From the current production process of iron oxide red in China, whether it is dry method (i.e. calcination method) or wet method (nitric acid method, sulfuric acid method, mixed acid method), there is a common problem that is very environmentally unfriendly, producing a large amount of acidic wastewater and steam, as well as ammonia nitrogen gas emissions. At present, the ammonia neutralization method is a process that uses ammonia (ammonia water, liquid ammonia, or ammonia gas) instead of iron filings, iron sheets, etc. as a neutralizing agent, air as an oxidizing agent, and ferrous salt solution as an iron source to prepare seed crystals first, and then oxidize the seed crystals to obtain iron oxide red industrial pigments. The pretreatment of mother liquor can produce by-product ammonium sulfate to eliminate the pollution caused by harmful substances in the mother liquor to the environment, and is therefore considered a relatively environmentally friendly production technology for iron oxide red. However, the ammonia neutralization method is considered a production process for iron oxide red industrial pigments that is not yet mature in technical practice, and currently has limited practical application in the industry. Integrating technological processing resources and producing iron oxide red in an environmentally friendly manner is the future trend.