Ferrous carbonate, also known as "siderite" in nature, is slightly soluble in water and soluble in an aqueous solution of carbon dioxide, generating Fe (HCO3) 2. When its solution is exposed to air, excess carbon dioxide escapes, and the precipitated FeCO3 rapidly hydrolyzes and oxidizes, transforming into FeO (OH) precipitation. Strong thermal decomposition generates carbon dioxide and ferrous oxide. In the laboratory, air is isolated and an alkali metal carbonate solution is added to the ferrous salt solution to obtain the product. The product quickly darkens when exposed to air and eventually turns brown FeO (OH). Ferrous carbonate can be used as a flame retardant and an iron additive in animal feed.
Application [2-3]
Ferrous carbonate can be used as a flame retardant and an iron additive in animal feed. The application examples are as follows:
1) Preparation of a ferrous carbonate/graphene composite material for negative electrode materials in lithium-ion batteries,
It includes step one: forming a suspension of graphene material, water-soluble ferrous salt, urea and water; Among them, the mass ratio of the graphene material to the water-soluble ferrous salt is 0.02-0.2:1; The ratio of the amount and concentration of the substance between the urea and the water-soluble ferrous salt is 20-100:1; Step 2: Place the suspension into a reaction kettle and control the temperature at 100-180 ℃ for hydrothermal reaction for 4-12 hours to obtain a ferrous carbonate/graphene composite material. The present invention also provides a lithium ion battery prepared using this ferrous carbonate/graphene composite material as the negative electrode material. The present invention adopts low-temperature hydrothermal synthesis of ferrous carbonate/graphene negative electrode material, which has high specific capacity and good cycling performance, and has good development prospects when applied to negative electrode materials for lithium-ion batteries.
2) Preparation of a submicron lithium iron phosphate cathode material belongs to the technical field of lithium ion battery cathode materials.
Including the preparation of ferrous carbonate slurry: adding antioxidants and carbonates to the ferrous sulfate solution to produce ferrous carbonate precipitate, filtering and washing to obtain ferrous carbonate filter cake, and stirring with water to prepare ferrous carbonate slurry; Synthesis of lithium iron phosphate precursor: The lithium dihydrogen phosphate solution and ferrous carbonate slurry are pumped into a colliding flow mixing reactor to generate a lithium iron phosphate precursor slurry. The slurry is aged, dehydrated, and concentrated to obtain a concentrated slurry; Preparation of lithium iron phosphate cathode material: add soluble organic matter, carbon nanotubes and dispersant into the thick slurry, and obtain carbon containing lithium iron phosphate cathode material after circulating dispersion, spray drying, calcination, cooling and crushing. The present invention uses a colliding stream mixed reactor to synthesize lithium iron phosphate precursor, with product particle size reaching sub micron level, effectively shortening reaction time; And the raw material utilization rate is high, the cost is low, and the product has good conductivity.