RELIABILITY OF SOME ORE CHARACTERIZATION TESTS
ball mill circuits (Bond, 1952). With the introduction of AG/SAG milling, HGPR and fine grinding in the flowsheet, specific comminution tests followed to suit these devices. Table 1 shows a summary-list of commercial comminution tests used in various comminution models. The applicability of these tests for the
SPECIFIC COMMINUTION ENERGY - SMC Testing
The model predicts the total comminution energy of most types of plant that contain conventional crushers, High Pressure Grinding Rolls (HPGR) and wet tumbling mills such as Autogenous (AG) Semi-autogenous (SAG), rod and ball mills. As well as the total specific energy it will also predict
USING THE SMC TEST® TO PREDICT COMMINUTION CIRCUIT …
the ball mill is less energy efficient than a crusher and has to input more energy to do the same amount of size reduction). Hence from equation 7, to crush to the ball mill circuit feed size (x. 2) in open circuit requires specific energy equivalent to: f x f x 2. 1 W c ic. 1.19* 4 2 M x x. 1 (10) For closed circuit crushing the specific ...
(PDF) THE MODELLING OF SCRUBBERS AND AG MILLS, WHEN TO …
The specific comminution energy for milling in the Bond test mill appears to be based on 60 J/rev, which defines the net energy required in the Bond ball mill to realise the same grinding ...
Modelling SAG milling power and specific energy ...
Comminution, particularly milling, is on average the largest consumer of energy in mining. Actual comminution circuits consist in most of the cases in coarse crushing, SAG milling, pebble crushing and secondary ball milling. In these circuits the SAG mill is the largest energy consumer.
Comminution testing - JKTech - University of Queensland
The SMC Test®, developed by Dr Steve Morrell of SMC Testing, is a cost-effective means to predict comminution circuit throughput, rock mass characteristics and blasting properties. Energy requirements for crushing and HPGR options can now be determined in addition to AG/SAG mills, and with Mic, ball mills.
Comminution | PDF | Mill (Grinding) | Industries
Ball mills • Used for the final stages of comminution using steel balls as the grinding • medium. • Balls have a greater surface area per unit weight than rods and are therefore better suited for fine finishing. • The length of the shell is 1-1.5. If the ratio goes up to …
Size Specific Energy (SSE) – Energy Required to Generate ...
Such value is computed for the last grinding time (14 min), since it approximately matches the specific energy range of the ball mill used in the industrial Minas Rio grinding circuit (4-5 kWh/ t
Energy and Cost Comparisons of HPGR-based Circuits | E & MJ
Up until now, tumbling mills such as AG/SAG mills and ball mills have had a dominant bearing on the design and economics of comminution circuits. However, it is commonly agreed that the majority of employed comminution processes are energy intensive and energy inefficient, accounting for up to 80% of overall process plant energy consumption and ...
Orway Mineral Consultants Canada Ltd. Mississauga, ON ...
The Bond equation is used to calculate ball mill specific energy from T 80to the final product P 80size. The total circuit specific energy is the sum of the SAG mill and ball mill specific energies. W SAG= R (Ms+16000)/(Ms.447.3) (4) W T= K a . K b . W SAG . [10. BWi. (T 80 -0.5-1700-0.5). EF5] + W BM . K BM(5) Where: W
Ball Mills - Mineral Processing & Metallurgy
Nowadays grinding mills are almost extensively used for comminution of materials ranging from 5 mm to 40 mm (3/16″—1 5/8″) ... 4.0 for overflow ball or pebble mills and 4.5 for grate discharge ball or pebble mills. ç is specific gravity of grinding media (for rods or balls normally 7.85) ... E is the specific energy required for the ...
THE OPTIMAL BALL DIAMETER IN A MILL
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 cases, the specific power consumption increases and the grinding capacity decreases (Concha et al. 1992; Katubilwa and Moys, 2009; Erdem and Ergun, 2009).
Estimation of the Specific Energy Requirement for Size ...
12%Typically, the specific energy necessary to reduce the feed material to the desired product size varies in the range of 5–50 kWh/t. Therefore, it is important to have a sound methodology for design and scale-up of ball mills from the energy efficiency and productivity points of view.
THE EFFECT OF BALL MILL OPERATING PARAMETERS ON …
THE EFFECT OF BALL MILL PARAMETERS ON MINERAL LIBERATION Hector E. Rojas Committee Chairman: Dr. G.T. Adel ... the breakage rates and energy specific breakage rates indicate that a change in breakage kinetics may be ... United States power consumption is related to comminution (Comminution and Energy Consumption, 1981). With this in
Quantifying the energy efficiency of fine grinding ...
In contrast, when the SSE75 was calculated, it showed the SAG mill consumed 20% less energy to produce final product material than the ball mill. Since the aim of a comminution circuit is to generate final product material, the SSE methodology gives a fairer indication of energy efficiency.
