Fundamental Study for The Production of Metallurgical Coke by Hydrothermal Treatment

研究了煤中矿物杂质在Ca(OH)_2/NaOH溶液中萃取的行为，萃取温度为180 ~ 250‰。其中，磷的脱除效果较好。在180 ~ 200℃范围内，磷的提取效果最好。研究还发现，浓度越低，效果越好；特别是对于Ca(OH)_2。以Ca(OH)_2为原料，最佳浓度范围为0.5 ~ 1.0 mol/kg-H_2O。NaOH 2.0 mol/kg-H_2O使磷的去除率提高。在NaOH的情况下，随着温度的升高或浓度的增加，煤物质的损失显著。当温度升高到200ºC以上时，磷酸钙复合物转化为难溶物质，如羟基磷灰石，并再次返回到残渣中。在NaOH条件下，SiO_2和Al_2O_3的萃取行为非常相似，温度越高、试剂浓度越高，SiO_2和Al_2O_3的萃取程度越高。此外，温度的升高可以促进SiO_2的脱除。Ca(OH)_2对SiO_2和Al_2O_3的萃取效果不明显。对比Ca(OH)_2和NaOH的效果，Ca(OH)_2表现出较好的效果。此外，Ca(OH)_2比NaOH更适用于生产工厂。在常压条件下，热水浴条件下，NaOH的除磷效果优于Ca(OH)_2。

The extraction behavior of mineral impurities from Brazilian coal was investigated from 180 to 250ﾟC in the Ca(OH)_2/NaOH solution...Among them, removal of phosphorus was better realized than other inert matters. The phosphorus extraction reached the highest results at lower temperatures between 180ﾟC and 200ﾟC.It was also found that lower concentrations could give better results; especially in the case of Ca(OH)_2. Using Ca(OH)_2, the better concentration range was considered to be from 0.5 mol/kg-H_2O to 1.0 mol/kg-H_2O. NaOH 2.0 mol/kg-H_2O leads more phosphorus to be removal. In the case of NaOH, significant lost of coal matter was observed either for the temperature increasing or for the concentration increasing. When the temperature goes up more than 200ﾟC, the calcium-phosphate complexes convert into hardly soluble matter such as hydroxyl apatite and turn back to the residue again.The SiO_2 and Al_2O_3 behaviors are quite similar: the higher the temperature and the reagent concentration, the higher the extraction degree of SiO_2 and Al_2O_3 in the case of NaOH. In addition, the increasing of temperature can promote more removal of SiO_2. The Ca(OH)_2 was not effective for SiO_2 and Al_2O_3 extraction.Compared the effects of Ca(OH)_2 and NaOH, Ca(OH)_2 showed more promising results. Furthermore, Ca(OH)_2 is much suitable than NaOH in the production factory. Nevertheless at atmospheric pressure conditions, hot water bath, NaOH is better than Ca(OH)_2 for removing phosphorus.