Clay washing is a beneficiation process in which mined ore is subjected to mechanical scrubbing and water washing to remove clay minerals, fines, and surface coatings from ore particles, thereby improving the grade, processability, and marketability of the product. In bauxite mining, clay washing is a primary beneficiation technique applied to pisolitic and lateritic bauxite ores where clay-rich material adheres to bauxite nodules or is intermixed with the ore. Scrubbers, trommel screens, and log washers are commonly used to mechanically agitate and wash bauxite ore with water, releasing clay fines that are then screened and classified out of the product. The wash water carrying clay fines is typically collected in settling ponds or processed through thickeners for water recovery and tailings management. In gold mining, clay washing improves liberation of gold-bearing minerals and reduces the clay load in grinding and leaching circuits. In iron ore mining, clay washing is applied to direct shipping ore (DSO) to meet customer specifications for silica, alumina, and moisture content. In diamond mining, clay washing — typically performed in scrubber drums or pug mills — is the first critical step in liberating diamonds from the clay-rich kimberlite matrix, and inadequate washing results in diamond loss in downstream processes. Clay washing efficiency depends on scrubbing intensity, water-to-ore ratio, retention time, and ore clay mineralogy.
