Nodular cast iron pipe anti-corrosion lining for conveying drinking water and manufacturing method

Abstract

The invention discloses a nodular cast iron pipe anti-corrosion lining for conveying drinking water and a manufacturing method, the nodular cast iron pipe anti-corrosion lining is made of cement mortar, the cement mortar is made of cement, water, sand and additives, the cement comprises the following concrete components by mass: 25%-70% of cement clinker and gypsum, 10%-70% of superfine slag powder, 5%-20% of silica fume powder. The cement clinker comprises the following main mineral components in percentage by mass: 30%-65% of C3S, 10%-50% of C2S, less than or equal to 10% of C3A, less than or equal to 1.5% of free calcium oxide fCaO and less than or equal to 1% of (Na2O + 0.658 K2O). According to the anti-corrosion lining disclosed by the invention, the strength of the cement mortar lining is improved, and the porosity of the lining is reduced, so that the rising of the pH value of water and the rising of the aluminum content caused by the precipitation of calcium and aluminum hydrates in the water delivery process of the cement mortar lining are reduced, and the corrosion resistance of the lining and the hygienic performance of the water are improved.

Description

technical field [0001] The invention relates to the technical field of pipeline cement mortar lining, in particular to an anticorrosion lining of a ductile iron pipe used for transporting drinking water. Background technique [0002] As an excellent water delivery pipe, ductile iron pipe has been widely used in water delivery network projects. Compared with other pipes, ductile iron pipes have the advantages of excellent mechanical properties, excellent corrosion resistance, good sealing performance, low accident rate, and low leakage rate. [0003] The cement mortar lining has good anti-corrosion performance and belongs to active anti-corrosion. However, most of the commercially available cements are construction cements, and there is no cement used for cement products in contact with drinking water. Since construction cement is mostly used in reinforced concrete structures, the alkalinity of the cement is required to form a passive film on the surface of the steel bar to...

AI Technical Summary

Problems solved by technology

However, for the cement mortar lining of ductile iron pipes conveying drinking water, due to the existence of calcium hydroxide, a hydration product, it is easy to cause the initial pH value of small-diameter pipes to increase.

In addition, alumina is also one of the main mineral components of cement, which leads to the increase of aluminum content in water quality in the early stage of water delivery by small-diameter pipes

Excessive consumption or long-term consumption of food or water containing aluminum is potentially harmful to the human body

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