South Cement Group has generally used this technology in its rotary kiln full plant with an annual output of 2 million tons of clinker.

The principle of this technology is: according to the characteristics and disposal requirements of hazardous waste, it is sent to different parts of the cement kiln through different processes, using the high temperature, large capacity, alkaline environment and perfect exhaust gas purification facilities in the cement kiln. Hazardous waste is sent into the kiln from different points in the cement kiln to achieve the effect of replacing fuel, raw materials or incineration with waste. The use of cement kilns for hazardous waste treatment not only reduces waste and makes it harmless, but also utilizes waste as fuel, saves pulverized coal, and achieves resource recycling.

Advantages of using cement rotary kiln to treat hazardous waste:

5.1 Huge amount of waste processed and sold in cement plants

The cement industry can use a lot of waste because the cement industry itself consumes a lot of energy. In addition to fuel, limestone, clay and other consumption is also very large. Generally 1.6 tons of raw materials can only produce 1 ton of cement, and 1 ton of coal can produce 6.2 tons of cement. A dry production line with a daily output of 2,000 tons of clinker consumes nearly one million tons of raw materials and fuel each year. Therefore, the potential of cement kilns to use waste is huge.

5.2 Operating characteristics of cement rotary kiln are suitable for incineration of hazardous waste

(1) High treatment temperature: At high temperatures, the toxic and harmful components in the waste are completely decomposed, and the general incineration removal rate reaches 99. 99%.

(2) Long duration: The cement rotary kiln barrel is long, and the waste stays for a long time under the high temperature of the rotary kiln.

(3) The incineration state is easy to stabilize: The cement rotary kiln is a combustion system with a large thermal inertia and a very stable combustion system. It does not cause large temperature fluctuations due to changes in waste input and properties, and the system is easy to stabilize and control.

(4) Alkaline environmental atmosphere: The raw material composition used in the production of cement determines the alkaline atmosphere in the rotary kiln, which can effectively suppress the emission of acidic substances and reduce or avoid dioxin generation after general combustion.

(5) No waste slag discharge: In the production process of the cement industry, there are only raw materials and clinker produced by the calcination process, and no problems such as slag generated by incineration of general incinerators; and since the operation of cement rotary kiln is under negative pressure, flue gas and dust rarely spills.

(6) Solidified heavy metal ions: Using the rotary kiln calcination process to treat hazardous waste, most of the heavy metal ions in the waste can be solidified in the clinker to prevent its re-penetration and diffusion causing pollution of water and soil.

(7) There are many incineration disposal points, and the adaptability is strong: The entire cement firing system has multiple different high-temperature feeding points, which can adapt to various wastes of different properties and forms. It is important to point out that the total amount of CO2 emitted when burning combustible hazardous waste in a cement rotary kiln is reduced by half compared to the total use of coal, which is of great significance for environmental protection.