Method for preparing sodium carbonate and sodium hydroxide by mirabilite liquid circulation

Abstract

The invention discloses a method for preparing sodium carbonate and sodium hydroxide by mirabilite liquid circulation. The method comprises the following steps: (1) the raw materials including 0.9-1.1parts by weight of mirabilite, 0.5-0.8 parts by weight of quicklime, 2.0-3.0 parts by weight of cresol and 4.0-4.5 parts by weight of water are mixed, uniformly stirred and subjected to a reaction under ordinary pressure for 0.5-1 h at 20-70 DEG C; (2) reaction slurry is filtered, a filtrate is a cresol-containing sodium salt solution, and a precipitate is calcium sulfate; (3) CO2 is introduced into the cresol-containing sodium salt solution, carbonization is stopped when pressure of CO2 is 0.05-0.25 MPa, carbonization temperature is 20-30 DEG C and pH of the solution is 10, the solution is layered, the upper layer is cresol, and the lower layer is a sodium carbonate solution with concentration being 10%-12%; (4) the sodium carbonate solution is evaporated and concentrated to be crystalized, sodium carbonate is prepared, or the sodium carbonate solution is causticized with calcium hydroxide for preparation of sodium hydroxide. Local mirabilite resources and different intermediate species are used, the production process and the intermediate species recovery process are simplified, the recovery flow and equipment are reduced, the reaction conditions are mild and easy to control, and energy consumption is low.

Description

technical field [0001] The invention relates to the production technology of inorganic chemicals, which belongs to the technology of producing soda ash and caustic soda by mirabilite, in particular a method for preparing soda ash and caustic soda by mirabilite liquid phase circulation method. Background technique [0002] 1. Method for preparing soda ash and caustic soda [0003] At present, the methods for preparing soda ash in the world mainly include the ammonia-soda method (also known as the Solvay method) and the combined soda-making method (also known as the Hou's soda-making method), among which the ammonia-soda method is the most widely used method. The ammonia-soda method has been researched and developed for hundreds of years. Both the process and the equipment are very mature, but there are still two major problems: first, the use of salt as raw material has a low utilization rate, only 72% to 73%, and the second waste Liquid handling is difficult. The waste liq...

AI Technical Summary

Problems solved by technology

The ammonia-soda method has been researched and developed for hundreds of years. Both the process and the equipment are very mature, but there are still two major problems: first, the use of salt as raw material has a low utilization rate, only 72% to 73%, and the second waste Liquid handling is difficult

After the carbonization of the intermediate bisphenol A, it is a solid-liquid two-phase, and the bisphenol A is recovered by filtration for recycling. Filtration requires the use of filtration equipment, which makes the equipment complicated

Images