Although it was developed nearly 50 years ago, Bond's method is still useful for calculating necessary mill sizes and power consumption for ball and rod mills. This paper discusses the basic development of the Bond method, the determination of the efficiency correction factors based on mill dimensions and feed characteristics, and the application of the results to designing grinding circuits.
WhatsApp: +86 18203695377For 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 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 18203695377The degree of impact is affected by parameters such as mill speed, ball size, mill diameter, mill filling volume, interstitial filling, and particle size. Impact, ... 20 mm (40%), 32 mm (10%), and 40 mm (10%) for dry finegrinding of calcite ore. Finer ball loads were unable to break coarser particles nipped in the feed. and mm:
WhatsApp: +86 18203695377Ball mill grinding efficiency is directly influenced by the size distribution of the grinding balls in the mill. Determining the ball size (or sizes) that should be added to a plant ball mill to obtain optimal performance requires consideration of a number of factors including: circuit feed size distribution, target grind size, and ore breakage characteristics.
WhatsApp: +86 18203695377For example, when the main grinding equipment is ball mill, the speed of the ball mill, the filling coefficient of the steel ball and the size of the grinding medium all have different effects on the final grinding efficiency. (1) The speed of ball mill. The speed of ball mill directly affects the motion state of steel balls and ores in the ...
WhatsApp: +86 18203695377• Ball mill specific grinding rate • Ball mill grinding efficiency The circuit output is defined as the production rate of fines by the circuit. It is calculated from three values: 1. The dry ore feed rate to the circuit (t/h). 2. The % fines in the circuit feed. 3. The % fines in the circuit product. Use this equation to solve for circuit ...
WhatsApp: +86 18203695377Grinding Material Comparison. Ball 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 ...
WhatsApp: +86 18203695377In order to obtain the input data of the simulation model, grinding tests with different grinding time were conducted. Among them, grinding times of Tongkeng ore are 0 min, min, 1 min, 2 min, 4 min and 6 min, respectively. Grinding times of Gaofeng ore are 0 min, 1 min, 2 min, 3 min and min, respectively.
WhatsApp: +86 18203695377Ball Mills. 【 Capacity 】 T/H. 【 Max Feeding Size 】 <25mm. 【 Discharge Size 】 【 Types 】Overflow ball mills, grate discharge ball mills. 【Advantages】 Designed for long service life and minimum maintenance, can grind and homogenize mineral ores down to the nano range, with a large processing capacity.
WhatsApp: +86 18203695377Step 1: Determine the returned sand ratio of the classifier, screen and analyze the new ore and returned sand of the ball mill, and calculate the particle size composition of the full ore of the ball mill, which is used as the original data for calculating the diameter of the steel ball; Step 2: From the particle size composition of the full ...
WhatsApp: +86 18203695377The paper demonstrates the application of this methodology to optimize solids concentration in ball milling of an iron ore from Brazil. The wet grinding experiments were conducted in bench ( m diameter) and pilotscale mills ( m diameter), and surveys in a fullscale industrial ( m diameter) mill.
WhatsApp: +86 18203695377for crushing the big rock tin ore stone to a smaller size before grinding. Crushers can be rough rock tin ore jaw crusher, ... After crushing the stone to a smaller size, need to grind it to power by tin ore ball mill grinding machine, wet pan mill or other rock grinding machine, so the tin concentrate can be released from stone.
WhatsApp: +86 18203695377It is a wellknown fact that the value of the Bond work index (wi) for a given ore varies along with the grinding size. In this study, a variability bysis is carried out with the Bond standard grindability tests on different critical metal ores (W, Ta), ranging from coarse grinding (rod mills) to fine grinding (ball mills). The relationship between wi and grinding size did not show a clear ...
