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Boric acid is a weak inorganic acid type which is generally being used in glass, ceramics, detergents, agriculture, nuclear energy, and medicine fields, which has white crystal color and which can easily dissolve in water. Boric acid is being produced from colemanite which is a boron mineral having wide reserves in Turkey. In recent years, intense studies have been performed on the alternative usage areas of boric acid in Turkey. In this study, boric acid was used as a leaching reagent for the demineralization of coal with high ash content. For the accurate determination of the success of boric acid in dissolving mineral matter, first a series of leaching tests were performed with boric acid, and then studies for removing mineral matter with strong acids such ashydrofluoric acid (HF), HCl, and H2SO4were performed. [ABSTRACT FROM PUBLISHER]

Demineralization of lignites from Nallihan, Turkey, was investigated using various aqueous acids, such as HCl, HNO3, and H2SO4, which were used at the concentrations of 5 and 10 vol%, hydrofluoric acid (HF) acid solutions of 5, 10, 20, 30, and 40 vol%. The experiments were done at 20, 40, 50, and 60°C temperatures in order to observe the heating effect on the removal yields. The best result was found for the sample being done experimentally with 5% HF. The ash content is decreased from 17.12 to 6.98 wt% and heating value is increased from 16,652 to 23,950 kJ/kg according to the original lignite. The yields are 59.23 and 44%, respectively. Fourier transform infrared and X-ray diffraction were used to observe the leaching effect of the mineral acids on the demineralization degree of Nallihan lignite. [ABSTRACT FROM PUBLISHER]

Desulfurization and demineralization by an aqueous caustic leaching method was investigated of an asphaltite sample from Harbul (Silopi, SE Anatolia, Turkey). The effects of different parameters, such as alkali concentration, time, and temperature, on the leaching efficiency were detailed and the experimental results are presented here. The caustic concentration varied from 0.1-1.0 M, temperature was 100-180°C, and leaching time varied from 4-16 h. The removal of total sulfur and ash increases with increasing alkali concentration, leaching temperature, and time. As a result of aqueous caustic leaching, the ash content of asphaltite was reduced from 32.49 to 18.00%, and 76% of combustible was recovered. Total sulfur and volatile matter content was reduced from 7.02 to 2.68% and from 46.74 to 25.10%, respectively. [ABSTRACT FROM AUTHOR]