Tu Yikang, Su Zijian, Zhang Yuanbo, Jiang Tao
School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
Waste Manag. 2023 Sep 2;171:227-236. doi: 10.1016/j.wasman.2023.08.034.
The utilization of virulent chromium slag has always been a worldwide problem, and lots of C-bearing dust produced in steel industry has not been utilized efficiently. Sintering is a potential method to treat these two kinds of solid wastes, but it is limited by small treatment capacity, incomplete detoxification of Cr(Ⅵ) when they were directly added into sintering process. In this study, an innovative technology of co-processing chromium slag and C-bearing dust via composite agglomeration process (CAP)-blast furnace method was put forward and systematically investigated. In the CAP, the chromium slag and C-bearing dust were first made into composite pellets and added into the matrix feed for co-sintering. The results showed that, 20% chromium slag and 5% C-bearing dust could be co-disposed by the CAP without destroying the quality of the sinters. Cr(VI) was completely reduced to Cr(III) or metal Cr. 12.83% Cr existed as metal Cr, and the rest of Cr existed in spinel as (Mg, Fe)(Cr, Al)O or in silico-ferrite of calcium and alumina as Cr(Ⅲ). After blast furnace smelting, 90.22% Cr in sinters entered stainless mother liquor to be recycled.
剧毒铬渣的利用一直是一个全球性问题，钢铁行业产生的大量含碳粉尘也未得到有效利用。烧结是处理这两种固体废物的一种潜在方法，但存在处理能力小、直接加入烧结过程中Cr(Ⅵ)解毒不完全等局限性。本研究提出并系统研究了一种通过复合造块工艺（CAP）-高炉法协同处理铬渣和含碳粉尘的创新技术。在CAP中，首先将铬渣和含碳粉尘制成复合球团，并加入到基体原料中进行共烧结。结果表明，采用CAP可协同处置20%的铬渣和5%的含碳粉尘，且不破坏烧结矿质量。Cr(VI)完全还原为Cr(III)或金属Cr。12.83%的Cr以金属Cr形式存在，其余的Cr以(Mg, Fe)(Cr, Al)O尖晶石形式或钙铝硅铁酸盐中以Cr(Ⅲ)形式存在。经过高炉冶炼后，烧结矿中90.22%的Cr进入不锈钢母液进行回收。
