Zero-waste valorisation of feldspathic ores Green application and sustainable sourcing of strategic raw materials

Purpose and goal

Potash (K2O) is one of the important macronutrients required for plant growth and currently has no profitable substitutes. In this project, feldspar ore that mainly contains K feldspar will be valued through mixed and zero-waste metallurgical processes where KCl, Al2O3 and SiO2 are produced. The use of ore in CO2 sequestration and whether it is conceivable to produce Ca-silicates and SiC are studied. The goals of the project are: o Provide new resources for KCl and Al2O3 o Provide of SiO2, Ca-silicates, and o SiC production from the same resources.

Expected effects and result

The consumption of potash in the EU is about 5.5 million tonnes / year, most of which is used in fertilizer production. In addition, alumina is used in many technical materials due to its desirable properties. Thus, the expected effects and results are: o To apply an environmentally sensitive manufacturing method to produce KCl and Al2O3 as well as SiO2, SiC and Ca silicates from process residues; and o To use feldspar ore mineral as a deposit for CO2 sequestration for the first time.

Planned approach and implementation

Research studies are organized on the point of performing a multistage processing including the following main sub-processes: a.Intensive milling for mechanical activation (WP2); b.CO2 sequestration (WP3); c.HCl leaching of the ore for dissolution of K-bearing minerals (WP4); d.Purification of the leach liquor (WP5); e.Roasting for conversion of AlCl3 to Al2O3 and vaporisation of KCl (WP6); f.NaOH treatment of siliceous residue of HCl leaching (WP7); g.SiC production from the precipitated SiO2 (WP8); and h.Ca-Silicate production from the precipitated SiO2(WP9).