Zeolite is the generic terms of zeolite minerals and a kind of aluminum silicate minerals containing aqueous alkali metal or alkaline earth metal. It has unique structure, adsorption, ion exchange, catalysis and acid resistance properties. It belongs to a kind of fine minerals. Fine mineral particles are very small and surface area is large. There are great difficulties of the separation and purification. Especially zeolite separation and purification technology is not mature. It is difficult to achieve high purity. But through scientists' continuous efforts and many tests, finally using sodium polytungstate high-speed centrifugation achieves good effect.

 

The specific method of sodium polytungstate high-speed centrifugation is as follows:

1. Smash rock to less than 200 meshes by mortar and pestle. And then put finer samples in the glasses with secondary distilled water stirring well.

2. Use the particle-liquid suspension with ultrasonic 3 min ~ 5 min. Then put ultrasonic slurry into the centrifuge tube, with 2500 RPM speed centrifugal 3 minutes and 30 seconds. Pour out the supernatant fluid to remove part of less than 1 micron.

3. Then pour the supernatant fluid in another centrifuge tube. Repeat the above operation 5 times. In order to ensure that the vast majority of less than 1 micron particles has been removed, and before each centrifugal, it needs ultrasound to make larger particles suspended.

4. Pour out the supernatant fluid, air drying, greater than 1 microns particle into more than 2.3 g/cm3 sodium tungstate solution. Ultrasonic 3 min ~ 5 min to make particles dispersed into the centrifuge tube.

5. With 1100 RPM speed, the suspending liquid is centrifugal 33 min. After the centrifugal, zeolite minerals will float on the surface of the liquid and the heavier particles (quartz, feldspar and a few zeolite) will sink in the bottom of the tube.

6. Pour out a centrifugal about half of heavy liquid in the pipe, to remove the buoyancy of the zeolite, and make stick steel spoon in centrifuge tube wall of zeolite prepared in a centrifuge tube.

7. Fill two centrifugal tubes with secondary distilled water, suspended matter and heavy liquid and ultrasonic to fully mix, now heavy liquid density should be about 1.15 g/cm3.

8. With 1400 RPM speed centrifuge for 10 min. Particles should sink to the bottom. The heavy liquid into the glass can be recycled.

9. Use the second distilled water filling centrifuge tube to ultrasonic 2 min, with 3000 RPM speed centrifugal 5 min, zeolite particle coagulation. Wash 3 times repeatedly to completely wash sodium polytungstate. zeolite minerals becomes pale and not "sticky".

10. Put the zeolite in the fume hood to dry. Sometimes the surface of the zeolite "skin" is green or brown. Remove it. Then you can get more pure zeolite minerals.