Heavy calcium + superfine processing equipment
There are many types of heavy calcium grinding and processing equipment. They are combined with ultra-fine grade machines to form an ultra-fine processing system, which can generally achieve the effect of ultra-fine production. At present, the mainstream demand for heavy calcium products in heavy calcium market is 600 to 1500 mesh heavy calcium products. The value-added rate of heavy calcium products is relatively low (compared with talc, barite, kaolin, etc.), and scale is one of the main factors affecting benefits.
Heavy calcium ultra-fine processing equipment is divided into grinding equipment and grading equipment. The grinding equipment includes Raymond mill, vibration mill, dry stirring mill, ring roller mill, vertical mill, ball mill, and impeller-type ultra-fine grade machine adopts the principle of forced eddy current.
Comparison of various types of ultra-fine processing equipment
| Device type | Product fineness (mesh) | Best fineness (mesh) | Advantage | Shortcoming |
| Raymond Mill (with classifier) | 100~1250 | <400 | The production of products below 400 mesh has great advantages | Low powder content, small production capacity for products above 800 mesh |
| Vibration mill (with classifier) | 1250~2500 | >1250 | High grinding efficiency, high content of fine powder | Large aspect ratio, serious over-grinding phenomenon |
| Dry mixing mill (with classifier) | 1250~6000 | >2500 | High grinding efficiency | – |
| Ring roller mill (with classifier) | 400~1500 | <1500 | Power saving, low investment | Single machine output is low, product stability is poor |
| Vertical mill (with classifier) | 200~1500 | <400 | High grinding efficiency | – |
| Ball mill (with classifier) | 600~6500 | 800~2500 | Large scale of stand-alone production | – |
Although Raymond mills are currently commonly used equipment in heavy calcium enterprises, most of the equipment is difficult to achieve large-scale production of ultra-fine heavy calcium.
Practice has proved that in the dry large-scale production of ultra-fine heavy calcium products with more than 600 meshes, there are mainly two types of technologies and equipment suitable for the development of the industry, namely, high-fine ball mills with ultra-fine grade machines and ultra-fine vertical mills with ultra-fine mills. Subdivision level machine.
Comparison of processing systems between vertical mill and ball mill
| Parameter | Ball mill + classifier | Ultrafine vertical mill + classifier | |
| Stand-alone production scale | Bigger | Big | |
| <400 mesh | Inappropriate | Very suitable | |
| 400~600 mesh | More appropriate | Very suitable | |
| High power consumption, but the specific surface area of the product is also high
|
Low power consumption | ||
| 600~1000 mesh | Very suitable | Very suitable | |
| High power consumption, high product specific surface area | Low power consumption | ||
| >1000 mesh | Very suitable | Need secondary classification | |
| Stable product quality | The quality of powder products under the secondary classification fluctuates | ||
| Higher specific surface area | |||
| Power consumption | <1250 mesh | High | Low |
| >1250 mesh | Same as <1250 mesh products | Slightly higher | |
| Product Adaptation Range | More suitable for paper and coating industry | More suitable for the plastics industry | |
Regarding the fluctuation of the quality (fineness) of the powder (lower grade) under the secondary classification of the vertical mill, the description is as follows: the vertical mill produces heavy calcium, and the fineness of the milled product is generally below 1000 mesh. If 1250 mesh is produced The above products must be classified twice. Similarly, the secondary classification of 800-mesh powder produced by the vertical mill results in different particle size distributions of the two lower products, which makes it difficult to define the quality of the lower products.
The use of ball mills and large classifiers makes it possible to produce single-machine heavy calcium on a large scale. The single-machine capacity of the ball mill is the largest, and its performance is more prominent when producing products with more than 1250 mesh. The superfine vertical mill has obvious energy saving effect when producing 400~1000 mesh heavy calcium products. The production of large classifiers has been very mature and reliable, producing heavy calcium powder below 2500 mesh, which greatly reduces investment costs and maintenance costs. The combined use of multiple large classifiers is an effective way to diversify products at the same time. The demand for ultrafine heavy calcium powder below 2μm is increasing rapidly, and the research on large-scale sub-micron classifiers is the main task at present.
Article source: China Powder Network