Abstract: This invention isolates in separate furnaces the three thermochemical processes required in manufacturing Portland cement and sulphur dioxide from a calcium sulfate source so as to yield improved pyrometallurgical treatment for each individual process. Separating these processes facilitates selection of the most kinetically suitable reactions by enabling the maintenance of optimum conditions for each process without compromising the thermal or kinetic efficiencies of the other processes.Only one fourth of the calcium sulfate is reduced to calcium sulfide in a separate ad hoc reduction furnace specifically designed for achieving enhanced reduction parameters which results in minimized reduction equipment size. Treating most of the calcium sulfate elsewhere works to avoid side reactions and allows Portland cement raw mix components to have an enhanced synergistic catalytic effect on reduction kinetics.