Coal analytical treatment

Analytical values for the eight coals after treatment with 2 M HN03 are given in Table III. The reported values are the averages of four determinations (duplicate determinations on different days). A comparison of the dry ash values for the HNOj-extracted residues described in Table III to the dry ash values for the raw coals described in Table I reflects the reduction in mineral matter caused by extraction of the raw coals with 2 M HN03. Carbonates, sulfates, and other minerals dissolve in the acid solution used to extract pyrite. 

Analytical Treatment of Hydrogenated Coal Liquids. Scheme A. Filtered coal liquids were distilled in a standard vacuum distillation apparatus to recover the gasoline (IBP-400°F) and gas-oil (400°-1000°F) cuts (see Figure 2). The treatment with anhydrous HC1 was applied to the composite of these cuts (IBP-1000°F) or to the gas-oil fraction, each diluted with an equal volume of n-hexane. 

In the classification of gas-solid reaction systems both the combustion and the gasification (reaction to produce a combustible fuel) of coal fall in the category where there is no solid reaction product. The analytical treatment... 

This decrease in the organic sulfur content of the Lovilia/ROM coal was corroborated by a series of extraction experiments employing ASTM procedures and other analyses for sulfur and iron. The removal of organic sulfur from the other two coals could not be confirmed by this method. However, the different extraction procedures pointed to possible changes in the mineral components and in the organic matrix itself of the coals after the chemical desulfurization treatment. Such changes can affect the analytical values obtained by ASTM procedures. 

The Mossbauer effect has been used as an analytical tool to characterize the diffrent iron-bearing minerals in coal. It has been pointed out that by the use of low-temperature measurements (in the presence of a large external magnetic field) and treatment of the coal samples, all the iron-bearing minerals can be identified correctly. The use of Mossbauer spectroscopy as a quantitative analytical tool presents several experimental difficulties. It is recommended that this spectroscopy be used as a complement to and not as a substitute for the standard techniques. 

Complex Mixture Extraction. Analytical SFE can also be used for complex mixture sample preparation. Typical examples using hazardous waste samples are described below. Sample A was a soil boring contaminated with coal gasification residuals and sample B was from a waste stream from a treatment facility. The major objective of these studies was to compare the extraction abilities (e.g., amount of material extracted) of three different fluid systems using approximately four-gram aliquots of the samples. The specific fluid systems, the extraction conditions, and the percentage of the total mass of material extracted from each sample are listed in Table II. 

Multielement analytical techniques - atomic absorption spectrometry, inductively coupled plasma mass spectrometry. X-ray fluorescence, neutron activation analysis, etc. - are used. The experimentation can be done directly on the mineral matter of the coal sample after the removal of the organic matter by a prolonged treatment of activation with oxygen plasma (low-temperature ashing). Neutron activation is also applied to online analyses of coal and fly-ashes on feeding-belts in order to provide information on a continuous basis. 

---