26-12-2013 дата публикации
Номер: US20130344333A1
Принадлежит:
The present invention provides methods for preparing trimanganese tetroxide with low BET specific surface area and methods for controlling particle size of trimanganese tetroxide and trimanganese tetroxide product. 1. A method for preparing trimanganese tetroxide , comprising:(1) a process for purifying air comprising purifying air by spraying dilute aqueous ammonia;{'sub': 4', '4', '2', '4', '2', '2', '4, '(2) a pretreatment of removing impurities from a MnSOsolution comprising adjusting pH value of the MnSOsolution with a concentration in a range of 150˜200 g/L to 5.5-6.0, introducing HS gas into the MnSOsolution until pH value reaches 2.5-3.0, separating the mixture by solid-liquid separation to obtain a filtrate and a solid, purifying the filtrate by removing impurities with oxidization of HO, adjusting pH value of the filtrate to 5-6 with a base, and separating the obtained mixture by solid-liquid separation to obtain a filtrate and a solid, so as to obtain MnSOsolution as filtrate for use;'}{'sub': 4', '4', '3', '4', '3', '4', '3', '4, '(3) a process for preparing seed crystal comprising cooling the MnSOsolution obtained in the pretreatment (2) from MnSOsolution to a temperature of less than 40° C., and introducing liquid NHinto the cooled MnSOsolution until pH value reaches 10.5-11.0, separating the mixture by solid-liquid separation to obtain a filtrate and a solid; washing the obtained solid, adding deionized water to the washed solid and forming a slurry, introducing the purified air obtained in the process (1) into the slurry, and oxidizing the slurry into MnO; separating the mixture by solid-liquid separation to obtain filtrate and solid, so as to obtain MnOseed crystal as solid for use; and'}{'sub': 4', '4', '3', '4', '3', '4', '4', '4', '4', '3', '4, '(4) a process for obtaining the final product by controlling oxidization comprising adding the MnSOsolution obtained in the pretreatment (2) from MnSOsolution into an oxidization reactor, adding MnOseed ...
Подробнее
