Removal of boron from metallurgical grade silicon by electromagnetic induction slag melting

A new purification process was developed to remove impurities in metallurgical grade silicon （MG-Si） by electromagnetic induction slag melting （EISM）. Vacuum melting furnace was used to purify boron in different slag systems. The results show that the removal effect in SiO2-CaO-Al2O3 systems is better than that in other slag systems by EISM. The boron content in MG-Si is successfully reduced from 1.5× 10^-5 to 0.2× 10^-5 during EISM at 1 823 K for 2 h. Meanwhile, Al, Ca and Mg elements in MG-Si are also well removed and their removal efficiencies reach 85.0%, 50.2% and 66.7%, respectively, which indicates that EISM is very effective to remove boron and metal impurities in silicon.

Boron removal in purifying metallurgical grade silicon by CaO-SiO_2 slag refining

Boron removal from metallurgical grade silicon （MG-Si） using a calcium silicate slag was studied. The results show that it is impossible basically to remove boron using a pure SiO2 refining. The oxidizing ability of CaO-SiO2 slag for boron removal was characterized by establishing the thermodynamic relationship between the distribution coefficient of boron （LB） and the activities of SiO2 and CaO. The experimental results show that the distribution coefficient and the removal efficiency of boron are greatly improved with the increase of CaO proportion in the slag. The maximal value of LB reaches 1.57 with a slag composition of 60%CaO-40%SiO2 （mass fraction）. The boron content in the refined silicon is reduced from 18×10^-6 to 1.8×10^-6 using slag refining at 1600 ℃ for 3 h with a CaO-SiO2/MG-Si ratio of 2.5, and the removal efficiency of boron reaches 90%.

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.

Future Resources for Eco-building Materials:I. Metallurgical Slag

In order to make an effectivily recycle use of iron and steel slags that are main industrial wastes generated in Chinese metallurgical industry, the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed, such as preparing cement-steel slag blended cement with steel slag after metal recovery, using the fine powder of blast furnace slag （BFS） for manufacturing slag cement and high performance concrete. A further research on using these available resources more efficiently were discussed.

Valorization of Metallurgical Waste in Technical Road： Case of Blast Furnace Slags

The main objective of this paper is to study the mechanical properties of a material formulated in the laboratory which is a GS （gravel slag） based on crushed aggregates treated with metallurgical waste which is the blast furnace slag. The authors show in particular, as a road application, the treatment of gravel slag provides mechanical properties allowing its use in road construction. We will introduce different contents of slag （10%, 15%, 20%, 25% and 30%） and test the mechanical properties of the mixtures obtained through CBR Punching tests, simple compression test and tensile test. This work is in the context of the valorization of blast furnace slag, which is found in large quantities as waste dumps that came to disturb the environment.

某冶炼铜渣综合回收铜铁的实验研究

这是一篇冶金工程领域的论文。某铜冶炼渣浮选尾渣中铁品位为37.42%,铜品位为1.86%,根据其矿石性质特点,采用烟煤作为还原剂,应用直接还原焙烧-磁选工艺回收铜尾渣中铜铁,实验结果表明:将铜冶炼渣、烟煤和生石灰(作为助还原剂)按100∶25∶20的质量比混合,在焙烧温度定1 200℃,时间为80 min,磨矿细度为-0.045 mm 80%,磁场强度为0.139 T条件下可获得铁品位为90.98%,铁回收率为90.13%,铜品位为5.82%、铜回收率为87.38%的含铜铁精矿,实现了冶炼渣铜中铜铁的综合回收。

冶金渣气系统中Marangoni-热毛细对流的数值模拟

高品质钢材制造与钢铁在高温熔池冶炼过程中渣/金/气界面流动传热等物理机制息息相关。考虑熔池向外界散热和渣气相界面变形,耦合熔渣表面张力随温度变化,建立高温矩形浅熔池内渣气流动传热模型,运用CLSVOF方法考察冶金渣气系统的界面Marangoni效应。研究结果表明:熔池内热毛细对流远强于Marangoni对流,热毛细对流显著影响冶金渣气系统的温度场分布和流场结构,贡献率约占96%。随着水平壁面温差增加,Marangoni-热毛细对流增强,相界面变形加剧,熔渣温度均匀性提高约0.018%/K,但是相界面附近壁面耐火材料腐蚀情况更加严重。

