General Introduction on Chinese patent of
Water Separation of Chrysotile

02 Dec 2004


Water Separation of Chrysotile Asbestos refers to Chinese patent-"Wet Gravity Separation Process on Asbestos Minerals". Inventor Prof.Rong Kui-yi, Song Xiumin, Patent number ZL98121630.7. International patent category number B03B 7£¯00. Patent registration date Oct.16, 2003. Patentee Rong Kui-yi. Declaration number CN 1102458C. Declaration date Mar.5, 2003.

Project Brief

Chrysotile Asbestos wet gravity separation, known as asbestos water separation. It is a brand new minerals separation process and has improved the traditional dry separation and screening completely.

When we say asbestos, we refer to fibrous spinnable natural minerals. For example, fibrous chrysotile (Serpentine) asbestos, fibrous Brucite asbestos, fibrous Sepiolite asbestos etc. Our patent water separation process applies to all of these asbestos, in most of the cases, we refer to chrysotile asbestos separation.

1. Disadvantages of traditional dry separation process

In the world asbestos industry, there are several separation processes which have been widely used, like dry breaking , dry loosening and dry screening, but they all have flaws:£º



During the process of breaking and loosening separation, a large amount of high quality medium and long asbestos could be broken or become short or even turn into stive due to no selection separation function in the process.

The asbestos has such a good absorbability which makes it really difficult to get rid of the stive, the wet grading inspection on products from dry separation process shows over about 40%-70% on 200 mesh stive, this has decreased the effective fiber a lot.

It's very difficult to prevent pollution from asbestos stive, huge power must be used to seal the stive.

The fact shows that the recovery ratio from dry separation process is really low, the percentage of medium long fiber and effective fiber becomes low while the harmful stive percentage becomes high.


However, all these flaws can not be easily observed, because there is the same problem with raw ore quality inspection which also employs the small size dry process to obtain data. As a result, the reported raw ore quality data are either not true or too low.

2. Advantages of wet separation


Good selection separation function: Water has permeability, it will easily permeate into fiber and ground, while asbestos has strong absorbability and expansibility in water, plus water makes asbestos fiber more ductile. Because of these characteristics, a good selection can be done in the process of breaking and loosening separation, as a result, this will greatly improve the separation and protect medium long fiber from being broken, secondary stive will also be reduced. The ratio of medium long fiber in fine asbestos and the overall productivity will both increase a lot, generally speaking, compared with the old dry process.( It depends on the raw ore ) the new process can increase the productivity about 30%-100%

High efficiency cleaning and dust removing function: Water can clean the dust absorbed by the fiber very well, thus a high efficiency dust removing is guaranteed, also high efficiency selection ensures the quality of silt content of the product, generally speaking, for asbestos from third degree to sixth degree, every 200% target dust can be controlled within 20%-30%, this has greatly improved the quality of asbestos.

Great improvement on selection separation and asbestos fiber recovery ratio: The density of water is much higher than air, asbestos is inclined to come up and separate from subsiding ground, therefore, selection separation efficiency is very high. Asbestos fiber becomes so easy to separate from in water, as a result, recovery ratio increases accordingly.

Environment protection: This asbestos wet separation patent technology applies all wet process in a closed circle during the whole course of processing, from breaking raw ore to the very end, no organic chemical agent is added. The process is done in a condition of none dust, none polluted water, none organic chemical agent, it makes none polluted air at all. The very characteristic of this process has completely solved the pollution problem which has frustrated the industry for a long time.

Cost effective on setting up factory: Wet separation process can bring high productivity of fine fiber and high recovery ratio, for the same amount and same quality of raw ore, the new wet process can reduce the investment on fine fiber at about 30%-50% than the old dry process does. ( It depends on the raw ore )

Reduce production cost: Because of the above mentioned reason, the wet process can reduce the production cost at about 30%-50% than the old dry process does. ( It depends on the raw ore )

Greatly benefit the customers

*** Environment benefit: Because of the good quality of wet separation asbestos, it can be distributed according to specific requirement or chosen for different degree of processing, customers don't need to do second time processing, this has stopped the severe asbestos pollution source from the plant ( usually in cities )

*** Economic benefit: Because of the cost of asbestos separation has been reduced, therefore the cost of asbestos products has been reduced accordingly, the plant will enjoy great economic benefit from this.

***Quality benefit: Same as the above mentioned reason, both the inside and outside quality of asbestos will improve a lot.

Greatly improve the compatibility with asbestos fiber substitutes: As the quality of wet separation asbestos improves, production cost reduces, it will help the safe utilization of asbestos and enhance the compatibility with asbestos fiber substitutes.

Thus it can be seen that wet separation is a brand new asbestos separation process, it not only brings huge economic benefits, but also significant social and environmental benefits.


2. Asbestos Wet Separation Process Chart

Characteristics of the process£º


1¡¢ From raw ore to finished product, it's a whole wet process;

2¡¢ The whole process uses water without any organic agent in a closed circle, and is supplied clean water at proper time;

3¡¢ The process starts breaking asbestos only when there is water between ground and fiber layers, this ensures the quality of the obtained fiber;

4¡¢ The process divides the separation into different stages, in fine selection stage, fiber of different length and different quality can be obtained£»

5¡¢ After bringing down the fine selected asbestos, fine grinding is employed in order to increase the fiber length and loosening quality;

6¡¢ Fine asbestos desliming and dehydrating are completed in two different stages. The percentage of moisture of fine asbestos can eventually reach at 20%. It can be transported over long distance, and used directly by wet separation processing factory. Drying process can be added in case of need.


3. The patent technology has already been put into practice

During the period of 1984 to 1986, the inventor together with his colleagues established a test plant in Yunnan province in China, the raw ore was graded as 2.232% based on the old dry method, asbestos quality was 6A short asbestos; However, based on the web separation process, the raw ore was graded as high as 15.43%, among which 5A-5C productivity takes 7.203% of the raw ore, the rest are 6-7 grade short asbestos. 5A¡«5C and 6A fine asbestos--0.075mm dust about 11.10¡«26.15£¥. The same quality raw ore was graded by old dry process as 6C, fine asbestos productivity 11.29%, 0.075mm dust about 83,21% ( considered unqualified ).

Later on, the test plant was forced to shut down due to the asbestos panic in the world. The patent inventor didn't stop, in the next ten more years, he used other ways to further research on this topic, by dividing his research into small projects, different stages, different operation conditions in an industrialization circumstance, he solved quite a few difficult problems on asbestos wet separation, for example, separation method, wet physical method (not chemical method) which increased fiber length and looseness, new efficient separation equipment, asbestos dehydrating and desliming, fiber minerals contractibility etc. Having solved all these problems, the patent application was approved.

Therefore, the patent "Wet Gravity Separation Process on Asbestos Minerals" is fully ready to put into industrial production.

We are here sharing this new information with all our colleagues in the industry, hoping to find partners and make effort together to bring contribution to the advancement of asbestos industry.




Patent Inventor: Rong Kui-yi(Professor), Song Xiumin (senior engineer)

Agent Contact£º
Mr. John Chan,
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