Submitted by: Wei Wu

In the 1940 s, scientists are beginning to test and research of alumina production by fluidized roasting technology. In recent 40 years, in the industrial production have been fluidized roasting technology shows its high quality, low consumption of strong advantages, technology development rapidly. Currently widely used in alumina production of roasting technology for Denmark gaseous suspension roasting, flash roasting in the United States, Germany three such as the cycle of roasting, including gaseous suspension roasting technology started late, the door is advanced, represents the latest level of fluidized roasting.

Introduced in shanxi aluminium plant in our country in 1987 the first Alcoa flash calciner after more than a decade, sequential and has introduced the German lurgi circulating fluidization calciner, Denmark Smith gas suspension calciner, which is given priority to with gas suspension calciner, accounted for 70% of the total. The current domestic aluminum oxide skin all adopt the fluidized roasting.

Fluidized roasting comparing rotary kiln obviously a little is as follows:

1, product quality is good 2, less investment 3, high thermal efficiency, low heat consumption 4, equipment simple, long life and low maintenance cost 5, light pollution

The aluminum hydroxide in the process of roasting with those changes?

1, attached water removal 2, crystallization water removal 3, crystal transformation

The effect of surface modification of aluminum hydroxide

Surface modification effect of evaluation can be divided into two categories: the basic category of the direct method, another kind is the indirect method. The direct method is the modification of powder directly into products, and then test the performance of products before and after modification, so as to determine the effect of surface modification. Indirect rule is indirect parameter can reflect the surface modification effect by measuring and comparing, to determine the effect of surface modification. General laboratory often use the indirect method to characterize the surface modification effect of poor.

1, the activation index

For to improve or inorganic filler pigments in the surface modification of polymer binders compatibility or surface water, the “activation refers to the number of” can be used to detect and characterize the effect of surface modification. General inorganic filler surface polarity, natural sedimentation and modified powder in water, the surface into a nonpolar, the nonpolar tiny particles, because of its large surface tension in the water, will float is not heavy.

2, the contact Angle(?)

Wetting Angle is one of the most intuitive method inspection surface modification. A certain affinity and wettability on the surface of the liquid and solid, the better, the smaller the theta, instead. As a result, such as organic Venus surface modification of inorganic fillers, surface modification agent, modifying agent on the surface covered more fully, inorganic filler in the greater the wetting contact Angle of water; The wetting contact Angle, the greater the surface of inorganic filler to the lower. Is suitable for the determination of powder material wettability method for capillary invasion through velocity method, also called dynamic.

3,viscosity

Under the constant temperature in some kind of liquid in the rotational viscometer, measuring its viscosity, then add a certain amount of powder (at least through 200 mesh sieve), the slurry viscosity increases. In the same conditions the viscosity of the modified sample, if the fluid has good wettability of modified samples, the slurry viscosity reduced. There are a lot of team USES the intermiscibility of organic binders and wettability. Viscosity decreased, which showed that the modified powder body and greatly improve the wettability of liquid paraffin, abate the gathered tendency between the particles, thereby reducing the flow resistance in the flow field, the lower the viscosity.

Hongcheng Aluminium Hydroxide Factory http://www.aluminiumhydroxide.cn

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