A hydrothermal oxidation method for production of alkali metal dichromate from carbon ferrochrome

The present invention provides a hydrothermal oxidation method for producing alkali metal dichromate from carbon ferrochrome, and the method comprises the following steps: formulating an initial reaction liquid by mixing carbon ferrochrome, an alkaline substance and water, in which the actual addition amount of the alkali is controlled smaller than the theoretically required amount; adding the initial reaction liquid into a reaction kettle, charging an oxidizing gas into the reaction kettle, and allowing the reaction to proceed for 0.5 to 3 h at a temperature of 150° C. to 370° C. and a pressure of 2 Mpa to 24 MPa; carrying out solid-liquid separation, cooling the resultant filtrate to a temperature of −12° C. to −20° C. to precipitate crystals, and carrying out separation by centrifuge to obtain alkali metal dichromate solution; adding CrO3 to the alkali metal dichromate solution until the degree of acidification reaches 100% or greater, concentrating the solution by evaporation, and cooling it to precipitate crystals, so as to afford alkali metal dichromate. The method has a simple process, is easy to control, and can directly produce sodium dichromate under hydrothermal conditions.