Environmental Projects, Inc.

Dale Lee Denham, Jr

Wayne C Hazen

Rudolph Pruszko

Roland Schmidt

David R Baughman

Ralph B Tacoma

John S Wold

A process for the production of sodium carbonate monohydrate is disclosed. The process includes heating a feed stream containing trona and insoluble impurities in a calcining apparatus to a temperature of less than about 350&deg; C. to form anhydrous sodium carbonate. The anhydrous sodium carbonate is contacted with a saturated sodium carbonate brine solution to form sodium carbonate monohydrate crystals. Sodium carbonate monohydrate crystals are separated from insoluble impurities.

Process for the production of sodium carbonate

The present invention provides a process for producing crystals of a polymorphic compound in a first crystal structure by introduction of the compound in a second crystal structure into a saturated brine solution of the compound under conditions in which formation of the first crystal structure is favored and without evaporation or changes in temperature. As the second crystal structure dissolves, the brine becomes supersaturated resulting in relief of supersaturation by formation of crystals of the first crystal structure. The process includes controlling supersaturation and its relief to achieve growth of existing crystals of the first crystal structure rather than nucleation and formation of new crystals. The resulting crystals are separated from insoluble impurities on a size separation basis.

Recrystallization process

The present invention provides a process for producing sodium carbonate monohydrate crystals by introduction of anhydrous sodium carbonate into a saturated sodium carbonate brine solution under conditions in which sodium carbonate monohydrate formation is favored. As the anhydrous sodium carbonate dissolves, the brine becomes supersaturated resulting in relief of supersaturation by formation of sodium carbonate monohydrate crystals. The process includes controlling supersaturation and its relief to achieve growth of existing sodium carbonate monohydrate crystals rather than nucleation and formation of new sodium carbonate monohydrate crystals. The resulting crystals are separated from insoluble impurities on a size separation basis.

Sodium carbonate recrystallization

Processes for purification of saline minerals using magnetic separation are disclosed. In particular, saline minerals can include trona, borates, potash, sulfates, nitrates and chlorides. The magnetic separation can include high intensity magnetic separation which can be conducted at greater than about 20,000 Gauss and up to greater than about 50,000 Gauss. Other embodiments of the invention include calcination of a saline mineral in an inert atmosphere or in an oxygen-containing atmosphere at a high temperature prior to magnetic separation. A further embodiment of the invention includes pre-alignment of particles on a surface to align the particles of high magnetic force during a magnetic separation step. Also disclosed are various embodiments of magnetic separation which include subjecting an ore to a preliminary magnetic field prior to magnetic separation.

Beneficiation of saline minerals

Disclosed are a variety of processes for the purification of saline minerals and in particular, trona. Some of the processes include a combination wet and dry recovery process which results in high recovery and purification at relatively low cost. The dry separation methods can include density separation, magnetic separation and electrostatic separation. Other processes include a modified slush process for the purification of calcined trona (sodium carbonate) by the introduction of anhydrous sodium carbonate into a saturated brine solution and subsequent separation of insoluble impurities.

Method for purification and production of saline minerals from trona

Disclosed is a method for beneficiating trona from a feedstream containing trona and impurities by a dry separation method, namely, electrostatically separating a first portion of impurities from the trona at a temperature between about 25.degree. C. and about 45.degree. C. The disclosed beneficiation of trona method may also include separation of impurities from trona by other dry separation methods, such as density separation, magnetic separation and size separation, and/or by wet separation methods.

Method for beneficiation of trona

A process is provided for recovering a saline mineral from an ore containing the saline mineral and impurities. The process generally includes the steps of separating a first portion of impurities from the ore by density separation, electrostatically separating a second portion of impurities from the ore, and magnetically separating a third portion of impurities from the ore. The process can further include the steps of crushing the ore and dividing the crushed ore into a plurality of size fractions before the above-referenced separating steps. Furthermore, in order to increase the efficiency of the separating processes, the process of the present invention may further include the steps of drying the ore to remove surface moisture therefrom and de-dusting the ore to recover valuable fines.

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Arvada, CO, United States of America

Dale Lee Denham, Jr