Investigation of ore settling in molten chloride salts

The Challenge

The economic viability of producing potash from potassium feldspar can be enhanced if the potassium chloride intermediate product can be separated from the molten salt mixture at elevated temperatures (>650°C) without cooling the solution.

Key Findings

Techniques including gravitational settling, high temperature filters, high temperature flocculants, layer testing, excess salt and settling under a vacuum were investigated for their ability to separate potassium chloride from a molten salt mixture.

These investigations demonstrated a limit to the natural settling capacity of the potassium chloride ore at or below the ore/salt concentration currently used in industry.

Mechanical separation using high temperature stainless steel mesh was able to retain up to 99.5% of potassium chloride ore, while allowing 87.0% of salt solution through at a salt:ore ratio of 9:1.

Benefits to WA

Improving the economic viability of producing potash (fertiliser) from potassium feldspar ore would support increased production and profits for existing processing facilities.

It may also be a critical enabler for the establishment of new processing facilities throughout the state, delivering increased employment and state government royalties.

Keywords: molten salts, potassium feldspar, potassium chloride, ore settling