Method for preparing high-activity light calcined magnesia through suspending-boiling multi-flow-state combined mode

Abstract

The invention relates to a method for preparing high-activity light calcined magnesia through a suspending-boiling multi-flow-state combined mode. The method comprises the following steps: taking magnesite with a grain size of 0-2 mm as thea raw material, decomposing the raw material inunder a suspending state of a suspending-state roasting decomposing furnace, feedingthe decomposed material particles to thea boiling-state decomposing furnace along with hot gas flow;, decomposing the material particles under a boiling state;, and continuously decomposing un-decomposed magnesite in a braising process of the boiling-state decomposing furnace. The method guarantees magnesite decomposition reaction to sufficiently perform, and has a decomposition rate higher than 99%. A magnesite resource utilization rate is increased by about 20%, and energy is saved by 35% or more. The whole system is in closed production, prevents flying loss of products and environmental pollution, improves a dischargefield operation environment, has dust emission concentration smaller than or equal to 10 mg / standard cubic meter, and completely realizes clean production; and existing reflecting kiln technology hasdust emission concentration generally equal to or higher than 200 mg / standard cubic meter.

Description

technical field [0001] The present invention relates to the technical field of metallurgy, in particular to a method for preparing high-activity light-burned magnesia by means of suspension-boiling multi-fluidity combination. Background technique [0002] Magnesite is one of my country's advantageous mineral resources, with a total reserve of more than 3 billion tons, accounting for a quarter of the world's magnesite reserves and ranking first in the world. Light-burned magnesia produced by calcination of magnesite is the most productive magnesia material. The annual production capacity of light-burned magnesia in my country is over 10 million tons. Light-burned magnesia has excellent alkali resistance and electrical insulation, strong adsorption capacity, high thermal conductivity, and large thermal expansion coefficient. It is widely used in metallurgy, building materials, and national defense. It is also an important industrial raw material. Its downstream products includ...

AI Technical Summary

Problems solved by technology

The reverberatory kiln can only use high-quality lump ore (50-300mm) resources, and a large amount of powder resources are wasted; the energy consumption per ton of products is equivalent to more than 240 kg of standard coal, which is too large; a large amount of dust is emitted during the production process, and the concentration exceeds 200 mg / standard cubic meter, which has serious adverse effects on the environment and ecology; manual operation is used in production, which is labor-intensive and low in automation; the product has poor activity and low added value

[0004] The suspension method calcination technology that has appeared in recent years to prepare light-burned magnesia has the characteristics of large transfer area, large comprehensive transfer coefficient, large transfer power, fast calcination speed and high thermal efficiency. The gaseous suspension preheating and pre-decomposition device transplanted is not suitable for the decomposition and calcination of magnesite. Because the residence time of magnesite in the suspension kiln is very short, the heat transfer and reaction time are insufficient, and the material decomposition is not complete. Some magnesite The ore particles are not really decomposed, and the quality of the prepared light-burned magnesia is uneven and stable, so the effect of calcining magnesite by suspension method is not ideal in practical application

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