Metal applications

Chromium VI is a dangerous product, present in solutions used in  leather and plating industries

It is highly toxic and must be eliminated from waste solutions down to very low levels to be released in the environment.

The acceptable limits are 0.1% in solids and 0.1 mg/l in liquids.

The present elimination techniques are based on a physico-chemical reduction and disposal of the treated product in controlled discharges associated with a high cost both economical and environmental high cost, with no valorisation of the chromium.  


ELSA developed a unique cementation process to reduce and valorise chromium VI waste solutions.

The CrVIin solution is reacts with iron powder in an optimised cementation reactor to form a ferrochromium oxide which can be sold as is to the steel industry producing ferrochromium alloys.

The result of the process is a solid with Cr, Fe and Oxygen with a final effluent which has less than 0.1mg CrIV (< 2mg/l Cr total) in complete conformity with the European regulations.

Products (by elsa) and properties

The solid produced by the optimized cementation process is an oxide mix containing 35 to 45% Fe, 20 to 25% Cr, the balance being mostly oxygen with some chlorine and sulphates.

Other metallic impurities remain very low < 0.2%.

The level of CrVI in the solid is less than 0.1%

The product is proposed to the steel industry is an additive in the fabrication of stainless steel.

Case studies

  • Vernier plant - CH