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Large amounts of Ti-bearing blast furnace slag (TBFS), diamond wire saw Si powder (DWSSP), and Al alloy scrap (AAS) are generated annually. Although these are industrial waste, they contain valuable Ti, Si, and Al resources. In this work, a novel process is developed for the simultaneous recycling of Ti, Si, and Al from these three wastes to prepare TiSi 2 and Al-Si alloys. TBFS, DWSSP, and CaO (flux) were mixed to form a mixed Ti-Si-slag, which was combined with AAS and underwent reduction smelting at 1823 K to prepare Si-Ti-Al alloys. Subsequently, TiSi 2 (98.7%) and low-Fe Al-Si (0.64 wt% Fe) alloys were prepared sequentially by separating the molten Si-Ti-Al melt via electromagnetic directional crystallization with a pull-down rate of 3 µm/s. The impurities in the Si-Ti-Al alloy were removed during the separation process by segregation at the boundary of the solid-liquid phase and volatilization. Furthermore, the entire process produces no waste acid or waste gas. Therefore, this work has introduced an efficient and environmentally friendly method for the value-added recycling of Ti, Si, and Al resources from accumulated TBFS, DWSSP, and AAS. [Display omitted] • A novel approach was proposed to simultaneously recycle three wastes. • Extracting Ti from Ti-bearing blast furnace slag while removing O from diamond wire saw Si powder. • Fe was removed from the Al alloy scrap while the Al alloy scrap was also recycled as an Al-Si alloy. • The entire process produces no waste acid or waste gas. [ABSTRACT FROM AUTHOR]

• Recycling diamond-wire saw silicon kerf and Ti-bearing blast furnace slag simultaneously. • TiO 2 , 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 TiO 2 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 TiO 2 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. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Al removal for the recovery silicon from DWSP by HCl leaching was proposed. • The kinetic mechanism based on the shrinking core model and homogeneous model was investigated. • The obtained mechanism of Al removal from DWSP was consistent with material characterization. • This mechanism provides practical value for facilitating impurities release. Abstract Impurity removal is essential for the recovery and regeneration of silicon resources from diamond wire saw powder by metallurgical purification technologies. In this paper, the aluminum was removed from the diamond wire saw powder via a direct HCl leaching method. In order to analyze the removal efficiency of various experimental conditions, certain parameters such as HCl concentration, leaching temperature, reaction time and liquid-solid ratio were also investigated. Particularly, the removal efficiency of Al reached 95.6% under the optimal leaching condition, such as the HCl concentration of 4 mol·L−1, the leaching temperature of 60 °C, the reaction time of 3 h, and the liquid-solid ratio of 10. The shrinking core model and homogeneous model were then respectively utilized to describe the leaching kinetics of the Al removal leaching process. The results indicated that the homogeneous model was more suitable than the shrinking core model. Moreover, the kinetics parameters regarding the reaction orders m =3, n =2.81, the activation energy E a =97.30 kJ mol −1, the frequency factor A =1.11×1014 min−1. Furthermore, the leaching mechanism of Al removal was revealed based on kinetic analysis and materials characterization. This work is of great practical value in terms of regenerating silicon resources from the diamond wire saw powder waste materials with efficient and low cost methods. [ABSTRACT FROM AUTHOR]

The installed capacity of solar photovoltaic power generation has grown rapidly in the last decades. With the rapid development of the photovoltaic industry, the demand for Si wafers, which are integral to solar cells, has grown dramatically. In the manufacture of Si wafers, the traditional loose abrasive sawing method (LAS) has gradually been replaced by the diamond-wire sawing method (DWS). However, during the diamond-wire wafer sawing process, approximately 35%−40% of the crystalline Si becomes diamond-wire sawing silicon waste (DSSW). Therefore, DSSW represents a resource worth recycling due to its low levels of impurities and high silicon content. Furthermore, recycling prevents DSSW from becoming environmental pollution and eliminates disposal costs. This review provides an overview of the recycling and reutilization of DSSW based on an extensive literature survey. In view of the rapid increase in DSSW production and current purification bottleneck of < 5 N, in-situ utilizations may be more feasible, such as the preparation of silicon containing alloys and functional ceramic materials, which not only frees from the complex purification process, but has a huge demand. Finally, based on the review, future prospects are proposed, aiming to identify research directions with significant potential in the resource utilization of DSSW and other silicon wastes. [Display omitted] ● DSSW with high silicon content represents a resource worth recovery and recycling. ● The proper purification process is a trade-off between cost and purity. ● In-situ utilizations of DSSW may be more feasible strategies. ● Modification facilitates real application of DSSW in lithium-ion batteries. ● DSSW has scalable applications in energy conversion and environmental catalysis. [ABSTRACT FROM AUTHOR]

The installed capacity of solar photovoltaic power generation has grown rapidly in the last decades. With the rapid development of the photovoltaic industry, the demand for Si wafers, which are integral to solar cells, has grown dramatically. In the manufacture of Si wafers, the traditional loose abrasive sawing method (LAS) has gradually been replaced by the diamond-wire sawing method (DWS). However, during the diamond-wire wafer sawing process, approximately 35%−40% of the crystalline Si becomes diamond-wire sawing silicon waste (DSSW). Therefore, DSSW represents a resource worth recycling due to its low levels of impurities and high silicon content. Furthermore, recycling prevents DSSW from becoming environmental pollution and eliminates disposal costs. This review provides an overview of the recycling and reutilization of DSSW based on an extensive literature survey. In view of the rapid increase in DSSW production and current purification bottleneck of < 5 N, in-situ utilizations may be more feasible, such as the preparation of silicon containing alloys and functional ceramic materials, which not only frees from the complex purification process, but has a huge demand. Finally, based on the review, future prospects are proposed, aiming to identify research directions with significant potential in the resource utilization of DSSW and other silicon wastes. [Display omitted] ● DSSW with high silicon content represents a resource worth recovery and recycling. ● The proper purification process is a trade-off between cost and purity. ● In-situ utilizations of DSSW may be more feasible strategies. ● Modification facilitates real application of DSSW in lithium-ion batteries. ● DSSW has scalable applications in energy conversion and environmental catalysis. [ABSTRACT FROM AUTHOR]