Co-processing of hazardous waste in industrial kilns refers to the use of existing high-temperature industrial kilns (such as cement kilns, sintering machines, ironmaking blast furnaces, rotary kilns, and coal-fired boilers) to co-process hazardous waste with other raw materials or fuels. While meeting the normal production requirements of the enterprise, ensuring product quality and environmental safety, it also realizes the harmless disposal and resource utilization of hazardous waste.
Due to the high internal temperature of industrial kilns, it is conducive to the incineration and disposal of hazardous waste. The heat energy generated during the incineration of hazardous waste can replace part of the heat energy generated by the combustion of fossil fuels. In addition, in cement kilns and other kilns, hazardous waste incineration residues can be used as building materials together with cement kiln products, which can replace some natural raw materials. The process of co-processing hazardous waste in industrial kilns reduces the consumption of fossil fuels and natural raw materials, while also reducing the emission of greenhouse gases and other air pollutants.

At present, my country has a large amount of hazardous waste, slow construction of hazardous waste treatment facilities, and insufficient disposal capacity. The advantage of industrial kiln co-processing hazardous waste technology is that it can not only reduce the investment in the construction of hazardous waste disposal facilities, but also effectively use the energy and resources in hazardous waste. It is one of the effective ways to alleviate the shortage of hazardous waste disposal capacity in my country.

Cement kiln co-processing technology

Cement kiln is a kind of building material equipment, mainly used for calcination of cement raw materials. Cement kiln co-processing technology is an important way to incinerate hazardous waste and municipal solid waste in developed countries. It is also an effective way to clean and efficiently utilize municipal solid waste and hazardous waste. This process can not only make full use of combustible components in hazardous waste Provide fuel for the high-temperature calcination process, and part of the inorganic solid components can also be used as calcination raw materials to reduce the use of some high-calcium ores. In addition, heavy metals can also be dispersed and adsorbed on cement clinker, and are safe within the specified concentration limit. widely used in building materials industry, etc. In 1974, Canada's Lawrence Cement Plant conducted research on the co-processing of waste incineration fly ash and other hazardous waste and other alternative fuels. Since then, the United States, Germany, Japan, the Netherlands and other countries have also carried out this research. At present, most cement plants in developed countries in Europe have adopted co-processing technology to treat hazardous waste as an alternative fuel, and the amount and type of these wastes have also developed from domestic waste to waste plastics, waste tires, oily sludge, etc. Hazardous waste, and gradually established and perfected its standard management technology system, accumulated a wealth of experience.
At present, the co-processing of solid waste in cement kilns has become the mainstream direction for my country's cement industry to seek green development. The alternative raw materials have developed from the initial conventional industrial waste such as flue gas desulfurization gypsum, coal gangue, power plant fly ash, blast furnace slag, sulfuric acid slag, etc. Soil containing heavy metals and organic matter and incineration fly ash, etc. With the continuous development of the theory and practice of co-processing hazardous waste in cement kilns, my country's relevant technical standards and policy specifications in this area are also gradually improving.

Co-processing technology for coal-fired boilers in power plants

A boiler is a thermal device that converts the internal chemical energy of coal, petroleum or combustible materials into water or steam heat. Power plant coal-fired boilers are the main co-processing high-temperature industrial kilns other than cement kilns. At present, wastes co-processed by boilers in power plants mainly include agricultural wastes such as poultry and livestock wastes, garbage-derived fuels, organic acids, packaging wastes, waste oils and straws. The replacement rate of wastes as fuels is about 10%. The fuel substitution rate of pulverized coal furnaces for co-processing wood chips is relatively high; about 40 power plant boilers (mainly fluidized bed boilers) in Finland use waste as alternative fuel, co-process waste about 400,000 tons per year, and the alternative fuel is 5- 30%; the Netherlands currently has 9 co-processing power plants, which are mainly used to dispose of coke, sewage sludge, biomass particles, municipal waste, coffee grounds, animal fat and bone meal, etc.; in the United States, the co-processing of power plant boilers is mainly biomass waste, in Florida alone there are three coal-fired power plants co-processing biomass waste.

Ironmaking blast furnace co-processing technology

Iron-making blast furnace is the main facility of modern iron-making. The application of co-processing solid waste technology using iron-making blast furnace began in 1995. A German steel company began to use iron-making blast furnace to co-process waste plastics, which not only reduced waste treatment costs, but also Reduced costs for the steel industry. Subsequently, Germany, Japan and other countries successively developed blast furnace treatment of electroplating sludge technology, chromium slag rotary kiln detoxification technology, and mature blast furnace injection plastic technology. Foreign researchers have studied the co-processing of several waste plastic products and lubricating oil in ironmaking blast furnaces. The results show that these wastes will not affect the quality of ironmaking, but can greatly reduce the use of fuel.

Epilogue

The use of industrial kilns to co-process solid waste, especially hazardous waste, has become one of the important development directions of solid waste disposal and recycling technology at home and abroad. After more than 40 years of development, some specific industrial furnaces such as cement kilns, power plant boilers and ironmaking blast furnaces have realized the co-processing of hazardous waste technologies at home and abroad. However, the feasibility and Environmental safety and environmental pollution control have always been the common concern of scholars from all walks of life and workers in related industries