Method for preparing high-quality calcium magnesia by superhigh-temperature calcination

Abstract

The invention relates to the field of preparation of refractory materials, particularly a method for preparing high-quality calcium magnesia by superhigh-temperature calcination, which is characterized by comprising the following steps: preparing dolomite and magnesite into a raw material in which the CaO content is 15-20 wt% and the MgO content is 80-85%; adding the raw material into a ball milling tank, grinding and mixing, and meanwhile, adding water to carry out slaking and slurrying; and drying the slurry, adding calcium lignosulphonate, evenly mixing, pressing into green bricks, and calcining. The calcination process comprises the following steps: heating to 1100 DEG C, keeping the temperature for 3-5 hours, heating to the final calcination temperature of 2000-2200 DEG C, keeping the temperature for 5-7 hours, vacuumizing, cooling with water to 1000 DEG C, introducing protective hydrogen, and continuing cooling with water to room temperature. Compared with the prior art, the calcium magnesia has the advantages of high hydration resistance and high corrosion resistance, thereby basically solving the problem of high hydration tendency in the magnesium-calcium refractory material, and facilitating the storage, transportation, building and the like in future.

Description

technical field [0001] The invention relates to the field of preparation of refractory materials, in particular to a method for preparing high-quality magnesia-calcium sand by ultra-high temperature calcination. Background technique [0002] At present, in order to meet the needs of the development of the metallurgical industry and further develop the advantages of magnesium-calcium refractories, it is necessary to solve the hydration problem of magnesium-calcium refractories. In recent years, scholars at home and abroad have conducted extensive research on this issue, and developed many methods to improve the hydration of magnesium-calcium refractory materials. However, it is not very ideal in terms of waterproofing effect: whether it is surface treatment, sealed packaging or production process control, it is necessary to isolate the product from the air as much as possible and prevent contact with water to achieve the purpose of waterproofing, but it is not fundamental. T...

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Problems solved by technology

However, it is not very ideal in terms of waterproofing effect: whether it is surface treatment, sealed packaging or production process control, it is necessary to isolate the product from the air as much as possible and prevent contact with water to achieve the purpose of waterproofing, but it is not fundamental To solve the problem of hydration, once the outer surface of the product is damaged, the protective layer that isolates the air will fall off, which will lead to rapid hydration of the product; at present, various additives can be added to improve the hydration performance. There are many kinds of such additives, including the following Generate liquid-based additives, such as Al 2 o 3 , Fe 2 o 3 、TiO 2 oxides, and CaF 2 , MgCl 2 and other salts, as well as solid solution-based additives such as CeO 2 、La 2 o 3 Such as rare earth oxides, the addition of these additives will inevitably lead to the decline of some high-temperature properties of magnesium-calcium materials, and the method of reducing its excellent high-temperature properties to obtain hydration resistance is obviously not ideal.

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