Because of this, the rod mill can effectively reduce 1″ feed size to 10 mesh or finer in open circuit. The voids (or interstitial space) within a rod load are …
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In some plants a ball-mill or rod-mill will reduce the ore to, say, 100 mesh and a tube-mill will finish the grinding to 200 mesh or finer. ... But when a classifier is arranged in open- circuit with a mill, the sand and slime are separated and flow, without further grinding, to their respective treatment. Unless such products are desired, open ...
Question: A two-stage grinding circuit using a rod mill in an open circuit with a ball mill in a closed circuit with a cyclone classifier is used to grind 100 tonnes per hour of ore (S.G. = 3). The circuit layout is illustrated in …
In some cases, open circuit single stage rod mills are used, especially where the product is used directly for gravity concentration or for example in the iron ore …
Grinding Circuits Problem 1 A two stage grinding circuit using a rod mill in open circuit and ball mill in closed circuit with a hydrocyclone classifier is used to grind 100 tons/hr of ore (sp. gr. 3.0). Overflow Hydrocyclone Water Feed Rod mill Ball mill Sump Pump Underflow The circuit is sampled and analysed for -200 mesh material and percent ...
Figure 8.3 shows that the rod mill product is classified and a more uniform feed size is, therefore, discharged to the ball mill whose primary function is to reduce the size of ore, …
Of course, even if we set a more appropriate cement fineness, it is difficult to change the current situation that the flow velocity in the open-circuit ball mill is only 1/2-1/3 of that in the closed-circuit ball mill with the same …
Open-circuit grinding is generally used in two-stage grinding as the first stage of grinding process. The material discharged from the rod mill enters second grinding equipment for fine grinding. In this way, the first-stage rod mill has a smaller crushing ratio and higher production capacity, and open-circuit grinding process is simple.
Bond quantified the rod mill power draw as a function of the Work Index, capacity, and a series of correction factors: PM = Wmtest,i FT Q. FT = F1 F2 F3 F4 F5 F6 . Rod Mill Draft Power Corrections F 1: Correction for Dry Grinding = 1.1 to 2.0. ... Feed prepared by open circuit crushing: 1.4:
Hi, there. Currently our open-circuit, wet overflow rod mill 6ft x 12ft, feed size <50mm, product size 90% < 2mm has a 14mt/hr throughtput. We would like to triple throughput capcity to 42Mt/hr per rod mill. What would be the scale up dimension of the new rod mill which has 42Mt/hr throughput capacity, given feed and product sizes remain unchanged?
Commentary on the apparatus of the Bond rod mill Work Index. by Alex Doll December, 2015 alex.doll@sagmilling. The Bond "Third Theory" of comminution was originally divided into three size classes reflecting the varieties of comminution equipment common during the time period when Bond (and his collaborators) were gathering the …
The main difference between a rod mill and a ball mill is the grinding medium. Rod mills use long steel rods as the grinding medium, while ball mills use steel balls. Additionally, rod mills are better suited to handling larger feed sizes, and they create a more uniform particle size distribution than ball mills.
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Open Circuit Rod Mill-Closed Circuit Ball Mill. This configuration has proven in the past to be a most reliable system due to the fact that rod mills are not particularly susceptible to variations in feed size. However, the necessity to procure grinding rods may limit the usefulness of this approach in certain locations.
Open circuit grinding consists of one or more grinding mills, either parallel or in series, that discharges a final ground product without classification equipment and no return of coarse discharge back to the mill. Some very simplistic examples of open circuit grinding are see below and are made of a Rod mill, Ball Mill or a Rod mill, ball ...
Figure 8.2 shows a flow sheet where the rod mill is in open circuit and the ball mill is in closed circuit with a classifier. This is a normal set-up as the primary function of a rod mill is to provide a uniform sized feed to the ball mill. Figure 8.3 shows that the rod mill product is classified and a more uniform feed size is, therefore, discharged to the ball mill whose …
Center Periphery Discharging Rod Mill. The center periphery discharging rod mill feeds the material through the journals at both ends of the mill, and discharges the grinding products through the circular orifice in the middle of the cylinder (Fig. 3).Ore pulp is characterized by short stroke, steep slope, and it can be coarsely ground with fewer fine …
The following equation is used to determine the power that a rod mill should draw. The Bottom Table lists many of the common size rod mills giving speed, loading and power data. The rod mill motor power is in horsepower at the mill pinion-shaft. For different length rod mills power varies directly as rod length.
