Osborn offers a wide range of standard and custom designed mills. Sizes range from 0,46 m diameter for laboratory use to 5 m diameter for large mining operations. Osborn has over 150 mills in operation throughout South Africa, together with various units in overseas territories.
Mills are identified by the type of grinding media used (i.e. rod, ball, etc.). Each design has characteristics that suit it to a certain grinding application. With one of the largest and most modern facilities in South Africa, Osborn also offers installation, commissioning, spares, reconditioning and after-sales service, plus the capability to supply the right unit for any type of inquiry.
New Concept Projects has formed a Joint Venture Agreement with Osborn and offers new Osborn Grinding Mills to clients throughout the world.
Our capability includes the supply of new mills based on existing proven Osborn designs, re-engineered with assistance of modern design techniques and 3D simulation packages. We also offer after sales support and spares backup to all Osborn mills currently operating in the market.
For projects carrying restricted budgets or accelerated timing requirements, NCP incorporates the supply of refurbished Grinding Mills into our portfolio to match project requirements. These options can be refurbished back to OEM specification and be supplied with warrantees equivalent to new equipment.NCP Mill Design Capabilities
1. Process Modeling through NCP developed Specific Energy Breakage Model
2. 3D Drafting
3. Structural Design FEA – Static & Dynamic Analysis
4. Bearing Fluid Film Analysis
5. Gear Train Design
6. Drive Train Torsional Analysis
7. Casting Simulations & Foundry Methodology Review
8. DEM Charge Analysis & Liner Design Optimization
9. Project specific chute design based on Trajectory TheoryNew Equipment Offered
1. Osborn Grinding Mills & Comminution Circuit Equipment
2. Osborn Crushing & Screening Plants & all related equipment
4. Mill Spares for all Mill makes
Rod Mills can accept feed up to approximately 25 mm and are generally selected to grind products in the 4 mm to +0,5 mm range. Grinding action is by line contact between rods which extend the length of the mill. Rod Mills are usually operated in open circuit. Most rod mill applications involve wet grinding where material is reduced in size from crusher product size to a size suitable for ball mill feed. To avoid breakage or tangling of rods, the L/D ratio of rod mills is kept within the limits of 1, 3/1 to 2/1.
Osborn supplies the three most common rod mill types: overflow, end peripheral and center peripheral discharge.Overflow:
An overflow mill is constructed with a feed opening at one end and a discharge opening at the other, both on the axis of the mill. Material leaves the mill by overflowing at the discharge end. Used for producing the finer end of the product range.End Peripheral Discharge (EPD):
The end peripheral discharge mill's steeper gradient produces a shorter retention time and thus a coarser product than the overflow type. Product is discharged through port openings equally spaced around the periphery of the shell at the discharge end. Grinding may be accomplished wet or dry. End peripheral discharge is used to good advantage in damp grinding of coke on steelwork sinter plants.Center Peripheral Discharge (CPD):
Feed is from both ends and is discharged at the center through discharge ports. The fact that the particles only travel half the mill length makes the CPD rod mill an outstanding unit for coarse grinding and rapid removal of finished material.
Ball mills accept feed that ranges in size from 80% passing 15 mm to fine feeds in regrind operations. Products may be as coarse as 0,5 mm or as fine as 40 microns or below. In a ball mill the length may be less than, equal to, or greater than its diameter. A short length mill has a lower retention time and produces a coarser product. Longer mills have a longer retention time and therefore produce a finer grind.Grate Discharge:
This mill type embodies the principle of steep pulp gradient, quick discharge operation. A grate and pulp lifter assembly at the discharge end of the mill enables a ball charge of 45%. The quick removal of ground material reduces overgrinding, especially when operated in closed circuit with a classifier.Overflow:
As the name implies, material is discharged from an overflow mill by overflowing the discharge opening. The overflow mill is simple to operate and maintain and is ideal for producing fine products such as in regrind operations.