In a process for forming a bulk hydroprocessing catalyst by sulfiding a catalyst precursor made in a co-precipitation reaction, up to 60% of the metal precursor feeds do not react to form catalyst precursor and end up in the supernatant as metal residuals. In the present disclosure, the metals can be recovered in a chemical precipitation step, wherein the supernatant is mixed with at least one of an acid, a sulfide-containing compound, a base, and combinations thereof to precipitate at least 50% of metal ions in at least one of the metal residuals, wherein the precipitation is carried out at a pre-select pH. The precipitate is isolated and recovered, yielding an effluent stream. The precipitate and/or the effluent stream can be further treated to form at least a metal precursor feed which can be used in the co-precipitation reaction. The process generates an effluent to waste treatment containing less than 50 ppm metals.