The feed is limited to 1 to meters in size. Thus, based on reduction ratio, the rock size is reduced to 10 to 15 cm. Typical reduction ratios are: Primary crusher: 3:1 to 10:1; Secondary crusher: 6:1 to 8:1; Tertiary crusher: 10:1 Therefore, if a 3 mm crusher product is required, maximum feed size to the secondary crusher would be 240 mm.
WhatsApp: +86 18838072829The largest HPGR Polycom in operation (Figure 5) using a maximum roll diameter of meters is processing diamondbearing rocks in Australia at a maximum feed rate of 600 to 800 mt/h with a top feed size of 150 millimeter (6″). This rock material is reduced in one pass to 57% 1 millimeter with a power input of less than 3 kWh/mt.
WhatsApp: +86 18838072829A series of tests were performed in a laboratory ball mill using (i) three loads of single size media,, 40,, and mm and (ii) a mixed load of balls with varying sizes.
WhatsApp: +86 18838072829The basic parameters used in ball mill design (power calculations), rod mill or any tumbling mill sizing are; material to be ground, characteristics, Bond Work Index, bulk density, specific density, desired mill tonnage capacity DTPH, operating % solids or pulp density, feed size as F80 and maximum 'chunk size', product size as P80 and maximum a...
WhatsApp: +86 18838072829In general, the feed size for a ball mill is usually less than 20mm or smaller. However, larger feed sizes of up to 50mm can be accommodated by some larger ball mills. The feed...
WhatsApp: +86 18838072829The feed samples of X, Y, and Z iron ores were ground in the BBM (ball mill refers to a BBM of size 300 mm × 300 mm with smooth liners) to identify the PSD, BWI, and RT of each ore. Grinding experiments were conducted according to Bond's standard test procedure [].For each iron ore sample, the RT taken to produce 250% circulating load in the BBM was measured by a new method.
WhatsApp: +86 18838072829For this work, our objective is to identify a feed size distribution from which maximum production of the target size can be achieved. Just to shed light on the target size, the mill product is defined by three classes; m 1 the feed size, m 2 the target size (−150 + 25 µm) and m 3 being the fines (<25 µm). A detailed procedure on how to ...
WhatsApp: +86 18838072829In such mills, attrition forces predominate but impacts also play a part in size reduction. They are classed as intermediate grinders and are more useful than ball mills for milling sticky materials. Selection Criteria for Sizereduction Equipment a) Mechanical Properties of the Feed
WhatsApp: +86 18838072829Type of Mill Media Size, in. Tip Speed, ft./sec. Ball mill ½ and larger — Attrition mill 1/ 8 3/ 8 600 1,000 Sand mill 1/ 64 8 2,000 3,000 Small media mill mm 3 mm 1,000 3,000 Choose the Right Grinding mill Consider the feed material's nature and the milling's objective By Robert E. Schilling, Union Process Inc.
WhatsApp: +86 18838072829This set of Mechanical Operations Multiple Choice Questions Answers (MCQs) focuses on "Ball Mill". 1. What is the average particle size of ultrafine grinders? a) 1 to 20 µm b) 4 to 10 µm c) 5 to 200 µm d) 50 to 100 µm 2.
WhatsApp: +86 18838072829By combining with SAG discharge and screening on the SAG discharge screens, top size control to the ballmill circuit feed is maintained while still unloading the SAG circuit (Mosher et al, 2006). A variant of this method is to direct pebblecrushing circuit product to the ballmill sump for secondary milling: while convenient, this has the ...
WhatsApp: +86 18838072829The ball mill motor power requirement calculated above as 1400 HP is the power that must be applied at the mill drive in order to grind the tonnage of feed from one size distribution. The ...
WhatsApp: +86 18838072829If you believe the entry ball size sets the initial point on ball population and exit size is fixed, since the ball wear is near linear, in some camps, this raises the P80 = can only result in grinding larger rock. Throughput can be optimized from the above plus: SAG mill optimization to feed ball mill optimized P80.
