The resource utilization technology on waste incineration fly ash

Applicating Company

Zhejiang Jinglan Environmental Technology co.Ltd

Technology Name

The resource utilization technology on waste incineration fly ash

Technical principle

1. Efficient decomposition technology of PCDD/FS  in fly ash adopt the low temperature thermal decomposition technology and equipment less than 400 °C were used to remove PCDD/FS in fly ash under anaerobic environment. The process has low temperature and low energy consumption, which is more than 85 % lower than that of high temperature processes such as melting, and the PCDD/FS degradation efficiency is more than 99 %.

2. The multi-stage reversal rinsing technology and equipment are used to wash the fly ash in circulating water and increase the filtrate concentration, so as to remove the soluble heavy metals and soluble salts in the fly ash. The water-cement ratio is as low as 1.5 : 1, which reduces the energy consumption of subsequent treatment.

3. Disposal technology of multicomponent washing wastewater. Step by step to remove impurities in water washing wastewater, using separation membrane and MVR system separation, the products are mainly industrial potassium salt, industrial sodium salt and industrial gypsum, which has great recycling value.

Scope of application

The technology is suitable for waste incineration fly ash harmless disposal resource utilization or other similar types of hazardous waste disposal

Process flow and description

1. The waste incineration fly ash was sent to a low-temperature pyrolysis system which is 350 ~ 400℃ for the decomposition of PCDD/FS . The PCDD/FS can be reduced from 2500-TEQ / kg to less than 50 ng-TEQ / kg, and the decomposition of PCDD/FS efficiency is greater than 99 %.

2. The detoxified fly ash enters the fly ash washing system for multi-stage reversal rinsing, the soluble salts and heavy metals in the incineration fly ash are transferred from the solid phase to the wastewater through the rinsing process. The treated fly ash disposal product meets the pollution control requirements in HJ 1134. The fly ash after washing is a high calcium-based active powder cake with strong activity, which can be used as an alternative material for building materials and has a wide range of application scenarios.

3. The washing wastewater produced by the washing process is treated with water to remove the heavy metals and hardness in the wastewater and then sent to the MVR evaporation crystallization system. The sodium and potassium salts in the wastewater are separated into industrial sodium and potassium salts that meet the corresponding product standards through the co-saturation point control of the salt solution in the MVR evaporation crystallization system, , and then sold for use.

Promotion prospects

The traditional landfill method of fly ash does not meet the requirements of sustainable development concept. Cement kiln technology is limited by disposal capacity, and other high temperature disposal processes have big energy consumption. Our technology of   ' low temperature thermal decomposition + water washing + MVR '  reduce resource consumption and have stronger legal compliance, it is the latest disposal process of fly ash resources which has advanced technology and do not rely on other industries to complete the disposal.