Regeneration of hydrochloric acid
AssigneeTechnological Resources Pty. Limited
InventorsMichael John Hollitt, Ross Alexander McClelland
Life of this patent
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Abstract
A process for forming an aqueous chloride leachant from a spent aqueous chloride leach liquor which process comprises passing a spent aqueous chloride leach liquor and gases containing hydrogen chloride through a preconcentrator to form a concentrated aqueous chloride leach liquor by partial evaporation of water therefrom and absorption of hydrogen chloride; withdrawing a portion of the concentrated aqueous chloride leach liquor; roasting the remainder of the concentrated aqueous chloride leach liquor to generate a metal oxide, and gases containing hydrogen chloride; and passing the gases containing hydrogen chloride to the preconcentrator.
Claims12
A process for forming an aqueous chloride leachant from a spent aqueous chloride leach liquor derived from a titaniferous material which process comprises the steps of:
- a) passing a spent aqueous chloride leach liquor and hot roaster gases containing hydrogen chloride and water vapor through a preconcentrator to partially evaporate water from and absorb hydrogen chloride in said spent aqueous metal chloride leach liquor and thereby forming a concentrated aqueous acid chloride leach liquor and cooled gases;
- b) withdrawing a portion of the concentrated aqueous acid chloride leach liquor and utilizing said portion as a part of an aqueous chloride leachant;
- c) roasting the remainder of the concentrated aqueous acid chloride leach liquor to generate a metal oxide and said hot roaster gases containing hydrogen chloride and water vapor therefrom;
- d) passing the hot roaster gases containing hydrogen chloride to step a);
- and
- e) recovering hydrogen chloride from the cooled gases exiting from the preconcentrator by dissolving in water to form regenerated hydrochloric acid.
Apparatus for forming an aqueous acid chloride leachant from a spent aqueous chloride leach liquor, comprising:
- a) preconcentrator means for contacting the spent aqueous chloride leach liquor with hot roaster gases containing hydrogen chloride to evaporate water from the spent aqueous chloride leach liquor thereby forming a concentrated aqueous acid chloride leach liquor and cooled gases;
- b) extraction means for extracting concentrated aqueous acid chloride leach liquor from the preconcentrator means and dividing it into first and second portions of concentrated aqueous acid chloride leach liquor;
- c) roasting means for roasting the second portion of concentrated aqueous acid chloride leach liquor to produce a metal oxide and said hot roaster gases containing hydrogen chloride;
- d) absorption means for absorbing hydrogen chloride in water;
- e) first conduit means for conducting said hot roaster gases containing hydrogen chloride generated in the roasting means to the preconcentrator means for contacting the spent aqueous chloride leach liquor;
- f) second conduit means for conducting cooled gases containing hydrogen chloride exiting from the preconcentrator means to the absorption means;
- and
- g) third conduit means for conducting the first portion of the concentrated aqueous acid chloride leach liquor from the extraction means for use as an aqueous acid chloride leachant, the third conduit means having a valve to control the flow of the first portion of concentrated aqueous acid chloride leach liquor.
In a process for regenerating an aqueous chloride leach liquor, comprising:
- a) passing a spent aqueous chloride leach liquor and a hot roaster gas containing hydrogen chloride and water vapor through a preconcentrator, the hot roaster gas transferring heat to the spent leach liquor to partially evaporate water therefrom with cooling of the gas, thus forming a concentrated spent leach liquor and a cooled gas;
- b) roasting the concentrated spent leach liquor to form a metal oxide and generate said hot roaster gas containing water vapor and hydrogen chloride;
- c) passing said hot roaster gas from said roasting through said preconcentrator, and removing the cooled gas containing hydrogen chloride from step (a);
- and
- d) dissolving the hydrogen chloride from said cooled gas in water to form regenerated hydrochloric acid;
- the improvement comprising:
- splitting said concentrated spent leach liquor into first and second portions, performing said roasting on said first portion, and withdrawing said second portion and utilizing the second portion as a regenerated aqueous metal chloride leach liquor, thereby increasing the chloride to water ratio in said roasting and increasing hydrogen chloride content in said hot roaster gas to ensure absorption of hydrogen chloride in said preconcentrator in an amount sufficient to enable utilization part of the concentrated spent leach liquor as a leachant.
Dependencies are inferred from the claim text.