What Is a Rotary Kiln?

Rotary bed kiln refers to rotary calcining kiln (commonly known as rotary kiln), similar in appearance to rotary bed, also called rotary bed kiln, which belongs to the category of building material equipment. Rotary kiln can be divided into cement kiln, metallurgical chemical kiln and lime kiln according to different materials. Cement kiln is mainly used for calcining cement clinker. There are two types of cement kiln: dry production and wet production. The metallurgical and chemical kiln is mainly used for the magnetization roasting of lean iron ore in iron and steel plants of the metallurgical industry; the oxidative roasting of chromium and nickel iron ore; the refractory plant roasts high-alumina vanadium ore; And chrome minerals. Lime kiln (ie active lime kiln) is used for roasting active lime and light-burned dolomite used in iron and steel plants and ferroalloy plants ^[1] .

Rotary bed kiln classification: Divided into variable diameter rotary bed kiln and through diameter rotary bed kiln according to appearance, according to use, it can be divided into cement rotary bed kiln, ceramsite sand rotary bed kiln, kaolin rotary bed kiln, lime rotary bed Kilns, etc., are divided into gas-fired rotary bed kiln, coal-fired rotary bed kiln, and mixed fuel rotary bed kiln according to different energy supply effects.

(1) Reduced diameter rotary bed kiln

Rotary bed kiln with a change in front and back diameter. Generally, the diameter changes from about 30 cm back and forth. Compared with the traditional rotary bed kiln, it has the advantages of energy saving and high output, but the variable rotary bed kiln is more difficult to process and more difficult to process than the traditional rotary bed kiln. More stringent equipment requirements.

(2) Rotary bed kiln

It is a rotary bed kiln with the same diameter before and after. Our common type of rotary bed kiln was invented by German Dietz in 1883. After years of evolution, the rotary bed kiln has become a universal device. It has better effect and higher output than traditional vertical kiln. Simple processing, but it is more energy consuming than the rotary bed kiln ^[1]

Kiln head part

The kiln head is the discharge part of the rotary bed kiln. The diameter is larger than the diameter of the rotary bed kiln. The stainless steel fish scale and the kiln body are used for sealing.

Kiln body part

It is the main body of a rotary bed kiln (rotary kiln), usually 30 to 150 meters long, cylindrical, with 3 to 5 rolling rings in the middle. The cylinders are mostly processed into 3 to 10 sections by the factory and welded after being transported to the destination by large trucks. The rolling ring part is also commonly known as (tire ring) cast from molten steel. Due to the load bearing part of the rolling ring kiln body, it is slightly thicker than the steel plate of other parts. The supporting tugboat is also a part of the kiln body and the rolling ring is correspondingly connected to the foundation. It is the load-bearing pillar of the entire rotary bed kiln. Usually a set of idler rollers consists of two idler rollers and two blocking wheels. The rotary bed kiln shall be covered with refractory bricks during normal operation.

Kiln tail part

The kiln tail part is also an important part of the rotary bed kiln. The shape of the rotary end kiln at the feed end is mainly responsible for feeding and sealing.

Rotary kiln support

1. The support frame of the rotary bed kiln can make our rotary bed kiln equipment more solid, so that it will not shake when working, and stable production;

2. The support frame of the rotary bed kiln mainly fixes our rotary bed kiln equipment. It can prevent the deformation of our rotary bed kiln equipment when it is used. Everyone knows that the rotary bed kiln equipment will deform if it is not operated properly. Have such a role;

3. Rotary bed kiln support can facilitate the lifting of our rotary bed kiln equipment, etc., and facilitate transportation.

Preheating tower

It is also called preheater, which is the equipment for the preliminary heating of the material by the exhaust heat of the exhaust gas from the rotary bed kiln before it enters the rotary bed kiln. Most of them are vertical structures. The principle is that the waste heat discharged from the tail of the rotary bed kiln is passed through a preheating tower filled with raw materials to realize the raw material heating process. Coupled with the preheating tower can effectively reduce energy consumption and improve the quality level of the finished product.

Cooler

On the contrary, the cooler and the preheater are devices that rapidly cool down the material of the rotary bed kiln after firing. It looks like a small rotary bed kiln, but it is smaller and shorter in diameter, no refractory bricks need to be laid, and it is replaced by lifting plates. The main role is to quickly cool the finished product.

conveyor

Conveyor belt is the material conveying device of rotary bed kiln. In the process of use, various types of damage often occur, such as: edge delamination, ulceration, defect and cracking; long-distance longitudinal tearing, deep scratches, holes, large area Wear, cover or peeling of rubber drums, internal defects of joints, etc. Among them, longitudinal tearing is the most urgent, edge damage is the most common, the internal defects of the joint are unavoidable, and the service life after repair is the most concerned ^[2]

(1) The technical performance and operation of the rotary bed kiln largely determine the quality, output and cost of the company's products. "As long as the large kiln is turned, there will be tens of millions." This folk ballad is a vivid description of the importance of the production of the transfer bed kiln.

(2) In the building materials industry, in addition to calcining cement clinker, the rotary bed kiln is also used for calcining clay, limestone, and slag drying; etc. In the production of refractory materials, the rotary bed kiln is used as the raw material to stabilize the size 2. Increased strength and re-processing.

(3) During the beneficiation process, a rotary bed kiln is used to magnetize and roast the lean iron ore, so that the original weak magnetism of the ore is changed to strong magnetism to facilitate magnetic separation.

(4) In the chemical industry, rotary bed kiln is used to produce soda, calcined phosphate fertilizer, barium sulfide, etc. In the 1960s, LapPle and others invented a new process for producing phosphoric acid in a rotary bed kiln. This method has the advantages of low energy consumption, low power consumption, no need for sulfuric acid, and the use of low and medium grade phosphate rock.

(5) The entire production process of cement is summarized as "two grindings and one burning". Among them, "one burning" is the process of grinding the raw meal prepared under the high temperature of a rotary bed kiln into clinker. Therefore, the rotary bed kiln is the host in cement production, commonly known as the "heart" of cement plants.

(6) In terms of environmental protection, developed countries in the world have used cement kilns to burn hazardous wastes and garbage for more than 20 years. This not only reduces waste and harmless waste, but also uses waste as fuel, saves pulverized coal, and To the recycling of waste ^[2] .