Evolution of Feldspar Flotation Technology

Feldspar and quartz are the most abundant rock-forming minerals in the Earth's crust, widely used in industries such as ceramics and glass. Due to their highly similar physicochemical properties, flotation serves as the core method for their efficient separation. Based on differences in reagent systems, feldspar flotation processes are primarily categorized into the following three types:

I. Fluoride-Acid Method

This traditional mainstream approach achieves efficient flotation by activating feldspar surfaces through the combined action of strong acids and fluoride ions (typically derived from hydrofluoric acid). The mechanism of hydrofluoric acid primarily involves: forming complexes with aluminum, creating fluorosilicate activation sites, and depositing on quartz surfaces to enhance amine collector adsorption. Despite its excellent separation efficiency, its application is increasingly restricted due to severe fluoride pollution and difficult wastewater treatment.

2. Fluoride-Free Acid Method

This method eliminates fluoride compounds, relying solely on strong acids like sulfuric or hydrochloric acid to reduce iron content in feldspar. While avoiding fluoride pollution, it still faces significant environmental pressures due to severe equipment corrosion, high acid consumption, and demanding production conditions.

3. Fluoride-Free, Acid-Free Method

This process entirely eliminates fluorides and acids. Under neutral or weakly alkaline conditions, selective separation of feldspar from quartz is achieved using mixed collectors. Quartz exhibits no floatability in this system, enabling efficient feldspar recovery. Its advantages are significant: zero pollution, low reagent consumption, no acid pretreatment required, minimal equipment demands, and a balance of economic benefits and environmental friendliness.

Overall, feldspar flotation technology is transitioning from “high-efficiency, high-pollution” to “green, efficient, low-cost” approaches. The fluoride-free, acid-free method has become the mainstream development direction. Future research should focus on developing new environmentally friendly reagents and fundamental studies on the surface property differences between feldspar and quartz to achieve cleaner flotation processes with higher selectivity and lower costs.