Cement Additives

Wet cement can contain soluble hexavalent chromium, which causes allergic chromate dermatitis in workers handling mortar and concrete. European regulations restrict soluble Cr(VI) in cement, so producers blend in an iron-salt reducing agent that converts it into insoluble, far less hazardous trivalent chromium.

Typically at the finish mill, metered onto the clinker and gypsum feed so grinding distributes the reducer homogeneously through the cement. Uniform distribution matters: the reducer must dissolve everywhere in the mix at the moment water is added.

By laboratory testing of the soluble Cr(VI) content of each cement type, followed by plant trials. The rate is then re-verified at routine intervals and after any change in raw materials or kiln operation, because reducer demand moves with clinker chemistry.

Dry and cool, in sealed original packaging on pallets, with first-in, first-out rotation. Moisture is the main enemy — damp air slowly consumes the reducing capacity of iron salts — so bags are opened only at the point of dosing and within the stated shelf life.