Wetsieving

Wetsieving is a particle size separation technique in which a sample is dispersed in water and passed through a stack of sieves with progressively smaller openings to determine the size distribution of the material. It is commonly used for sands, soils, and various mineral materials, especially when the material contains moisture or cohesive clays that complicate dry sieving.

In a typical wet sieving procedure, the sample is placed on the top sieve of a stack and wetted with water. The assembly is agitated, either by a mechanical shaker or manual shaking, to promote passage of particles smaller than each sieve through the screen while larger particles remain on the preceding sieve. The wash water carries fines down the stack until they are retained by the appropriate sieve or exit through the bottom screen. After shaking, each sieve and the pan are dried and weighed to determine the particle-size distribution. For clays or sticky materials, dispersants or pre-dispersion steps may be used to minimize aggregation.

Equipment commonly includes a sieve stack, a water source or wash bottle, a shaker or hand mixer, a collection tray, and a drying oven or desiccator. The procedure can be batch-based or continuous, and durations vary with material type and required precision.

Applications include soil texture analysis (determining sand, silt, and clay fractions), quality control of sands and aggregates, and preparation of feed sizes in mineral processing. Wet sieving is particularly advantageous for moist, dusty, or cohesive samples and reduces dust generation compared with dry sieving, but it may be less effective for very fine fractions beyond the mesh size and requires careful dispersion to avoid fines loss or over-wetting.