How to make Sodium sulfate
1. A process for the preparation of anhydrous sodium sulfate from a thenardite ore containing sodium sulfate, consisting essentially of the steps of:
a) crushing the thenardite ore;
b) lixiviating the crushed ore in a first lixiviating step with water or an exhausted solution from a following or succeeding step, at a temperature between about 20° C. and 40° C., to obtain a suspension comprising a sodium sulfate saturated solution, sludges and insoluble material;
c) settling the sludges and insoluble material from the saturated solution of step b) to separate a clarified saturated solution;
d) crystallizing the clarified saturated solution of step c) in a first crystallization step, at a temperature between 32° C. and 20° C., while maintaining the height of the solution so it does not exceed about 15 centimeters, to obtain a Glauber salt which has crystals of sodium sulfate with ten molecules of water and an exhausted solution with the density of about 1.21 g/cc, wherein the exhausted solution is drained and recycled back to the first lixiviation step;
e) melting the Na2 SO4.10H2 O crystals, at a temperature of about 60° C. to dissolve the Na2 SO4.10H2 O crystals, at a temperature of about 60° C. to dissolve the Na2 SO4.10H2 O crystals in their own crystallization water, to obtain a suspension comprising a sodium sulfate saturated solution with a density of 1.335 g/cc and crystals of anhydrous sodium sulfate in a proportion of about 17% by weight of the Glauber salt from which it originated;
f) settling anhydrous sodium sulfate crystals from the suspension of step e) and removing a part of the sodium sulfate saturated solution and thereby obtaining a suspension of anhydrous sodium sulfate crystals with 35% of solids by weight;
g) lixiviating the crystals of anhydrous sodium sulfate in a second lixiviation step, with an exhausted solution obtained after a succeeding crystallization step is carried out to obtain a saturated solution;
h) filtering the saturated solution of the second lixiviating step together with the part of the saturated solution removed from step f) to obtain a clarified saturated solution;
i) crystallizing the clarified saturated solution of the filtering step h), in a second crystallization step and maintaining the height of the solution so it does not exceed about 15 centimeters, to obtain a Glauber salt which has crystals of sodium sulfate with ten molecules of water and an exhausted solution, wherein the exhaust solution is drained;
j) melting the crystals of Na2 SO4.10H2 O at a temperature about 40° C. and 60° C. to dissolve the crystals Na2 SO4.10H2 O in their own crystallization water, obtaining a suspension containing a saturated solution of sodium sulfate with a density of 1.335 g/cc and anhydrous sodium sulfate crystals in a proportion of about 17% by weight of the Glauber salt from which it originated;
k) settling the anhydrous sodium sulfate crystals from the suspension of step j) and separating a part of the saturated solution of density of 1.335 g/cc and thereby obtaining a suspension of anhydrous sodium sulfate crystals with 35% solids, by weight, and the separated saturated solution is recycled back to the second crystallization step;
l) and drying the suspension of anhydrous sodium sulfate crystals of step k) to obtain anhydrous sodium sulfate.
a) crushing the thenardite ore;
b) lixiviating the crushed ore in a first lixiviating step with water or an exhausted solution from a following or succeeding step, at a temperature between about 20° C. and 40° C., to obtain a suspension comprising a sodium sulfate saturated solution, sludges and insoluble material;
c) settling the sludges and insoluble material from the saturated solution of step b) to separate a clarified saturated solution;
d) crystallizing the clarified saturated solution of step c) in a first crystallization step, at a temperature between 32° C. and 20° C., while maintaining the height of the solution so it does not exceed about 15 centimeters, to obtain a Glauber salt which has crystals of sodium sulfate with ten molecules of water and an exhausted solution with the density of about 1.21 g/cc, wherein the exhausted solution is drained and recycled back to the first lixiviation step;
e) melting the Na2 SO4.10H2 O crystals, at a temperature of about 60° C. to dissolve the Na2 SO4.10H2 O crystals, at a temperature of about 60° C. to dissolve the Na2 SO4.10H2 O crystals in their own crystallization water, to obtain a suspension comprising a sodium sulfate saturated solution with a density of 1.335 g/cc and crystals of anhydrous sodium sulfate in a proportion of about 17% by weight of the Glauber salt from which it originated;
f) settling anhydrous sodium sulfate crystals from the suspension of step e) and removing a part of the sodium sulfate saturated solution and thereby obtaining a suspension of anhydrous sodium sulfate crystals with 35% of solids by weight;
g) lixiviating the crystals of anhydrous sodium sulfate in a second lixiviation step, with an exhausted solution obtained after a succeeding crystallization step is carried out to obtain a saturated solution;
h) filtering the saturated solution of the second lixiviating step together with the part of the saturated solution removed from step f) to obtain a clarified saturated solution;
i) crystallizing the clarified saturated solution of the filtering step h), in a second crystallization step and maintaining the height of the solution so it does not exceed about 15 centimeters, to obtain a Glauber salt which has crystals of sodium sulfate with ten molecules of water and an exhausted solution, wherein the exhaust solution is drained;
j) melting the crystals of Na2 SO4.10H2 O at a temperature about 40° C. and 60° C. to dissolve the crystals Na2 SO4.10H2 O in their own crystallization water, obtaining a suspension containing a saturated solution of sodium sulfate with a density of 1.335 g/cc and anhydrous sodium sulfate crystals in a proportion of about 17% by weight of the Glauber salt from which it originated;
k) settling the anhydrous sodium sulfate crystals from the suspension of step j) and separating a part of the saturated solution of density of 1.335 g/cc and thereby obtaining a suspension of anhydrous sodium sulfate crystals with 35% solids, by weight, and the separated saturated solution is recycled back to the second crystallization step;
l) and drying the suspension of anhydrous sodium sulfate crystals of step k) to obtain anhydrous sodium sulfate.