Combined additive for burnt fly ash vitrification and burnt fly ash vitrification method

Abstract

The invention discloses a combined additive for burnt fly ash vitrification. The combined additive comprises B2O3 and graphite. The invention also discloses a burnt fly ash vitrification method. The method comprises the following steps of: adding the B2O3 and the graphite into fly ash, wherein the weight ratio of the B2O3 to the fly ash is 1: (4-10), and the weight ratio of the graphite to the fly ash is 1: (20-50); and performing vitrification treatment at the temperature of between 1,150 and 1,350 DEG C for 30 to 80 times. Because the graphite of a certain proportion is added and can be reacted with CaSO4 in the burnt fly ash in the heating process, the volatilization of sulfur elements is promoted, the influence of a yellow phase is reduced, the treatment time is shortened and the retention rate of heavy metals is improved.

Description

technical field [0001] The invention relates to the field of solid waste treatment, in particular to a combined additive used in the incineration fly ash vitrification method and the incineration fly ash vitrification method, which can reduce the difficulty of vitrification and improve the vitrification effect. Background technique [0002] Incineration fly ash is the combustion product of solid waste (such as domestic waste) treated by incineration. Because the heavy metal leaching rate is higher than the national standard, it is listed as hazardous waste. Vitrification is an advanced technology for harmless incineration fly ash. It heats incineration fly ash and additives to a molten state and cools to form a chemically stable glass body. The purpose of harmlessness is achieved by virtue of the extremely low heavy metal leaching rate of the glass body. [0003] The key to vitrification technology is to form a chemically stable glass body. How to reduce the temperature of v...

AI Technical Summary

Problems solved by technology

The formation conditions of the glass body are related to the processing temperature and material composition. When the processing temperature is high, the impurities are less and easy to vitrify, but the energy consumption is high, the cost is high, and the retention rate of heavy metals will be greatly reduced; when the processing temperature is low, Incineration fly ash has more impurities and is difficult to vitrify

Due to the influence of sulfur-containing compounds in the incineration fly ash, a layer of yellow substance-yellow phase will be formed on the surface of the product when the melt is cooled. The existence of the yellow phase will hinder the formation of the vitreous network structure and cannot be obtained in a short processing time Good vitreous body, while prolonged processing time will also reduce the retention rate of heavy metals

The above factors restrict the application and development of vitrification technology, and hinder the harmless process of incineration fly ash in my country