Additives and methods for reducing hexavalent chromium in cement

(22) 26.10.2007

(43) 15.07.2009

(45)12.09.2012/27.04.2016

(73) Mapei S.p.A., 20158 Milano (IT)

(57) This invention relates to a method for reducing hexavalent chromium in common cement. This method consists in the use of selected antimony(III) compounds directly added to cement before, during or after grinding. The efficacy of the method relies on the fact that the antimony(III) is a strong reducing agent in alkaline solution and can effectively reduce chromium(VI) to less toxic and less soluble chromium(III). The antimony(III) compounds are in liquid form or in form of suspension of solid particles in a liquid carrier. …

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