- Rubber liners instead of steel
- Steel mounting frame
- UL Motor
Industrial Ball Mills use horizontal rotating cylinders that contain the grinding media and the particles to be broken. The mass moves up the wall of the cylinder as it rotates and falls back into the “toe” of the mill when the force of gravity exceeds friction and centrifugal forces. Particles are broken in the toe of the mill when caught in the collisions between the grinding media themselves and the grinding media and the mill wall. In ball mills the grinding media and particles acquire potential energy that becomes kinetic energy as the mass falls from the rotating shell. Ball mills are customarily divided into categories that are mainly defined by the size of the feed particles and the type of grinding media. Intermediate and fine size reduction by grinding is frequently achieved in a ball mill in which the length of the cylindrical shell is usually 1 to 1.5 times the shell diameter. Ball mills of greater length are termed “tube mills," and when hard pebbles rather than steel balls are used for the grinding media, the mills are known as "pebble mills.’’ In general, ball mills can be operated either wet or dry and are capable of producing products on the order of 100 um. This duty represents reduction ratios as great as 100. The ball mill, an intermediate and fine-grinding device, is a tumbling drum with a 40% to 50% filling of balls. The material that is to be ground fills the voids between the balls. The tumbling balls capture the particles in ball/ball or ball/liner events and load them to the point of fracture. Very large tonnages can be ground with these devices because they are very effective material handling devices. The feed can be dry, with less than 3% moisture to minimize ball coating, or a slurry can be used containing 20% to 40% water by weight. Ball mills are employed in either primary or secondary grinding applications. In primary applications, they receive their feed from crushers, and in secondary applications, they receive their feed from rod mills, autogenous mills, or semi-autogenous mills. Regrind mills in mineral processing operations are usually ball mills, because the feed for these applications is typically quite fine. Ball mills are sometimes used in single-stage grinding, receiving crusher product. The circuits of these mills are often closed with classifiers at high-circulating loads. Options:
The 911MPELM2000 is a laboratory machine, which is suitable for pulverizing and homogenizing hard and brittle materials in the dry and wet state. The closed milling pulverizing system guarantees complete recovery of the samples. Final fineness of down to 40 μm can be achieved, depending on the milling time and the specific properties of the sample material. The optimum filling of a 911MPELM2000 is around 1-1.3 Liters of sample material.
The surface of the cast grinding steel ball is not allowed to have the casting defects such as the crack, and the obvious gas porosity, inclusion, shrinking cavity, cold shut, elephant skin, etc. It is not allowed to have the shrinkage cavity, shrinking porosity, gas porosity, inclusion, and other cavity defects on the section including plane pasting through the pouring gate and the ball centre. Testing Method and Inspection Rules
- Impact Test
- Rockwell Hardness Test Specimen Preparation
- Chemical Composition Inspection
- Surface Hardness Inspection
- Internal Quality Inspection
- Rod mill grinding rods of all sizes and length.
- High hardness, range is 45~55HRC
- Low bending, less than 1.5mm/m
- Dense microstructure , Bainite +Pearlite+Carbide
- Low breakage rate, more than 15000 times/ 3.5m
- Low unit consumption, 40% reduction compared to unprocessed round steel
A rod mill uses steel rods as the grinding media in tumbling mills is an efficient means to feed ball mills a product finer than could be made in a crusher but coarser than could be made in a ball mill. The principal use for rod mills, which were invented to make ball mill feed in a wet-grinding rod mill-ball mill circuit. Rod mills came into use in the United States beginning in 1900s and eventually became recognized as efficient fine crushers. The 1st ever built rod mill (2 m in diameter by 4 m long) was to be installed at a mine where a coarser feed was required for shaking tables. Crushing rolls and rod mills were eventually used commonly to prepare feed to shaking tables. Later, rod mills of 2.9 m in diameter by 3.9 m long replaced most roll crushers. Rod Mills cannot be to short: With the increase in the diameter of rod mills, problems occurred in the shorter rod mills with rods tangling. When the rods were short relative to the diameter, some were lifted toward a vertical position, and continued tumbling caused tangling. This led to the arbitrary rule that the length of rods should be at least 1.5 times the mill diameter inside new shell liners.
Our forged steel grinding balls commonly used low-carbon alloy, high manganese steel, high carbon and high manganese alloy steel. On the basis of these material we have developed a series of competitive and efficient patent forged grinding balls. Our products range from 20mm to 150mm, 1 inch to 6 inch, and we can also offer all size of products according to clients’ demand. Features:
- forged steel grinding ball has high hardness: surface hardness to 58-65HRC, volume hardness of 57-64HRC
- impact toughness high: impact toughness more than 12J / cm2.
- broken rate is low: the actual broken rate is not higher than 0.5%.
