The production process of rotary kiln

The cylinder of rotary kiln is made of thick steel plate and installed at an inclined Angle of 3%~3.5%. The barrel is lined with refractory. The calcination belt of the high temperature rotary kiln should also increase thermal insulation refractory. The weight of the kiln body is transmitted to the supporting roller through the roller fixed on the kiln body, and several sets of supporting wheels are determined according to the length of the kiln body. The operation of rotary kiln is transferred by the main motor through the reducer to a big gear fixed on the cylinder body with a spring plate, which drives the cylinder body to operate slowly. In order to ensure that the kiln body can turn during the failure and maintenance of the main transmission device, and to prevent the barrel body deformation caused by kiln shutdown, the auxiliary transmission system shall be equipped. The feeding end of rotary kiln is the kiln tail, and the discharging mouth is the kiln head. Feeding tube is set at the kiln end, burner is set at the kiln head to supply heat, and the fuel of rotary kiln is heavy oil, coal powder or gas.

Compared with the raw materials calcined by shaft kilns, the application of rotary kiln calcination has the following advantages :(1) the kiln has large production capacity, high degree of automation and high labor productivity; (2) It can burn small particles below 30mm to improve mine utilization rate and make full use of mine resources; (3) Product quality is stable and uniform; (4) Simple masonry, less brick type, stable movement, less maintenance.

Its disadvantages are as follows :(1) heavy weight of individual equipment, high one-time investment; (2) High heat consumption; (3) It covers a large area.

Rotary kilns are widely used in the refractory industry. Common uses include calcined clay, high alumina, magnesia, high iron ore, magnesia chrome sand, magnesia alumina spinel, dolomite and active lime, etc.

Ultra-high temperature rotary kiln uses heavy oil as fuel and calcines at temperatures above 1850℃ without oxygen enrichment. It is suitable for calcination of high-purity refractory raw materials, such as calcined alumina, synthetic mullite, magnesium-aluminum spinel, magnesium-chromium sand and magnesium-calcium sand. The calcining system of ultra-high temperature rotary kiln is composed of primary fan, heavy oil system, burner, kiln head car, rotary kiln, efficient cooling tube, dust collecting room, blanking tube, heat exchanger, smoke exhauster, dust collector and so on.

In order to achieve ultra-high temperature calcination, the following measures are taken:

(1) The lining of the calcining belt is high-grade refractory, and the outer layer is heat insulation material. Controlling the surface temperature of the cylinder is conducive to improving the calcining temperature and saving energy at the same time.

(2) By recovering waste heat from flue gas at the kiln end, preheating primary air and adjusting the secondary air into the kiln, the calcining temperature is greater than 1850℃ under the condition of not enriching oxygen.

(3) Adopting the mechanical atomizing burner, through adjusting the primary air system, the diameter and length of the burner flame can be effectively changed, so as to adjust the length of the calcining belt and the flame temperature.

(4) Through the automatic regulation of pressure in the kiln and the pressure of the combustion system, ensure the stability of combustion, and have the characteristics of flexible and reliable regulation.

It was used to calcine corundum with a primary air with 26% oxygen content, and the oxygen-enriched operation made the flame temperature reach 2300 ° C and the kiln end temperature drop to 800 ° C, and the fuel consumption was estimated to be reduced by 20%~30%. Therefore, calcining enriched gas is an effective measure to save energy.

The technical characteristics of rotary kiln :(1) adopt the kiln type with large diameter, short length and two points support, which not only reduces the moving amplitude of kiln body up and down, but also saves the floor space; (2) The kiln body is driven by frequency conversion and speed regulating motor and equipped with auxiliary motor, which is stable in work and easy to adjust; (3) Kiln head kiln tail is equipped with spring vane type sealing structure, which is simple and reliable.