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以V_2O_5浓度为17.85 g·L~(-1)的模拟一步法石煤提钒反萃液为研究对象。以沉钒产品纯度及其中杂质离子存在状态、杂质离子存在时多聚钒酸铵(APV)晶体状况为指标,讨论了模拟反萃液中的Fe~(3+),Al~(3+),Ca~(2+),K~+等金属杂质离子对酸性铵盐沉钒效果的影响。研究结果表明:Fe~(3+),Al~(3+)妨碍沉钒过程的顺利进行且会降低产品V_2O_5的纯度,并造成沉钒母液的p H值改变,增加后续母液处理的成本和难度;而Ca~(2+),K~+仅会影响产品V_2O_5的纯度,对沉钒率和母液p H值的影响并不显著;4种杂质离子均会使产品多聚钒酸铵(APV)的晶体形貌发生改变,但是每种杂质改变APV晶体形貌的方式各异:Fe~(3+)会破坏APV晶体的完整性并改变其晶体颗粒大小,K~+破坏APV晶体的完整性;Ca~(2+)使APV晶体表面粗糙,晶体颗粒之间黏连,形成大块颗粒;Al~(3+)形成的杂多酸的非晶体状态阻碍APV晶体的顺利长大。同时得到了反萃液沉钒指标良好时,4种杂质离子浓度的控制范围:Fe~(3+)浓度应<0.1 g·L~(-1),Ca~(2+)浓度应<0.9 g·L~(-1),K~+浓度应<2.0 g·L~(-1),Al~(3+)浓度应<3.0 g·L~(-1).
The simulated one-step extraction of stripping vanadium from coal with V 2 O 5 concentration of 17.85 g · L -1 was studied. The purity of vanadium product, the existence of impurity ions and the crystal state of polyvovanadate (APV) in the presence of impurity ions were discussed. The effects of Fe 3+, Al 3+, , Ca ~ (2 +), K ~ + and other metal ions on the vanadium precipitation of acidic ammonium salts. The results show that Fe 3+ and Al 3+ prevent the smooth vanadium precipitation process and reduce the purity of the product V 2 O 5, resulting in the change of p H value of the vanadium precipitation mother liquor and the cost of subsequent mother liquor treatment. However, Ca ~ (2 +) and K ~ + only affect the purity of V_2O_5, and have no significant effect on the vanadium precipitation rate and the mother liquor p H value. All four kinds of impurity ions will make the product poly ammonium vanadate APV) crystal morphology change, but each impurity changes APV crystal morphology in different ways: Fe ~ (3 +) will destroy the integrity of APV crystal and change its crystal particle size, K ~ + destroy APV crystal Integrity; Ca ~ (2+) roughened the surface of APV crystals and formed conglobation between the crystal grains; the amorphous state of heteropolyacids formed by Al ~ (3+) hindered the smooth growth of APV crystals. At the same time, when the vanadate index of the stripping solution is good, the control range of the four impurity ion concentrations is: Fe 3+ concentration should be less than 0.1 g · L -1 and Ca 2+ concentration should be less than 0.9 g · L -1, K + concentration should be less than 2.0 g · L -1, and Al 3+ concentration should be less than 3.0 g · L -1.