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WhatsApp: +86 18203695377Open Circuit Grinding. The object of this test was to determine the crushing efficiency of the ballmill when operating in open circuit. The conditions were as follows: Feed rate, variable from 3 to 18 T. per hr. Ball load, 28,000 lb. of 5, 4, 3, and 2½in. balls. Speed,
WhatsApp: +86 18203695377Ball mills are used for wet grinding iron ore, g old/copper ore, nickel ore and other ores, as wel l as lime/limestone for flue gas desulphurisat ion systems, coal and other raw materials. Rod mill :
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WhatsApp: +86 18203695377poor blending is anticipated the most difficult grind ing ore should be given the most weight in determi nation of ball size, although this size may be too large for the softer ore. Through past experience some mill manufacturers have prepared tables that specify ball sizes for each mill size. Tables are usually set up with different
WhatsApp: +86 1820369537718:20:34 xinhai Ball mill is a common grinding equipment in concentrator, the main role is to provide qualified grinding products for the subsequent dressing process. The ball grinding process is a process in which the steel ball rotates in the cylinder at a certain speed and rises with the wall of the cylinder.
WhatsApp: +86 18203695377Four different laboratory ball mills and stirred mills have been tested to grind seven ore samples with feed sizes ranging from mm to 150 μm. A case study on full scale operations of a MW IsaMill replacing the existing 4 MW regrind ball mill at Kumtor Gold Mine in Kyrgyzstan is also included. This paper summarizes the major findings ...
WhatsApp: +86 18203695377This therefore suggests that the ball mill should be run within its ... observed that 30mm diameter balls were better than 10 and 20mm diameter balls in grinding a quartzite ore of feed size
WhatsApp: +86 18203695377the bigger 4 mm + mm monosize feed. This therefore shows that should the material feed size continue to decrease, the smaller balls will perform better than the larger balls during milling, as was mentioned by Katubilwa et al. Effect of ball diameter size on mill power draw The mill power draw for each mill run was determined from the
WhatsApp: +86 18203695377Output size: Application: Gold, rock, sand, cement, quartz, silica sand etc., as well as copper, lead, zinc, chrome and other ores for grinding How It Works Get The Price Products display Overview Introduction: The ball mill is a tumbling mill that uses steel balls as grinding media.
WhatsApp: +86 18203695377according to the industrial grinding size target, always between 28 and 325 Tyler mesh (60045 microns). The detailed grinding cycles procedure can be found in [5,18]. Once finished the grinding cycles, a minimum of five, the ball mill Bond's work index w i [kWh/sht] can be calculated using Equation (2). In order to express it in metric ...
WhatsApp: +86 18203695377In Fig. is shown a large ball mill, designed for the dry grinding of limestone, dolomite, quartz, refractory and similar materials; this type of mill being made in a series of sizes having diameters ranging from about 26 in. to 108 in., with the corresponding lengths of drum ranging from about 15 in. to 55 in.
WhatsApp: +86 18203695377If a ball mill uses little or no water during grinding, it is a 'dry' mill. If a ball mill uses water during grinding, it is a 'wet' mill. A typical ball mill will have a drum length that is 1 or times the drum diameter. Ball mills with a drum length to diameter ratio greater than are referred to as tube mills. Ball mills may be ...
WhatsApp: +86 18203695377Chen et al. [8] showed for an oscillatory ball mill that the median particle diameter d 50 (and also other percentiles such as d10 and d90) were well fitted by Rittinger's model for the grinding of DLactose from 450 to 150µm. For experiments on spruce saw dust on the same type of mill, Karinkanta et al. [9] showed, however, that d 50
WhatsApp: +86 18203695377A total of 120 t of Cristalino ore was prepared and sent to CIMM, where it was crushed and screened prior to grinding tests. The processing equipment included a m (8′) diameter by m (2′) length AG/SAG mill equipped with a 20 kW motor, a cone crusher, a m (3′) diameter by m (4′) length ball mill equipped with a 15 kW ...
WhatsApp: +86 18203695377UNTIL THE THIRD THEORY OF COMMINUTION of "Work Index" method of determining crushing and grinding mill size was ... The sample for a rod mill grindability test should be no finer than 80% passing ″, and the sample for a ball mill grindability test should be no finer than 80% passing 6 mesh. ... Tin ore: 8: : : Titanium ore: 14 ...
WhatsApp: +86 18203695377The 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.
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