摘要
高钛渣是钛矿经过电炉熔炼后二氧化钛含量高的富集物,含有少量Fe,Si,Cr,Al,Mn等元素,通常被用于硫酸法和氯化法生产钛白粉。本文提出利用镁粉还原高钛渣直接制备钛合金粉末的新思路,采用还原-热处理-脱氧三步过程实现制备低氧钛合金粉末。以某冶炼厂的高钛渣为原料,分别在Ar和H_(2)气氛,温度为750℃下,利用Mg粉还原高钛渣,考察了氩气和氢气下还原产品的元素含量变化,对还原后的产品进行900~1200℃、Ar条件下的热处理,以减小孔隙率对氧含量的影响。结果表明,Ar气氛下还原产品形貌不规律,孔隙率高,需要更高的热处理温度才能降低孔隙率,H_(2)气氛下的还原产品形貌密实规整,孔隙率低。利用Mg粉对氢气还原后的热处理产品进行深度脱氧。结果表明,第一步还原后,Ar和H_(2)条件下产品的氧含量分别为4.320%和0.960%。对氢气条件下的热处理产品进行深度脱氧后得到了氧含量为0.047%的氢化钛合金粉末产品,产品的主要物相为TiH_(1.924)及含有少量的HFe_(2)Ti,Ti_(5)Si_(3)H_(0.9)和Cr_(1.8)TiH_(5.3)。本研究为高钛渣的综合利用提供一种新的思路。
Titanium and its alloys exhibit remarkable properties,such as high specific strength,low density,strong corrosion resistance and good biocompatibility.They have been used in aerospace,chemical industry,biology and other fields;however,their high manufacturing cost restricted wider range of applications.Currently,titanium alloy products are mainly produced by titanium sponge chlorinated and reduced from titanium dioxide which originate from upgraded titania slag(UGS),and then to be refined and machined.UGS is a kind of enrichment with high content of titanium dioxide after smelting process in electric furnace,the product also contains a small amount of oxides such as oxides of Fe,Si,Cr,Al,Mn.UGS is generally used to produce titanium dioxide through sulfuric acid method or chlorination method.Sulfuric acid method has long manufacturing time and a complex process,produces titanium dioxide with poor quality,and creates serious pollution of FeSO_(4)and dilute H_(2)SO_(4)waste liquid.Meanwhile,the chlorination process of producing titanium dioxide also generates toxic and corrosive substances.In recent years,producing titanium from titanium dioxide by metal thermal reduction has become a research hotspot.The oxygen content of titanium powder reduced from titanium dioxide by metal reduction cannot meet the industrial requirements due to the difficulty of removing oxygen from Ti-O solid solution.Whereas,as presented by a previous study,Ti powder produced by the reduction of titanium dioxide trough magnesium thermal reduction in the presence of hydrogen could readily achieve the ultimately lower level of oxygen content,compared to the process which without the presence of hydrogen.The oxygen content of titanium powder produced by such method could be readily lower than 0.15%(mass fraction).The metal thermal reduction method used oxide as the precursor with no need for lengthy chlorination process and had small levels of pollution,and thus would drive crucially future research interests.Based on the shortcomings of the traditional smelting methods of UGS,considering the characteristics of UGS and the advantages of metal thermal reduction method,a new thought that preparing titanium alloy powder directly by magnesium powder reduction of titanium and other element oxides in UGS without removing metal elements was presented in this paper.A three-step process including reduction,heat treatment,and deoxidation was used to prepare low oxygen content titanium alloy powder.The UGS as raw material which from RioTinto Group was ball milled with Mg powder and then reduced in Ar and H;atmosphere respectively at 750℃.The change of elements content,especially the difference in oxygen content and phase composition of powder under different atmospheres were investigated.The reduced products were subjected to heat treatment in Ar at 900~1200℃to explore the influence of heat treatment temperature on the morphology of the reduced products under different atmospheres.The results exhibited that at same temperature,the morphology of the products after heat treatment in Ar was irregular with high level of porosity,while the morphology of the products in H_(2)atmosphere was dense and regular,and was less porous.Mg was used to deoxidize the heat-treated products after hydrogen reduction.The deoxidization experiment was carried out in H_(2)atmosphere at 750℃.The results showed that the oxygen content of the products reduced by Mg in the first step in Ar and H_(2)was 4.32%and 0.96%,respectively.The reduced product in H_(2)was more favorable for heat treatment due to its lower oxygen content.Titanium hydride powder with 0.047%oxygen content was obtained after deep deoxidation.The main phase of the product was TiH_(1.924)with a small amount of HFe_(2)Ti,Ti_(5)Si_(3)H_(0.9)and Cr_(1.8)TiH_(5.3),and the contents of S and P were lower than 0.001%.The reduction,heat treatment and deoxidization experiments were carried out in a tubular atmosphere furnace.This study also provided a new thought for the comprehensive utilization of high titanium slag,and provided valuable technical parameters for the preparation of titanium products.
作者
郭学益
董朝望
夏阳
田庆华
曾广
郑泽邦
Guo Xueyi;Dong Zhaowang;Xia Yang;Tian Qinghua;Zeng Guang;Zheng Zebang(School of Metallurgy and Environment,Central South University,Changsha 410083,China;School of Mate⁃rials Science and Engineering,Central South University,Changsha 410083,China;State key Laboratory of So⁃lidification Processing,Northwestern Polytechnical University,Xi′an 710072,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2021年第12期1464-1471,共8页
Chinese Journal of Rare Metals
基金
湖南省自然科学基金项目(2019JJ20031)
湖南省重点研发项目(2019SK2061)
西北工业大学凝固技术国家重点实验室开放课题项目(sklsp201904)资助
关键词
高钛渣
还原
合金
粉末
upgraded titania slag
reduction
alloy
powder
作者简介
郭学益(1966-),男,湖南长沙人,博士,教授,研究方向:有色金属循环利用、先进材料制备,E-mail:xyguo@csu.edu.cn;通讯作者:夏阳,副教授,电话:0731-88876089,E-mail:yang.xia@uqconnect.edu.au
