A method for producing prefluxed metal oxide from a metal salt selected from nickel hydroxide, cobalt hydroxide, mixed nickel-cobalt hydroxide, nickel carbonate, cobalt carbonate, mixed nickel-cobalt carbonate and combinations thereof includes providing a mixture of at least one slag making oxide and a metal salt selected from the group consisting of nickel hydroxide, cobalt hydroxide, mixed nickel-cobalt hydroxide, nickel carbonate, cobalt carbonate, mixed nickel-cobalt carbonate and combinations thereof, blending with a binder, blending in a flux additive to form a slag-making mixture, forming the slag-making mixture into prefluxed agglomerates, and calcining the prefluxed agglomerates to produce a prefluxed metal oxide. An agglomerate is provided which includes a metal salt selected from nickel hydroxide, cobalt hydroxide, mixed nickel-cobalt hydroxide, nickel carbonate, cobalt carbonate, mixed nickel-cobalt carbonate and combinations thereof, a slag making oxide, and a flux additive. An agglomerate is provide which includes a metal oxide selected from nickel oxide and cobalt oxide, and slag, wherein the metal oxide is encapsulated in the slag.