Application of ultra-fine vertical grinding in the processing of heavy calcium carbonate and talc powder

1. Characteristics of superfine vertical mill structure (1) Working principle of vertical mill Vertical mill is to crush the material by the relative movement of the grinding roller and the grinding disc. As the rolling roller pressure increases, the material fineness changes. Small; the fine material is brought up by the airflow, and is classified by the grading device above it, and the coarse powder falls into the grinding disc to be pulverized again; the qualified fine powder is sent out by the wind to the bag dust collector for collection.
(2) Structural characteristics of ultra-fine vertical mill 1 The grinding disc and the grinding roller are designed with curved surface curve. The material enters the rough grinding zone coarse grinding first according to the grinding track, and then the ultra-fine grinding is performed by the fine grinding zone.
2 The pressure of the grinding roller is as high as 10-15MPa. According to the material characteristics, the rotation speed of the grinding disc and the pressure of the grinding roller can be reasonably controlled. The grinding efficiency is high, and the content of 2-10μm in the discharge is high.
3The unique inner air ring design, the wind speed at the wind ring reaches 30 m/s or more, which ensures that the fine material after ultra-fine grinding enters the classifying device under the action of the airflow, and the coarse particles fall into the wind ring from the grinding machine. discharge.
4 Optimize the graded rotor from the perspectives of structural dimensions, materials, mechanical strength, and blade placement. A reasonable rotor gap sealing method is adopted to ensure the classification effect and classification accuracy. The graded rotor adopts the advanced and efficient dynamic-static combination method. The static blades play the role of coarse screening large particles, and the moving blades play the role of controlling the product d50, d97 and d100 grain size indexes to achieve the product super-segmentation level.

2, the application of ultra-fine vertical grinding in the processing of heavy calcium carbonate powder from the perspective of the diversified demand of heavy calcium carbonate powder products, the vertical mill + engineering is used in the design of vertical milled powder engineering system The secondary (or tertiary) grading process, the first is the use of vertical mill for large-scale energy-saving ultra-fine production; the second is the use of secondary grading to facilitate product refinement. Figure 7 is a process flow diagram of a company's heavy calcium carbonate powder.

Figure 7 Process flow chart of a company's heavy calcium carbonate powder

Direct production of d97=13-40μm heavy calcium carbonate by fine vertical grinding system, the output of single machine can reach 5-12 t/h, the energy saving effect is obvious; the secondary (or three times) classification system is used to produce d97=5-13μm heavy Calcium carbonate, the single machine output reaches 1.8-6.0t / h, the ultra-fine pulverizing ability of the vertical mill can meet the requirements of the fine classifier.

Table 1 Specifications of heavy calcium carbonate powder produced by ultra-fine vertical mill

3. Application of ultra-fine vertical grinding in talc powder processing A company adopts ultra-fine vertical grinding to produce talcum powder. The technical indexes of talcum powder products are shown in Table 2.

Table 2 Technical indicators of talcum powder produced by ultra-fine vertical mill

4. Conclusion During the “Thirteenth Five-Year Plan” period, equipment technology innovation and industrial production technology innovation are the focus of upgrading and transformation of non-metallic mineral powder industry. The ultra-fine vertical grinding equipment technology has the advantages of green energy saving, product stability and large-scale production. The successful application of ultra-fine vertical grinding in the processing of non-metallic mineral powders such as heavy calcium carbonate and talc helps to promote the upgrading of non-metallic mineral powder processing equipment technology in China and enhance the non-metallic mineral powder equipment technology in China. Competitive strength on the top.