Abstract

Jet mills are used to produce fine products in many industries. Spiral jet mills and fluidized bed jet mills are widely used. They differ in that the destruction of particles occurs as a result of the abrasion process. The use of impact ejector jet mills is limited by a relatively low consumable concentration of material. When the consumable concentration of the material increases the acceleration speed of particles and the material grinding degree decrease. To eliminate this disadvantage a new method and design of an ejector jet mill for fine grinding of bulk materials has been developed (patent of Russian Federation No. 2711252). The technological process occurs at excessive external pressure of the ejected gas. It is shown that it is feasible to increase the pressure at the beginning of the acceleration tube when the pressures ratio of the working and secondary gas is higher than the critical one. It increases the consumption concentration of bulk material and the acceleration speed of crushed particles. This allows reducing the specific energy consumption and increasing the grinding degree. Experimental studies have confirmed an increase in the consumption concentration by 1.6–1.9 times and an increase in the grinding degree by 1.3–1.7 times compared to a typical ejector jet mill.

Highlights

  • Jet grinding is a promising method for obtaining of fine materials being used in many industries where the quality of the finished product is of big importance

  • The use of an ejector jet mill with external pressure allowed to increase the grinding degree of quartz sand by 1.7 times and the grinding degree of feldspar by 1.3 times compared to a typical ejector jet mill

  • It is seen from the presented data that the consumption concentration μ in an ejector jet mill with external pressure is 1.6 times greater when grinding quartz sand and 1.9 times greater when grinding feldspar compared to a typical ejector jet mill

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Summary

Introduction

Jet grinding is a promising method for obtaining of fine materials being used in many industries where the quality of the finished product is of big importance. It is known that jet mills provide a relatively high purity of the finished product by chemical composition. This type of equipment uses the energy of compressed gas to accelerate and crush particles. Spiral jet mills and fluidized bed jet mills are widely used They differ in that the main process of particle destruction is abrasion. The use of an impact ejector jet mills and countercurrent jet mills have not received the widespread due to abrasive wear and limited material concentration. The aim of this work is to increase the consumable concentration of the crushed material and the particles velocity in an ejector jet mill.

Published under licence by IOP Publishing Ltd
Conclusions

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