Patented Aug. 2, 1927. 1,637,451 UNITED STATES PATENT OFFICE. RICHARD MOLDENKE, CF wATCHUNG, NEW 3ERSEY. PROCESS OF TREATING ALUMINOUs oREs. No Drawing. Application filed July 9, 1925. Serial No. 42,579. This invention relates to the treatment of Water, to said solution or the solution of aluminous ores and the salient object of the ailmonia may be added to the alum solution invention is the production of aluminum hy hot or cold; or I may pass dry ammonia gas droxide in a particularly pure state, in order over the alums in layers, whichever way is 60 that the same may be successfully used in the found most convenient and practical, under production of metallic aluminum by the the conditions of Operation, for producing customary electrolytic reduction in the pres granular alumina from the hydrate. The ence of carbon. - . . . aluminum hydrate obtained by leaching, in With the foregoing object in view, a suit stead of being of the usual gelatinous form, able aluminous ore, such as “altunite,” is first is, as Suggested, in granular condition, and, ground and treated substantially in accord therefore, is much more effective and suit ance with either of the prior patents to the able for its intended purposes. applicant herein No. 1,282,273 dated October It will be manifest that the aluminum hy 22, 1918 or to Edel Moldenke, No. 1457.78, drate is produced as a precipitate, the fil tate containing potash and ammonium sul datedBriefly June stated, 5, 1923. these processes" . . . involve. . a phates. Said filtrate may be treated in such treatment of alunite, for the purpose of lihanner, by fractional crystallization or rendering the valuables therein soluble, and otherwise, so as to separate therefrom the consists in mixing the cominuted ore with potassium and annonium sulphates and en sulphuric acid to form a pasty mass, thei'e- able then to be used in the fertilizer industry upon heating the same in such manner that or in such other commercial fields which are the resulting material may be formed into ope) to their use. a cake, thereafter breaking the cake into The aluminum hydroxide obtained as de pieces and subjecting it to heat at a higher scribed is exceptionally pure in that it is S. () 2 5 temperature than the previous heating and almost entirely free from the very trouble finally extracting the valuables therefrom by some impurities ordinarily contained there leaching with water. The potash and all in, namely, silicon and iron. Accordingly, mina, together with any soda present, are it is in condition for successful use for its converted into sulphates and separated from various intended purposes, mainly for use the silica. . in the production of metallic aluminum by The solution, produced as above described, manipulating it electrolytically in a cryolite is thereafter evaporated to such extent as to “bath, as now practised. crystallize out potash alum, leaving behind The foregoing process is the preferred and all the aluminum sulphate and ally soda typical method of practising the invention, st alum present, together with any iron which but is not intended as being exclusive as to might have been present in the mother liquor details of operation, or slight modifications from the potash alum. Sufficient ammonium therein, or as to the employment of equiva sulphate (or potassium sulphate, or potas lent operations and materials, the scope of sium and ammonium sulphates mixed), is the invention being commensurate with the 40 now added to the liquor, whereupon the am appended claims. monium aluminum alum is crystallized out Having thus fully described the invention, (or more potash alum or potash and alm what I claim as new and desire to secure by monia alum mixed) depending on the par Letters Patent is: . . . ticular procedure adopted. 1. The process of recovering aluminum in The foregoing process removes all iron the folm of alumina from ores containing from the recovered alums and the mother aluminum and potassium which comprises liquors may be used over again until they treating the said ores with Sulphuric acid to contain so much iron that they may be dis convert, the aluminum and potassium and carded. It will thus be apparent that all sodium compounds associated there with into 105 the values in the alunite are obtained, in a sulphates of such metals, separating the substantially pure state in the form of potash potassium alum thus formed from the mix ammonium alum and ammonium aluminum ture, treating the mixture containing alumi alum. nunn with an ammonium compound capable I now pass ammonia, preferably produced of converting the aluminum into ammonium O synthetically, either through the solution of aluminum alum, separating the ammonium the alums or add ammonia dissolved in aluminum alum thus formed, and treating 1,687,451.

the potassium alum and the aluminum alum monia to convert Se into aluminum thus produced with ammonia to convert the hydrate. 40 aluminum into aluminum hydrate. 5. In the process of recovering aluminum 2. The process of recovering aluminum in in the form of alumina from ores containing the form of alumina from ores containing aluminum and potassium, the steps which aluminum and potassium which comprises comprise treating the said ores with Sul treating the said ores with Sulphuric acid, phulic acid to convert the aluminum and 45 Separating the potassium aluminum com potassium and sodium compounds associated pound thus formed from the mixture, treat there with into the sulphates of such metals, ing the mixture containing aluminum with Separating the potassium alum thus formed ammonium Sulphate, separating the am from the mixture, treating the said mixture monium aluminum alum thus formed, treat with ammonium Sulphate to convert, the 50 ing the potassium aluminum compound and aluminum into an ammonium aluminum the aluminum alum thus produced with ann alum, and treating the potassium and alumi 5. monia to convert the aluminum into alumi num alums thus formed with ammonia to num hydrate, and separating the aluminum convert the aluminum into aluminum hy hydrate therefrom. drate. - 55 3. In the process of recovering aluminum 6. The process of recovering aluminum in in the form of alumina from ores containing the form of alumina from ores containing SC aluminum and potassium, the steps which aluminum and potassium which comprises comprise treating the said ores with sul treating the said ores with sulphuric acid, phuric acid, separating the potassium alumi Separating the potassium aluminum.com SO num alum thus formed from the mixture, pound from the mixture of soluble com treating the mixture containing aluminum pounds thus formed, treating the mixture 5 with an ammonium compound capable of containing aluminum with an ammonium converting the aluminum into ammonium compound capable of converting the alumi aluminum alum, and treating the aluminum num compound into ammonium aluminum 65 alum thus formed with ammonia to convert alum, separating the impurities from the the aluminum into the form of a hydrate. ammonium aluminum alum thus formed, ad 4. In the process of recovering aluminum Inixing the potassium aluminum compound from alunite ore, the steps which comprise with the ammonium alum, and treating the converting a portion of the aluminum in said mixture with ammonia to convert the 0 said ore into a potassium alum, Separating aluminum contained in said compounds into the potassium alum therefrom, converting aluminum hydrate. s the remaining portion of the aluminum con in testimony whereof I have signed the tained in said ore into an ammonium alumi foregoing specification. num alum and treating the potassium alum. and ammonium alum thus formed with am RICHARD MOLDENKE.