Calcium transformation during the high-temperature pyrolysis process of high-alkali coal from Xinjiang
The existence forms of calcium contained in the high-alkali coal from Xinjiang,China and the calcium transformation during the high-temperature pyrolysis process were investigated using extraction method.The results show that the calcium contained in high-alkali coal mainly exists in the form of ammonium acetate soluble calcium and hydrochloric soluble calcium,while there is some water soluble calcium contained in Tianchi Energy coal.The water soluble calcium in Tianchi Energy coke prepared at 1 500 ℃ is apparently high because CaS contains in Tianchi energy coal and CaS is still left in the coke.The ammonium acetate soluble calcium in Wucaiwan coke prepared at 1 500 ℃ is apparently higher than that in the cokes from other coals because the content of silicon and aluminum in Wucaiwan coal is low and a part of CaO is still left in the coke.With the increase of pyrolysis temperature,the calcium content of the resulted coke increase.The calcium contained in the coke prepared at 1 200 ℃ mainly exists in the form of ammonium acetate soluble calcium species including anhydrite and quicklime and others.In the case of the coke prepared under the temperature range of 1 200-1 400 ℃,the contained anhydrite decomposition leads to a slightly increase of water soluble calcium,however,the calcium still mainly exists in the form of ammonium acetate soluble calcium as CaO.When the pyrolysis temperature increases from 1 400 ℃ to 1 500 ℃,the chemical reaction between CaO and silicon and aluminum makes ammonium acetate soluble calcium be transformed into hydrochloric soluble calcium.
high-alkali coalcalciumexistence formpyrolysis process
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万方数据
维普