含锌冶金渣选矿试验研究

提锌冶金渣是冶炼工序产生的除尘灰采用回转窑还原焙烧提锌工艺的附属品,作为冶金固废长期堆存给公共资源造成污染,一直没有得到很好的开发利用。本文对该含锌冶金渣的性质和成分进行研究,得知该渣中的金属元素主要为铁和锌,同时进行了光学电镜矿物组分鉴定,最终通过物理选矿的方法制定综合回收利用方案,达到高效回收固废资源的目的。

包钢高炉渣中特殊成分对钢渣自粉化行为的影响

这是一篇冶金工程领域的文章。我国钢渣累计堆存量大,给资源和环境造成巨大压力。本文提出“应用熔融高炉渣与钢渣混合以实现钢渣自粉化”的新思路,就包钢高炉渣中特殊成分(CaF_(2)和CeO_(2))对钢渣自粉化的影响机理进行系统研究。以分析纯CaO、SiO_(2)、CaF_(2)、CeO_(2)为原料,按n(CaO)∶n(SiO_(2))=2∶1的配料制备了纯C_(2)S试样,接着分别掺入不同质量分数的CaF_(2)和CeO_(2),将试样在1450℃恒温焙烧1 h后随炉冷却,探究CaF_(2)和CeO_(2)对C_(2)S自粉化行为的影响规律。结果表明,将CaF_(2)掺入C_(2)S中,当CaF_(2)含量低于2.5%时,对C_(2)S的自粉化几乎没有影响,但在CaF_(2)含量超过2.5%时,试样出现了不同程度的结块现象,影响了C_(2)S的自粉化,考虑到过量的CaF_(2)会对环境产生影响,因此CaF_(2)的掺入量应控制在2.5%以下;将CeO_(2)掺入C_(2)S中,当CeO_(2)含量为0.25%时,C_(2)S仍能完全自粉化,但CeO_(2)含量超过0.5%时,C_(2)S不再出现自粉化现象,因此CeO_(2)含量必须低于0.25%,C_(2)S自粉化效果较好。

精炼渣酸性氧化浸出制备黑铜电解液实验

这是一篇冶金工程领域的文章。研究了双氧水氧化酸性浸出法从高铜高锡阳极炉精炼渣中脱除铜制备黑铜电解液。主要考查了双氧水用量、反应温度、硫酸浓度、固液比和反应时间等因素对铜脱除效果的影响。结果表明,在精炼渣20.0 g,2.0 mol/L硫酸溶液200 mL,S/L=1/10,浸出温度65℃,双氧水用量10.0 mL,搅拌速度400 r/min和浸出时间60 min时,Cu、As的平均浸出率分别达到88.98%、87.33%,而Ni和Sn的浸出率仅为7.72%和1.34%,浸出液中铜离子浓度为48.48 g/L,可用于黑铜电解液的补充液。

工业硅渣浮选熔融分离提纯金属硅的实验研究

介绍了使用工业硅渣浮选获得的工业硅粉,通过高温熔融法,分离残余渣相提纯工业硅,考察了不同气氛及熔剂添加量对渣-硅分离效果和工业硅杂质含量的影响。分别在空气气氛、氩气保护气氛及添加不同含量复合熔剂条件下,将10 g精矿样品于1450℃熔融处理5 min,随后淬冷制样磨抛统计样品单位截面积内硅滴的尺寸分布,以判断硅滴熔融聚集长大与渣相分离的特性。同时,检测不同条件下,熔融处理后获得的工业硅典型杂质含量变化。结果表明:惰性保护气氛会阻碍硅滴聚集长大与残余渣相分离,添加1%~2%的熔剂可加速硅滴长大集聚与渣相分离。在空气气氛并添加2%熔剂的条件下,可显著脱除熔融工业硅中的钙、铝杂质,可在一定程度上脱除部分铁、钛杂质。