- loss of forged grinding ball round rate is low.
- dropping test in 8m high tester for more than 20,000 times.
Our automatic production line for the grinding cylpebs is the unique. With stable quality, high production efficiency, high hardness, wear-resistant, the volumetric hardness of the grinding cylpebs is between 60-63HRC,the breakage is less than 0.5%. The organization of the grinding cylpebs is compact, the hardness is constant from the inner to the surface. Now has extensively used in the cement industry, the wear rate is about 30g-60g per Ton cement. Grinding Cylpebs are slightly tapered cylindrical grinding media with length equalling diameter, and all the edges being radiused. Grinding Cylpebs are made from low-alloy chilled cast iron. The molten metal leaves the furnace at approximately 1500 °C and is transferred to a continuous casting machine where the selected size Cylpebs are created; by changing the moulds the full range of cylindrical media can be manufactured via one simple process. The Cylpebs are demoulded while still red hot and placed in a cooling section for several hours to relieve internal stress. Solidification takes place in seconds and is formed from the external surface inward to the centre of the media. It has been claimed that this manufacturing process contributes to the cost effectiveness of the media, by being more efficient and requiring less energy than the conventional forging method. Because of their cylindrical geometry, Cylpebs have greater surface area and higher bulk density compared with balls of similar mass and size. Cylpebs of equal diameter and length have 14.5% greater surface area than balls of the same mass, and 9% higher bulk density than steel balls, or 12% higher than cast balls. As a result, for a given charge volume, about 25% more grinding media surface area is available for size reduction when charged with Cylpebs, but the mill would also draw more power.
High-pressure grinding rolls (HPGRs) have struggled for acceptance into the hard-rock mining sector. CRITICAL HPGR PARAMETERS HPGR roll diameters typically range from 0.5 m to 2.8 m, depending on the supplies, and roll widths vary from 0.2 m to 1.8 m. The aspect ratio of the rolls also varies as a function of manufacturer. Typical HPGR throughput rates range from 20 to 3,000 tph, with installed motor power as high as 3,000 kW per roll. The roll surface is protected with wear-resistant materials, and it has been these that have traditionally stymied HPGR acceptance, but solutions are now in place. When operating an HPGR, the two most important operating parameters are
- Operating pressure
- Roll speed
- Specific throughput
- Specific pressing force
- Maximum pressure between the rolls
- Specific energy input
Starting as small as 13 feet (4 m) in diameter on 330 HP and as large as 24' (14.5 m) in diameter on 3,300 HP, the 911MPE Semi & Fully Autogenous Mills tumble crushed ore without iron or steel grinding media. They are used when the crushed ore pieces are hard enough to perform all the grinding. SAG mills tumble mainly ore but they use up to 15% volume of steel balls to assist grinding. Semi-autogenous mills are more common. The AG Mill or SAG grinds primary crusher product and prepares it for final grinding in a ball mill. Its product is usually passed over a large vibrating screen to separate oversize ‘pebbles’ from correct-size particles. The correct-size material is sent forward to a ball mill for final grinding. The oversize pebbles are recycled through a small eccentric crusher, then back to the SAG or autogenous grinding mill. This procedure maximizes ore throughput and minimizes electrical energy consumption. Assuming your ore is AG-amenable: 7 TPH to 15 TPH is a comfortably production average for a 13' x 4.5' AG Mill. A 13' x 6' SAG Mill has a reasonable range of:
- 20 to 30 TPH for gold ore SAG & Ball Mill duty
- 25 to 40 t/h for copper porphyry SAG & Ball Mill duty
The 911MPE-GM2024 is a mini but continuous grinding mill (8" diameter X 9 5/8" long) with an approximate capacity of 3 to 10 Kg/Hr (dependent on feed size and hardness).
- 75 mm diameter x 800 mm Long spiral classifier with tilt regulation from 16 to 22 degree
- 200 mm Diameter X 240 mm Long Grinding Mill which can be used as Ball Mill or Rod Mill
- Mill Motor Power of 1.03kW
- Feed Ore is pre-crushed to 1.5 mm
The 911MPEPPGR426 is a small 300 kilo to 3.5 ton per 24 hour day capacity grinding mill acting primarily as a rod mill but can effortlessly be converted to a ball mill. Thanks to the integrated spiral classifier, it forms an easy to operate closed-circuit grinding plant. It includes a fine ore hopper, vibrating feeder and starter rod load. It is the perfect small grinding circuit for pilot plant operations or small micro mining. Under specific conditions, it will grind finely crushed ( -6mm) ore to 75 microns. This is a Dual Media mill (rod or ball). This continuous grinding mill is offered as a rob mill or ball mill of 420 mm X 600 mm (17" X 24") or as a grate discharge ball mill of 420 mm X 450 mm (17" X 18").