1) Room temperature aging method. Weigh a certain amount of oxalic acid and ammonium ferric sulfate, add water to dissolve, stir with a magnetic stirrer at room temperature for 30 min, aging for 3 h. When the reaction is complete, wash with distilled water and anhydrous ethanol for several times, carry out solid-liquid separation, and dry it at 60 for 12 h, to obtain a light yellow ferrous oxalate product.
2) Water bath heating method. Weigh a certain amount of oxalic acid and ammonium iron sulfate, divided into 4 parts, were added to water, volume ratio of 3:1 ethylene glycol (EG) and water, volume ratio of 1:1 EG and water, EG, with a collector-type thermostatic heating magnetic stirrer at 90 , stirring for 3h, to be completely reacted, washed with distilled water and anhydrous ethanol several times, solid-liquid separation, drying at 60 for 12h, to get light yellow Ferrous oxalate product.
3) Rheological phase method. Weigh a certain amount of oxalic acid and ammonium ferric sulfate, divided into two parts, were placed in the mortar, one add a small amount of water, one add a small amount of EG, at room temperature, grinding 30 min, then the product was removed, washed with distilled water and anhydrous ethanol for several times, solid-liquid separation, drying at 60 in the oven for 12 h, to get light yellow ferrous oxalate product.
4) Solvent heat method. Weigh a certain amount of oxalic acid and ammonium ferric sulfate, divided into 3 groups of 4 parts each, to which were added water, EG and water with a volume ratio of 3:1, EG and water with a volume ratio of 1:1, EG, and stirred with a magnetic stirrer at room temperature for 30 min, and then loaded into a reactor, respectively, at 120 , 150 , 180 in the oven reaction for 3 h. When the reaction was complete, removed, and washed with distilled water and anhydrous ethanol for several times, solid-liquid separation, drying in the oven at 60 for 12 h, to get the light yellow ferrous oxalate product.