双层桨耦合混沌搅拌强化铜渣提取有价金属模拟研究

铜冶炼渣作为火法炼铜生产过程中产生的固体废弃物之一,经常需要大量堆存且难以处理。为了强化铜冶炼渣提取有价金属元素的过程,结合双层刚性组合桨与混沌转速方法,对铜冶炼渣湿法提取有价金属元素工艺过程的固-液混合性能进行水模型研究。结果表明:下层叶轮叶片数量的增加有利于卷起沉底颗粒加快混合过程,但增强复杂的上升流场与均相流场之间的干涉会对固相悬浮产生影响,下层叶轮的上升流场对稳定悬浮时间的影响强于上层叶轮的均相流场,在转速阈值为200 r/min,换速间隔为5 s的Logistic混沌转速条件下,上层桨叶为圆二叶、下层桨叶为圆四叶的搅拌桨对湿法浸出有利,达到稳定悬浮的时间为55.2 s,最多悬浮颗粒数为120粒,混合能耗W、单位混合能耗W*以及单位混合功率P*分别为322.38 J,2.69 J和487.78×10^(-4) J/s,对比各项指标最低值,优化幅度均在10%以上,可在较低能耗下,有效提高铜冶炼渣与浸出液的混合程度,并通过增大反应接触面积,提高有价金属元素的提取效率。

冶金渣活化过硫酸盐降解有机废水的研究进展

冶金渣作为冶金行业产生的固体废弃物,成分复杂、处理难度大,资源化利用面临挑战。将冶金渣用作催化剂,通过过硫酸盐高级氧化工艺处理有机废水是实现冶金渣资源化利用的有效方式。综述了国内外关于冶金渣作为催化剂活化过硫酸盐的最新研究进展,包括钢渣、铜渣、电解锰渣和赤泥。此外,阐述了冶金渣活化过硫酸盐工艺的强化策略。最后分析了冶金渣作为过硫酸盐催化剂在目前应用中存在的问题及未来的研究方向,以促进相关工作的发展。

两步还原钒渣过程中熔渣的黏度与结构特性

这是一篇冶金工程领域的论文。针对当前钒铁生产面临环境污染严重、流程冗长以及能耗较高等一系列问题,拟利用光伏硅片切割废料和铝灰分别作为预还原和终还原阶段的还原剂,对钒渣进行两步还原直接制备钒铁合金,研究了两步还原反应过程中对应渣系的黏度和熔体结构的演变规律。结果表明,1873 K时,对应预还原过程的FeO-V_2O_3-Cr_2O_3-MnO-SiO_(2)-TiO_(2)-CaO渣系,随着渣中FeO组元含量的减少和SiO_(2)组元含量的增加,铁铬尖晶石逐渐分解,影响熔体结构的主要因素由渣中FeO含量的变化转变为SiO_(2)含量的变化,导致结构复杂度由0.176增至2.517,相应地,渣系黏度由0.092 Pa·s增至0.476 Pa·s;对应终还原过程的FeO-Cr_2O_3-MnO-V_2O_3-Al_2O_3-SiO_(2)-TiO_(2)-CaO渣系,随着渣中FeO、Cr_2O_3、MnO、V_2O_3组元含量的减少和Al_2O_3组元含量的增加,锰铬尖晶石逐渐分解,渣系由固液混合相转变为单一液相,影响熔体结构的主要因素为渣中Al_2O_3含量的变化,渣系由预还原阶段硅酸盐为主的熔体结构转变为终还原阶段铝硅酸盐为主的熔体结构,结构复杂度由0.252增至2.248,相应地,渣系黏度由0.091 Pa·s增至0.372 Pa·s。

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.

