Show flotation on chemistry chemi stry BY THOMAS A most workers have approached flotation from the physical standpoint and what few chemical theories have been evolved are based on colloids coll my own idea of notation flotation phe phenomena nomona was that it is physical until I 1 came to investigate the purification of aluminum oxide by flotation the aluminum oxide produced by calci ning bauxite cannot be floated that produced by calci ning alunite can be floated from alunite by calci ning aluminum oxide is produced along with potassium sulphate the potassium sulphate is leached beached from the calcines by hot water acts either as an acid or a base and it is inconceivable that some reaction between the and the potassium does not take place by the law of absorption the salt resulting from this reaction the soluble would to a large extent remain on the particles after washing in the filter press in the case of bauxite no such opportunity for the absorption of a reaction product which fulfils fulfills the requirements for subsequent flotation occurs the flotation of sulphide in pure water with oils does not occur always there is present either from the ore or added mechanically chani cally an acid or alkali soluble in some degree and which can react with the sulphide the products of the reaction being concentrated on the sulphide particles by absorption here it is necessary to emphasize the extreme chemical activity of very dilute solutions the cyanide process has made most engineers familiar with the fact that this particular reaction takes place only in extreme dilutions and investigations into geological chemistry testify to the activity of very dilute acid and alkaline solutions we know all too little of the chemistry of solutions of the dilution employed in cyaniding cyan iding and flotation this reasoning leads to the conclusion that we always have on the surfaces of the floatable minerals held by absorption a soluble salt produced by the reaction between the mineral and the acid or alkali present in extreme dilution I 1 have never encountered a case of flotation where the above conditions were not fulfilled and in the case of aluminum oxide derived from bauxite where the conditions are not fulfilled the material does not float As to oils it seems that the flotation takes place when two conditions are fulfilled namely the oil must be soluble and it must be an unsaturated hydrocarbon in the chemical sense virtually every oil carries some of these unsaturated soluble hydra hydrocarbons carbons and those that do not cause consulting E engineer ng ineer industrial engl co salt lake utah no flotation phenomena these soluble TIL saturated hydrocarbons in extremely dilute solution again react with the salts on thee the surface of the mineral with a reaction n aki akin J to and this product is the true agent of flotation the flotation circuit with its small amount of materials in solution and its multitude of possible reactions forms a vety very complex example of the phase rule which no doubt explains its great sensitiveness also preferential flotation is more clearly seen in the light of the phase rule thus in working out flotation problems one should endeavor to produce by reaction with the mineral to be floated a salt soluble to some degree and whose base will react with the soluble oil perhaps the metal salts of these oils can be produced outside the flotation circuit and simply added as we now add oil and their solubility and the law of absorption would do the rest our oun lack of knowledge of the chemistry of extremely dilute solutions and the complex phase relations of course makes the prediction of results impossible nevertheless I 1 have found it the only theory applicable to my own observations on the flotation of aluminum oxide |