A process for producing an iron oxide weighting material from an iron chloride solution. The iron chloride solution is introduced into an elevated temperature reactor as an atomized mist. The moisture is evaporated from the mist to form iron chloride solids which then react with the steam produced during the evaporation to form particulate iron oxides and hydrogen chloride gas. The iron oxides then are compacted and introduced into a calcination zone maintained at a temperature in the range of from about 400.degree. C. to about 1300.degree. C. The compacted iron oxide is calcined to reduce the surface area of the particles. The calcined iron oxide then is ground to a predetermined particle size.