Temperature control during bauxite calcination is a key link to ensure product quality. The following are the specific methods and parameters of temperature control during bauxite calcination:

I. calcination temperature range

The calcination temperature of bauxite is usually between 1400℃ and 1600℃. The specific temperature needs to be adjusted according to the grade and use of bauxite:

Super bauxite: sintering temperature is 1600℃ to 1700℃.

Grade I bauxite: the sintering temperature is 1500℃ to 1600℃.

Grade II bauxite: the sintering temperature is 1600℃ to 1700℃.

Grade III bauxite: the sintering temperature is 1500℃ to 1550℃.

II. Temperature control stage

The calcination process is usually divided into the following stages:

Preheating stage (400℃ to 600℃): This stage is mainly used to remove crystal water from bauxite. The kiln tail temperature should be controlled at 220℃ to 400℃.

High temperature calcination stage (1400℃ to 1600℃): This stage is the main calcination stage of bauxite, and the temperature needs to be accurately controlled according to the grade of bauxite.

Cooling stage: After the calcination is completed, the materials should be slowly cooled to normal temperature to prevent pulverization caused by rapid cooling.

III. Temperature control method

Inverted flame kiln: suitable for small batch production, the temperature is controlled at 800℃ to 1200℃. The inverted flame kiln ensures the uniform heating of materials through the design of flame backflow.

Rotary kiln: suitable for large-scale production, the calcination temperature is generally from 1400℃ to 1600℃. The temperature is controlled by adjusting the rotating speed of the kiln and the fuel supply.

Shaft kiln: The calcination temperature is usually 1400℃ to 1600℃, and the temperature is adjusted by controlling the fuel supply and ventilation conditions.

IV. Precautions for temperature control

Avoid over-burning or under-burning: too high calcination temperature will lead to too much glass phase formation, while too low temperature will lead to under-burning of materials.

Uniform heating: ensure that the materials are heated evenly in the kiln to avoid local overheating or supercooling.

Temperature fluctuation control: In the high-temperature calcination stage, the temperature fluctuation should be controlled within 10℃.

By accurately controlling the calcination temperature, the fire resistance and mechanical properties of bauxite can be effectively improved to meet the needs of different industrial applications.