烟道气碳化水镁石副产碱式碳酸镁碳捕集技术

Carbon Capture Technology of Basic Magnesium Carbonate as a By-product of Brucite Carbonized by Flue Gas

以天然水镁石(Mg(OH)_2)浆液为原料,在固液质量比1∶6,反应温度40℃,反应压力1.01×10~5 Pa,模拟烟道气的CO_2体积分数为15%的条件下进行碳捕集,同时产出副产品碱式碳酸镁(4MgCO_3·Mg(OH)_2·4H_2O),此方法不仅降低了捕集成本,而且副产高附加值产品.对反应过程中体系的pH值和物质组成进行了检测,探讨了不同气速对反应时间的影响,并对最终产物进行了滴定分析和热失重分析.结果表明:反应终止的pH值为7.73~7.74,较适宜的气速为60mL/min,此时CO_2回收率达40.87%.最终产物碱式碳酸镁的镁含量达到43.16%(质量分数),失重量达到56.26%,符合碱式碳酸镁产品的行业标准.

Brucite（Mg（OH）2） as raw material, the carbon capture by absorbing carbon dioxide （15 %, volume fraction） of simulated flue gas was carried out under the condition that the solid-liquid mass ratio was 1 ： 6, the reaction temperature was 40 ℃ and the reaction pressure was 1. 01 × 10^5 Pa. The cost of capture was reduced by deputy producting high value-added products such as basic magnesium carbonate （4MgCO3 · Mg（OH）2 · 4H2O）. The changes of pH value and substance composition during the reaction were determined, the influence of gas velocity on reaction time was discussed, and the final product was analyzed by titration and ther- mogravimetric analysis. The experimental results show that the pH value of the termination reaction is 7.73-7.74, the suitable gas velocity is 60 mL/min, and the recovery rate of CO2 is 40.87%. The final product basic magnesium carbonate magnesium content reaches 43. 16% （mass fraction of MgO）, and its weight loss reaches 56.35%. Above results are complied with the industry standard of magnesium carbonate products.