^(-1)。

转炉炉渣配比对烧结矿性能的影响

将钢渣用于烧结配料,研究不同含量的钢渣对烧结矿冶金性能的影响,找出合适的钢渣配比。试验结果表明:随着钢渣加入量的增大,垂直烧结速度增大,成品率和转鼓强度则先增加、后减少,而烧结机利用系数呈现出逐渐增大的趋势。综合以上因素,在焦粉配比不变的情况下,为了保证成品率和烧结矿强度,同时,考虑烧结利用系数,稳定生产,钢渣最佳配比不宜大于5%。

120 t转炉热态渣循环利用工艺研究

唐山中厚板材有限公司为提高转炉热态渣的利用率,对转炉冶炼过程炉渣产生机理进行分析,探索热态渣循环利用的途径。试验全留渣双渣法,即第一炉按原单渣法冶炼出钢和不倒渣溅渣护炉,根据铁水硅含量将数据固化在模型中,保证终点二元碱度控制在3.5~3.8,第二炉加入废钢和铁水进行双渣冶炼,出钢后倒出40%~50%炉渣再溅渣护炉,完成一组正常的冶炼。同时,通过优化副枪自动炼钢模型、增强转炉底吹强度、改造双渣氧枪等措施,保证第一炉碱度控制在3.0以上,实现循环渣造渣方法的自动控制。实施热态渣循环利用后,渣中FeO含量降低2.1%,钢铁料消耗降低4.355 kg/t,稳定了低P高端品种钢的生产工艺,提高命中率22.5%。

白云尾矿与转炉渣制备烧结透水砖及性能研究

为充分利用白云鄂博再选尾矿和包钢转炉渣,以其为原料采用高温煅烧的方式制备烧结透水砖。结果表明:选定钢渣骨料级配5~10 mm∶2.5~5 mm∶0~2.5 mm=4∶3∶3,最佳方案为尾矿掺量25%,成型压力30MPa,烧结温度1180℃,保温时间50 min,此时透水砖的粘结相为镁铁尖晶石相和硅酸钙相,抗压强度为28 MPa,透水系数为0.091 cm/s,均优于国标《烧结普通砖》(GB/T 5101-2017)中MU25(25 MPa)的抗压强度要求和《透水路面砖和透水路面板》(GB/T 25993-2010)中A级0.02cm/s的透水系数要求。

转炉碳磷氧化转折温度的热力学模型

高碳出钢对于提高钢液洁净度十分有利,但同时也给转炉脱磷带来了严峻挑战。针对高碳出钢时脱磷时间缩短、冶炼中后期发生回磷现象等问题,建立了基于离子分子共存理论(IMCT)的转炉碳磷氧化转折温度的热力学模型。通过该模型预测了最佳一次倒渣温度区间。为了避免冶炼中后期发生回磷现象,应在合适的倒渣温度区间内倒渣,同时实现转炉双渣吹炼一次倒渣高效脱磷。结合现场生产数据及脱磷热力学,重点分析当一倒渣碱度、一倒渣中MgO含量、一倒渣中FeO含量等参数变化时对各组元活度的影响,从而判断出对最佳一倒温度区间的影响,找到碳磷发生选择性氧化的最佳温度区间。

260 t转炉终点余锰含量控制实践

针对转炉冶炼终点余锰含量不合理影响产品质量和生产成本的问题,分析了铁水中锰含量、转炉终点温度、底吹状态、炉渣碱度及渣量等因素对终点余锰含量的影响,结果表明,转炉底吹状态、炉渣碱度及渣量是影响终点余锰含量的主要原因。采取优化转炉底吹制度和转炉吹炼工艺制度后,转炉终点余锰含量可以稳定控制在0.10%~0.12%。