Roasting reaction generator and nano aluminum oxide production method

Abstract

A roasting reaction generator comprises a strong oxidizing atmosphere high-temperature furnace, a high-pressure air suction and supply machine, a premixed natural gas spray gun, an oxygen generator and a control system. The method for producing nano aluminum oxide by using the roasting reaction generator comprises the following steps: in high-temperature fuel gas sprayed by the premixed natural gas spray gun, the mixing ratio of natural gas to oxygen is 1: 1-1: 2; the high temperature range is 1200-1800 DEG C, the single aluminum hydroxide particle fine powder is instantly subjected to dehydration reaction under the action of high temperature, the aluminum hydroxide fine powder particles are heated to the absolute temperature above the theoretical temperature of 732K, crystal water is removed, crystal form conversion is performed, and the like, so that gamma-type active nano aluminum oxide is generated, and crystal particles cannot grow up; the alpha-crystal-form aluminum oxide can be produced by increasing the flame temperature or the heating time. The invention aims at saving energy, protecting the environment, and being high in production efficiency and controllable in roasted aluminum oxide crystal particles.

Description

technical field [0001] The invention relates to a roasting reaction generator and a method for producing nano-alumina by using the roasting reaction generator. Background technique [0002] At present, the roasting process of producing γ crystal and α crystal alumina at home and abroad is: tunnel kiln and rotary kiln, the products are fired for a long time, high energy consumption, serious environmental pollution, uneven particle size of alumina crystals, and uncontrollable particle size , it is impossible to produce nano-scale high-grade alumina. When alumina is roasted in a tunnel kiln, only α-crystalline alumina can be produced. Put the industrial β-alumina powder into the sagger, stack it on the kiln car in a pyramid shape, line up into the kiln, and process it through calcination at a high temperature above 1400°C. The alumina core material in the sagger is cooked by the heat conduction of the alumina itself. Therefore, the size of the inner and outer particles is dif...

AI Technical Summary

Problems solved by technology

Generally, the conversion rate of α crystal form alumina reaches more than 95% on average. The higher the conversion rate of α crystal form alumina, the more fully the calcination, the higher the calcination temperature, and the conversion rate is easy to achieve. However, the calcined alumina fine powder requires After fine grinding treatment, it can be used as a raw material for ceramics or refractory materials, and the reactivity of alumina is poor.

The quality of the alumina powder skin and inner core of each sagger is different, and the quality of the inside, outside, and top and bottom of each sagger is different, the thermal efficiency is low, the loss is large, the pollution is serious, the consumption of the sagger is large, and the alumina crystal particles cannot be controlled.

When the rotary kiln roasts alumina, the cleaned wet aluminum hydroxide is fed into one end of the kiln, and heavy oil or gas is sprayed from the other end of the rotary kiln, and the reactions such as drying, removal of crystal water and crystal transformation are completed in the kiln. process, the alumina roasting process is unevenly heated, and the raw materials near the wall of the cylinder often appear to be discharged for a long time or in large pieces at the same time. The quality depends on the homogenization treatment in the later stage, and it is impossible to produce high-grade nano-alumina.

The thermal energy of the gas is discharged from the other end after passing through the rotary kiln, and part of the alumina is taken away at the same time. The thermal efficiency is low, the loss is large, the pollution is serious, and the alumina crystal particles cannot be controlled. It is necessary to provide a product with an average index after homogenization.

Images