In the standard AC closed circuit ball mill grindability test the work index is found from. where Pi is the opening in microns of the sieve mesh tested, and Gbp is the net grams of mesh undersize produced per revolution of the 12″ x 12″ test ball mill. The closed circuit 80% passing size P averages P1/log 20 for all sizes larger than 150 mesh.
WhatsApp: +86 18203695377where d is the maximum size of feed (mm); σ is compression strength (MPa); E is modulus of elasticity (MPa); ρb is density of material of balls (kg/m 3); D is inner diameter of the mill body (m).. Generally, a maximum allowed ball size is situated in the range from D /18 to D/24.. The degree of filling the mill with balls also influences productivity of the mill and milling efficiency.
WhatsApp: +86 18203695377More balls with small size results in fine powder. As a thumb rule powder to be milled should be taken as 25% of total ball weight. If the quantity of charge is very less then milling balls will ...
WhatsApp: +86 18203695377To estimate the circulating loads in and the efficiency of each of the two classifiers operating in closed circuit with a ball mill: Original feed may be applied at the ball mill or the primary classifier. T—Tons of original feed. X—Primary circulation factor. Y—Secondary circulation factor. A—% of minus designated size in feed.
WhatsApp: +86 18203695377rate at each screen size is calculated from a torquemill test as in the example that follows. Torque mill solids load during test: kg ( lb) of ball mill feed sample from plant survey. Sample is reconstituted with water to be the same percent solids as the plant ball mill discharge. Mill speed: rpm (65 percent of critical speed)
WhatsApp: +86 1820369537721 CONCLUSIONS Continued In the present work, equations were also derived, giving: zthe ballmill power drawP as a function of its dimensions: internal mill diameter D and length L, zthe ballmill power drawP as a function of the feed D f (mm) and the product size d (mm), the Bond work index w i (kWh/short ton) and the mill throughput T (short ton/h), zthe ballmill dimensions (D and L), when ...
WhatsApp: +86 18203695377The ball mill was run for seven time intervals, ranging from to 30 min. ... Traditionally, these parameters have been estimated via either direct calculation of S i by onesizefraction method ...
WhatsApp: +86 18203695377and with the decreased grain size, the necessary ball size also decreases (Olejnik, 2010; 2011). For each grain size there is an optimal ball size (Trumic et. al., 2007). The bigger ball in relation to the optimal one will have an excess energy, and consequently, the smaller ball mill has less energy necessary for grinding. In both
WhatsApp: +86 18203695377The specific rates of breakage of particles in a tumbling ball mill are described by the equation Si = axαi(Q(z), where Q(z) is the probability function which ranges from 1 to 0 as particle size ...
WhatsApp: +86 182036953772. Calculation of Power, Speed and Medium Loading of Ball Mill Power calculation G' — the quantity of loading medium and material, T; Dm — effective inner diameter of mill barrel, m; K'5 — grinding medium coefficient, check table 19. Table 19 Grinding Medium Coefficient K' 5
WhatsApp: +86 18203695377The formula for calculating shaft power: P = QE. Where: P = Shaft Power. Q = Mill Capacity. E = Specific Power of Mill. Let's solve an example; Find the shaft power when the mill capacity is 20 and the specific power of mill is 24. This implies that;
WhatsApp: +86 18203695377[1] Working Operations of ball mill In case of continuously operated ball mill, the material to be ground is fed from the left through a 60° cone and the product is discharged through a 30° cone to the right.
WhatsApp: +86 18203695377The purpose of the primary crusher is to reduce the ROM ore to a size amenable for feeding the secondary crusher or the SAG mill grinding circuit. The ratio of reduction through a primary crusher can be up to about 8:1. Feed: ROM up to m. Product: 300mm (for transport) to 200mm (for SAG mill) Feed Rate:
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WhatsApp: +86 18203695377Based over his work, this formula can be derived for ball diameter sizing and selection: Tdm <= 6 (log dk) * d^ where D m = the diameter of the singlesized balls in = the diameter on the largest chunks of ore stylish to mill feed in mm.
WhatsApp: +86 18203695377Introduction where W is the specific energy for grinding in kW h/ton, Wi is the work index in kW h/ton, P80 is the mill product d80 Grinding process mathematical modelling and com size in lm and F80 is the mill feed d80 size lm. puter simulation particularly in mineral industry had been Given W, Wi and F80, one can calculate the product size ...
WhatsApp: +86 18203695377for the rod mill and for the ball mill. The particle size distributions reported are shown in Figure 1. It follows that the No 1 rod mill/ball mill circuit was operating very effi ciently when comparing the combined operating work indices for both mills with the rod mill and ball mill laboratory work indices.
WhatsApp: +86 18203695377By 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 18203695377When the internal diameter of the ball mill was over m, S S was calculated through equality (16) [32]. B was the maximum diameter (50 mm), and D the effective inner diameter of the ball mill ( mm). (16) S S = × B − D (4) The calculation of motor power of ball mill. The media addition was calculated via equality (17 ...
WhatsApp: +86 18203695377An online calculator lets you calculate Top Ball Size of Grinding Media for your mill. Use this Equation Method to properly grind your ore.
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