The Fengxin area of Yichun, Jiangxi Province, boasts abundant lepidolite reserves, whose ore bodies contain 40%–50% associated albite — a high-value non-metallic mineral resource. Nevertheless, flotation tailings generated during lepidolite processing (primarily composed of feldspar and quartz) retain 0.62% iron impurities (calculated as Fe₂O₃). This restricts the product whiteness to merely 43%, far below the industry thresholds for premium ceramic-grade feldspar, which require Fe₂O₃ content below 0.15% and whiteness above 60% . Efficient removal of finely disseminated, weakly magnetic iron-bearing impurities to realize high-value utilization of associated feldspar has long been a critical technical bottleneck for comprehensive mineral exploitation in this region.

To tackle this issue, the project deployed four SLon-5000 VPHGMS to establish an intensive iron removal and purification process dedicated to lithium flotation tailings (Figure 1). Industrial operational data verifies that the separator’s background magnetic field strength of up to 1.8 T enables effective capture of microscale weakly magnetic iron minerals embedded within feldspar grains. After separation, the Fe₂O₃ content of feldspar concentrate drops from 0.62% to 0.13%, while whiteness rises sharply from 43% to 60%, fully complying with quality standards for high-end ceramic raw materials.

Relying on this technology, a demonstration plant with an annual processing capacity of 33 million tons of low-grade lepidolite ore has been constructed locally, producing over 20 million tons of premium feldspar concentrate every year. This application not only achieves full comprehensive utilization and value enhancement of massive associated minerals generated during primary lithium extraction, but also supplies vital technical and equipment support for quality improvement, efficiency growth and green transformation of China’s non-metallic mineral industry.

Fig 1. Application site and process flow diagram of SLon-5000 separators in Fengxin, Jiangxi