SODIUM MONOCHROMATE OBTAINING PROCESS Russian patent published in 2006 - IPC C01G37/14 

FIELD: production of chrome compounds such as sodium monochromate of chromite ores.

SUBSTANCE: process comprises steps of oxidation calcining of charge containing chromite ore, soda ash and filler; leaching prepared cake by means of solution of sodium carbonate; filtering pulp; repulping slime; subjecting it to secondary filtration; returning solution to step of leaching cake and returning slime to step of calcining. Lime-sludge filler is used as charge filler. Content of CaO is selected depending upon quantity of impurities in ore. Extraction degree of chrome from chromite ore is equal to 90%.

EFFECT: simplified process for producing sodium monochromate due to lowered melting capability of charge, prevention of charge sticking onto walls of furnace, enhanced quality of product due to its increased concentration and reduced content of impurities, also at processing poor and highly poor ores.