ECONOMICALLY VIABLE PROCESS FOR RECOVERING COPPER NICKEL, COBALT FROM POLYMETALLIC SEA NODULES

摘要

In a process for separating Cu, Ni and Co from polymetallic sea nodule comprising the steps of (a) treating the said nodules and purified coconut shell charcoal mixed in required proportion, pulverized in finely-divided state, with dilute sulphuric acid at just boiling temperature for a short duration and filter pressed, separating insoluble residue cake (i), (b) neutralizing the solution obtained from step (a) with sodium carbonate solution at a controlled pH to precipitate out completely iron carbonate solution at a controlled pH to precipitate out completely iron carbonate cake (ii), (c) adding 0.2 to 0.4% of sodium metabisulphite to the solution obtained from step (b) which on heating to boiling and filter pressed cake (iii), (d) neutralizing the solution obtained from step (c) with sodium carbonate at pH 6.0-7.5 and filter pressed cake (iv), (e) on further neutralizing the solution obtained from step (d) at pH 8.0-9.0 and filter pressed, the nickel carbonate precipitates out and the left over nickel precipitated from the end solution as nickel oxide, (f) the cake (iii) & (iv) dissolved in hot dilute hydrochloric acid and precipitating out copper sulphide on passing through it H2S gas, filter pressed cake which on dissolution in nitric acid converted to copper nitrate, (g) the solution obtained from step (f) after boiling of H2S gas on treating with sodium hypochlorite, cobalt peroxide precipitated with sodium carbonate and from the end solution, nickel oxide and permanganate recovered, (i) cake (i) and (ii) leached with hot ammoniacal alkaline solution to dissolve out adherent metal values and ammonia freed from the solution obtained, to separate out the three metals as said above, (j) the improvement providing essentially simple chemical quantitative recovery of nickel 1.35%, cobalt 0.45% and scanty percentage of copper values based on initial content of said metal values in the nodule sample at its processing cost of $1.35/ lb i.e. 1/10th lesser than hitherto been reported, thus opening up vast potentialities for industrialization. Drawing Sheets: NIL Total Pages: 08. Fig. Nil