Preparation Of Ferrous Oxalate And Polyphosphorus Ferric Sulfate From Ferrous Sulfate Heptahydrate (PPFS)

Ferrous oxalate is an important chemical raw material,which is widely used in lithium industry materials,coatings,dyes,ceramics,glass and other industrial fields.Polymerric phosphoric ferric sulfate(PPFS)as a new inorganic polymer flocculant is widely used in the purification process of industrial wastewater,municipal wastewater,industrial water,and drinking water.As a kind of solid waste,the free accumulation of red iron slag,not only causes the waste of resources,but also pollutes the environment more seriously.Therefore,if the recycling of hematite slag can be combined with the preparation of ferrous oxalate and PPFS,the waste of resources and the environmental pollution can be reduced,as well as the demand for ferrous oxalate and PPFS in the market can be met.In this dissertation,ferrous sulfate oxalate and PPFS were firstly prepared with the analytical reagent ferrous sulfate as the raw material.At the same time,the optimum conditions for the preparation of the two products were obtained.Then under the optimal conditions,the homemade ferrous sulfate was used in the laboratory.Ferrous oxalate and PPFS were prepared from raw materials,and the products were characterized by XRD,FTIR,TG-DSC,ICP-AES,SEM,and TEM.The specific work is as follows:(1)In the preparation of ferrous oxalate by liquid-phase precipitation method,FeSO4 · 7H2 OAR was firstly used as a raw material,and a combination of single factor and response surface experiments was used.The optimum synthesis conditions were optimized:the ratio of ethylene glycol was 80%,the reaction temperature was 27?,the concentration of ferrous sulfate was 9%,and the aging time was 73 minutes.The obtained ferrous oxalate(FeC2O4 · 2H2 OAR)product had a purity of 99.80%and a particle size of 1.527 ?m;And then under the optimal conditions,FeSO4 · 7H2OHM was used as a raw material to prepare ferrous oxalate(FeC2O4 ·2H2OHM).By comparison and analysis,FeC2O4 · 2H2OHM reached the standard of battery grade oxalate.(2)In the process of one-step oxidation of PPFS,FeSO4 · 7H2OAR was firstly used as a raw material,and single factor and response surface method were combined to optimize the synthesis conditions:98%sulfuric acid addition amount 4.7 g,reaction temperature 30?,aging time 9 h,aging temperature 20?.The basicity of PPFSAR salt obtained was 14.44%;Followed by the use of FeS04 · 7H2OHM as the raw material under the optimal conditions,the prepared PPFSHM was 14.43%,and PPFSHHM met the national standard for first-class products.