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用高钙含钒钢渣经钠盐焙烧后的焙砂样品以及焦钒酸钙合成样品,在15—75℃范围内进行了碳酸化浸取动力学研究。碳酸化浸取提钒,主要是把钢渣中的碳酸钙溶解,使钒呈钒酸钠形式进入溶液,钙转变成碳酸钙沉淀。研究表明,在碱性溶液中通入CO_2气体,随着pH值的下降,首先生成Na_2CO_3,随后生成NaHCO_3。此碳酸化浸取的液-固反应过程,用颗粒表面溶解反应的收缩核心模型进行描述,在反应初期阶段是Na_2CO_3的溶浸作用,然后则主要是NaHCO_3的溶浸作用,后者的反应速度比前者快。用焦钒酸钙合成样品进行研究,证实了所推论的反应机理。在所试验的温度范围内,碳酸化浸取焦钒酸钙合成样品的反应表观活化能为25.3千焦/摩尔。
The kinetic study of carbonation leaching was carried out in the range of 15-75 ℃ with calcine samples calcined by high-calcium vanadium-bearing steel slag after calcination with sodium salt and calcium pyrophosphate. Carbonation leaching extraction of vanadium, mainly calcium carbonate slag dissolved in the form of vanadium vanadate into the solution, calcium into calcium carbonate precipitation. The results show that CO_2 gas is introduced into the alkaline solution, and then Na_2CO_3 is first formed and then NaHCO_3 is formed with the decrease of pH value. The liquid-solid reaction process of carbonation leaching is described by the shrinking core model of particle surface dissolution reaction, which is the Na_2CO_3 leaching at the initial stage of the reaction, and then the predominant NaHCO_3 leaching reaction. The latter reaction rate Faster than the former. The synthesis of calcium pyrophosphate samples was studied, confirming the deduced reaction mechanism. The apparent activation energy for the carbonated leaching of calcium pyrophosphate in the tested temperature range was 25.3 kJ / mol.