Method for preparing baking soda by metathesis

Abstract

The invention provides a method for preparing baking soda by metathesis. The method is characterized in that a solution C obtained after separating solid sodium hydrogen carbonate from metathesis reactor extraction liquid B by a solid-liquid separator is divided into two parts of C1 and C2, the solution C1 enters an ammonium hydrogen carbonate dissolver, and the solution C2 enters an ammonium salt production process; the solid sodium hydrogen carbonate separated from the metathesis reactor extraction liquid B by the solid-liquid separator enters the subsequent production process of the baking soda; raw material solid ammonium hydrogen carbonate is added into the ammonium hydrogen carbonate dissolver, and a solution A1 discharged out of the ammonium hydrogen carbonate dissolver enters a metathesis reactor; a saturated or nearly-saturated solution A2 of a raw material sodium salt enters the metathesis reactor; the ammonium hydrogen carbonate and the sodium salt are subjected to a metathesis reaction in the metathesis reactor to produce the sodium hydrogen carbonate. By adopting a process provided by the invention, the utilization rate can reach 99.6% or above, the production cost is reduced, the amount of the solid ammonium hydrogen carbonate entering the product baking soda along with the sodium hydrogen carbonate is reduced, the ammonia content of the product baking soda is lowered, and the situation of sale difficulty of the baking soda is solved.

Description

technical field [0001] The invention belongs to the technical field of chemical production, and in particular relates to a method and a device for preparing sodium bicarbonate by metathesis. Background technique [0002] Conventional metathesis method for preparing baking soda, the method of adding solid ammonium bicarbonate directly into saturated or nearly saturated sodium salt solution for metathesis reaction, solid ammonium bicarbonate is submerged or suspended in saturated or nearly saturated sodium salt solution before dissolving Simultaneous metathesis reaction. [0003] Solid ammonium bicarbonate goes through two processes when it enters saturated or nearly saturated sodium salt solution: the dissolution process and the double decomposition reaction process; during the dissolution process, the dissolved ammonium bicarbonate reacts with the sodium ions in the sodium salt solution to form solid bicarbonate Sodium, causing part of the solid sodium bicarbonate to adhere...

AI Technical Summary

Problems solved by technology

[0003] Solid ammonium bicarbonate goes through two processes when it enters saturated or nearly saturated sodium salt solution: the dissolution process and the double decomposition reaction process; during the dissolution process, the dissolved ammonium bicarbonate reacts with the sodium ions in the sodium salt solution to form solid bicarbonate Sodium, causing part of the solid sodium bicarbonate to adhere to the surface of undissolved solid ammonium bicarbonate, on the one hand causes the dissolution rate of ammonium bicarbonate to decrease, and on the other hand causes peritectic (solid sodium bicarbonate wraps solid ammonium bicarbonate); Ammonium bicarbonate enters the product baking soda along with solid sodium bicarbonate, the ammonia content of baking soda increases, the application of baking soda is restricted, and sales are difficult. At the same time, the utilization rate of raw material ammonium bicarbonate decreases, and the production cost rises sharply

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