含钛高炉渣/绿矾协同焙烧富集金红石机理研究

Study on the Mechanism of Rutile Beneficiation by Roasting Titanium-bearing Blast Furnace Slag with Copperas

含钛高炉渣和绿矾是以钒钛磁铁矿为原料经选矿后冶炼生铁和二氧化钛工艺中排出的两种主要固体废弃物,上述两种固废的共同处置对钛铁工业的发展具有重要意义。采用含钛高炉渣和绿矾为原料,提出了一种富集金红石的新工艺。含钛高炉渣和绿矾经过共焙烧,其中绿矾热分解为二氧化硫和三氧化二铁,进而二氧化硫和含钛高炉渣中的钙钛矿及含钛辉石发生硫酸化反应,钙镁组分转化为硫酸盐,而钛组分被富集为金红石。系统地研究了工艺参数对含钛高炉渣富集过程的影响。研究发现,加入Na_(2)SO_(4)可以显著提高Ti的富集效率。在绿矾与含钛高炉渣质量比为2、硫酸钠添加量为10%、焙烧温度为650℃、保温时间4 h的最优条件下,含钛高炉渣中钛的转化率达98%,富集后金红石含量约为8.6%,后续可通过浮选进一步富集。Na_(2)SO_(4)的加入促进了熔融Na_(3)Fe(SO_(4))_(3)的形成,熔融物能够渗透含钛高炉渣内部进行硫酸化反应,气液固相反应加速了钛的富集过程。

Titanium-bearing blast furnace slag(TBFS)and copperas are two major solid wastes discharged from pig iron and titania production with vanadium-titanium magnetite ore as feedstock.Co-disposal of the above two wastes is of great importance for the development of ferrotitanium industry.In this study,a novel process for rutile beneficiation was proposed by using TBFS and copperas.TBFS and copperas were co-roasted,where copperas was thermally decomposed into sulfur dioxide and ferric oxide,and the sulfur dioxide continued to react with the CaTiO_(3) and titanium-bearing diopside in TBFS.During the sulfation reaction of TBFS,the calcium and magnesium was converted into corresponding sulfates,while titanium was beneficiated to rutile.The effects of process parameters on beneficiation were studied systematically.It was found that addition of Na_(2)SO_(4) significantly enhanced the conversion efficiency of Ti.Under the optimal conditions,i.e.a mass ratio of copperas to TBFS of 2,Na_(2)SO_(4) dosage of 10%,roasting temperature of 650℃,roasting time of 4 h,the conversion efficiency of Ti reached 98%.The content of rutile reached 8.6%,which can be further beneficiated by flotation.The addition of Na_(2)SO_(4) promoted the formation of molten Na_(3)Fe(SO_(4))_(3),which was able to penetrate inside the TBFS and proceed sulfation reaction with inner TBFS.And gas-liquid-solid phase reactions facilitated the beneficiation of titanium.