Recovery of nickel and preparation of ferronickel alloy from spent petroleum catalyst via cooperative smelting–vitrification process with coal fly ash

ABSTRACT

Spent petroleum catalyst (SPC) is a highly toxic material since it contains heavy metals and hazardous substances. A novel recycling technology based on the cooperative smelting–vitrification process by using coal fly ash (CFA) as a fluxing material was proposed. The benefits of employing CFA in this cooperative smelting–vitrification process of SPC have been demonstrated via the results of lab-scale and scale-up experiments. The experimental results indicated that with a collector iron (Fe) addition of 26 wt%, a C/O molar ration of 1.4, and an H₃BO₃ addition of 14 wt%, the maximum nickel (Ni) recovery was ∼98% by controlling the CFA addition of 40–50 wt%, basicity of 0.4–0.5, smelting temperature of 1550°C, and smelting time of 60 min, respectively. In this process, a ferronickel (Ni–Fe) alloy with a high Ni grade of 10 wt% was successfully obtained, which could be directly further produced stainless steel. Meanwhile, a glass slag with a low Ni content (below 0.12 wt%) was also obtained, and its leaching characteristics further confirmed it is a non-hazardous slag because heavy metals were successfully encapsulated in glass slag, and thereby, this proposed method achieved the transformation from hazardous solid waste to general solid waste. The results of the 10 kg scale-up experiment indicated the possibility of industrialization of this new technology. Therefore, the process proposed in this study is a practical and promising process for Ni recovery from SPC and reutilization of CFA.

GRAPHICAL ABSTRACT

KEYWORDS:

• Hazardous solid waste
• smelting–vitrification process
• ferronickel alloy
• nickel recovery
• glass slag

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available with the article.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China (No: 2019YFC1907500) and Basic Research Foundation of Northeastern University (No. N2125033).