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.
Claims35
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 roasting reactor to form droplets of said solution;
- supplying a first heat source into said spray roasting reactor at said upstream end of said reactor defining a first heating zone, and heating said droplets 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 a second heating zone and supplying a second heat source into said second heating zone of said spray roasting reactor, said second heating zone being positioned downstream of said first 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 reactor.
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 reactor, said reactor having an internal heating chamber;
- supplying a first heat source into said spray of droplets in a first heating zone at said upstream end of said reactor 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 through a 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 reactor.
A spray roasting reactor for recovering metal oxide particles, said reactor comprising:
- a chamber having an inlet end and a discharge end;
- a liquid supply at said inlet for feeding a solution containing metal compounds into said chamber;
- a first heat source coupled to said chamber for heating said solution in a first heating zone to a first temperature to form metal salts;
- a second heat source coupled to said chamber downstream of said first heating zone to heat said metal salts to a temperature to convert said metal salts to metal oxides, where said second temperature is higher than said first temperature;
- and
- a discharge device for discharging said metal oxide particles from said second heating zone.
Dependencies are inferred from the claim text.