Method for preparing high-activity magnesium oxide from magnesite

Abstract

The invention provides a method for preparing high-activity magnesium oxide from magnesite. The method includes the following steps of breaking, grinding, twice calcinating, magnetic separating and the like. By means of the neutral-reduction two-section calcinating process, calcinating is conducted at a low temperature, it is ensured that the magnesite is decomposed into an MgO amorphous body under the low-temperature calcinating conditions, the magnesite is calcinated for decomposing one part under the neutral conditions, the MgCO3 can be incompletely decomposed to generate CO, the generatedCO is used for later-stage calcinating as reduction gas so that weak-magnetic iron minerals in the magnesite can be reduced into strong magnetic iron minerals, the undecomposed magnesite continues tobe decomposed in the reduction and calcinating process through magnetic separation removal, the magnesite is finally completely decomposed through calcinating under the two-section low-temperature conditions, the rapid generation of MgO crystals under the high-temperature conditions is avoided, the content of the MgO amorphous body in the obtained activated magnesium oxide is high, activity is high, and the citric acid detection CAA value is 13-15 seconds.

Description

technical field [0001] The invention relates to the technical field of magnesite calcining, in particular to a method for preparing high-activity magnesium oxide from magnesite. Background technique [0002] my country is rich in magnesite resource reserves, with proven reserves of about 3.1 billion tons, accounting for a quarter of the world's total reserves, mainly distributed in Liaoning and Shandong provinces, whose total reserves account for about 95.11% of the country's total reserves, of which Liaoning The province is mainly concentrated in the southern part of Liaoning, such as Haicheng, Yingkou and other areas. There are 12 proven mining areas with reserves of 2.577 billion tons, accounting for about 85% of the country's total reserves and 20% of the world's total reserves. Existing calcination methods for magnesium oxide include fixed bed type (such as tunnel kiln, downdraft kiln, shuttle kiln, pusher kiln and insulation cylinder), semi-fixed bed type (such as verti...

AI Technical Summary

Problems solved by technology

[0004] At present, lump ore magnesite is mostly used to calcinate active magnesia, mostly at 800~1000°C, which is very easy to cause over-burning or under-burning, and the number of pores in the fired material is small and the density is high. Magnesium oxide has large grain size and significantly reduced activity

In addition, magnesite is often accompanied by impurities such as iron oxide and ferrous oxide that have not been removed, which affects the quality of active magnesium oxide and reduces its activity.