Patent GB-654695-A (GB)
Title: Improvements in or relating to the purification of metal compounds
Inventor: ARDEN THOMAS VICTOR
IPC: C22B3/00
Filed: 1948-04-22
Abstract: Various metal salts are separated by treatment with an organic solvent and an adsorbent material which in the presence of said solvent exhibits a different retentivity for the salt of one metal than for the salts of the others.  The adsorbent may be packed in a column to which is added the mixture of salts, preferably having a common anion, and the solvent then passed through.  The salts may be added in solid form, or as a slurry or concentrated aqueous solution; in the latter case, the solution is preferably taken up in a small quantity of adsorbent which is added to the top of the column.  Or an organic solution of the salts may be added directly to the top of the column.  As an alternative extraction procedure, an organic solution of the salts may be successively treated with small quantities of adsorbent. Adsorbent materials specified are paper pulp or cotton activated by treatment with nitric acid or 4 per cent hypobromite solution and subsequently washed, activated alumina, calcined ball clay, alginic acid and cation-exchange resins.  Solvents specified are diethyl ether, tetrahydropyran, acetone, methyl-n-propyl ketone, methyl acetate, ethyl butyl ether of ethylene glycol, and ethyl alcohol.  In some cases, the addition of 0.5-12.5 per cent by volume of an acid corresponding to the salt anion is advantageous. When the solvent is immiscible with water, the inside of the glass or porcelain column used may be coated with a film of water repellent substance, preferably dichlor-dimethyl silane.  The following examples of separations are given: (i) scandium from yttrium, cerium, praseodymium, neodymium, lanthanum, samarium, ytterbium, holmium and calcium as nitrates (using cellulose pulp, and diethyl ether and nitric acid); (ii) zirconium from hafnium as nitrates (as in (i)); (iii) mercury from copper and cadmium as chlorides (using cellulose pulp and methyl acetate).  Mercury may be separated from bismuth also when sodium phosphate is present in the adsorbent; (iv) zirconium from hafnium as nitrates (using cellulose pulp, and ethyl butyl ether of ethylene glycol and nitric acid); (v) gold from platinum, palladium and iridium as chlorides (using cellulose pulp, and ether and hydrochloric acid); (vi) iridium from platinum and palladium as chlorides (using cellulose pulp, and acetone and hydrochloric acid); (vii) rhodium from platinum, palladium and iridium (as in (vi)); (viii) nickel from copper, lead, mercury, arsenic, &c. as chlorides (using cellulose pulp, and acetone or methyl-n-propyl ketone and hydrochloric acid).  The nickel is strongly retained; (ix) vanadium from other specified metals as nitrates using cellulose pulp and ether; the effluent contains the vanadium; (x) cobalt from nickel and ferric chlorides (using cellulose pulp and ethyl alcohol, cobalt is recovered from the first portion of the effluent); (xi) as in (x), except used ethyl alcohol and hydrochloric acid, ferric chloride is present in the first portion of the effluent; (xii) scandium from calcium as nitrates (using cellulose pulp and ether-nitric acid mixture).  Specification 654,696 is referred to.