Lervätska

Lervätska, literally clay liquid, is a suspension of fine clay particles in water. The term is used in several fields, including geotechnical engineering, mining, ceramics and environmental science. A lervätska mixture typically contains dispersed clay minerals such as kaolinite, illite or montmorillonite, along with water and sometimes small amounts of silt, organic matter or other impurities. The rheology of the suspension depends on solids content, particle size distribution, pH and electrolyte conditions, and it can range from a thin liquid to a viscous, plastic slurry. Many clays exhibit shear-thinning behavior and thixotropy, which aids pumping, mixing and casting.

Production and management of lervätska involve mechanical mixing of dry clay with water, sometimes with dispersants or deflocculants to improve stability and reduce settling. The stability of the suspension is influenced by charge on particle surfaces and the presence of dissolved salts. Dewatering of lervätska can be achieved by settling, filtration or centrifugation, leaving behind a clay-rich solid and a clarified liquid. Handling considerations include controlling dust from dry clay, managing turbidity in water bodies, and ensuring appropriate containment to prevent environmental release.

Applications are diverse. In geotechnical work, lervätska is used for slurry walls and trench stabilization, jet grouting and drilling fluids. In ceramics, it is the slip used for casting and forming clay-based products. In environmental remediation and mining, it can transport and stabilize clay-bearing materials. Safety considerations emphasize proper PPE for workers and monitoring of dust and water quality to limit exposure and environmental impact.