Prediction model to estimate the specific energy and ...
Using the proposed analytic relationships, the required comminution energy and semi-autogenous mill operating time to achieve the specific product particle size distribution can be estimated with high accuracy (R 2 = 0.96). Finally, the accuracy of the results was evaluated by a ball drop-weight test.
Specific Energy Requirement and Design - DJB Consultants
Specific Energy Requirement and Design These equations form the Basis of DJB's "Millpower2000" Simulation Program for estimating power requirements and mill sizes vs mill throughput objectives. It is an iterative process, but the software can accommodate a large number of geo-comminution samples in a time-efficient manner.
The energy efficiency of ball milling in comminution ...
In practice, energy losses in the present designs of mills are such that the efficiencies range from less than 1% for fluid energy mills, to over 80% for roll crushers; ball and roller mills, on ...
Predicting the overall specific energy requirement of ...
In order to address grinding efficiency (defined as the increase in mass specific surface vs. net specific energy input) the energy consumption of two pilot scale vertical roller mills (200 mm and 670 mm table diameter) was compared to that of a sequence of laboratory comminution equipment covering the same size range. The sequence consisting ...
Ultra-fine grinding mechanism of inorganic powders in a ...
"The Ultra Fine Grinding Mechanism of Inorganic Powers and Surface Modification in a Grinding Media Agitated Mill (1): Consideration on Specific Comminution Energy", Preprint of 36th Symposium on Powder Science and Technol., Japan, 170 (1998).
Reprint from ABB Review, 3/2014 Bigger is better ABB drive ...
A ball mill is a slightly inclined, horizontal rotating cylinder, partially filled with ceramic balls, flint pebbles or stain-less steel balls, that grinds material to the necessary fineness by friction and impact with tumbling balls 2. Throughout the 1 Different processes used in comminution 2 Ball mill at Boliden Aitik copper mine comminution ...
Estimation of the Specific Energy Requirement for Size ...
Design engineers generally use Bond equation to estimate specific energy requirements using a parameter called, Bond Work Index, which is determined experimentally in a laboratory ball mill [1–3]. Morrell [4–6] has proposed different equations for the specific energy and Work Index. Both the set of equations have been widely tested.
20150821 Morrell Method-GMG-ICE-v01-r01 Morrell method …
C.2.4 Fine Particle Tumbling Mill Specific Energy 11 C.2.5 Total Net Comminution Specific Energy 12 C.3 Conventional Crushing/Ball Mill Circuit 12
Comminution | Multotec
The comminution process reduces particle sizes by breaking, crushing, or grinding of ore, rock, coal, or other materials. The process is most often used in the field of mining and / or mineral processing, where mineral ore is broken down into small particles, by hammer, roller / vibrating disc mills and jaw, gyratory and cone crushers.
GeolabsGlobal | South Africa | Comminution
The Bond Ball Work Index Test determines the resistance of ore to grinding in a ball mill, expressed as a work index kilo Watt-hour per ton (kWh/t). The work index is then used to calculate the specific energy requirements for sizing ball mills or determining their throughput for a target grind. Sample Requirements: 10kg -3.35mm
(PDF) Measurement of electrical energy consumption in a ...
The specific comminution energy for milling in the Bond test mill appears to be based on 60 J/rev, which defines the net energy required in the Bond ball mill to realise the same grinding...
Study on the Selection of Comminution Circuits for a ...
Standard drop weight, SMC, and Bond ball work index tests have been conducted to investigate the comminution circuit of a magnetite ore located in Eastern Hebei, China. In addition, simulations based on JKSimMet and Morrell models have been performed to compare the specific energy consumption of various comminution circuits. According to the desired …
A method for predicting the specific energy requirement of ...
a = specific energy to grind coarser particles . W b = specific energy to grind finer particles . Implicit in this approach is the assumption that the specific energy is grinding independent of the processing route and is believed to be applicable to all tumbling mills in the following circuit configurations: crush-rod-ball, crush-ball, crush-HPGR-
Energy saving with separate fine grinding
Energy saving with separate fine grinding. Separate grinding and subsequent blending is a commonly used practice in the cement industry, enabling the lowering of the specific electric energy demand by using highly efficient comminution techniques. While ball mills are not the most energy-efficient mills, VDZ's research has shown that in some ...
AMIT 135: Lesson 7 Ball Mills & Circuits – Mining Mill ...
For overflow ball mills, the charge should not exceed 45% of the mill volume . For grate discharge mills, the charge should occupy about 50% of the mill volume . Bond developed a relationship that can be used to determine the percent charge by volume as a function of the vertical height above the charge, He, and the radius of the mill, R, i.e.,