Method of preparing zinc carbonate
OwnerRaymond Lee Nipinventor
Life of this patent
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Abstract
A method for preparing basic zinc carbonate from die casting ash, zinc skimming or zinc ash includes heating urea or a mixture of urea and ammonia and carbon dioxide with water in a closed vessel with zinc ash. After zinc is dissolved in sufficient quantities, the solution is cooled and filtered. The filtered solution is cemented with zinc dust to precipitate heavy metals and the filtered. The solution is preferably heated a second time to remove an iron precipitate. The solution is then heated a third time to precipitate the dissolved zinc as basic zinc carbonate, which is washed and dried. The filtrate and gases recovered from the heating steps are reused in the process.
Claims22
A method of producing basic zinc carbonate, comprising:
- heating a solution made from urea with added zinc ash in a vessel to produce zinc and impurities dissolved in the solution and a residual;
- cementing the solution by adding zinc dust to form a slurry;
- filtering the slurry to remove a first precipitate and to produce a first filtrate;
- heating the first filtrate to form a second precipitate in the first filtrate;
- filtering the first filtrate to remove the second precipitate and to produce a second filtrate;
- heating the second filtrate to form a third precipitate comprising basic zinc carbonate;
- harvesting the basic zinc carbonate;
- and
- washing the basic zinc carbonate.
A method of producing zinc carbonate, comprising:
- heating a solution made from urea with zinc ash in a vessel to produce a zinc value and impurities dissolved in the solution and a residual;
- cementing the solution with zinc dust to form a slurry;
- filtering the slurry to remove a first precipitate comprising heavy metals and iron and to produce a first filtrate;
- heating the first filtrate to form a second precipitate comprising iron in the first filtrate;
- filtering the first filtrate to remove the second precipitate and to produce a second filtrate;
- heating the second filtrate to form a third precipitate comprising basic zinc carbonate;
- harvesting the basic zinc carbonate;
- and
- washing, drying, and milling the basic zinc carbonate.
A method of producing zinc oxide, comprising:
- heating a solution made from urea with added zinc ash in a vessel to produce zinc and impurities dissolved in the solution and a residual;
- cementing the solution by adding zinc dust to form a slurry;
- filtering the slurry to remove a first precipitate and to produce a first filtrate;
- heating the first filtrate to form a second precipitate in the first filtrate;
- filtering the first filtrate to remove the second precipitate and to produce a second filtrate;
- heating the second filtrate to form a third precipitate comprising-basic zinc carbonate;
- harvesting the basic zinc carbonate;
- washing the basic zinc carbonate;
- and
- calcining the basic zinc carbonate to form the zinc oxide.
A method of producing zinc oxide, comprising:
- heating a first solution made from urea with added zinc ash in a first vessel to form a first solution;
- bubbling gas evolved from the first vessel into a second vessel containing a second solution of zinc ash in water to form zinc and impurities dissolved in the second solution;
- cementing the second solution by adding zinc dust to form a slurry;
- filtering the slurry to remove a first precipitate and to produce a first filtrate;
- heating the first filtrate to form a second precipitate in the first filtrate;
- filtering the first filtrate to remove the second precipitate and to produce a second filtrate;
- heating the second filtrate to form a third precipitate comprising basic zinc carbonate;
- harvesting the basic zinc carbonate;
- washing the basic zinc carbonate;
- and
- calcining the basic zinc carbonate to form the zinc oxide.
Dependencies are inferred from the claim text.