Coal carbonization waste

Fig. 2. Carbonate minerals, which play important roles in the hydrogeochemistry of coal mines and coal mine wastes (a) A typical siderite concretion (from the mudstone overlying the Halifax Hard Seam at Bullhouse, West Yorkshire, UK) long axis of concretion is 11 cm (b) Patchy films of creamy-white ankerite on a cleat surface of coal (from the Main Seam, Ravensworth Grange Opencast Coal Mine, Durham, UK) maximum width of hand specimen is 10.5 cm.

The ability of mineralized soil to control the migration of aluminum was observed in another study. Acidic leachate from coal waste containing aluminum was percolated through soil containing varying amounts of calcium carbonate (Wangen and Jones 1984). Soluble aluminum was found to decrease dramatically as the pH of the percolating leachate increased and aluminum oxide precipitates formed at pH 6, no dissolved aluminum was measured. The authors concluded that alkalinized carbonaceous soils provide the best control material for acidic leachates from coal mineral wastes. 

An alternative method of preparation of zeolite-carbon adsorbents is the treatment of mixtures clay mineral with hard coal and waste carbon deposits. The treatment consists of several physicochemical processes i.e. formation, carbonization, activation and crystallization, presented in this paper. The adsorbents prepared with this procedure are not a simple mixture of two components but strongly dispersed material resulting fi om thermochemical transformation, thus fecilitating the surface structure. 

Activated carbon has been tested for the cleanup of highly colored waste streams such as result from dyeing operations [78]. Coal carbons are 99% effective for dye removal and accept dye loadings as high as 0.40 kg dye/kg carbon. Lignite carbon is also useful, but less effective. 

The particulate matter carried forward in gas streams can also cover a wide range of materials including inorganic mineral matter, organic particles and "natural" materials like wood particles. Inorganic substances possibly with carbon particles, are common foulants in combustion systems where fossil ftiels like oil and coal or waste materials like domestic refuse are burnt. Even with "clean" fuels such as natural gas, problems of fouling may arise as a result of poor combustion... 

Coal, clay ore processing Oil, grease and solids separation in chemicals and food industry Non-ferrous metal and process liquids recovery Coal carbonizing, plastics manufacture, metal processing Metal processing Pesticides, dye stuffs Desalination of industrial waters, waste waters with dissolved contaminants... 

Summary of review ofDqbrowski et al. (2004) adsorption mechanisms Phenolic compounds are to be found in contaminated water sources. At low concentrations, drinking water can be rendered unpalatable and contaminants may be carcinogenic to humans. Phenols are by no means rare on the industrial scene and are associated with oil refineries, with sites of coal gasification and coal carbonization, as well as the petrochemical industry. The production of plastics, colours, pesticides and insecticides are other examples of sources of phenols. Degradation of waste and used plastics produces phenols. 

When used in energy recovery, recycled tyres provide about a 20% carbon footprint advantage over coal, but waste tyres have substantially more carbon emissions than other fossil fuels. 

Fuel switch. The choice of fuel used in furnaces and steam boilers has a major effect on the gaseous utility waste from products of combustion. For example, a switch from coal to natural gas in a steam boiler can lead to a reduction in carbon dioxide emissions of typically 40 percent for the same heat released. This results from the lower carbon content of natural gas. In addition, it is likely that a switch from coal to natural gas also will lead to a considerable reduction in both SO, and NO, emissions, as we shall discuss later. 

Combustion of coal and other fuels Gasification of coal, peat, wood wastes Carbonization of coal (decomposition without oxygen)... 

The chemical characteristics of biomass vary over a broad range because of the many different types of species. Table 8 compares the typical analyses and energy contents of land- and water-based biomass, ie, wood, grass, kelp, and water hyacinth, and waste biomass, ie, manure, urban refuse, and primary sewage sludge, with those of cellulose, peat, and bituminous coal. Pure cellulose, a representative primary photosynthetic product, has a carbon content of... 

Typically, 40—50% of the carbon atoms ia lignite are ia aromatic stmctures while 60—70% of the carbon atoms ia Illinois bituminous coal are ia aromatic stmctures (7,8). By all of these measures, waste fuels are significantly more reactive than coal, peat, and other combustible soHds. 

Some beehive ovens, having various improvements and additions of waste heat boilers, thereby allowing heat recovery from the combustion products, may stiU be in operation. Generally, however, the beehive oven has been replaced by waH-heated, horizontal chamber, ie, slot, ovens in which higher temperatures can be achieved as well as a better control over the quality of the coke. Modem slot-type coke ovens are approximately 15 m long, approximately 6 m high, and the width is chosen to suit the carbonization behavior of the coal to be processed. For example, the most common widths are ca 0.5 m, but some ovens may be as narrow as 0.3 m, or as wide as 0.6 m. 

The fuel properties of wood can be summarized by ultimate and proximate analyses and deterrnination of heating value. The analytical procedures are the same as those for coal, but with some modifications. Analytical results generally vary about as much within a species as they do between species, except that softwood species generally have a higher carbon content and higher heating values than hardwood species because of the presence of more lignin and resinous materials in softwood species (see Fuels from waste). 

Adsorption. Adsorption (qv) is an effective means of lowering the concentration of dissolved organics in effluent. Activated carbon is the most widely used and effective adsorbent for dyes (4) and, it has been extensively studied in the waste treatment of the different classes of dyes, ie, acid, direct, basic, reactive, disperse, etc (5—22). Commercial activated carbon can be prepared from lignite and bituminous coal, wood, pulp mill residue, coconut shell, and blood and have a surface area ranging from 500—1400 m /g (23). The feasibiUty of adsorption on carbon for the removal of dissolved organic pollutants has been demonstrated by adsorption isotherms (24) (see Carbon, activated carbon). Several pilot-plant and commercial-scale systems using activated carbon adsorption columns have been developed (25—27). 

The modern natural-gas industry has its origins in the nineteenth centuiy as urban gas works that distributed synthesis gas (a mixture of carbon monoxide, hydrogen and carbon dioxide made by the incomplete combustion of coal, oil, or organic wastes in the presence of steam). Gas works illuminated London streets even before 1800, and subsequently... 

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