Hexavalent chromium will cause a serious bad symptom to humans, making it difficult to cure the pain which perishes a dermatitis or eczema. In recent years, the pollution problem of hexavalent chromium has attracted people’s great attention. The cost of treating industrial waste slag contains hexavalent chromium is very expensive, and secondary pollution can be caused easily too, If it can be used in cement production, both the environmental pollution and the cement productive cost will be reduced. However, the problem of hexavalent chromium also introduced to cement industry accordingly. So how to reduce the Hexavalent chromium content in cement?
Ferrous sulfate, Stannous chloride and Stannous sulfate are widely used in cement industry as a reducing agent, and all these three agents have very good effects. But the cost of Stannous chloride and Stannous sulfate are too high to be used on a large scale (Stannous chloride: USD 8000/MT, and Stannous sulfate: USD 9500-12700/MT). Ferrous sulfate is a common and cheap chemical which only cost USD80-160/MT, non-toxic with very stable chemical property. What’s more, adding q.s. ferrous sulfate into cement will not affect the product property such as bending strength,
compressive strength and water solubility etc.
In June 2003, EU has issued regulations that the cement and the cement production which the content of water soluble hexavalent chromium exceeding 0.0002% were prohibited from selling and using. It has been found that adding 0.09% ferrous sulfate into the cement will reduce the hexavalent chromium content to 0.00012%, it is lowcost and effective, What’s more, the experimental results shows that the reductive stability of ferrous sulfate is present well, and the packet of the cement can be kept up the content of exavalent chromium no more than 0.0002% in 180 days.
Ferrous sulfate mono granular and powder can be mixed into cement when producing, ferrous sulfate granular can be put into clinker to be grinded together, and ferrous sulfate powder can be mixed with finished cement to be used to reduce the content of water soluble hexavalent chromium.
Ferrous sulfate, Stannous chloride and Stannous sulfate are widely used in cement industry as a reducing agent, and all these three agents have very good effects. But the cost of Stannous chloride and Stannous sulfate are too high to be used on a large scale (Stannous chloride: USD 8000/MT, and Stannous sulfate: USD 9500-12700/MT). Ferrous sulfate is a common and cheap chemical which only cost USD80-160/MT, non-toxic with very stable chemical property. What’s more, adding q.s. ferrous sulfate into cement will not affect the product property such as bending strength,
compressive strength and water solubility etc.
In June 2003, EU has issued regulations that the cement and the cement production which the content of water soluble hexavalent chromium exceeding 0.0002% were prohibited from selling and using. It has been found that adding 0.09% ferrous sulfate into the cement will reduce the hexavalent chromium content to 0.00012%, it is lowcost and effective, What’s more, the experimental results shows that the reductive stability of ferrous sulfate is present well, and the packet of the cement can be kept up the content of exavalent chromium no more than 0.0002% in 180 days.
Ferrous sulfate mono granular and powder can be mixed into cement when producing, ferrous sulfate granular can be put into clinker to be grinded together, and ferrous sulfate powder can be mixed with finished cement to be used to reduce the content of water soluble hexavalent chromium.
This post first appeared on Ferrous Sulfate Monohydrate Powder|RECH CHEMICAL, please read the originial post: here
