## 1 Introduction  
In recent years, waste catalyst resource utilization technology, including pyro-technology, wet technology, and biotechnology, has received extensive attention. In particular, the pyrometallurgical enrichment technique has been remarkably developed and has been used to efficiently recover valuable metals. However, green and sustainable technologies for utilizing enriched smelting slag have yet to be developed. In the process of recovering platinum group metals from three-way catalysts (SACs-3) through iron collection, the final glassy slag is mainly constituted by high contents of silicon or silicon aluminum glassy slag, which can be used as raw materials for aluminosilicate- or silicate-series microcrystalline glass [1; 2; 3]. Furthermore, B\({}_{2}\)O\({}_{3}\), flux agent, added to the smelting process can be used as the nucleating agent in the preparation of microcrystalline glass [4; 5]. A large amount of final glassy residue is generated in the process of iron capture and the recovery of platinum group metals from SACs, though the corresponding comprehensive utilization and treatment capacity is relatively weak. The low value-added treatment methods of pit landfill, open pile, paving, or use as raw material for cement are still the main treatment methods of final slag, which also contains toxic heavy metal elements such as chromium, lead and cadmium. Therefore, the accumulation and retention of a large amount of metallurgical solid waste will certainly bring continuous potential risks and threats to the surrounding natural environment and human survival. The use of final slag as a raw material for the preparation of microcrystalline glass can not only realize the resource utilization of smelting final slag and generate additional economic benefits but also result in zero solid waste in the whole recycling process, which is a win-win situation for both economic and environmental protection [6; 7; 8]. In recent years, techniques for preparing microcrystalline glass using metallurgical final slag after heat treatment have attracted extensive attention [9; 10; 11; 12; 13]. [PERSON] et al. [9] studied the effect of the amount (mass fraction) of pickling sludge on the properties of microcrystalline glass prepared from smelting slag with silica aluminate as the main component, and the results demonstrated the best overall performance of microcrystalline glass with 21% (mass fraction) of pickling sludge. The sample obtained by heat treatment at 900 \({}^{\circ}\)C for 1.2 h had a density of 3.04 g/cm\({}^{3}\), a water absorption of 0.11%, a Vickers hardness of 742.72 HV, a flexural strength of 119.32 MPa, and an acid and alkali resistance of 99.16% and 99.79%, respectively. [PERSON] et al. [11] used the sintering method to prepare microcrystalline glass with iron tailings as the main raw material, and the results showed that the performance of the base glass melted under a melting temperature of 1400 \({}^{\circ}\)C and a holding time of 2 h was strong, the performance of the microcrystalline glass specimens obtained by crystallization treatment under a crystallization temperature of 900 \({}^{\circ}\)C and a holding time of 2 h was better, and both specimens' compressive strength was 158.32 MPa, their density was 2.74 g/cm\({}^{3}\), and their coefficient of thermal expansion was 6.8 \(\times\) 10\({}^{-6}\) K\({}^{-1}\). [PERSON] et al. [12] prepared microcrystalline glass by adding TiO\({}_{2}\) as a nucleating agent in a one-step process in laterite; with the increase in TiO\({}_{2}\), the main crystalline phase started to change from \(\mu\)-cordierite to the pseudosapphire phase and the crystallinity, grain size, and acid and alkali resistance of the microcrystalline glass were improved. [PERSON] et al. [13] successfully produced CaO-Al\({}_{2}\)O\({}_{3}\)-SiO\({}_{2}\)(CAS) glass-ceramic materials from molybdenum tailings (MTs). A large volume of raw MTs, 41-49 wt%, can be recycled.