Coal leached

Unreacted pyrite was not touched by the acids whether hot or cold. Behavior of Mineral Matter During Coal Leaching... 

Historically, soda ash was produced by extracting the ashes of certain plants, such as Spanish barilla, and evaporating the resultant Hquor. The first large scale, commercial synthetic plant employed the LeBlanc (Nicolas LeBlanc (1742—1806)) process (5). In this process, salt (NaCl) reacts with sulfuric acid to produce sodium sulfate and hydrochloric acid. The sodium sulfate is then roasted with limestone and coal and the resulting sodium carbonate—calcium sulfide mixture (black ash) is leached with water to extract the sodium carbonate. The LeBlanc process was last used in 1916—1917 it was expensive and caused significant pollution. 

More recendy, the molten caustic leaching (MCL) process developed by TRW, Inc. has received attention (28,31,32). This process is illustrated in Eigure 6. A coal is fed to a rotary kiln to convert both the mineral matter and the sulfur into water- or acid-soluble compounds. The coal cake discharged from the kiln is washed first with water and then with dilute sulfuric acid solution countercurrendy. The efduent is treated with lime to precipitate out calcium sulfate, iron hydroxide, and sodium—iron hydroxy sulfate. The MCL process can typically produce ultraclean coal having 0.4 to 0.7% sulfur, 0.1 to 0.65% ash, and 25.5 to 14.8 MJ/kg (6100—3500 kcal/kg) from a high sulfur, ie, 4 wt % sulfur and ca 11 wt % ash, coal. The moisture content of the product coal varies from 10 to 50%. 

Calcining, sintering or smelting of nickel copper matte or acid leaching or electrorefining of roasted matte Coal soots, coal tar, pitch and coal tar fumes Hardwood dusts... 

Human activities have resulted in exposure of Antarctic fishes to petroleum-derived PAHs (McDonald et al. 1992). Fish captured near Palmer station on the Antarctic peninsula had induced EROD activities and elevated concentrations of biliary PAH metabolites of phenanthrene and naphthalene when compared to conspecifics from reference sites (McDonald et al. 1995). Artificial reefs consisting of oil and coal flyash stabilized with cement and lime in Florida waters near Vero Beach contained elevated PAH levels ranging from as high as 1.2 mg fluoranthene/kg and 0.25 mg naphthalene/kg. But there is negligible leaching because seawater is not an effective medium for removing PAHs from reef bricks or the ash (Frease and Windsor 1991). 

Ledgemont A process for removing sulfur from coal by an oxidative leach with lime and ammonia. Developed by Hydrocarbon Research. 

TRW Meyers [Named after the three CalTech professors who founded the company Thompson, Ramo, and Wooldridge] A chemical method for desulfurizing coal. The iron pyrites is leached out with a hot aqueous solution of ferric sulfate, liberating elemental sulfur. The resulting ferrous sulfate solution is re-oxidized with air or oxygen ... 

Coal ash was converted to a low-carbon vitreous slag, impervious to leaching and valued as an aggregate in construction or as grit for abrasives and roofing materials trace metals from petroleum coke were also encased in an inert vitreous slag. 

Gainesville, FL with individual fractions of three individual petroleum products at 24-25 °C for 24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method 625. Average 2,4-dimethylphenol concentrations reported in water-soluble fractions of unleaded gasoline, kerosene, and diesel fuel were 50, 99, and 108 pg/L, respectively. 2,4-Dichlorophenol may also enter groundwater by leaching from coal tar, asphalt runoff, plastics, and pesticides (quoted, Verschueren, 1983). 

Cement made with hazardous waste fuels contains essentially the same amount of metals as cement made using traditional fossil fuels, such as coal, coke, or oil. Also, tests show cement made with hazardous waste fuels has essentially identical leaching characteristics as those of cement produced solely with traditional fuels. This means the metals are no more likely to leach out of the cement made using hazardous waste fuels than if it were made using coal, coke, or oil. 

Figure 12. Ion microprobe depth profiles of lead and thallium in coal fly ash taken before (unextracted) and after solvent leaching with H2O or DMSO...

Standard procedures using leaching for determining inorganic species in low rank coals are well established. The procedures adopted for this study are given below. All lignite samples were crushed finer... 

The limitation of water leaching is that some minerals which are not soluble within the coal sample may dissociate on leaching. For the acid leaching, a major problem arises from the dissolution of minerals. This means that both cations exchanged onto the surface are removed as well as ions from the minerals and it is not possible to determine the amount of ions related to the two different environments. 

Surfaces of finely divided nickel also promote the formation of aniline. A practical route to tlie preparation of electrodes coaled with a finely divided metal involves electroplating nickel onto a cathode from a solution containing a suspension of finely divided Raney nickel (Ni 50% A1 50%) or Devarda copper alloy (Cu 50% A1 45% Zn 5%), Some alloy particles stick to the cathode surface which is then activated by leaching out the aluminium using hot aqueous sodium hydroxide... 

Sodium carbonate was made historically by the Leblanc process. The first commercial production was carried out by the Leblanc process. In this process, sodium chloride was treated with sulfuric acid to produce sodium sulfate and hydrochloric acid. Heating the sodium sulfate with coal and limestone produced a black ash that contained sodium carbonate, calcium sulfide, unreacted coal, and calcium carbonate. Sodium carbonate was separated from the black ash by leaching with water. The overall reaction is as follows ... 

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