An environmentally friendly strategy for the preparation of high-purity quartz using combined collector reverse flotation coupled with acid-leaching technology

Abstract

High-purity quartz sand is an important raw material in the high-end silicon industry and is globally recognised as a key strategic resource. Currently, the problems of high energy consumption, long cycle time, low yield, and serious environmental pollution caused by by-products of the production process remain to be solved. In this study, a reverse-flotation anionic/cationic combined collector coupled with an acid-leaching process was developed to prepare high-purity quartz sand from vein-like quartz ores as raw materials. First, quartz with a purity of 99.9338% SiO₂ was pretreated. Subsequently, iron and silicate impurities, such as feldspar and mica, were removed from the ore by reverse flotation using an anionic/cationic combined collector, and the lattice impurity ions were removed by utilising a low-fluorine hot-pressure rotary acid-leaching process. Under the optimal process conditions, the purity of SiO₂ in the product reached 99.9980%. A complete set of reversed-flotation anionic/cationic collector–acid-leaching systems were constructed to purify Asian vein quartz into high-purity quartz sand for industrial application in photovoltaics and semiconductors.