An integrated and efficient process for borax preparation and magnetite recovery from soda-ash roasted ludwigite ore under CO–CO2–N2 atmosphere

• Published in: International journal of minerals, metallurgy and materials metallurgy and materials, 2023-11, Vol.30 (11), p.2169-2181
• Main Authors: You, Jinxiang, Wang, Jing, Rao, Mingjun, Zhang, Xin, Luo, Jun, Peng, Zhiwei, Li, Guanghui
• Format: Article
• Language: English
• Subjects: Atmosphere; Borax pentahydrate; Boron; Carbon dioxide; Carbonation; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion and Coatings; Dosage; Efficiency; Fourier transforms; Gases; Glass; Iron; Lasers; Leachates; Leaching; Liquor; Ludwigite; Magnetic separation; Materials Science; Metallic Materials; Metallurgy; Natural Materials; NMR; Nuclear magnetic resonance; Particle size; Raman spectra; Roasting; Sodium; Sodium carbonate; Surfaces and Interfaces; Thin Films; Tribology; Wet grinding
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-023-2643-4

To realize the comprehensive utilization of ludwigite ore, an integrated and efficient route for the boron and iron separation was proposed in this work, which via soda-ash roasting under CO–CO 2– N 2 atmosphere followed by grind-leaching, magnetic separation, and CO 2 carbonation. The effects of roasting temperature, roasting time, CO/(CO+CO 2 ) composition, and Na 2 CO 3 dosage on the boron and iron separation indices were primarily investigated. Under the optimized conditions of the roasting temperature of 850°C, roasting time of 60 min, soda ash dosage of 20wt%, and CO/(CO+CO 2 ) of 10vol%, 92% of boron was leached during wet grinding, and 88.6% of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51wt%. Raman spectra and 11 B NMR results indicated that boron exists as B(OH) 4 − in the leachate, from which high-purity borax pentahydrate could be prepared by CO 2 carbonation.