Metals feed coal from

Table L Metals Analysis of Reactor Deposit and Feed Coal From Run FB-61...

Immiscible wetting in mixers Sol-gel processes Pellet flocculation <0.3 Low Up to 10 ton/hr Wet processing based on flocculation properties of particulate feed Coal fines, soot and oil removal from water Metal dicarhide, silica hydrogels Waste sludges and slurries... 

Studies of fresh ash produced by coal combustion have shown that many trace elements (As, B, Bi, Cd, Cr, Cu, Ge, Hg, Mo, Pb, Ni, Se, Sr, Tl, V, W, Zn) are enriched in the fly ash compared to the bottom ash (Hansen Fisher 1980 Eary et al. 1990 Mukhopadhyay et al. 1996 Karayigit et al. 2001). For example, Mukhopadhyay et al. (1996) reported 10-20 times enrichment of most trace elements in the fly ash compared to the feed coal and association of As with crystalline Fe-0 and Fe-S phases in the bottom ash from a power plant in Nova Scotia fed by eastern Canadian coal. Elements enriched in fly ash are typically those more easily volatilized. Because fly ash particles also have smaller sizes and therefore greater reactivity than bottom ash, the probability of metal leaching is correspondingly greater. Ainsworth Rai (1987) and Rai et al. (1988) found that most of the Cu, Mo, Se, Sr, and V in fly ash was readily soluble. 

The amount of halides (usually chlorides or fluorides) and volatile metals in raw coal gas can vary significantly depending on the amounts in the feed coal and the type of coal gasification reactor. However, these trace components are effectively removed from the coal gas in the cooling and water washing before conventional acid gas removal. Halides removal is a potential problem for hot gas cleanup processes. 

In this process EAF dust, other zinc-bearing wastes, recycled materials, coke or coal, lime, and silica are mixed and fed to a rotary furnace. The zinc and other volatile nonferrous metals in the feed are entrained in the furnace off-gas and are carried from the furnace to an external dust collection system. The resulting oxide (zinc calcine) is a crude zinc-bearing product that is further refined at zinc smelters. A byproduct of the process is a nonhazardous, iron-rich slag that can be used in road construction. Solidification technologies change the physical form of the waste to produce a solid structure in which the contaminant is mechanically trapped. 

Sulphites rarely occur in natural waters. They are chiefly of artificial origin (wastewaters from the production of sulphite cellulose and thermal processing of coal). They are washed out into atmospheric waters from urban and industrial air pollutants. In waters, sulphites are slowly oxidized into sulphates, consuming dissolved oxygen. Chemical oxidation is accelerated by catalytic effects of various metals, particularly the Co(II) compounds. In water treatment, sulphites are used for dechlorination, removal of oxygen from feed waters for steam boilers, and in the technology of wastewaters for reduction of Cr(VI) to Cr(III). 

---