Analysis of ball mill grinding in many aspects
Date：2019-07-11 15:49 Source：未知Views:
1. Grinding body grade of ball mill
First of all, there are many ways to grade the grinding balls.The basic principles are:
1. Material hardness is high, the selected steel ball diameter is large;
2. Big mill diameter, big impact force and small ball diameter;
3. When using double layer storage partition, the ball diameter should be smaller than the single layer partition of the same row.
4. Generally four levels of ball, big ball, small ball, big ball in the middle, that is, "there are two ends, more in the middle"...
Secondly, the milling efficiency of steel ball is very high
When the ball mill is grinding powder, the following ball ratios have the highest grinding efficiency and are economical.
2. Choose abrasive medium (abrasive ball) wear-resistant material
In 1994, Chinese building materials industry formulated JC/t535-94 standard for "casting grinding balls with chromium alloy in building materials industry".On this basis, the national standard GB/t17445-1998 "casting grinding ball" was promulgated.The specified varieties are high chromium ball, medium chromium ball, low chromium ball, bainite ductile iron ball, chemical composition, mechanical properties, casting ball specification and test method.
3..High quality grinding balls should have the following characteristics:
(a) wear resistance: sufficient wear resistance for cutting wear, deformation wear and fatigue peel wear;High hardness, suitable for cutting wear;High strain fatigue, contact fatigue and impact fatigue, suitable for deformation wear and fatigue wear life;
(b) good impact toughness: high impact resistance without rupture under repeated impact and wear conditions;
(c) high hardenability: ensure the entire phi 100mm ball evenly damaged, not lost circle;
(d) excellent metallurgical quality: produced in accordance with specified standard components without casting slag defects, such as slag inclusion and sand inclusions.
Specifically, the coarse grinding box should choose high chromium ball, fine grinding box can choose low chromium ball.For wet grinding, low chromium ball or forged steel ball should be chosen, because the wear resistance of high chromium ball cannot be fully reflected in the case of corrosion.From the point of view of wear resistance, cast balls made of metal molds should be selected.
Several parameters considered by two - stage ball method of mill
(1) diameter of the big ball.Like multistage balls, it depends on the size of the material being ground.The difference is that it is based on the representative granularity of the material.In practical application, the diameter of quadratic ball in multistage ball can be used as standard.For example, in the multistage ball, the ball diameter is 100 mm, in the second ball, should choose Φ 90 mm steel ball.
(2) the ratio of two balls.In principle, it should be ensured that particle incorporation does not affect the filling rate of large spheres.Usually, small balls make up 3 to 5 percent of the weight of large balls.In practical application, the lower limit should be adopted first, and then added according to the production situation.
(3) diameter of the ball.It depends on the size of the gaps between the big spheres, the diameter of the big spheres.According to the relevant information, the diameter of the ball should be 13% to 33% of the large ball..