Lithium Fluoride: Lithium Sulphate Solution Precipitated with Hydrofluoric Acid in Acid, Finished with Soda (Kraft and Beck, US 3,326,631)

Lithium fluoride precipitated in neutral solution is so fine it will hardly filter. Kraft and Beck start the precipitation in strong acid, which gives coarse crystals, and only then neutralise with soda to bring down the rest. Result: 52.8 g of lithium fluoride from one litre of solution, 94 % of the lithium. Source: G. Kraft and H. Beck, US 3,326,631 (1967), Example 1. Hydrofluoric acid is deadly and burns deep into skin; work in a fume hood. Picture drawn by Youblob.