doi:10.16186/j.cnki.1673-9787.2023030002

Received:2023-03-01

Revised:2023-05-29

Online Date:2023-11-30

Study of iron removal and phase transition law of titanium gypsum in acidsolution（Online）

GUAN Xuemao, ZHANG Zihan, LIU Songhui, ZHU Jianping

School of Materials Science and Engineering， Henan Polytechnic University， Jiaozuo 454000， Henan， China

Abstract:In order to solve the problem of impurities in titanium gypsum and the law of phase change of gypsum under atmospheric pressure， titanium gypsum was used as raw material and treated by acid leaching method， the iron removal effect of titanium gypsum and the phase change pattern of gypsum were investigated under the conditions of acid type and concentration， reaction temperature and time in the reaction process， and different raw material handling conditions. The experiments showed that： compared with hydrochloric acid、oxalic acid and nitric acid， sulfuric acid has the best removal effect and no other impurities are generated；with increasing acid concentration， gypsum dihydrate-anhydrite phase transformation occurred in sulfuric acid solution， dihydrate - hemihydrate gypsum transformation occurred in both nitric acid solution and hydrochloric acid solution， and calcium oxalate was finally produced in oxalic acid solution； in the sulfuric acid solution reaction， the conversion of gypsum dihydrate-anhydrite can be promoted when the sulfuric acid concentration， reaction temperature and reaction time are increased； when the raw materials are processed， the raw materials that are not dried and ground do not affect the change of physical phase， which can reduce the operation steps and energy consumption of raw materials and save the cost of titanium gypsum pretreatment. The above experiments can be one of the ways to effectively solve the problem of impurities in titanium gypsum， reduce the experimental consumption and cost， and at the same time， the phase change law of gypsum can be derived.

Key words:titanium gypsum;iron removal effect;phase change law;acid solution;anhydrite

CLC:TQ177.375