In a process for forming a bulk hydroprocessing catalyst by sulfiding a catalyst precursor in a co-precipitation reaction, up to 60% of the metal precursor feeds do not react to form catalyst precursor and stay in the supernatant. In one embodiment, at least a precipitant is added to the product mixture at a molar ratio of precipitant to metal residuals in the supernatant ranging from 1.5:1 to 20:1 to precipitate at least 50 mole % of metal ions in the residuals forming additional catalyst precursor. The remaining metal residuals can be recovered via any of chemical precipitation, ion exchange, electro-coagulation, and combinations thereof to generate an effluent stream containing less than 50 mole % of at least one of the metal residuals. In one embodiment, at least one of the metal residuals is recovered and recycled for use as a metal precursor feed in the co-precipitation reaction.