Patent ID: 11884548
Assignee: GLOBAL CHEMICAL CO., LTD.
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 6:
7. A method of making zinc carbonate, comprising:
a) preparing an aqueous zinc ammonia carbonate solution from a zinc source, ammonia and carbon dioxide, wherein the ammonia and the carbon dioxide are present in a ratio by moles or by weight effective to dissolve the zinc in the zinc source;
b) removing one or more metal impurities from the aqueous solution;
c) adding 2 to 8% of silica into the aqueous zinc ammonia carbonate solution with agitation, then boiling the aqueous solution until the zinc precipitates;
d) heating a slurry comprising the precipitated zinc to a temperature of about 90° C. or more until the ammonia is substantially absent to obtain the zinc carbonate; and
e) drying the zinc carbonate at a temperature of around 100° C. to 150° C. for a length of time sufficient to remove water, but retain a significant part of the CO2 in the zinc carbonate.