电解法用于促进蛇纹石矿物固定CO_2的研究

Using Electrolytic Method to Promote CO_2 Sequestration in Serpentine by Mineral Carbonation

采用自制的电解反应器来电解NaCl溶液,利用阳极产生的酸性溶液溶解出蛇纹石中的镁离子,用阴极产生的碱性溶液吸收模拟烟气中CO2,然后将反应后的两极溶液混合形成MgCO3沉淀.结果表明:在电流强度在0.5 A时电解效率最高,电流效率与NaCl溶液的浓度关系不大.在阳极得到的酸性溶液用于溶解蛇纹石中的镁,其性能与相同pH值的盐酸溶液相差不大,可以用于直接浸取蛇纹石中的镁.用阴极得到的碱性溶液吸收模拟烟气中的CO2,得到的溶液与浸取出的Mg2+在85℃下反应可以得到固体沉淀.干燥后采用XRD以及TGA对固体沉淀进行表征,发现产物为较纯净的碱式碳酸镁[Mg5(CO3)4(OH)2.4H2O],这种物质在环境中是稳定、无害的而且还具有一定的经济意义.该方法可用于氯碱工业比较发达的地区,其阳极产生的酸性废液可以充分利用,而阴极产生的碱性溶液也不必进行分离即可进一步反应,该过程在相对低温以及常压下进行,同时还得到H2与Cl2,以及较纯净的固体产品,因此可以大大降低矿化成本.

A novel method for promote carbon sequestration by mineral carbonation using electrolysis was studied in this article, which used the electrolytic reactor to electrolyze NaCl solution. The acid solution produced from anode was used to dissolve Mg^2＋ from serpentine, and the basic solution produced from cathode was used to adsorb CO2 in simulation smoke, then these two solutions were mixed to form MgCO3 deposition. The results indicate that the highest current efficiency could be get when current was 0.5 A and it was not depend on the concentration of NaCl solution obviously. The acid solution produced from anode can dissolve Mg^2＋ from serpentine, which dissolve capacity was almost the same with the same pH of HCl solution in our research; therefore, it can replace HCl solution to dissolve serpentine. The basic solution produced from cathode after adsorbing CO2 of simulation smoke can react with Mg^2＋ to form solid deposition at 85℃. Being determined by XRD and TGA, it was found that the deposition was mainly pure basic magnesium carbonate [Mg5 （CO3）4 （OH）2,4H2O] ,which both environment benign and economically. It＇s an excellent method for use in the regions which have more Chlor-Alkali industry, which acid solution produced from anode can be well utilized and basic solution from cathode may make farther reaction without separation, moreover, the reactions can be processed at low pressure and relative low temperature, and the pure H2 ,Cl2 and pure solid products can be obtained in this process, which makes the mineral carbonation process more economical.