Difference between solid and liquid mixing: Industrial applications involve the mixing of solids to solids such as free-flowing solids to pasty materials, solids to liquids, and solids to gas, liquids to liquids, and liquids to gas.
| Liquid mixing | Solid mixing |
|---|---|
| (i) Fluid mixing is generally associated with liquid-liquid mixing and liquidgas mixing. | (i) Mixing of solids to some extent resembles the mixing of low-viscosity liquids. |
| (ii) Liquid mixing depends on the creation of flow currents, which transport unmixed material to the mixing zone adjacent to the impeller. | (ii) In heavy masses of particulate solids there are no such currents possible and mixing is accomplished by some other means. |
| (iii) Power required for mixing and the blending of liquids is less. | (iii) Power required for mixing of dry solids is comparatively higher. |
| (iv) In liquid mixing, a well-mixed product is usually a truly homogenous liquid phase. | (iv) In solid mixing the product often consists of two or more easily identifiable phases, each of which may contain individual particles of considerable size. |
| (v) A “well-mixed” liquid product samples are homogenous in nature. | (v) A “well-mixed” solid product samples differ markedly in composition. |
| (vi) Design, construction, and operation of fluid mixing equipment are specific and are termed as liquid agitators. | (vi) Design, construction, and operation of solid mixing equipment are different than liquids and are commonly referred to as mixers and blenders. |
| (vii) The liquid mixing technology has been extensively studied and understood. | (vii) The understanding of solid mixing, and the design of solid mixers is an art rather than a science. |
| (viii) The liquid mixing technology is simple. | viii) Solid mixing is more complex. |
What is the application of mixing in pharmacy?