Chromium removal grinding aid for cement and preparation method thereof

The invention provides a chromium removal grinding aid for cement and a preparation method thereof. The method comprises steps of: adding ferrous sulphate into a cladding material solution under protection of inert gas, stirring uniformly and carrying out rectification to obtain organic matter cladded ferrous sulphate; carrying out polymerization on starch and methyl acrylate, under protection ofinert gas and existence of an initiator, to obtain starch and methyl acrylate graft copolymer; carrying out amidation reaction on the starch and methyl acrylate graft copolymer in an organic solvent to obtain a chromium curing agent; and mixing well the organic matter cladded ferrous sulphate, the chromium curing agent and a grinding aid to obtain the chromium removal grinding aid for cement. During a grinding process, organic matter cladded on ferrous sulphate surface is destroyed, and exposed ferrous sulphate reduces hexavalent chromium in the cement; during a hydration process, the chromium curing agent in the grinding aid precipitates and solidifies the hexavalent chromium generated in the hydration process through sequestration, thereby further increase chromium removal rate.