Cobalt catalysts

A process for preparing a cobalt catalyst precursor, which process includes

• in a support impregnation stage, impregnating a particulate porous catalyst support with a cobalt salt, and partially drying the impregnated support, with the resultant partially dried impregnated support containing residual moisture;
• and
• in a calcination stage, calcining the partially dried impregnated support to obtain the cobalt catalyst precursor, with the calcination being effected in air at a temperature between 95° C. and 400° C., and by using an air space velocity and a support heating rate such that all reducible cobalt is present in the support of the precursor as a supported cobalt oxide of formula unit CoOaHb, where a≧1,7 and b>0.

12 A process according to claim 10, which includes, in the calcination stage, initially heating the impregnated support until it reaches a calcination temperature, Tc, and thereafter;

• maintaining it at the calcination temperature, Tc, for a period of time, tc.

A process according to claim 12, wherein the heating rate up to the calcination temperature, Tc, is nonlinear.

14 A process according to claim 12, wherein the period of time, tc, for which isothermal calcination is applied at the calcination temperature;

• Tc, is between 0,1 and 20 hours.

A process for preparing a cobalt catalyst precursor, which process includes

• in a support impregnation, stage, impregnating a particulate porous catalyst support with a cobalt salt, and partially drying the impregnated support, with the resultant partially dried impregnated support containing residual moisture;
• and
• in a calcination stage, calcining the partially dried impregnated support by passing air over and around the partially dried impregnated support and by heating the impregnated support to a temperature between 95° C. and 400° C. to obtain the cobalt catalyst precursor, with the heating rate of the impregnated support and the space velocity of the air being controlled such that the residual moisture in the support is first driven off, whereafter decomposition of the cobalt salt into decomposition products comprising oxide(s) and any water of. hydration, is effected, and with all reducible cobalt then being present in the support of the precursor as a supported cobalt oxide of formula unit CoOaHb, where a≧1,7 and b>0.