响应曲面法优化微波干燥碳酸稀土的实验研究

Optimization on Experiment of Microwave Drying of Rare Earth Carbonate Using Response Surface Methodology

采用中心组合设计(CCRD),三因素五水平响应曲面法(RSM),研究了微波功率、干燥时间和物料厚度间的交互作用对碳酸稀土脱除吸附水的影响,模拟得到二次多项式回归方程的预测模型。结果表明:物料厚度一定,脱水率随微波功率和干燥时间的增大而增加;微波功率一定,脱水率随物料厚度增加而降低,优化的最佳工艺参数为:微波功率800 W,干燥时间12 min,物料厚度2 cm,脱水率98.88%,实际测得97.69%,相对误差为1.31%。红外光谱(FT-IR)分析表明微波干燥后碳酸稀土不再含有吸附水;粒度分析表明微波干燥后的碳酸稀土具有粒度细和分布均匀的特点。

The central composite rotatable design（ CCRD） of response surface methodology（ RSM） was used to study the effect of interaction among three variables,microwave power,drying time and material thickness on the dehydrating absorbed water of rare earth carbonates,and a response surface methodology model using the second-order polynomial was obtained. The results showed that dehydration rate increased with the increase of microwave power and drying time at fixed material thickness,and decreased with the increase of material thickness when other conditions were fixed. The optimal operation conditions of microwave power,drying time and material thickness were 800 W,12 min and 2 cm,respectively. Under the optimal conditions,the dehydration rate was 97. 69%,and the relative error differed by only 1. 31% from the predicted value of model（ 98. 88%）. Fourier transform infrared spectroscopy（ FT-IR） and size analysis indicated that the rare earth carbonate after microwave drying had no adsorbed water,and had the characteristics of small size and uniform distribution.