Metallurgical solid waste steel slag cement manufacturing method

Abstract

The invention relates to a metallurgical solid waste steel slag cement manufacturingmethod. Metallurgical solid waste steel slag is immersed into a certain amount of water (or other liquid), and the obtained mixture is put into a pressure container, heated and pressurized, and subjected to heat preservation and pressure maintaining for a certain period of time, so that the water (or other liquid)permeates into dicalcium silicate and tricalcium silicate dense crystals in the steel slag, the pressure container is instantly opened to release pressure, so that the air pressure is rapidly reduced.Due to the fact that the water permeates into the overburnt dicalcium silicate and tricalcium silicate in the steel slag, water molecules are rapidly vaporized and expanded under the huge pressure difference, the crystallization density of the dicalcium silicate and tricalcium silicate is reduced, the specific surface area is increased, the hydration speed of the overburnt dicalcium silicate, tricalcium silicate and other substances is increased, and the early hardness of steel slag cement is improved. Free calcium oxide and magnesium oxide completely react to generate calcium carbonate through pressurization release of carbon dioxide and a catalyst. Due to stable components of magnesium carbonate, later magnesium oxide of the steel slag cement can be avoided. Due to the unstable expansion of the calcium oxide, a great amount of magnetically-separable iron alloy powder can be obtained through reduction.

Description

technical field [0001] The invention relates to a method for preparing cement from metallurgical solid waste steel slag. Background technique [0002] In the process of steel production, about 10% of solid waste steel slag is produced. Because the steel smelting temperature is above 1560 degrees Celsius. The crystals of dicalcium silicate and tricalcium silicate in steel slag are very dense (the sintering temperature of dicalcium silicate C2S and tricalcium silicate C3S in cement is 1460 degrees Celsius) and it is difficult to hydrate. The hydration and solidification rate is much slower than that of cement, resulting in low early strength of steel slag cement, which affects the application of steel slag cement. Furthermore, steel slag contains a certain amount of free magnesium oxide and calcium oxide, which absorb carbon dioxide in the air at the later stage of steel slag cement solidification, and the volume expands, resulting in a decrease in concrete strength. Conte...

AI Technical Summary

Problems solved by technology

The hydration and solidification rate is much slower than that of cement, resulting in low early strength of steel slag cement, which affects the application of steel slag cement

In addition, steel slag contains a certain amount of free magnesium oxide and calcium oxide, which absorb carbon dioxide in the air at the later stage of steel slag cement solidification, and the volume expands, resulting in a decrease in concrete strength.