Acid concentration 2. Leaching time 3. Solid to liquid ratio 4. Leaching temperature 5. Bauxite particle size.
Iron increases the acid consumption and also contaminates the alum.
The leaching of the alum was therefore controlled to maximise the yield of alum and obtain minimum extraction of iron oxide. The samples were crushed and sieved in various mesh sizes. 2.1 Effect of sulphuric acid concentration on leaching Twenty grams of 60 mesh bauxite sample was used. Acid corresponding to acid ratio of 1 mole of alumina to 2 moles of acid was diluted to 200 m1, mixed with the bauxite and boiled for 4 hours, filtered and the residue was washed to make up the leached liquor. 2.2 Effect of leaching time Acid ratio of 1 mole alumina to 4 moles of acid, diluted to 200 ml was mixed with 20 grammes of 60 mesh bauxite and boiled Leaching was conducted at different periods from 1 to l0 hours.