A grinding mill is generally a type of machine that breaks a material into smaller pieces. These mills can differ in terms of the types of materials they can grind, and how they grind them. Some of the most common types include ball mills, pellet mills, hammer mills, and disk mills.
Engineers and other professionals often refer to the process of grinding as a unit operation. This is a term used to describe a specific step in a process. For example, a material might be needed in a certain final form, such as a granule, in order to be applied for a specific task, or to make a specific product. The grinding mill is used to achieve this desired form.
One of the most common types of grinding mill is a ball mill. This machine is typically used to grind material into powder. The ball mill uses a cylindrical container that rotates on a horizontal axis. This container is generally filled with the material to be ground, and a grinding medium, which refers to a substance that does the grinding. Some of the common grinding mediums used in the ball mill include stainless steel balls, ceramic balls, and flint pebbles.
A disc mill is another type of grinding mill. Its general form is that of two opposing discs, between which material is fed to be pulverized or crushed. Some of the common applications of the disc mill are for making peanut butter, milling field corn, and discarding various types of ammunition shells. This tool is a less popular version of the grinding mill since it requires heavy maintenance.
The hammer mill incorporates a steel barrel, in which, as the name implies, a series of hammers are mounted onto a central shaft. When material is inserted into the barrel, it begins spinning at a high speed. This motion sets the hammers into action, crushing the material. A hammer mill usually also features screens of a specific size, through which the ground material passes. Hammer mills are used for applications such as waste disposal, fruit juice processing, and converting used pallets into mulch.
There are many continued advancements in grinding mill technology. These technological improvements typically intend to improve the fineness of the finished product. For example, some machines can specify the exact particle size of the ground material. Many universities and engineering programs also work with private equipment companies to help develop the best grinding mills possible.