It is necessary to remove chlorine containing 1-2％ in bottom ashes and 10-20% in fly ashes to utilize incineration ashes as cement (Portland cement) materials. Incineration ash reutilization system can remove chlorine in incineration ashes effectively performing separation ,washing and dewatering according to features of each ash.
Features
【Bottom Ashes】
- Removal of foreign substances by wet separator
- Bottom ashes contains obstructive substances like unburned residues, metals or something at 5 -10%. This system adopts wet separator, so, 3 processes, i.e., 1.flotation separation of unburned residues 2.washing and separation of metals and other foreign substances 3.washing and separation of incineration ashes are operated all together in the machine. Therefore, it can prevent troubles of systems located at downstream side caused by obstructive substances.
- High effective desalination
- This system adopts classification washing with wet vibrating screen and wet cyclone, it washes big particle ashes containing a little chlorides by supplying a little amount of water, and small particle ashes containing much chlorides by supplying much amount of water. Therefore, it can desalinate bottom ashes effectively. Furthermore, As rinsing the dehydrated cake, the chloride concentration of treated bottom ashes can be decreased under 0.2% with washing water whose amount is five times as much as volume of bottom ashes.
【Fly Ashes】
- Effective desalination
- The chloride concentration of treated fly ashes is decreased by washing fly ashes at dissolving tank and rinsing dehydration cakes.If hot water(50 degrees centigrade) can be used, the desalination rate is enhanced ,and the chloride concentration of treated fly ashes can be decreased under 0.3%.
- Trouble prevention
- Troubles like pipe blockage by calcium scale often happen in conventional fly ash treatment facility because the calcium concentration of the slurry fly ashes dissolve in is so high(thousands mg/L). This system can prevent such troubles in-between pipe from dissolving tank to dehydrator which bring fly ash slurry by applying backwash water supplied from dilution pipe and back wash air supplied from blower to make calcium scale drained to the tank.
Overview of construction
- Washing and separating equipment(bottom ashes)
- Unburned residues, metals and other obstructive materials are removed by wet separator, and bottom ashes are washed and selected to send vibrating separator. Bottom ashes are selected into two classes by particle size with wet vibrating separator. Those bigger than 2mm are rinsed by fresh washing water,and brought to the cement material tank. Those less than 2mm are selected again into two classes,bigger than 150 μm class and less class by wet vibrating screen. Those less than 150 μm contain chloride in high concentration, so they are washed again.
- Washing equipment(fly ashes )
- Fly ashes are washed in dissolving tank. If hot water (50℃) can be used, the desalination rate is enhanced.
- Dehydrater
- Each slurry containing bottom ashes less than 2mm or fly ashes is dehydraded by dehydrater(filterpress).At this time, the desalination rate is enhanced by rinsing cakes with fresh washing water. Finally, treated ashes approximately 35% of moisture content are produced by pressing sludge after rinsing.
