Inorganic Chemicals Industry ›› 2026, Vol. 58 ›› Issue (2): 76-82.doi: 10.19964/j.issn.1006-4990.2025-0063

• Environment·Health·Safety • Previous Articles     Next Articles

Study on extraction of magnesium from chromium slag

YAN Chunyu(), ZENG Yijun, QIU Zirong, QUAN Xuejun(), LI Gang()   

  1. School of Chemistry and Chemical Engineering,Chongqing University of Technology,Chongqing 400054,China
  • Received:2025-02-10 Online:2026-02-10 Published:2025-08-01
  • Contact: QUAN Xuejun, LI Gang E-mail:yan2134838656@163.com;hengjunq@cqut.edu.cn;47922138@163.com

Abstract:

Chromium slag is the solid waste generated during the production of chromium salts from chromite.After deep extraction of chromium and aluminum from the chromium slag,a low-chromium slag is obtained.This low-chromium slag mainly contains valuable metal elements such as iron and magnesium,and has significant recovery value.In order to address the challenge of resource utilization of low-chromium slag, an ammonium sulfate roasting-acid leaching process was proposed.The experiment used ammonium sulfate as the roasting agent.Based on the different thermal decomposition characteristics of MgSO4 and Fe2(SO43 at high temperatures,by precisely controlling the roasting temperature,efficient and selective extraction of magnesium was achieved,while simultaneously promoting the stabilization and enrichment of iron.The results showed that under the optimal process conditions of a baking temperature of 700 ℃,a baking time of 40 min,an ammonium sulfate dosage of 1.5 times the theoretical amount,an acid leaching time of 30 min,and a stirring speed of 500 r/min,the extraction rate of magnesium reached 99.38%,and the mass fraction of iron oxide in the magnesium extraction residue phase exceeded 90%,providing a basis for the high-value utilization of iron.This process enabled efficient separation of magnesium and iron from the low-chromium slag.It provided technical support for the comprehensive utilization of multiple metal elements in chromium slag,and was of great significance for promoting the development of circular economy and reducing environmental pollution.

Key words: chromium slag, extraction of magnesium, ammonium sulfate roasting, acid leaching

CLC Number: