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测定了硫酸钡不同工艺制成品的粒度分布。证明北京三厂中间产品(湿膏)本来粒度很细有97％是在4μm以下,但烘干后成品粒度变粗,80μm以上的粒子占62％。这对造影效果会产生重要影响。喷雾干燥产品的粒度分布与原湿膏基本相同。用电泳法测定了硫酸钡混悬剂的动电位,确定硫酸钡是荷负电的。混悬剂的动电位在22mv以下可产生絮凝,适合于反絮凝的动电位是在50～66mv之间。电解质中六偏磷酸钠、焦磷酸钠和柠檬酸钠的反絮凝效力是按上列顺序减低的。例如配制100％硫酸钡混悬液三种电解质最适宜的浓度分别为5×10~(-3)M、2×10~(-2)M和3×10~(-2)M。本文用粘度分析法研究了混悬液的絮凝反絮凝过程,所得结果与动电位和沉降容积的结果基本吻合,惟粘度法方便迅速并能反映出细小的变化,可用数字和曲线作鲜明的对比。但此法要求颗粒要细(10μm以下)否则会发生机械性阻碍无法测定。
The particle size distribution of different products of barium sulfate was determined. Proved that Beijing Third Factory intermediate products (wet paste) originally 97% of the fine particle size is below 4μm, but the finished product after drying particle size becomes coarse, more than 80μm particles accounted for 62%. This can have a significant effect on the contrast effect. Spray-dried product particle size distribution and original wet cream is basically the same. The electrokinetic method was used to determine the zeta potential of barium sulphate suspension. It was confirmed that barium sulphate was negatively charged. The dynamic potential of the suspension at 22mv can produce flocculation, the dynamic potential for deflocculation is between 50 ~ 66mv. The deflocculating efficacy of sodium hexametaphosphate, sodium pyrophosphate and sodium citrate in the electrolyte is reduced in the order listed above. For example, the optimum concentration of the three electrolytes in 100% barium sulfate suspension is 5 × 10 -3 M, 2 × 10 -2 M and 3 × 10 -2 M, respectively. In this paper, the flocculation deflocculation process of the suspension was studied by viscosity analysis, and the results are basically consistent with the results of the dynamic potential and sedimentation volume, but the viscosity method is convenient and rapid and can reflect small changes, can be sharp contrast with the number and curve . However, this method requires fine particles (10μm or less) or mechanical failure can not be measured.