An approach for simultaneous treatments of diamond wire saw silicon kerf and Ti-bearing blast furnace slag

Abstract

Both diamond wire saw silicon kerf (DWSSK) and Ti-bearing blast furnace slag (TBBFS) are largely accumulated industrial wastes and important resources of Si and Ti. Currently, both are treated using independent approaches. In this study, a novel approach is proposed to simultaneously extract Ti from TBBFS to prepare TiO2 and recycle Si from DWSSK to prepare high-purity Si. Firstly, DWSSK (86.9 % Si) was employed as a reductant to extract Ti from TBBFS to prepare bulk Si-Ti alloys, and the largest extraction rate was 99.4 %. Secondly, Si and Ti in the bulk Si-Ti alloy were separated using a HF-containing acid solution. Ti in the Si-Ti alloy dissolved into the HF-containing acid solution, and high-purity Si was obtained after acid leaching. The purity of Si in DWSSK increased from 86.9% to 99.94%. Thereafter, a NaOH solution was used to precipitate Ti(OH)4 from the HF-containing acid solution, and TiO2 was prepared by roasting Ti(OH)4. Notably, the new approach had the advantage of concurrently eliminating impurities while recycling DWSSK. Finally, NaOH and HF solutions were used to prepare high-purity NaF (>98 %) to treat the waste solutions. The results of this study provides a new and sustainable technology for clean utilization of DWWSK and TBBFS.