Boron separation from Si–Sn alloy by slag treatment

This study investigates a purification process for metallurgical-grade silicon(MG-Si) in which Si is alloyed with tin(Sn) and Ca O–Si O_2–Ca Cl_2 slag is used to remove boron(B) impurity. Acid leaching was performed to remove the Sn phase after slag refining to recover high-purity Si from the Si–Sn alloy. The effect of refining time was investigated, and acceptable refining results were realized within 15 min. The effects of slag composition and Sn content on the removal of B were also studied. The results indicate that increasing Sn content favors B removal. With the increase of Sn to 50% of the alloy, the final B content decreased to 1.1 × 10^(-4) wt%, 93.9% removal efficiency.

Correlation between the Sulphide Capacity Index and the Slag Basicity

The relationships between the sulphide capacity index and the optical basicity, the mole fraction of oxygen ion and the Bell's ratio were investigated based on extensive lab scale equilibrium and industry scale quasi-equilibrium experimental data in the temperature range of 1300 1600℃. Although the sulphide capacity index has good relations with different representations of slag basicity. according to the data obtained under the lab scale equilibrium experimental conditions,the similar relations do not exist according to the data obtained under the industry scale quasi-equilibrium experimental conditions. So it is concluded that the sulphide capacity index, which has been considered as a measure of the slag basicity. can not be used for virtually all oxide slags of interest in the field of ironmaking and steelmaking.

以硅酸钠为抑制剂浮选回收工业硅精炼渣中的单质硅

提出一种以硅酸钠(SS)为抑制剂从工业硅精炼渣(硅酸盐)中浮选回收单质硅的新方法。通过溶液化学、接触角和zeta电位测试,研究SS与硅酸盐的相互作用机理。研究发现,添加SS后,回收的硅含量从(72.12±5.08)%(质量分数)提高至(81.14±1.77)%(质量分数)。浮选过程中,SS水解成亲水性较强的H_(2)SiO_(3)和HSiO_(3)^(−),与硅酸盐发生物理/化学吸附,导致硅酸盐表面接触角从6.62°降至0°,从而降低了硅酸盐的可浮性。

电石渣焙烧制备活性氧化钙及粒级影响规律

电石渣→氧化钙→电石的循环利用,是实现电石渣钙质资源循环回用的有效途径,但由于电石渣组成复杂、提纯困难,目前仍难以实现大规模制备活性氧化钙循环利用。系统考察了电石渣焙烧过程的物相形貌变化,研究了不同粒径范围的电石渣成分组成差异,通过研究电石渣粒度特征及各粒级电石渣的焙烧特性,确定颗粒分级对电石渣制备活性氧化钙性能的影响。结果表明:电石渣中杂质集中在<45μm及>180μm颗粒中,酸不溶物、Fe、C等主要集中在150μm以上颗粒中;焙烧过程中,钙质组分在350~460℃、550~720℃两阶段逐渐转化为氧化钙,大部分碳质杂质颗粒能在800℃以下完成分解,影响制备活性氧化钙产品性能;活性氧化钙的抗压强度主要受颗粒粒度影响,活性度受粒径、成分共同影响,细颗粒会填补压制过程中颗粒间间隙,提高强度但阻碍水分渗透,粗颗粒中杂质过多难以分解且分解形成大型孔道,影响产品强度、活性,45~106μm较适宜制备活性氧化钙,活性度达411 mL(以4 mol/L标准盐酸计),抗压强度达2.46 MPa。上述研究可为电石渣循环回用提供借鉴。

含钛高炉渣提钛技术研究进展

含钛高炉渣作为我国大宗固体废弃物之一,不仅占用大量的土地及污染环境,且因其中的钛资源及其他有价组分未得到有效利用,导致了严重的资源浪费。介绍了含钛高炉渣的性质,综述了湿法、火法和选择性富集等提钛工艺的原理及优缺点。随着双碳目标的提出,新型提钛技术应将传统方法与非常规冶金技术相结合,朝着绿色环保、经济高效、短流程的方向发展。