Method for producing sodium chromate by roasting chromium ore and small amount of soda

The invention discloses a method for producing sodium chromate by roasting chromium ore and a small amount of soda. The method is characterized in that chromium ore and calcined soda are mixed, wherein the added quantity of the calcined soda is 35% to 45% of theoretical required amount for complete reaction with dichromium trioxide in the chromium ore; then the mixture is added to a rotary kiln for first roasting, the temperature of materials at a hot space in the kiln is 1000 DEG C to 1050 DEG C, wrought materials are cooled and leached to obtain a sodium chromate leaching solution and firstchromium dregs; the first chromium dregs are dried and crashed for second roasting with newly added calcined soda, the use amount of the calcined soda is 30% to 50% of theoretical required amount forcomplete reaction with the dichromium trioxide in the first chromium dregs; the sodium chromate leaching solution and second chromium dregs can be obtained through roasting and leaching processes, the second chromium dregs, li