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 results and effects:

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. 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).