COLLOIDAL AQUEOUS HYDROXIDE SUSPENSION OF AT LEAST ONE TRANSITION ELEMENT THAT REDUCES CHROMIUM IN CEMENT

摘要

A novel aqueous suspension (A) of tin hydroxide (Sn(OH) 2) (I) of pH more than 2, for reducing the hexavalent chromium (Cr 6 +) content of cement to less than 2 ppm, contains (I) at 0.5-80 wt. % (as solids based on water) and is stabilized mechanically and/or by a water-soluble stabilizer (II). Independent claims are given for: (a) the use of the obtained cement for producing a concrete composition comprising the (A)-treated cement, water and conventional components; and (b) concrete compositions comprising cement, water and conventional components, where (A) is added in the mixing stage to reduce the soluble Cr 6 + content to 2 mg per kg of cement or less.