Roasting method for producing sodium chromate using chrome iron ore as raw material

Abstract

The method for preparing sodium chromate by calcining chromite includes the following steps: pulverizing chromite and sieving with 200 mesh sieve, adding sodium carbonate whose added amount is 80-150% of chromite amount, and adding magnesite, baudisserite, periclase, brucite or synthetic magnesium oxide, magnesium hydroxide and magnesium carbonate and calcining them at 1000-1200 deg.c for 10-60 min. under the condition of oxidation atmosphere, then extracting clinker and dissolving sodium chromate so as to obtain the goal of preparing sodium chromate. The conversion rate of chromite can be upto 97-99.5%.

Description

technical field

[0001] The invention belongs to the technical field of inorganic synthesis, and more specifically relates to a process method for roasting chromite ore with calcium-free filler. Background technique

[0002] Sodium chromate is prepared from chromite ore, generally by adding an appropriate amount of sodium carbonate to chromite ore, then adding an appropriate amount of limestone, dolomite and slag, and mixing. Roasted at 1100-1200°C in a rotary kiln. The clinker is leached, and the sodium chromate is transferred into the solution to achieve the purpose of preparing sodium chromate. According to the traditional process, when chromite is roasted, the amount of calcium oxide added must be close to the amount calculated by the empirical formula. If the amount of calcium oxide is insufficient, the oxidation rate of chromite will decrease, which will directly affect the chromium yield. But above-mentioned method, owing to have added the filler that contains a larg...