Patent ID: 6048578
Filing Date: 2000-04-11
Classification: B01D,C22B,C23C

Abstract:
An improved closed loop, carbon monoxide self-contained process for the production of nickel or a nickel-coated object by the nickel vapor deposition process, comprising(a) placing an object to be treated with nickel carbonyl by said nickel vapor deposition process in a deposition chamber;(b) feeding a gaseous mixture comprising nickel carbonyl and carbon monoxide to said deposition chamber;(c) depositing nickel on said object to produce said nickel or nickel-coated object in said chamber and a nickel carbonyl-depleted gaseous mixture;(d) removing said nickel carbonyl-depleted gaseous mixture from said chamber;(e) removing nickel carbonyl from said nickel carbonyl-depleted gaseous mixture in a primary nickel carbonyl condensation unit to produce a first reduced-concentration nickel carbonyl-containing gas; the improvement comprising(f) condensing said first reduced-concentration nickel carbonyl-containing gas in a secondary condensation unit operative in an alternate freeze-thaw mode by, stepwise,(i) freezing said first reduced-concentration nickel carbonyl-containing gas to produce a first solid nickel carbonyl;(ii) melting said first solid nickel carbonyl to produce a first liquid nickel carbonyl;(iii) removing said first liquid nickel carbonyl from said secondary condensation unit; to produce a second reduced concentration nickel carbonyl-containing gas having a nickel carbonyl concentration of less than 5 V/V %; and(g) feeding said second reduced-concentration nickel carbonyl-containing gas to a nickel carbonyl reactor containing nickel powder to produce a fresh gaseous mixture comprising fresh nickel carbonyl and carbon monoxide.