WhatsApp: +86 18838072829The larger feed size, the more work that the ball mill needs to do on the ore. ... small,the total feeding capacity of the ball mill is very close to the maximum processing capacity of the ball ...
WhatsApp: +86 18838072829Ball Mill Breakage Efficiency. Consider a ball mill circuit processing material of a given feed size and at a given throughput rate to a target product size, the latter which once again distinguishes the "fines" from the "coarse" material. The production rate of fines or new product size material can be calculated from the circuit feed ...
WhatsApp: +86 18838072829Mill variables such as ball size, mill speed, etc., were maintained at conditions recommended by the manufacturer. ... Figure 3 shows the product rate increase versus time at three different feed rates. The maximum product rate obtained by the test procedure is essentially independent of feed rate. At the two higher feed rates, the mill exit ...
WhatsApp: +86 18838072829product size is estimated as a func tion of size and hardness of the mill feed, and milling operating conditions (NapierMunn et al., 1996). A more reali stic approach is the socalled Population ...
WhatsApp: +86 18838072829The ball mill is used for the grinding of a wide range of materials, including coal, pigments, and felspar for pottery, and it copes with feed up to about 50 mm in size. The efficiency of grinding increases with the holdup in the mill, until the voids between the balls are filled. Further increase in the quantity then lowers the efficiency.
WhatsApp: +86 18838072829High temperature of the ball mill will affact the efficiency. 3 For every 1% increase in moisture, the output of the ball mill will be reduced by 8% 10%. 4 when the moisture is greater than 5%, the ball mill will be unable to perform the grinding operation. 5. The bearing of the ball mill is overheated and the motor is overloaded.
WhatsApp: +86 1883807282917. Kick's law (1885) the energy required to reduce a material in size is directly proportional to the size reduction ratio dL/L, that is the ratio of the initial particle size to the finial particle size This implies that P equal to 1. If P = 1 then 2 1 ln L L CE putting C = KKfc gives: 2 1 ln L L fKE cK KK is not dimensionless.
WhatsApp: +86 18838072829The objective function was to find the ball mix that guarantees maximum production of the floatable size range ( − 75 + 9 μ m) applicable to a platinumbearing ore. The simulated product size distributions were found to display a close match with the measured product from an operational mill.
WhatsApp: +86 18838072829Clinker grain sizes depend on pre crusher settings but are in some cases still up to 50mm when fed to the ball mill and therefore, it is necessary to adjust the grinding tools accordingly. The more that alternative fuels are used in the clinker production process, the finer and hence better the clinker becomes for the ball milling process.
WhatsApp: +86 18838072829With larger diameter tools you may be stepping down 50% 100% of the tool diameter. But when using miniature end mills with a higher flute count, only step down between 5% 15%, depending on the size of the diameter and risk of deflection. The feed rate should be increased to compensate for the decreased axial engagement.
WhatsApp: +86 18838072829Feed material soft, hard, brittle, fibrous dry or wet Size reduction principle friction Material feed size* < 20 mm Final fineness* < 20 µm Batch size / feed quantity* minimum 1 l / maximum 20 l Rotation speed 15 80 min1 No. of grinding stations 1 Material of grinding tools hardened steel Grinding drum sizes 5 l / 10 l / l / l
WhatsApp: +86 18838072829F80 = 80% passing size of the circuit feed, in microns. P80 = 80% passing size of the circuit product, in microns. Example. The dry feed of a ball mill circuit is 300 t/h. The power at the pinion of the ball mill is 1800 kW. F80 = 80% passing size of the circuit feed, in microns = 2500 um. P80 = 80% passing size of the circuit product, in ...
WhatsApp: +86 18838072829Ball mills equipped with a .drying compartment and adequately swept with hot gas (/s above the ball charge),can handle feed with above 10 per cent moisture and a maximum size of around 25mm,preferably much a tandem hammer mill, the maximum feed moisture content may be around 12 per cent if the mill exit diameter is large enough ...
WhatsApp: +86 18838072829