THE CERAMIC BALLS IN THE STRUCTURE OF THE UKRAINIAN GRINDING MEDIA MARKET
WHAT DO WE KNOW ABOUT THE GRINDING BALL “DIAMETER” CONCEPT?
We recently announced that we have researched the ceramic ball market. We were very interested in this niche. Having understood in detail the technology of using ceramic grinding balls, we had the idea to compare the specific consumption of a ceramic and steel ball. So, in some industries (for example, in cement), along with steel balls, ceramic balls are also used. The main requirement is that when using ceramic balls, the lining of the mill must also be ceramic.
In June of this year, our laboratory of metals was equipped with a semi-industrial two-chamber mill, earlier we wrote about it here. Only a few weeks passed the mill was installed and connected to the power supply. Our technical department developed a test methodology that regulated all stages: preparation, grinding, sampling and analysis of the data obtained.
The grinding (mill work) lasted 50 hours. The mill turned around at a speed of 45 revolutions per minute. Balls with a diameter of 40 mm were used as a grinding medium. In total, 1000 kg of material was crushed (500 kg in each of the chambers). Every 2 hours, the mill replaced the crushed material (quartz sand). Before the start, a geometric measurement and weighing of a sample of grinding balls of each type was carried out. After 50 hours of work, a representative sample was re-selected and re-measured and weighted.
We will present the result of this test in the summary table below.
1,108
| Steel | Ceramics | |
| Total weight of balls, kg | ||
| before tests | 25,035 | 25,140 |
| after testing | 24,775 | 24,032 |
| change, kg | 0,260 | |
| change, % | 1,039% | 4,407% |
| Medium diameter, mm | ||
| before tests | 40,6 | 41,6 |
| after testing | 40,4 | 40,8 |
| change, kg | 0,200 | 0,800 |
| change, % | 0,493% | 1,923% |
| Average ball weight, gr | ||
| before tests | 269,2 | 139,7 |
| after testing | 266,4 | 133,5 |
| change, kg | 2,800 | 6,200 |
| change, % | 1,040% | 4,438% |
As can be seen from the table, steel is almost 4 times less abrasioned than ceramics. Although the hardness of the two materials is almost identical. This proves that the hardness of grinding balls is not always an indicator of low specific consumption. Each case of the use of grinding balls is unique and should be analyzed from different “angles”.
During the experiment, we noted another feature. Since the crushed material was a little wet, when selecting ceramic balls from the mill, we saw that the sand “covered” each ceramic ball with a solid lump. Perhaps for this reason, this type of grinding media is used for dry grinding.
For the specialists of the company “Energosteel” it was the first experience in laboratory tests on their own. We are confident that in the future we will compare different types of grinding media made of different materials. We also plan to expand the analyzed parameters – we will add the “residue on the sieve” parameter to the comparison of the grinding results. You will find out about this in our next publications.