Carbonated steel slag aggregate and preparation method thereof

Abstract

The invention discloses a carbonated steel slag aggregate and a preparation method thereof. The method comprises the following steps: sieving steel slag subjected to iron separation, taking particles with size between 0.5-25 mm particle for high pressure water flushing, and naturally drying the particles; immersing the dried steel slag particles in a mixed solution of 20-300 g / L caustic soda and 60-300 g / L sodium carbonate for 24 h, and maintaining the temperature at 20-60 DEG C; draining the soaked steel slag particles, immediately placing the particles in a sealed carbonation reactor, and introducing CO2 gas with purity over 99.9% for curing at the temperature of 70-90 DEG C for 0.5 h, and with the CO2 gas pressure at 0.2-0.5 MPa; cooling the steel slag particles subjected to carbonation treatment under natural conditions to room temperature, so as to obtain the carbonated steel slag aggregate. The steel slag aggregate treated by the method has compact surface structure to reduce water for concrete mixing; free magnesium oxide and free calcium oxide are conversed into carbonate precipitation to eliminate the hidden trouble of adverse stability; CO2 can be stored stably; the amount of natural aggregate is reduced to save nonrenewable resources; and the method has easily available raw materials and simple process.

Description

Technical field [0001] The invention relates to a carbonated steel slag aggregate and a preparation method thereof, and belongs to the technical field of solid waste treatment and reuse. Background technique [0002] Although my country's natural aggregate resources are widely distributed, since the concrete industry consumes at least 3.6 billion tons of natural sand and gravel each year, there has been a phenomenon that the stone resources are unsustainable. At the same time, the massive mining of natural stone has caused damage to the original landform and plant cover, soil erosion and deterioration of the natural landscape, which seriously affects the sustainable development of society. Therefore, finding new materials to replace natural aggregates is one of the effective ways to change this situation. [0003] At present, the accumulated steel slag in my country is as high as 500 million tons, which not only occupies a large amount of arable land, but also severely pollutes th...

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Problems solved by technology

However, although the steel slag that has experienced a high temperature of 1650°C has high hardness, the surface porous structure caused by the overflow of volatile components seriously affects the water consumption of concrete mixing, and the high content of free magnesium affects its stability. Therefore, it cannot be directly used as bone. material