Common types of Grinding Mills

The type of grinding mill is identified by the type of grinding media utilized. Each type of mill has characteristics that adapt it to certain grinding applications. The operational characteristics of each mill type must be evaluated in relation to the objectives of the grinding requirements being studied in order to select the optimum mill. The common mill types are discussed in the following sections.

The type of grinding mill is identified by the type of grinding media utilized. Each type of mill has characteristics that adapt it to certain grinding applications. The operational characteristics of each mill type must be evaluated in relation to the objectives of the grinding requirements being studied in order to select the optimum mill. The common mill types are discussed in the following sections.

Rod mills can accept feed up to approximately 2” diameter and generally are selected to grind product to the – 4 mesh to – 35 mesh range. Grinding actions is by line contact between rods extending the length of the mill. Rods tumble and spin in roughly parallel alignment and in so doing simulate the crushing and grinding action from a series of roll crushers. Large particles spread the ends of rods and is so doing impart an additional action termed scissoring. These actions result in preferential grinding of coarse material and a minimum production of slimes and excessively large material termed tramp oversize. A relatively uniform sized product is produced. Due to the nature of the grinding action, rod mills can sometimes advantageously replace the fine crushing of damp or sticky material that tends to coat the faces of crushing surfaces. Rod mills can produce a final product on sand brick, lime, or coke breeze where the feed contains low moisture and is often ground dry. In the metal mining industry most rod mill applications involve wet grinding were material is reduced in size from crusher product size to a size suitable for ball mill feed. Rod milling in the size range utilized is more efficient than ball milling in that the desired product is obtained at a lower cost per ton. This is due to several reasons:

Prospecting & Mining Basics Many factors are involved in the selection of grinding media. Why Milling with Rod Mill is more Efficient than Ball Mill What is an Overflow Grinding Mill End Peripheral Discharge Mill Center Peripheral Discharge Rod Mill Approximate capacities for wet grinding Mills What is a Ball Mill and How does it Work Grate Discharge Ball Mill Overflow Ball Mill Pebble Milling What is AG Autogenous Grinding & How it Works What is SAG Semi-AutoGenous Grinding and How it works Compare Wet and Dry Grinding Open Circuit Grinding Closed Circuit Grinding Single and Multi Stage Grinding Mill Power and Grinding Capacity Variables associated with mill power and capacity Effect Rock Feed Size on Grinding Mill Capacity Mill Horsepower Consumption Derivation Calculated Mill Power Mathematical Sizing of Grinding Mills Using Bond's Equation Correction Factors in Example Calculation for Ball Mill Sizing Bond Laboratory Procedure Thompson Sizing Test Determine energy requirement for grinding mineral Thompson Laboratory Procedure Grinding Mill Charge Movement Instrumentation and Control of Grinding Circuits Limestone Grinding Control

Metals Native Elements, Gold Groups and Ismetric Identifying Tin Minerals Instrumentation and Control of Grinding Circuits Mining and the Environment Primary Crushing Derivation of a Chemical Formula from the Analysis of a Mineral Section of an Exploratory Pit with Timber Wood Crusher Maintenance Platform Iron Composition, Crystallization, Structure and Occurrence Metals and their Ore Minerals Crusher Product Size Distribution Calibration Curves for Screened Feed Bulk Spample: How to choose a Sampling Point Methods of Prospecting Cryptocrystalline Quartz Varieties Occurrence and Use

THE GROWING POPULARITY OF THE TUBE MILL THE BALL MILL The Giesecke mill The Marcy mill The Marathon mill CHOICE OF CYLINDRICAL OR CONICAL MILLS The Mary Murphy mill The Hardinge conical mill PROPORTIONAL NUMBER OF TUBE MILLS TO STAMPS THE POSITION OF THE TUBE MILL THE ESSENTIAL FACTORS GOVERNING CAPACITY The Elko Prince mill SPEED OF ROTATION The speed of cylindrical mills SIZE OF FEED AND DISCHARGE VOLUME OF FEED The experiments for determining the proper tonnage of feed to the tube-mills A large feed has the same advantage over a small feed THE AMOUNT OF MOISTURE IN PULP The amount of ore fed to the mill influences The feed launder is of insufficient inclination THE LOAD OF PEBBLES The Danish pebble The Santa Gertrudis mill The Anaconda concentrating plant CHARACTER OF THE LINING The El Oro lining developed The El Tigre mill Forbes type of liners A pebble lining for a 5 by 22-ft. tube mill Two picked men line the mill in three shifts CHARACTER OF THE DISCHARGE OPENING The Allis-Chalmers adjustable ball mills The following advantages are shown for the device THE FEEDING DEVICE POWER REQUIREMENTS APPLICATION OF POWER Roller bearings have not generally been applied to tube mills The cost of grinding ores by the tube mill TUBE MILL FOUNDATIONS In considering concrete foundations Concrete must be placed in freezing weather A foundation on a clay or shale base AMALGAMATING WITH TUBE MILL Whether amalgamating on plain copper plates The amount of surface used for amalgamating AMALGAMATING IN CYANIDE SOLUTION The recovery by amalgamation is materially smaller AMALGAMATING IN TUBE MILLS The Hardinge mill at the Plymouth Con. mill An amalgamator such as shown can be attached to any tube mill For successful inside amalgamation We may advantageously amalgamate gold ores AMALGAMATING IN THE TUBE MILL CIRCUIT The Rainbow mill GRINDING ORES WITH THE TUBE MILL FOR FLOTATION Pine-tar oil in Hardinge conical mills CRUSHING EFFICIENCIES Under the heading of "Volume of Feed" THE TYLER STANDARD SCREEN SCALE SIEVES THE USE OF WROUGHT IRON AND ALLOY STEELS CHOICE OF MATERIAL FOR THE WORK