According to the discharge method, the wet rod mill can be divided into three types: [overflow rod mill, open rod mill, and peripheral rod mill], and the overflow rod mill is the main one. It can be used as a first-class open-circuit grinding, and is widely used in first-class grinding equipment in concentrators, artificial stone sand, and ...
the rod mill product is precisely the feed size distribution, and it has been demonstrated that a rod mill achieves the same level of fine particles at a lower energy consumption …
At the end of this lesson students should be able to: Explain the use of rod mills in mineral industry. Explain rod mill operation. Recognize different design parameters of rod mills. …
of the mill data base with only a limited number of variables considered. 3.2 Rod Mill Design A different approach is taken with the rod mill design where equations by Bond and Rowling are used to calculate the mill power draw. The Morgärdshammar equation and the IMM equations are shown for comparison. The method of use is similar to the AM ...
The Work Index values listed in Table I and II apply directly to a wet grinding overflow type rod mill 7.5 feet in diameter in open circuit; and to a wet grinding overflow type ball mill 7.5 feet in diameter in …
There are several reasons why rod mills are always run in an open circuit: 1. Size Reduction. One of the primary purposes of a rod mill is to reduce the size of the …
It can be very difficult operationally to trade grind for throughput in an SAG circuit—once designed and constructed for a given circuit configuration, an SAG mill circuit has limited flexibility to deliver varying product sizes, and a relatively fixed unit power input for a given ore type is typically required in the SAG mill.
FIGURE 1. Layout of Grinding Circuit for Problem 2 S ANDS (coarse) BALL MILL A two-stage grinding circuit using a rod mill in open circuit with a ball mill in closed circuit with a rake classifier is used to grind 30 tons per hour of ore (SG 3.0). The circuit layout is illustrated in Figure 1 above. Assume that the circuit was sampled and the
Open circuit grinding consists of one or more grinding mills, either parallel or in series, that discharges a final ground product without classification equipment and no return of coarse discharge back to the mill. Some very simplistic examples of open circuit grinding are see below …
The mill product can either be finished size ready for processing, or an intermediate size ready for final grinding in a rod mill, ball mill or pebble mill. AG/SAG mills can accomplish the same size reduction work as two or three stages of crushing and screening, a rod mill, and some or all of the work of a ball mill.
This paper provides a simple guiding framework for grinding circuit optimisation, focussing on common themes in past optimisation success stories, the conditions for success and …
Figure 8.2 shows a flow sheet where the rod mill is in open circuit and the ball mill is in closed circuit with a classifier. This is a normal set-up as the primary function of a rod mill is to provide a uniform sized feed to the ball mill. Figure 8.3 shows that the rod mill product is classified and a more uniform feed size is, therefore, discharged to …
Running a rod mill in an open circuit also results in lower energy consumption. In a closed circuit, the material being processed is continuously recirculated through the mill, which requires more energy to operate. By allowing the material to exit the mill once it has been ground to the desired size, less energy is required to operate the mill.
The rod mill is a kind of equipment for grinding ore. According to different working conditions, the rod mill performs different grinding tasks. ... When dealing with less hard ores, the 19-25mm ore be ground to 6-10mm, the configuration of the rod mill and the sieve in a closed circuit is simple and the cost is low. Besides, the dust removal ...
the rod mill product is precisely the feed size distribution, and it has been demonstrated that a rod mill achieves the same level of fine particles at a lower energy consumption level [15]. We also have throughput, which directly affects the residence time [16] and impact on the material reduction rate [2].
Working Principle of Rod Mill. Rod mill is a common equipment for grinding operation in mineral concentrator, which is mainly suitable for rough grinding operation. Is through asynchronous motor reducer with small gear coupling, the surrounding big gear reduction drive under its impetus, drive the rotary rotate, cylinder body is equipped with ...
The bauxite mine has an open circuit compartmented rod/ball mill, with an alkaline wet medium and at room temperature. The study consisted of sampling the grinding circuit, data collection from the plant historian system, a BWI test and particle size distribution, and Bond theory and power model calculations.
The presence of "fines" in open circuit rod mill feed has long been recognized as an important factor for both stable and efficient mill operation. Although addition of extra fines to rod mill feed was common practice in the past, few details have been reported. The fortunate exception is the experience at Frood Stobie.
Milling circuit - open and closed. The milling circuit is the complete mill system from beginning to end, including feed mechanism, mill, classifier, separator, product collector, etc. In a closed mill circuit the oversize particles are returned from the post milling processes to be remilled (see figure below) whereas with an open circuit the ...
When calculating rod mill power for a rod-milling-only application, use an inefficiency factor of 1.4 when the feed is to be prepared with open circuit crushing, and use 1.2 when the feed is to be prepared …
