Carbonization of aluminum hydroxide from leeching solution

Abstract:
Alumina is extracted from various deposits such as bauxite, nepheline syenite, alonite,
clay minerals, etc. The common method of extracting alumina from bauxite is the Bayer
process, which is the most popular and most practical method because of the high and
suitable bauxite reserves in the world. Due to the considerable reserves of nepheline
syenite and the lack of suitable bauxite reserves in the country, the extraction of alumina
and other by-products, such as cement and carbonate and sulfate salts, from nepheline
syenite is very much taken into consideration. In this thesis, thus, sinter method was used
to produce alumina from nepheline syenite.For the production of aluminum hydroxide
from sources of nepheline syenite, it first sintered by lime and after sintering it leched with
alkali solution. Next step is desilication of leching solution for carbonization process. In
this study, desilicated aluminate solution was prepared from Azarshahr pilot and the
parameters affecting the carbonization of aluminate solution were investigated. The
parameters investigated in this study were the amount of pH, amount of neutralization of
the alkaline alumina solution, temperature of carbonization, different seed ratio, carbon
dioxide gas injection rate and the agitation rate. XRD, XRF, LPS, SEM, UV, and ASS
were, subsequently, used to analyze the results.