According to one or more embodiments presently described, a mixture of lead oxide and lead metal particles may be formed by a method that includes forming a molten metal lead material from a solid lead metal supply material, introducing the molten metal lead material into a reaction zone of a reactor, and contacting the molten metal lead material with an oxidizing gas in the reaction zone to oxidize a portion of the molten metal lead material and form at least solid lead oxide particles and solid lead metal particles. The molten metal lead material may be introduced to the reaction zone in a laminar flow or as atomized molten particles. The weight ratio of formed solid lead oxide particles to solid lead metal particles may be less than 99:1.