The invention discloses a method for utilizing 
pyrite to simultaneously reduce 
phosphogypsum and 
titanium white waste residue green 
vitriol for producing 
sulfuric acid. The technological process comprises the following steps: evenly mixing the 
pyrite, the 
phosphogypsum and the 
titanium white waste residue green 
vitriol, which are finely ground into a certain particle size, according to a certain proportion; (2) after the mixture is tabletted, directly enabling the mixture to react for a certain period of time at certain temperature to obtain a 
solid reduced product and SO2-containing 
tail gas,wherein the obtained 
solid reduced product is used as a pre-melt type 
steelmaking slagging agent; (3) carrying out dust removal and purification on the SO2-containing 
tail gas obtained in the step (2), and then sending the purified product to a 
sulfuric acid system to prepare the finished product 
sulfuric acid. The process utilizes the 
pyrite to simultaneously reduce the 
phosphogypsum and the 
titanium white waste residue green 
vitriol producing sulfuric acid, thus realizing the treatment and recycling of the phosphogypsum and the titanium white waste residue green vitriol, and obtaining sulfuric acid and the 
steelmaking slagging agent-
calcium ferrite product. The phosphogypsum 
decomposition rate of the method can reach 98wt% or above, the SO2 concentration of the 
kiln gas can reach 15 vol% or above, and the purity of the 
solid phase product 
calcium ferrite can reach 90wt% or above. The method is simple in process, free from 
discharge of three wastes, and remarkable in environmental and economic benefit advantages.