Application of spiral hydrograph top-type small hydrocyclone in kaolin super-segmentation

The hydrocyclone is a widely used wet mechanical separation and classification equipment , which has many advantages such as simple structure, no moving parts, small floor space, large processing capacity, low equipment manufacturing and maintenance cost ^[1] . In recent years, with the rapid development of non-metallic mineral industry, its application in the field of non-metallic mineral increasingly widespread, especially small diameter cyclones are increasingly being applied in ultra-fine grading. China Kaolin Company is an enterprise that applied hydrocyclones to kaolin super-segmentation class earlier. The research and production practice of many years proves that the φ10mm hydrocyclone can be used for wet sub-segmentation processing of Suzhou kaolin resources. Effectively control the particle size distribution of the product, but there are still some drawbacks, mainly because the inner surface of the top cover of the cyclone is a circular plane, and the material entering from the tangential direction is rotated for one week, and the plane of the newly entered raw material is generated. The cross flow disturbs the initially formed rotating flow field, resulting in a decrease in separation efficiency. In order to further improve the classification efficiency of the small-diameter hydrocyclone, our research team designed a new type of small hydrocyclone, which can increase the -2μm content in the overflow product to over 92%, and the content of harmful impurities. Get better control.

First, the characteristics of the spiral hydrograph top cover type small hydrocyclone

This new type of hydrocyclone-spiral platform-type small hydrocyclone is a φ10mm hydrocyclone with a bottom diameter of 1.9mm used in the large production of China Kaolin Company (hereinafter referred to as the ordinary cyclone). Based on the improvement, the spiral protrusion is arranged on the circular circular plane of the inner surface of the top cover of the ordinary cyclone. After the improvement, the raw material to be separated flows into the trailing edge spiral at a high speed from the raw material inlet in the tangential direction. The countertop rotates. Due to the action of the spiral projection, the raw material rotates in the same direction of rotation on the different flow levels after the rotary flow for 1 week, which effectively solves the existing common flow. The drawback of the cyclone flowing in the circular circular plane on the inner surface of the inner surface of the top cover due to the absence of the spiral projection is that the classification efficiency is improved. The structure of the spiral hydrograph top cover type small hydrocyclone is shown in Figure 1.

Second, the test device and conditions

(1) Test raw materials The test uses the overflow product of φ25mm cyclone classifier of Guanlan Concentrator of China Kaolin Company as the feed material. The indexes (%) of the raw materials are: Si0 ₂ , 46.97; Fe ₂ 0 ₃ , 0.31; _{A1 2 0 3, 37.49; S0} 3, 1.12; K 2 0,0.34; Na 2 0,0.06; CaO, 0.07; MgO, 0.13; Ti0 2, 0.35; IL, 14.90; α quartz, 1.49; -2μm content ( Centrifugation), 74.03. D ₅₀ (centrifugation method) 0.92 μm, pulp pH value 7.2, slurry concentration (solid content) 9.8%.

(2) The test device test uses a common cyclone and four spiral hydrographs with a diameter of 1.7mm, 1.8mm, 1.9mm and 2.0mm respectively for comparison test, in order to guarantee each The working conditions of the individual cyclones are exactly the same. The above five single cyclones are uniformly installed in the same test device for testing. The structure of the test device is shown in Fig. 2.

Third, the results and discussion

(I) Comparison of the classification effect of the new cyclone with different underflow caliber The underflow caliber of the cyclone is an important structural parameter of the hydrocyclone, which has a significant impact on the classification performance of the hydrocyclone ^[2] . In this test, referring to the production process parameters of the φ10mm hydrocyclone in the current large-scale production of China Kaolin Company, the set feed pressures (MPa) are 0.65, 0.7, 0.75 and 0.8 respectively. Under these four pressures, the underflow caliber is 1.7. The classification results of the new cyclones of mm, 1.8mm, 1.9mm and 2.0mm are shown in Figure 3.

It can be seen from Fig. 3 that as the diameter of the underflow of the new cyclone increases, the content of -2 μm in the overflow product gradually increases. When the underflow diameter is 1.9mm, the content of -2μm in the overflow products under the four kinds of pressure is the highest; when the diameter of the underflow is 2.0mm, the content of -2μm in the overflow product is slightly decreased.

(II) Comparison of the classification effect of the new cyclone and the ordinary cyclone under different pressures Due to the new cyclone with an underflow diameter of 1.9 mm, the overflow product has the highest content of -2 μm, and the new cyclone is now Ordinary cyclones are compared. When the feed pressure (MPa) is 0.65, 0.7, 0.75 and 0.8, respectively, the content of -2μm and D ₅₀ (median diameter) in the overflow product of the new cyclone and the ordinary cyclone are shown in Fig. 4 and Fig. 5, respectively. .

As can be seen from Fig. 4, the overflow product of the new cyclone has a higher -2 μm content than the conventional cyclone, both above 92%, up to 94.62%.

The results in Figure 5 show that the overflow product of the new cyclone has a lower D ₅₀ than the conventional cyclone, which further embodies the advantages of the new cyclone in the super-segmentation stage.

(III) Comparison of sulfur removal effect Suzhou kaolin mine is a mineral resource rich in alumite . Reducing the sulfur content of its products is the primary prerequisite for the development and application of such resources. China Kaolin Company uses φ10mm hydrocyclone to treat Suzhou kaolin, which can control the S0 ₃ content in the product below 0.8% ^[3] . In this test, the desulfurization effect of four new cyclones with four underflow calibers under different pressures was examined. The results are shown in Fig. 6. It can be seen from Fig. 6 that the new cyclone has a good sulfur removal effect and can control the SO ₃ content in the overflow product to be below 0.65%, which fully satisfies the production requirements.

(IV) Comparison of yields Under different feed pressures, the overflow yield of a new hydrocyclone with different underflow calibers was compared. The results are shown in Fig. 7.

It can be seen from Fig. 7 that the yield of the new cyclone with an underflow caliper of 1.9 mm is lower than that of other underflow caliber cyclones, and the increase of the feed pressure has little effect on the yield of each cyclone.

Fourth, the conclusion

(1) The new type of spiral-tipped top-type small hydrocyclone has better super-segmentation performance than the ordinary cyclone, and can increase the -2μm content of the overflow product to over 92%, up to 94.62%. The requirements of the national “Eleventh Five-Year” science and technology plan, and the feed pressure needs to be controlled at around 0.75 MPa. .

(2) The new type of spiral pedestal top cover type small hydrocyclone can be applied to the beneficiation process of Suzhou kaolin without changing the existing production process parameters.

(3) The new type of spiral-sinking top-type small hydrocyclone can be applied to the beneficiation of other kaolin resources or non-metallic minerals only by changing the diameter of the underflow, and the application prospect is good.

references:

[1] Wang Yuanwen, Zhang Shaoming, Fang Ying. Experimental study on separation performance of hydrocyclone [J]. Chemical Minerals and Processing, 2005 (11): 25-28.

[2] He Tingshu, Zhang Yonghong. The influence of the straight pipe section of the hydrocyclone on the grit surface [J]. Metal Mine, 2003 (2): 43-45.

[3] Zhang Zhongfei, Li Yong, Pu Zhengxing, et al. Application of Small Diameter Cyclone in Sulfur Removal Process of Suzhou Kaolin[J].Non-metallic Mines,2003,26(2):39-41,47.

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