Liquid cement additive for reducing content of water-soluble Cr<6+> in cement

Abstract

The invention provides a liquid cement additive for reducing the content of water-soluble Cr<6+> in cement. The liquid cement additive has good Cr<6+> elimination ability, and also has the advantages of reasonable price, small mixing amount, and small influences on the performances of cement. The liquid cement additive comprises, by mass, 5-10% of sodium borohydride, 5-10% of sodium sulfite, 5-10% of sodium nitrite, 5-10% of sodium formate, 1-5% of polyglycerol, 0-15% of alcohol amine, 0.5-1% of NaOH, and the balance of water, wherein the alcohol amine is at least one of triethanolamine, triisopropanolamine, diethanol isopropanolamine and methyldiethanolamine, and the pH value of the liquid cement additive is 10-14. The liquid cement additive has good Cr<6+> elimination ability, and has the advantages of reasonable price, small mixing amount, and small influences on the performances (such as water requirement of normal consistency and intensity) of cement.

Description

Technical field [0001] The invention relates to a method for reducing the water-soluble Cr of cement 6+ The content of liquid cement additives belongs to the field of building materials. Background technique [0002] Cement is the basic raw material used in industrial and civil construction concrete. After mixing with water, the cement contains water-soluble Cr 6+ It will dissolve quickly. At this time, use freshly mixed cement paste, mortar or concrete in the plastic stage, and bricklayers and concrete workers will be exposed to the soluble Cr in the cement for a long time. 6+ If reasonable labor protection measures are not adopted, sensitive people will cause skin allergies, so that incurable cement allergic contact eczema is formed, which usually manifests as pain, ulceration, and even loss of labor ability in severe cases. Water-soluble Cr in cement 6+ The sources are: 1) Cement mixed materials, such as chromium-containing industrial waste slag, which is currently water-solubl...

AI Technical Summary

Problems solved by technology

For the way of using reducing agent, the current domestic and foreign patents and data show that the use of reducing agents such as ferrous sulfate heptahydrate and stannous chloride, stannous sulfate, zinc sulfate, zinc chloride and manganese sulfate has a good effect on eliminating Cr 6+ capacity, but the dosage of ferrous sulfate heptahydrate alone will be relatively high, generally 0.2%-0.4% in cement, while stannous chloride, stannous sulfate and manganese sulfate are limited in market acceptance due to their high prices. However, products such as zinc sulfate a

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