Use and properties of alumina balls
1. The angle of repose. The alumina angle of repose refers to the
inclination of the material naturally accumulating on a smooth
plane. The alumina with a larger repose angle is more soluble in
the electrolyte, and can be well covered on the electrolyte crust
during the electrolysis process, and the flying loss is also small.
2. A-Al2O3 content. The content of a-Al2O3 in alumina reflects the
degree of alumina roasting. The higher the degree of calcination,
the more a-Al2O3 content, the hygroscopicity of alumina decreases
with the increase of a-Al2O3 content. Therefore, alumina for
electrolysis is required to contain a certain amount of a-Al2O3.
However, the solubility of a-Al2O3 in the electrolyte is inferior
to that of Υ-Al203.
3, the weight. The bulk density of alumina refers to the weight of
a unit volume of material in a natural state. Aluminium, which
generally has a small bulk density, facilitates dissolution in the
4. Particle size. The particle size of alumina refers to the degree
of its thickness. The particle size of alumina must be appropriate,
too coarse in the electrolyte to dissolve slowly, or even
precipitate; the rules are easy to fly loss.
5. Specific surface area. The specific surface area of alumina
refers to the total surface area of the sum of the outer surface
area per unit weight of the material and the surface area of the
inner pores. It is an important indicator of the level of material
activity. Alumina having a large specific surface area has good
solubility in an electrolyte and is active, but is hygroscopic.
6, wear coefficient. The so-called wear coefficient is the
percentage change of the fractional content in the sample after the
alumina is rubbed in a fluidized bed under controlled conditions.
The wear coefficient is a physical indicator of the strength of
According to the physical properties of alumina, alumina can
usually be divided into three types: sand, flour and intermediate.
These three types of alumina have large differences in physical
properties. The sand-like alumina has a small bulk density, a large
specific surface area, a slightly smaller angle of repose, and a
smaller amount of a-Al2O3, and the coarse particles are more and
more uniform, and the strength is higher. Flour-like alumina has a
large bulk density, a small specific surface area, contains a large
amount of a-Al2O3, more fine particles, and poor strength. The
physical properties of the intermediate alumina are somewhere in