金红石型TiO2分散浆的制备及其流变特性

研究了金红石型TiO₂颗粒在水相体系的分散性及其流变特性，通过zeta电位、黏度等参数表征浆体的分散状况，确定了合适的分散剂为聚丙烯酸钠、其用量为4%（与TiO₂质量比），分散浆中TiO₂合适的固含量为20%。通过稳态剪切测量法，发现分散浆中的固含量、pH和盐强烈影响其流变特性。分散浆存在剪切稀化现象，符合幂律模型，并呈现假塑性流体行为且无触变性。NaCl导致分散浆黏度降低， Na⁺离子浓度越大，浆体黏度越小；而CaCl₂的存在会使分散浆出现絮凝现象。分散浆合适的pH为12，增大或减小体系pH，浆体黏度均降低。当温度从25℃提升到50℃时，分散浆黏度略微降低，通过阿伦尼乌斯方程可以很好地描述温度对黏度的影响。频率扫描结果显示，分散浆在低频下呈凝胶状态，在高频下表现得更像是溶液。随着固含量的下降，分散浆交叉频率值降低。

Preparation of rutile TiO2 dispersion slurry and its rheological properties

The dispersibility and rheological properties of rutile TiO₂ dispersion slurry were studied in this paper. The dispersion of slurry was characterized by zeta potential, viscosity and so on. The suitable dispersant was sodium polyacrylate with the appropriate dosage of 4% (mass ratio to TiO₂), and the suitable solid content of TiO₂ in the dispersion slurry was 20%. Through steady shear measurements, it was found that the solids content, pH and salt in the dispersed slurry had strong influence on the rheological properties. The dispersed slurry had shear thinning phenomenon, which was consistent with the power-law model. And it exhibited pseudoplastic fluid behavior without thixotropy. NaCl decreased the viscosity of the dispersion slurry, and the higher the Na⁺ ion concentration, the lower the viscosity of the slurry. The presence of CaCl₂ caused the dispersion to flocculate. The suitable pH of the dispersion slurry was 12, and the viscosity of the slurry decreased while the pH of the system increased or decreased. The viscosity of the dispersion was slightly reduced when the temperature was raised from 25℃ to 50℃. The effect of temperature on the viscosity could be well described by the Arrhenius equation. The frequency sweep showed that the dispersed slurry took a state of gels at low frequencies and it didn’t at high frequencies. The dispersion cross frequency value decreased with the decreasing solid content.