喷雾干燥制备仲钼酸铵微球及其煅烧还原过程研究

Study on the preparation of ammonium paramolybdate microspheres by spray drying and their calcination reduction process

摘要:

本文以仲钼酸铵为原料，采用喷雾干燥法制备了中空的仲钼酸铵前驱体微球，并将其煅烧还原成方形或球形的多孔单质钼。表征了仲钼酸铵前驱体微球的形貌及其在煅烧还原后的形貌和成分，并研究探讨了还原温度、升温步段和气氛对仲钼酸铵微球还原的影响。结果表明，随着溶液浓度的增大，微球的粒径范围增大，表面凹坑增多，并且团聚现象愈发明显；随着进料速率的增大，微球的粒径范围有一定的减小，且表面的凹坑减少；随着喷雾干燥温度的增大，微球的粒径范围先增大后减小，而表面的凹坑显著增多；在800℃下，利用氢氩混合气还原可以得到方形或近球形单质钼，而利用纯氢气还原则可得到球形单质钼。

Abstract:

In this paper, hollow ammonium paramolybdate precursor microspheres were prepared from ammonium paramolybdate solution by spray drying, and they were calcined and reduced to square or spherical molybdenum. It was characterized that the morphology of the ammonium paramolybdate precursor microspheres, and the morphology and composition were studied after calcination and reduction of ammonium paramolybdate precursor microspheres. The effects of reduction temperature, heating process and atmosphere on the reduction of ammonium paramolybdate precursor microspheres were also investigated. Consequently, as the concentratione of solution increase, the particle size range of microspheres become bigger, pits in the surface increase, and the agglomeration phenomenon becomes more obvious; with the increase of feed rate, the particle size range of microspheres decreased a little, and pits in the surface decrease; with the increase of spray drying temperature, the particle size range first increase and then decrease, while pits in the surface increase evidently; at the temperature of 800℃，the square or near spherical molybdenum can be obtained by hydrogen-argon mixer reduction, while the spherical molybdenum can be obtained by pure hydrogen reduction.