1, for different reasons.
Hazardous waste HW24 is toxic and made of basic chemical raw materials. Hazardous waste HW48 is toxic and produced by the mining and smelting of nonferrous metals.
2, in different ways.
Hazardous waste HW24 is acid sludge produced by flue gas purification in sulphuric acid production from pyrite.
Hazardous waste HW48 is produced by smelting. Details are as follows.
Dust and wastewater treatment sludge collected by dust collection (removal) device in copper pyrometallurgical process, wastewater treatment sludge produced in crude zinc refining process, leaching residue produced by conventional leaching of zinc roasting ore in lead-zinc smelting process, jarosite residue produced by leaching zinc roasting ore with hot acid jarosite in lead-zinc smelting process, and sulfur residue (leaching residue) produced by atmospheric oxygen leaching or pressurized oxygen leaching of zinc sulfide ore.
Extended data:
Choosing the best and practical method for a waste involves many factors, such as the composition, nature, state, climatic conditions, safety standards, treatment costs, operation and maintenance of the waste. Although many methods can be successfully used to treat hazardous waste, the common treatment methods are still classified as physical treatment, chemical treatment, biological treatment, heat treatment and solidification treatment.
1. Physical treatment: Physical treatment is to change the structure of solid waste into a form convenient for transportation, storage, utilization or disposal through concentration or phase change, including compaction, crushing, sorting, concentration, adsorption and extraction.
2. Chemical treatment: Chemical treatment is to destroy harmful components in solid waste by chemical methods, so as to achieve harmlessness or transform them into forms suitable for further treatment and disposal. Its purpose is to change the chemical properties of the treated substance, thus reducing its harmfulness. This is a common pretreatment measure before the final disposal of hazardous waste, and its treatment equipment is conventional chemical equipment.
3. Biological treatment: Biological treatment is to decompose degradable organic matter in solid waste by microorganisms, so as to realize harmless or comprehensive utilization. Biological treatment methods include aerobic treatment, anaerobic treatment and facultative anaerobic treatment. Compared with chemical treatment, biological treatment is generally cheaper and more widely used, but the treatment process takes a long time and the treatment efficiency is not stable enough.
4. Heat treatment: Heat treatment is to destroy and change the composition and structure of solid waste through high temperature, and at the same time achieve the purpose of volume reduction, harmlessness or comprehensive utilization. The method includes incineration, pyrolysis, wet oxidation, roasting and sintering. Incineration technology is used to treat high calorific value or high toxic waste harmlessly, and the waste heat from incineration is recovered for comprehensive utilization, physical and chemical treatment, staff bathing and life. Thereby reducing the processing cost and energy waste.
5. Curing treatment: Curing treatment is to fix or coat waste with solidified matrix to reduce its harm to the environment. It is a relatively safe treatment process for transporting and disposing of waste, mainly used for hazardous waste and radioactive waste, and the volume of solidified body is much larger than that of original waste.
6. Each treatment method has its advantages and disadvantages and its applicability to different wastes. Because of the different components and properties of hazardous wastes, it is difficult to have a unified model. According to the characteristics of each kind of garbage, we can choose a treatment method with strong applicability.
Baidu encyclopedia-hazardous waste