The lockedcycle wet grinding procedure was started by preparing 2 kg model quartz mineral feed ( vol.%), 5 kg of different steel ball sizes ( vol.% (small ball size, ~20 mm (22) and big ball size, ~40 (15)), and 860 mL of water. The mill was operated at 54 rpm, representing ~ 70% of the critical speed of the mill for 20 min.
WhatsApp: +86 18838072829Chemical Engineering questions and answers. QUESTION 7 BOND Work Index: Part (1) A ball mill grinds a nickel sulphide ore from a feed size 80% passing size of 8 mm to a product 80% passing size of 200 microns. Calculate the mill power (kW) required to grind 300 t/h of the ore if the Bond Work index is 17 kWh/t.
WhatsApp: +86 18838072829Rod Mill Feed Size Size Distribution. Typically, feed to rod mills comes from closed circuit crushing with screens with a top size of 1 to 1¼", or 25 to 32 mm (F80 of 15,000 to 20,000 µm). Deviations above this size have often been associated with extremely poor efficiency, as measured by the Bond Operating Work Index, especially on ores ...
WhatsApp: +86 18838072829The feed size from mm cubes to a product having the following sizes. ... The diameter of the ball mill is 800 mm and diameter of the balls are 60 mm. If the operating speed is 55% less than the critical speed ( Answer: N = 22 rpm) ( Answer : N = 22 rpm ) 17.
WhatsApp: +86 18838072829The size of the feed was minus 50 mm, plus 40 mm and the power required was kW/(kg/s). The screen analysis of the product was: What power would be required to crush 1 kg/s of a material of compressive strength 45 MN/m2 from a feed of minus 45 mm, plus 40 mm to a product of mm average size? ... SOLUTION The critical speed of the ball ...
WhatsApp: +86 18838072829From the ball mill feed size distribution calculate the %+75 μ as: 100 = % +75 μ. 2. From the ball mill discharge size distribution calculate the %+75 μ as: 100 % = % +75 μ. ... COF P80 values in the ball mill feed and discharge (instead of using the closest incremental sieve) by interpolation between the ...
WhatsApp: +86 18838072829I am working in a plant with single stage grinding using a ball mill we operate the mill power at around 1400KW the feed size is 20mm. we use 78mm/64mm steel balls. the ball mill is in closed circuit with classification cyclones. there are 3 cyclones and we operate 2 with a pressure of about 90KPa. the Cyclone Overflow is around 95 microns.
WhatsApp: +86 18838072829It was found that the ball mill consumed kWh/t energy to reduce the F 80 feed size of lm to P 80 product size of lm while stirred mill consumed kWh/t of energy to produce ...
WhatsApp: +86 18838072829Faster Finer Cooler the most powerful Ball Mill. Max. speed 2000 rpm. Up to 5 mm feed size and µm final fineness. Two grinding stations for jars of min. 50 ml and max. 125 ml. GrindControl to measure temperature and pressure inside the jar. Aeriation lids to control the atmosphere inside the jar.
WhatsApp: +86 18838072829For the feed size of 90% passing mm (Fig. 6 a), the maximum capacity was obtained with 100% of a makeup ball size of mm. As the feed size is reduced to ... largest ball size in the mill [mm] f j. weight fraction in size interval i in the feed to the mill [] f 90.
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 ...
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WhatsApp: +86 18838072829In a similar manner, this study is aimed at optimising the ball mill from a feed size distribution perspective. As already mentioned, separation efficiency is a function of the feed size. For leaching, finely ground ore is usually required to achieve optimal leaching operations. ... Ball size (mm) Feed PSD F 80 = x i (µm) Mass fraction Time ...
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 18838072829circuit P80 target size) material in the ball mill. It can be measured and then increased through ... (ten) of equilibrium ball charges for the torque mill (top sizes). Table 1 89 mm ( in) 64 mm ( in) 38 mm ( in) 50/50 wt% 76/25 mm 50/50 wt% 51/25 mm ... Example test mill feed and product size distributions and cumulative grinding ...
WhatsApp: +86 18838072829Ball mill: Ball mills are the most widely used one. Rod mill: The rod mill has the highest efficiency when the feed size is <30mm and the discharge size is about 3mm with uniform particle size and light overcrushing phenomenon. SAG mill: When the weight of the SAG mill is more than 75%, the output is high and the energy consumption is low ...
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. As a result, the mill output will increase with this reduced size to approximately 77,000 tons ...
WhatsApp: +86 18838072829It was found that 30% of energy can be saved by using stirred mill compared to a ball mill for a feed size of mm ground to a P 80 less than 100 µm. The comparative performance of the HPGRball mill and HPGRstirred mill comminution circuit obtained in the present work is shown in Fig. 11 .
WhatsApp: +86 18838072829For example, I was told by a client his ball mill feed was P80 = 9mm but when I went to look at the feed belt, I saw this below. The conveyor belt is 15 mm thick, therefore the rocks on it are more like 2030mm. ... Ball size. mm. 80100. Ball charge weight. ton. Up to 55t. Ball charge by volume % v/v. Up to 35%. Total charge by volume % v/v ...
WhatsApp: +86 18838072829The entire mill feed enters the drum via a chute or spout and an internal spiral carries the feed into the trunnion liner. The drum feeder may be used in lieu of a spout feeder when headroom limits direct spouting. The drum also provides a convenient method of adding grinding balls to a ball mill. The drum is generally lined with Manganese Steel.
WhatsApp: +86 18838072829Planetary Ball Mill PM 400 for size reduction with the highest degree of fineness powerful short grinding times reproducible results Learn more. Retsch GmbH. Search. English. ... Up to 10 mm feed size and µm final fineness ; 4 grinding stations for jars from 12 ml up to 500 ml, jars of 12 80 ml can be stacked (two jars each) ...
WhatsApp: +86 18838072829F80 is the milling circuit feed 80% passing size, µm, fSAG is a calibration parameter for pebble crushing and/or fine feed (typically for 80% passing six inch mill feed and when no pebble crusher is present). WiBM is the Bond ball mill work index, unitless CFnet is an empirical adjustment to a ball mill circuit [CFnet = × ln(P80)]
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