Våtsiktning

Våtsiktning, often translated as wet sieving or wet screening, is a method used to separate solid particles based on their size by passing them through a sieve or screen in the presence of a liquid, typically water. This process is particularly useful for separating very fine particles that might otherwise clump together or clog the sieve when dry sieving is attempted.

The principle behind våtsiktning is straightforward. A slurry of the material to be sieved is prepared, and this slurry is then washed over a sieve of a specific mesh size. The liquid helps to disperse the particles, preventing agglomeration and ensuring that only particles smaller than the sieve aperture can pass through. Particles larger than the sieve mesh are retained on the sieve surface.

This technique finds applications in various fields. In geology and soil science, it's used to determine the fine-grained fraction of soil or sediment samples. In the mining and mineral processing industry, våtsiktning is employed to classify ores and to recover fine mineral particles. It is also utilized in the pharmaceutical industry for the purification of active pharmaceutical ingredients and in the food industry for processing powders.

The efficiency of våtsiktning depends on factors such as the viscosity and flow rate of the liquid, the particle size distribution of the material, and the properties of the sieve. Careful control of these parameters is essential to achieve accurate and reproducible results. After the sieving process, the retained material and the material that passed through are typically dried and weighed to determine the particle size distribution of the original sample.