Methods of stabilizing treating incineration residues

Methods of stabilizing treating incineration residues)

1. Melting Solidification Method:
   • This method involves melting the incineration residues at a temperature of 1500°C to form slag.
   • Heavy metals are stabilized in a glassy state at high temperatures. (Advantages)
   • High stability: The melted slag is highly stable in a glassy state, reducing the possibility of harmful substance leaching.
   • Volume reduction: Incineration residue volume is reduced by approximately 1/3 to 1/2, saving landfill space.
   • Potential for recycling: Slag can be recycled into road construction materials, artificial aggregates, soil amendments, etc. (Disadvantages)
   • High treatment cost: Due to the use of high-temperature melting furnaces, the treatment cost is high.
   • Increased energy consumption: Significant energy is required to maintain high temperatures.
   • Volatile emissions of low-melting-point metals leading to the generation of harmful substances.
2. Cement Solidification Method:
   • Hazardous materials bind with minerals like CaO and SiO2 in cement, forming hydration crystals and adsorbing them.
   • In this method, incineration residues are mixed with cement and water to form blocks or pellets. Cement binds the particles of incineration residue to form stable blocks. (Advantages)
   • Relatively inexpensive treatment cost: Treatment cost is lower compared to other solidification methods.
   • Simple treatment process: Can be processed without the need for special equipment or techniques.
   • High strength: Cement solidified blocks have high strength and can be used as construction materials. (Disadvantages)
   • Volume increase: Incineration residue volume increases by approximately 1.5 times.
   • Lower stability: Higher potential for harmful substance leaching compared to melting solidification method.
   • Recycling constraints: Cement solidified blocks are difficult to recycle.
3. Chemical Treatment Method:
   • Chemicals are used to fix or leach out hazardous substances in incineration residues through precipitation, coagulation, neutralization, oxidation-reduction reactions, etc.
   • Hazardous metals stabilized using agents such as sodium hydroxide-based solutions or organic chelating resins. (Advantages)
   • Selective treatment capability: Specific hazardous substances can be selectively treated.
   • Reduction in treatment space: Reduction in incineration residue volume is possible.
   • Enhanced recyclability: Removal of hazardous substances increases the recyclability of incineration residues. (Disadvantages)
   • High treatment cost: Expenses incurred for chemicals, treatment facilities, and operations.
   • Secondary pollution risk: Potential for secondary pollution due to chemical usage.
   • Complexity of treatment technology: Treatment processes are complex and require specialized expertise.
4. Acid Extraction Method:
   • Acidic solutions are used to extract heavy metals suspended in water towards the solution.
   • Extracted heavy metals can then be converted into metal hydroxides using caustic soda or into metal chelate compounds using metal hydroxides and chelating agents. (Advantages)
   • High treatment efficiency: Effective removal of hazardous substances.
   • Selective treatment capability: Specific hazardous substances can be selectively targeted.
   • Enhanced recyclability: Removal of hazardous substances improves the recyclability of incineration residues. (Disadvantages)
   • High treatment cost: Expenses incurred for acidic solutions, treatment facilities, and operations.
   • Secondary pollution risk: Potential for secondary pollution due to the use of acidic solutions.
   • Complexity of treatment technology: Treatment processes are complex and require specialized expertise.