Patent GB-855709-A (GB)
Title: Improvements relating to the recovery of nickel from solution
Inventor: ARDEN THOMAS VICTOR
IPC: C01C3/11
Filed: 1956-02-28
Abstract: An ion exchange resin for use in the recovery of nickel from solutions in which the nickel is present as a complex cyanide anion (see Group III) is prepared by treating a crosslinked polymer containing halo alkyl groups with insufficient tertiary amine to react with all the haloalkyl groups, and then with a primary and/or a secondary amine to react with the remaining haloalkyl groups.  It is preferred to use sufficient tertiary amine, preferably trimethylamine, to react with from 40% to 60% of the haloalkyl groups.  A haloalkylated cross-linked polymer of styrene is preferred.  In an example, a halomethylated cross-linked polymer of styrene is treated with sufficient trimethylamine to react with 60% of the halomethyl groups, followed by monoethylamine to react with the remainder.  An ion exchange resin to recover gold prior to the nickel extraction may be prepared by treating a cross-linked polymer containing haloalkyl groups with sufficient secondary amine to react with substantially all the groups.  In the example a halomethylated cross-linked polymer of styrene is treated with dimethylamine.ALSO:Nickel is recovered from solutions containing it and other metals as complex cyanide anions by passing the solution through a bed of an ion exchange resin to remove the nickel, followed by elution of the bed to recover the nickel.  The ion-exchange resin for the recovery of the nickel is prepared by reacting a crosslinked polymer containing haloalkyl groups, for example a haloalkylated crosslinked polymer of styrene, with insufficient tertiary amine, for example trimethylamine, to react with all the haloalkyl groups, and preferably with sufficient to react with from 40% to 60% of the groups, and then treating with a primary and/or a secondary amine to react with the remainder of the groups.  If gold is present, the solution may first be passed through a preliminary bed to remove the gold.  An ion exchange resin for the step of extracting the gold may be prepared by treating a haloalkylated crosslinked polymer with sufficient secondary amine to react with substantially all the haloalkyl groups.  It is convenient to pass the solution through the first bed until gold starts to appear in the effluent, and to pass this effluent through the second bed until nickel starts to appear in the effluent.  The beds are then eluted to recover the gold and nickel and to regenerate the beds.  The eluting solution for the nickel may be a strong solution of sodium carbonate, bicarbonate, hydroxide, cyanide, thiocyanate, or mixtures of these.  It is preferred to use an eluting solution containing cyanide and caustic alkali.  If cyanide is absent it is desirable to further regenerate the resin by treating it with a solution containing cyanide.  In an example, a solution obtained by leaching a gold ore with sodium cyanide in the conventional manner, and containing Na4Fe(CN)6, Na3Cu(CN)4, Na2Ni(CN)4, and NaAu(CN)2, was first passed through an anion exchange resin prepared by treating a halomethylated crosslinked polymer of styrene with dimethylamine. All the gold and a little of the other metals are absorbed.  The effluent solution was then passed through an anion exchange resin prepared by treating a halomethylated crosslinked styrene polymer with sufficient trimethylamine to react with 60% of the halomethyl groups, followed by monoethylamine to react with the remainder. Nearly all the nickel is absorbed, together with traces of copper and iron.  The bed is then eluted with 2N NaCN, of which 4 bed volumes will extract over 90% of the nickel.