Hydrofining catalysts

DETAILED DESCRIPTION OF THE INVENTION Preferably the vanadium compound and oxygen containing compound (a) used in step (A) of the process of this invention is selected from the group consisting of ammonium and alkali metal orthovanadates, ammonium and alkali metal pyrovanadates, ammonium and alkali metal metavanadates, divanadium pentoxide and hydrated forms thereof, vanadium dioxide and hydrated forms thereof, divanadium trioxide and hydrated forms thereof.
Preferably the nickel (II) compound (i.
e.
, divalent nickel compound) (b) used in step (B) of the process of this invention is selected from the group consisting of nickel carbonate, nickel bicarbonate, basic nickel carbonate (Ni.
sub.
2 (OH).
sub.
2 (CO.
sub.
3)), nickel nitrate, nickel sulfate, nickel halides, nickel acetate, nickel formate, nickel oxalate, nickel carboxylates containing from 3-12 carbon atoms, nickel oxide and nickel hydroxide.
It is presently preferred to carry out step (A) under such conditions and using such amounts of (a), (b), (c) and (d) as to obtain a substantially clear solution.
It is believed that this solution comprises complex cations that contains divalent nickel (i.
e.
, Ni.
sup.
+2) and ammonia, and anions that contain vanadium and oxygen.
However, it is within the scope of this invention to obtain in step (A) a solution having solid particles dispersed therein.
In this case, the solution plus dispersed solids can be used as is in step (B), or preferably, the dispersed solid particles are separated from the solution by any suitable separation means such as filtration, centrifugation or settling and subsequent draining before step (B).
In a presently most preferred embodiment, the vanadium compound is NH.
sub.
4 VO.
sub.
3, the nickel compound is NiCO.
sub.
3, and ammonia is added as a concentrated aqueous solution containing about 5-10 mole/1 NH.
sub.
3.
The solution obtained in step (A) preferably contains the following concentrations of V and Ni, given as the number of gram-atomic weights (herein referred to as mole) per liter solution, and of NH