8 years ago We are looking at a 1 MTPA comminution circuit that goes from a tertiary crush to a single ball mill (closed on a cyclone cluster) to produce a 100 µm P80 product. We're doing a tradeoff study. Closing the tertiary on the screen or leaving it open! (The crushing plant runs 11 h per day, the mill 24 h/d.)
WhatsApp: +86 18838072829Breakage functions used to predict output particle size in roller mill grinding with wheat may be used in future to predict size reduction of feed ingredients in hammer milling. ... (Dirkzwager et al., 1998; Ball et al., 2015), or report PSD values based on unstandardized ... Factors that may affect the milling of feed ingredients such as ...
WhatsApp: +86 18838072829A Bond ball mill work index is then performed on the mill product for the design of SAGball mill circuits. This is important because it was found that there was a kWh/t higher ball mill work index if the mm ball mill test feed size is obtained by SAG mill grinding compared with crushing.
WhatsApp: +86 18838072829Fig. 5 shows the variation of size class 1 (M1) with the milling time for the two feed size distributions. For this coarser feed the 50 + 20+10 mm ball diameter mix breaks the material at a faster rate compared to the other ball matches. The availability of a ball size for a particular feed size ensures breakage occurs at a faster rate.
WhatsApp: +86 18838072829OBJECTIVES In this module, you will learn how to characterize the performance of ball mill circuits. Specifically, after completing this module, you will be able to: List and describe the four elements of the functional performance equation for ball mill circuits. Define and calculate the classification system efficiency of a ball mill circuit.
WhatsApp: +86 18838072829Product Size: All passing 6 mesh with 80% passing 20 mesh. Net power from pilot plant: KWH/ST. Mill, gear and pinion friction multiplier: Mill Power required at pinionshaft = (240 x x ) ÷ = 5440 Hp. Speed reducer efficiency: 98%. 5440 Hp ÷ = 5550 HP (required minimum motor output power).
WhatsApp: +86 18838072829fixed knives parallel to the drum axis. Chip size is gen erally controlled by feed rate. The chip size can range from approximately 2 inches (5 cm) down to less than inches ( cm) in size. Once the firststage grinding or chipping is completed, the feedstock is milled to the desired particle size. Hammer mills are common equipment for ...
WhatsApp: +86 18838072829The product of SEC and the preset output yields the required grinding power, which conditions the choice of size and drive of a mill. ... CDBM for initial size of ball mill feed and EF5 for final milling size; these factors are only introduced if exceed 1. For RWI and BWI in kWh/t, the formulas below are valid: ·BWI 7 F 80 EF4
WhatsApp: +86 18838072829A ball mill also known as pebble mill or tumbling mill is a milling machine that consists of a hallow cylinder containing balls; mounted on a metallic frame such that it can be rotated along its longitudinal axis. The balls which could be of different diameter occupy 30 50 % of the mill volume and its size depends on the feed and mill size.
WhatsApp: +86 18838072829program. At the time of this research, mill ball charged, feed rate, and average moisture were 7 tons (ball size was 100 mm) per week, 720 t/h and 5%, respectively. Then, ball abrasion rate was calculated by Equations 4, 5 and 6. Total mill feed per week = 720*24*7*= 114912 tons (4) Total ball charge per week = 7*106 g (5)
WhatsApp: +86 18838072829Fig. 5 shows the effects of varying makeup ball composition on the amount of M2 produced for different flow rates in cubic metres per hour. The mill under study has the maximum ball diameter of 40 mm [11]. In this research, the size combinations used were 50 and 40 mm, 40 and 30 mm, 30 and 20 mm and lastly 20 and 15 mm.
WhatsApp: +86 18838072829Hard ore Work Index 16 = 100,000/65,000 = kwh/t For the purposes of this example, we will hypothesize that the the crushing index of the hard ore with the increased energy input of kw/t reduces the ball mill feed size to 6,500 micrometers.
WhatsApp: +86 18838072829Factors Influencing Choice of Size Reduction Equipment 1. Feed and Product Size Feed Size Product Size Coarse Crushers 1500 40mm 50 5mm Intermediate Crushers 50 5mm 5 Fine Crushers. (Grinders) 5 2mm < Fine Milling < down to m
WhatsApp: +86 18838072829The process Comminution involves size reduction and sizewise classification called as screening/ separation. Milling is one of the most important industrial processes. The electric power ...
WhatsApp: +86 18838072829smallest ball size in the mill [mm] d max. largest ball size in the mill [mm] f j. weight fraction in size interval i in the feed to the mill [] f 90. 90% passing size of the feed [L] F optimum weight fraction of mm balls in the makeup [] g i. weight fraction in size interval i in the feed to the circuit [] J
WhatsApp: +86 18838072829the feed to the ball mill was 25 mm, which is very high for ... measures to establish the inputoutput pairing for MIMO systems. ... In the multisegment ball mill model, the sizedependent ...
WhatsApp: +86 18838072829Ball mills can be used for dry or wet grinding of various ores and other grindable materials. It has stable operation, reliable operation, large production capacity ... Ball Mill. Discharge fineness: mm. Feed size.: 25 mm. Output: ... Input size(mm) Discharge size(mm) Capacity(t/h) Motor power (kw) Weight (t) Ф900×1800: 39: :
WhatsApp: +86 188380728298 years ago Like For ball mill, Bond (1958) was proposing an empirical formula giving the top size of balls (makeup balls) DM function of the feed size xG (80% passing size µm), the ore true specific gravity sg, the ore Bond Work Index Wi (kWh/st), the fraction of critical speed fc and the inside mill diameter D (m):
WhatsApp: +86 18838072829K'4 — feed size and product size coefficient of mill. G3 G4 — The production capacity of existing or experimental mills with newly designed and parameters (feed size or product size calculated according to the new generation level) is shown in Table 16. The values of G1 and G2 above should be calculated according to actual data.
WhatsApp: +86 18838072829The energy consumption of the total grinding plant can be reduced by 2030 % for cement clinker and 3040 % for other raw materials. The overall grinding circuit efficiency and stability are improved. The maintenance cost of the ball mill is reduced as the lifetime of grinding media and partition grates is extended.
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 18838072829Fig. 1 shows the cumulative particlesize distributions for output from the STR100 mill for each of the feed fractions, milled through a gap of mm. These output size distributions represent the columns of the breakage matrix, B, and are shown in Table were constructed for each roll gap. Looking at the top row in Table 2, the quantity of material>2057 μm tends to increase ...
WhatsApp: +86 18838072829In the case of an elevator ball mill, the reduction of feed size from 30 mm to 18 mm produced an increase in output of 8%. This corresponded to 4 times the benefit predicted by the Bond formula.
WhatsApp: +86 18838072829Based on his work, this formula can be derived for ball diameter sizing and selection: Dm <= 6 (log dk) * d^ where D m = the diameter of the singlesized balls in = the diameter of the largest chunks of ore in the mill feed in mm.
WhatsApp: +86 18838072829the optimisation of a ball mill circuit and is supported with typical case study done by HOLTEC in a mio t/a ... to improve mill output and reduction in power consumptions in the ball mill system. DIAGNOSTIC STUDY ... • High variations in the mill feed size on +25 mm sieve observed, which shall result in variation in the mill ...
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