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

Highlights: • Recycling diamond-wire saw silicon kerf and Ti-bearing blast furnace slag simultaneously. • TiO₂, high-purity Si and NaF were prepared through one approach. • Using a waste to recycle the other waste. 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.