Chinaunix首页 | 论坛 | 博客
  • 博客访问: 202951
  • 博文数量: 124
  • 博客积分: 2970
  • 博客等级: 少校
  • 技术积分: 1240
  • 用 户 组: 普通用户
  • 注册时间: 2012-03-08 10:28
文章分类

全部博文(124)

文章存档

2012年(124)

我的朋友

分类: IT业界

2012-03-27 13:33:41

Minerals hardness decides the choice of mill

 

The hardness of a material is probably the most important characteristic to consider when deciding on what type of mill to choose. Trying to grind a material which is too hard, such as sand in most types of beater mill, will result, either in costly damage to the mill or an expensive maintenance requirement. Most types of readily available hammer mills for agricultural grinding are not suitable for grinding most types of minerals.
Hardness of minerals is expressed on Mohs scale - a numerical index ranging from 1 for talc (the softest mineral) to 10 for diamond (the hardest known material). Table below shows Mohs scale of hardness.
Hardness No.
Mineral (example)
Common practical test
1
Talc or graphite
Marks paper - like a pencil
2
Rock salt or gypsum
 
3
Calcite
Can be marked with fingernail
4
Fluorspar
Can mark a copper coin
5
Apatite
 
6
Felspar
Can mark window glass
7
Quartz
Can mark a knife blade
8
Topaz
 
9
Sapphire
 
10
Diamond
 
In general, the harder the material, the more specialised and expensive the type of mill used has to be. In addition if a particular mill can be used over a range of hardness scales, the harder the material the lower the throughput for a given size requirement. Another characteristic of a material to be aware of is brittleness, which is the degree to which a material will easily break. Most minerals are brittle, as opposed to metals which are ductile, although some to a greater degree than others. Brittleness does not equate with hardness as brittle materials can be hard or not particularly hard. Materials which are not brittle to some degree, metals or soft plastics for example, cannot easily be milled.
 

With its high quality products such as , , , , , Henan Hongxing mining machinery Co.Ltd has ascended in the front rank of the world in the exporting of mining equipments.

阅读(879) | 评论(0) | 转发(0) |
给主人留下些什么吧!~~