水热法制备方铁锰矿Mn_2O_3

Preparation of Bixbyite Mn_2O_3 by Hydrothermal Method

采用水热法,以锰硝酸盐和尿素为原料,制得中间产物碳酸锰,经煅烧后,获得方铁锰矿Mn2O3。主要考察了水热反应的温度和时间,不同反应物浓度,煅烧温度以及加入表面活性剂对产物的影响。利用DSC/TG、XRD和SEM对中间产物及最终产物进行了表征。结果表明:水热反应的温度对所得中间产物的种类有影响;不同煅烧温度所得产物的晶型和形貌不同;水热反应时间长,颗粒越大;反应物浓度越大,产物粒径越小;水热反应温度低时,得不到完整结构的晶体;添加表面活性剂,产物的形貌为球形,粒径大大减小,但团聚严重。

In this paper, manganous nitrate and carbamide were used to get the manganous carbonate mid-pro-duction by hydrothermal method and then they calcined the mid-production to get the bixbyite Mn2O3. It was mainly considered the effects on the products, such as the time and temperature of hydrothermal method, the concentration and ratio of the reactants, the kinds and dosages of the surfactant. The mid-products and final products were charactered by DSC/TG,XRD and SEM. The results show that the temperature of hydrothermal reaction has effect on the types of mid-products. The structure and the morphology of final products are different in different calcined temperature. The longer the reaction time is, the larger the size is. The thicker the concen-tration is, the smaller the product size is. The whole structure crystal can＇ t come together under the low reaction temperature. The morphology of products are sphericity and the sizes are minished by adding surfactants but the conglomeration is serious.