Process and apparatus for the recovery of metal oxide particles
AssigneeAndritz Inc.
InventorAlbert Lebl
Life of this patent
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Abstract
A process for the recovery of metal oxides from a solution containing metallic salts by spray roasting of these solutions. The process is particularly suitable for spray roasting spent pickling acids. The process feeds the solution to a reactor for spray roasting of the droplets in at least two stages, where at least one evaporation stage follows at least one conversion stage to convert the metal salts to metal oxides. The device for implementing the process includes a spray roasting reactor having a first heating zone to evaporate the water and a second heating zone to convert the metal salts to oxides.
Claims27
A process of recovering metal oxide particles from a solution containing metal salts, said process comprising the steps of:
- spraying said solution containing said metal salts into an upstream end of a spray roasting reactor to form droplets of said solution, said spray roasting reactor having a single heating chamber with an upper portion at said upstream end defining a first heating zone and a lower portion defining a second heating zone;
- supplying a first heat source into said spray roasting reactor to said a first heating zone, and heating said droplets in said first heating zone to a first temperature to evaporate a substantial portion of liquid from said droplets to form substantially dry particles of metal salts;
- directing said particles of metal salts to said second heating zone and supplying a second heat source into said second heating zone of said heating chamber, said second heating zone being positioned below and downstream of said first heating zone whereby said particles of metal salts fall directly from said first heating zone through said second heating zone, and heating said particles of metal salts at a second temperature higher than said first temperature to convert said particles of metal salts to particles of metal oxides;
- and
- discharging said particles of said metal oxides from said heating chamber.
A process for producing metal oxide particles from metal salts, said process comprising the steps of:
- feeding an aqueous solution containing a metal salt into an upstream end of a spray roasting reactor to form a spray of droplets directed toward a downstream end of said spray roasting reactor, said spray roasting reactor having a top wall, a bottom wall and a side wall an internal heating chamber with an upper portion defining a first heating zone and a lower portion defining a second heating zone;
- supplying a first heat source into said spray of droplets in said first heating zone at said upper portion of said internal heating chamber and heating said droplets to a first temperature in said first heating zone to evaporate a substantial portion of water from said droplets and to form substantially dry metal salt particles;
- directing said metal salt particles downwardly through the second heating zone in a direction toward said downstream end and supplying a second heat source into said second heating zone and heating said metal salt particles to a second temperature to form metal oxide particles, where said second temperature is higher than said first temperature and where said second heating zone is immediately downstream of said first heating zone in said reactor;
- and
- discharging said metal oxide particles from said downstream end of said internal heating chamber of said reactor.
Dependencies are inferred from the claim text.