Adsorption of cobalt by lignite

Studies similar to earlier ones which had established the feasibility of extracting nickel by the lignite adsorption route were conducted on the adsorption extraction of cobalt on lignite, and with equal success.

Optimal values of variables such as pH, sorbent/sorbate ratio, adsorbent particle size, contact time, temperature, and the effect of excess ammonium carbonate were evaluated.

The rate of adsorption of cobalt was found to be slower than that for nickel. However, the recovery of over 99% cobalt from ammoniacal carbonate solutions, at optimal conditions, was comparable to that for nickel.

The cobalt was recoverable as metal, by ignition of the loaded lignite, or in solution, by elution with sulfuric acid in single or multiple stages.