Process for producing sodium carbonate and/or sodium bicarbonate from an ore mineral comprising sodium bicarbonate

Abstract

In a process to produce sodium carbonate and/or sodium bicarbonate from an ore mineral comprising sodium bicarbonate, a production solution comprising sodium carbonate is introduced into less basic compartments of an electrodialyser comprising alternating less basic and more basic adjacent compartments separated from each other by cationic membranes, the more basic compartments being delimited by anionic faces of bipolar membranes on one side and by the cationic membranes on the other side; a solution comprising sodium hydroxide is produced into the more basic compartments by combination of sodium ions flux crossing the cationic membrane and hydroxyl ions flux crossing the anionic face of the bipolar membranes, and is then extracted from the electrodialyser to be used as a reaction solution; the reaction solution is put into contact with the mineral ore to form a solution comprising sodium carbonate; and the solution comprising sodium carbonate is divided into a part used as the production solution and a remaining part used as a produced solution.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a U.S. national stage application under 35 U.S.C. §371 of International Application No. PCT / EP2009 / 050075 filed Jan. 6, 2009, which claims the priority benefit of European Application No. 08150104.1 filed Jan. 8, 2008, the whole content of such application being incorporated herein by reference for all purposes.TECHNICAL FIELD OF THE INVENTION[0002]This invention relates to a process for producing sodium carbonate and / or sodium bicarbonate from an ore mineral comprising sodium bicarbonate, in particular from trona, nahcolite or from other mineral underground ores, rich in sodium bicarbonate values, such as Wegscheiderite or Decemite.BACKGROUND OF THE INVENTION[0003]Nahcolite is an ore consisting primarily of sodium bicarbonate. There are for instance vast quantities of nahcolite in the Piceance Creek Basin in Northwestern Colorado, which deposits are in the form of beds and disseminated crystals in the Saline Zo...

AI Technical Summary

Benefits of technology

[0012]The invention aims at producing sodium carbonate and / or sodium bicarbonate from ore minerals, in a simple, economical way, avoiding the large energy consumption of the known processes.

Problems solved by technology

This process is however very energy intensive, mainly due to the calcination step, which requires the use of large quantities of coal, fuel, gas or mixtures thereof.

In flue gas treatment sodium bicarbonate is most likely among the most efficient chemicals for the removal of a wide range of pollutants (most notably the acidic one), and its use is limited only by the competition of less efficient but much cheaper chemicals such as lime or even limestone.

Because of the nature of this most important process, the production cost of the sodium bicarbonate is even above the cost of the sodium carbonate.

However, this process requires the introduction of sodium sulfates into the acid compartments of the electrodialysers, which appears to be difficult to put into practice in a cost effective and efficient way.

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