"Efficient Bauxite Desilication: How Selective Grinding Redefines Beneficiation Standards"

As the core raw material for alumina production, bauxite has long been plagued by silicon-containing impurities (such as kaolinite and illite), which restrict smelting efficiency. Sodium aluminosilicate formed during the dissolution process not only causes aluminum loss but also increases alkali consumption and production costs. To address this challenge, Chinese researchers have developed an innovative "selective grinding-coarse-fine separation" technology based on in-depth studies of bauxite's process mineralogy, offering a breakthrough solution for efficient bauxite desilication.

Traditional technologies, such as stage grinding with single separation and classification-flotation, achieve limited desilication but suffer from conflicts in flotation conditions for coarse and fine particles, high reagent consumption, and insufficient concentrate Al/Si ratio. The new process creatively integrates flash flotation principles with coarse-fine classification technology. By adopting a synergistic strategy of "targeted grinding + size-specific separation," it achieves dual breakthroughs in desilication efficiency and cost control. Its core logic lies in leveraging the significant differences in flotation properties between coarse and fine particles: coarse diaspore monomers and rich aggregates in the grinding-classification circuit are directly recovered via rapid flotation (Concentrate 1), while fine pulp enters a conventional flotation circuit (Concentrate 2). This "separate treatment" model avoids recovery loss of coarse particles due to long flotation paths and reduces interference from fine gangue in concentrate quality. 

Experimental data validate the technology's superiority: with a raw ore Al/Si ratio of 5.83, the concentrate yield reaches 83.09%, Al/Si ratio increases to 12.61, and Al₂O₃ recovery hits 90.39%. Compared to traditional processes, it reduces concentrate processing cost by 6-11 RMB/ton, cuts reagent consumption, and improves concentrate dewatering performance and subsequent Bayer process efficiency. The key innovation is "selective grinding"—targeting diaspore-rich aggregates and 放宽 the grinding fineness to 60%-65%-75μm, avoiding over-grinding of valuable minerals. Rapid flotation of coarse particles shortens separation time, balancing resource recovery and energy efficiency.

 Validated by small-scale and continuous tests, the technology's technical advancement and economic rationality are fully recognized. As an innovation in bauxite beneficiation, it promotes efficient utilization of low-grade bauxite resources in China, supports cost reduction in the alumina industry, and drives the sector toward green, efficient, and sustainable development.