Scale-up validation of an integrated process for boron/iron separation and boric acid preparation from ludwigite ore

Abstract

Ludwigite ore is a strategic mineral resource unique to China. Its efficient and comprehensive utilization is of paramount importance for ensuring the healthy and sustainable development of China’s industry and national defense security. This study presents and validates a scale-up integrated process for separating boron and iron from boron–iron mixed concentrate (BIMC) and producing reduced iron powder and high-purity boric acid. The process involves reductive soda-ash roasting in a rotary kiln, followed by wet-grinding, magnetic separation, and fractional crystallization. Under optimized parameters, the process achieved a boron leaching efficiency of 70.23%, an iron grade in the magnetic concentrate of 94.12wt%, and a corresponding recovery of 93.35%. The recovered reduced iron powder can be used as feed for short-process steelmaking. The boron-rich liquor was then used to prepare high-purity boric acid (>99wt%) with a regular morphology by adjusting the pH with sulfuric acid, and the corresponding aqueous chemical behaviors were investigated. This integrated process offers a promising approach for the efficient and environmentally friendly utilization of boron–iron complex ore.

Keywords

ludwigite ore / reductive-soda roasting / reduced iron powder / scale-up validation / solution chemistry / boric acid

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