有机酸与钙质砂反应过程及其动力学研究

Study on reaction process and kinetics of organic acid and calcareous sand

研究小分子有机酸(乙酸、苹果酸)对热带钙质砂的溶蚀作用,采用浸泡和淋溶两种模拟方式探究溶蚀过程的动态变化。结果表明,在不同浓度有机酸溶液的溶蚀下,扩散过程影响Ca^(2+)、Mg^(2+)的溶出,符合Stumm方程动力学模型。在3种不同浓度有机酸溶液中,100 mmol/L的有机酸溶液对钙质砂的溶蚀作用最显著,溶出速率苹果酸﹥乙酸。溶蚀反应中,镁方解石、文石成分发生主要变化,总质量减少率高达11.72%,溶蚀作用较为显著。

Calcareous sand from the tropics was selected to study the dissolution of small organic acids(acetic acid,malic acid).The dynamic changes of the dissolution process of calcareous sand were studied by soaking and leaching simulation.The results showed that the dissolution of Ca^(2+)and Mg^(2+)in different concentrations of organic acid solution was mainly affected by the diffusion process,which was consistent with the Stumm equation dynamics model.Among the three organic acid solutions with different concentrations,the organic acid solution with the concentration of 100 mmol/L had the most significant dissolution effect on calcareous sand,and the dissolution rate was malic acid and acetic acid.In the dissolution reaction,the composition of magnesium calcite and aragonite changed mainly,and the maximum reduction rate of total mass was as high as 11.72%.