Sitting in the solid waste disposal workshop drinking coffee, is such a picture somewhat contrary? On January 3, the reporter walked into Guiyang Conch Environmental Protection Technology Co., Ltd., located in Qingzhen Economic Development Zone, to find out.
Walking into the factory area of Guiyang Conch Panjiang Cement Co., Ltd., trees are verdant and huge pipelines are circling in midair, which is the main channel for transporting materials in the co-processing of cement kilns. Overlooking
the Conch Environmental Protection Factory.
In the southern corner of the plant, a red and white four-storey building is the site of the Conch Cement Kiln Comprehensive Utilization Kiln Solid Hazardous Waste Disposal Project. The first and second floors are raw material storage, the third floor is laboratory, and the fourth floor is disposal workshop and office area, covering an area of only 45.5 mu, which is economical and intensive. It is hard to imagine that
this four-storey building is a workshop for solid waste and hazardous waste treatment projects.
In 2019, the project was completed and put into operation, which is the first project in Guiyang to dispose of hazardous waste and solid waste by cement kiln.
Here, 150 tons of hazardous waste and 120 tons of solid waste from Guiyang City, Qingzhen City and surrounding areas are disposed of every day. Hazardous wastes mainly come from aluminum ash, overhaul slag and other non-ferrous metal smelting wastes, dyes, paint wastes and other industrial hazardous wastes in Qingzhen Circular Economy Industrial Park. Solid waste is mainly domestic waste from surrounding urban and rural areas. The disposal process of the
cement kiln comprehensive utilization solid waste hazardous waste project effectively utilizes the characteristics of the high temperature of the cement kiln, and the material stays for more than 30 minutes, so that the organic matter is completely decomposed after being fully burned at high temperature for a long time, and is completely absorbed and converted into non-toxic calcium chloride, calcium sulfate and calcium fluoride in the alkaline environment of the cement kiln. Finally, it becomes clinker , adds limestone, and is made into recyclable cement products.
Process Flow Diagram.
On the digital screen of the four-storey office area, from material delivery, to material proportioning and mixing, to transportation, high temperature incineration and decomposition, and finally into the cement rotary kiln.. In a series of disposal processes, the temperature of each link is displayed in real time.
On one side, workers sit on the operating chair to operate the mechanical gripper. Through a glass room and a surveillance camera, the mechanical gripper accurately grasps the solid and dangerous waste materials in the storage pit, and preliminarily mixes the materials according to a fixed ratio.
This material mixing process is called "compatibility", which is to mix solid hazardous wastes with different acidity and alkalinity in a certain proportion, so that the content of harmful elements such as fluorine, chlorine and sulfur can be effectively controlled after they are burned at high temperature in the cement kiln.
The staff monitored the production of the whole link through the digital screen.
Here, only two staff members are needed to complete the whole process of solid hazardous waste co-disposal. After the break, the staff also made hot coffee and enjoyed it heartily. There was no other odor in the air except the aroma of coffee.
"Our disposal space is in a negative pressure environment, so that the hot flue gas of incineration can only enter but not exit under the suction of negative pressure.". These solid hazardous wastes, including solid, semi-solid and liquid, contain a variety of organic wastes, which are toxic, infectious and corrosive, and put forward higher safety requirements for our disposal process. Cheng Lin, director of the company's laboratory, introduced.
"At present, we can dispose of 27 categories and 370 sub-categories of hazardous wastes produced by chemical raw materials and products manufacturing, non-ferrous metal smelting and calendering, non-metallic mining, paper making and paper products industries." Cheng Lin said that every time hazardous waste and solid waste are received, the laboratory will quickly and accurately monitor a variety of heavy metals and harmful elements in the samples through sampling, so as to achieve accurate and controllable production process.
Laboratory sample testing.
The operator uses the manipulator to grab the material on the operating chair. The materials co-disposed
by the cement kiln are in the state of slurry and slag, and are finally transported to the cement kiln through a closed pipeline for incineration and decomposition at a high temperature of 1800 degrees Celsius. It is understood that sludge from sewage treatment plants in Guiyang City, Qingzhen City and other places will also be effectively disposed of here. After incineration, the ash is mainly aluminosilicate, which is mixed with other materials and calcined into clinker at high temperature to achieve "eating dry and squeezing clean". The gray pipeline in the
figure is the hazardous waste solid waste slurry and slag conveying pipeline. Chengcheng, deputy director of production department
of Guiyang Conch Environmental Protection Technology Co., Ltd., said that at present, the co-disposal method of waste in cement production process is considered to be the "best available technology" to achieve environmental harmlessness. The new dry process cement kiln is used to incinerate solid waste and hazardous waste, which not only disposes of waste, but also provides effective resources for cement production, and truly achieves the goal of harmlessness, reduction and resource utilization.
