Separation techniques of heterogeneous mixtures Case of liquid solid mixtures Sedimentation and decantation Separating a mixture of mud and water Allow the muddy water to stand for a while The sand particles settle at the bottom of the beaker This is called sedimentation Sedimentation allows for the appearance of two distinct phases The liquid phase and the solid phase or sediment The solid phase is called the sediment To separate both phases, the liquid is slowly poured into another beaker This is called decantation Both phases were separated by decantation The mixture was separated by sedimentation followed by decantation Centrifugation In some cases, sedimentation may take a long time This is the case of very fine solid particles suspended in a liquid Centrifugation can be used to accelerate the sedimentation of the solid phase For example, centrifugation can be used to separate water from extremely fine particles of sand that are suspended in water Separating a mixture of water and extremely fine particles of sand The mixture is poured in several centrifuge test tubes The test tubes are ready to be put in the centrifuge The tubes containing the mixtures are now introduced in the centrifuge The centrifuge rotates the tube at a very high speed which forces the fine solid particles to settle at the bottom of the tubes The tubes are now removed from the centrifuge The fine solid particles are deposited at the bottom of the tubes Sedimentation allows for the appearance of two clear phases The liquid phase and the solid phase are sediment The liquid is ready to be decanted Decantation The liquid phase and the solid phase are separated by decantation Filtration Separating orange juice from its pulp The mixture is poured in another beaker through a filter paper The solid pulp is ready to be put in the centrifuge The mixture is poured in another beaker through a filter paper The solid pulp is retained by the filter paper while the liquid juice passes through it to the other beaker The solid phase and the liquid phase were separated by filtration Vacuum filtration Filtration may be accelerated by creating a difference in pressure on both sides of the filtration funnel Buckner funnel This is done by connecting the flask to running water Equipment of vacuum filtration Stand Buckner funnel Porous plate Rubber bung Buckner flask Water pump Rubber tubing Tap Place a moistened filter paper in the buckner funnel Open the tap Running water extracts air from the buckner flask This lowers the pressure inside the flask The difference in pressure between both sides of the flask will accelerate the movement of the liquid downwards towards the flask Pressure outside the flask is bigger than the pressure inside the flask Gently pour the mixture in the funnel End of vacuum filtration The solid particles are retained on the filter paper The liquid phase is recovered in the flask, close the tap Residue Filtrate Scrape the residue with a spatula into another container End of separation techniques of heterogeneous liquid solid mixtures