The invention discloses a method for recovering
nitric acid by pyrolyzing
nitrate. The method comprises the following steps: (1) conveying the
nitrate into at least two preheaters, heating the nitrateto firstly liquefy the
nitrate, and then heating the nitrate to a temperature less than
decomposition temperature in order to obtain a nitrate hot fluid; (2) conveying the nitrate hot fluid into a
decomposer, and heating the nitrate hot fluid with a high temperature gas to maintain the
internal temperature of the
decomposer at 500-800 DEG C in order to decompose the nitrate into a
mixed gas and asolid
powder; and (3) separating
mixed gas and the
solid powder, conveying a part of the
mixed gas into a
nitric acid recovery tank, heating the remaining mixed gas to 500-800 DEG C, and then returning the heated remaining mixed gas into the
decomposer to heat the nitrate hot fluid in order to thermally decompose the nitrate hot fluid. The method for recovering
nitric acid has the advantages of less
corrosion damages to devices, no introduction of other
impurity components and no interference in the heating process, good
decomposition speed and
decomposition rate of the nitrate, and high recycling rate of the nitric acid.