### Grinding Balls & Rods

The original charge to a mill is generally between 40% and 50% of mill volume for ball mills and 35% to 45% mill volume for rod mills. As a general figure rod mills will have a void space within the charge of around 20% to 22% for new rods. In ball mills the theoretical void space is around 42% to 43%. It has been found that as grinding rods wear a 4″ or 4½” rod will generally break up at about 1½” diameter. …

### Coarse Grinding in a Ball Mill

The cobber concentrate is ground in two ball mills in closed circuit with rougher, magnetic separators and cyclones. The calculated.ball mill power consumption is 13.8 Kwhr/Ton of crude. The cyclone overflow is deslimed, and upgraded in finisher magnetic separators. Diameter to Length Ratio in Mills Rod mill L/D ratio is about 1.4:1.

### Ball Mill Design/Power Calculation

A wet grinding ball mill in closed circuit is to be fed 100 TPH of a material with a work index of 15 and a size distribution of 80% passing ¼ inch (6350 microns). The required product size distribution is to be 80% passing 100 mesh (149 microns). In order to determine the power requirement, the steps are as …

### Calculate Top Ball Size of Grinding Media - …

Calculate Top Ball Size of Grinding Media -FRED C. BOND Equation & Method. Previous Next. 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 stone discusses the basic development of the Bond method, the determination of the efficiency correction factors based on mill dimensions ...

### Energy and exergy analyses for a cement ball mill …

Nowadays, ball mills are used widely in cement plants to grind clinker and gypsum to produce cement. In this work, the energy and exergy analyses of a cement ball mill (CBM) were performed and some measurements were carried out in an existing CBM in a cement plant to improve the efficiency of the grinding process.

### Ball Mills - Mineral Processing & Metallurgy

On the class of work for which it is especially suitable the power consumption of a rod mill is about three-quarters that of a ball mill with the production of less undersize. The rod and liner consumption is also about 75% of that of a ball mill, and rods cost less than balls because they are more easily manufactured. Outside of this special sphere of work a rod mill cannot compete with a ball mill.

### EFFECTS OF GRINDING MEDIA SHAPES ON BALL MILL …

terms of energy requirements and steel consumption related to grinding media and liners. Spherical grinding media are predominantly used in final stages of ore grinding. The spherical balls change shape through breakage and wear. Though this is universal in milling, its contribution and effect on milling kinetics, load behaviour and mill power is not fully established. One area that is usually ...

### Mill (grinding) - Wikipedia

Ball mills are commonly used in the manufacture of Portland cement and finer grinding stages of mineral processing, one example being the Sepro tyre drive Grinding Mill. Industrial ball mills can be as large as 8.5 m (28 ft) in diameter with a 22 MW motor, drawing approximately 0.0011% of the total worlds power (see List of countries by electricity consumption). However, small versions of ball …

### Ball mill - Wikipedia

A ball mill is a type of grinder used to grind, blend and sometimes for mixing of materials for use in mineral dressing processes, paints, pyrotechnics, ceramics and selective laser sintering. It works on the principle of impact and attrition: size reduction is done by impact as the balls …

### Cement mill - Wikipedia

The grinding action employs much greater stress on the material than in a ball mill, and is therefore more efficient. Energy consumption is typically half that of a ball mill. However, the narrowness of the particle size distribution of the cement is problematic, and the process has yet to receive wide acceptance. High-pressure roll presses

### how to estimate the wear rate for Ball mill - Page …

08.12.2009 · Re: how to estimate the wear rate for Ball mill. Most practical way to by measuring empty height and calculating the % volumetric filling of grinding media.Alternative way to make track of mill main drive kW consumption reduction and add makeup charge according to the extent of fall in power consumption.

### Ball Mill - an overview | ScienceDirect Topics

The ball mill is a tumbling mill that uses steel balls as the grinding media. The length of the cylindrical shell is usually 1–1.5 times the shell diameter (Figure 8.11).The feed can be dry, with less than 3% moisture to minimize ball coating, or slurry containing 20–40% water by weight.

### Ball Mills - an overview | ScienceDirect Topics

A feature of ball mills is their high specific energy consumption; a mill filled with balls, working idle, consumes approximately as much energy as at full-scale capacity, i.e. during grinding of material. Therefore, it is most disadvantageous to use a ball mill at less than full capacity. Ball mills have the following advantages: • universality and high capacity • permanence of a ...

### 5 Ways To Improve Grinding Efficiency Of Ball …

This same principle is applied in ball mill cement grinding either with the use of division head, classifying liners or ox. Choosing grinding ball material is usually based on cost-effectiveness as regards material consumption. There are however reports that increase in the specific gravity and surface hardness had resulted in significant improvement in the use of grinding energy.

### THE OPTIMAL BALL DIAMETER IN A MILL

The ball size in a mill has a significant influence on the mill throughput, power consumption and ground material size (Austin et al., 1976; Fuerstenau et al., 1999; Kotake et. al., 2004). The basic condition, which must be met while grinding the material in a mill is that the ball, while breaking the material grain, causes in it stress which is higher than the stone hardness (Bond, 1962 ...

### TECHNICAL NOTES 8 GRINDING R. P. King

mill is the energy consumption. The power supplied to the mill is used primarily to lift the load (medium and charge). Additional power is required to keep the mill rotating. 8.1.3 Power drawn by ball, semi-autogenous and autogenous mills A simplified picture of the mill load is shown in Figure 8.3 Ad this can be used to establish the essential ...

### Ball mill - LinkedIn SlideShare

5. The ball mill is used for grinding materials such as coal,pigments,and fedspar for pottery. Grinding can be carried out in either wet or dry but the former is carried out at low speeds. The advantages of wet grinding are less power consumption,increased capacity,no dust formation etc…

### ball mill grinding media metal consumption

SAG mills are autogenous mills that also use grinding balls like a ball mill. A SAG mill is usually a primary or first stage grinder. SAG mills use a ball charge of 8 to 21. The largest SAG mill is 42 (12.8m)

### how to decide ball mill grinding media adding size

Calculate Top Ball Size of Grinding Media . Calculate Top Ball Size of Grinding Media -FRED C BOND Equation Method Previous Next 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

### what is the weight of a ball mill grinding ball

In Grinding, selecting (calculate) the correct or optimum ball size that allows for the best and optimum/ideal or target grind size to be achieved by your ball mill is an important thing for a Mineral Processing Engineer AKA Metallurgist to do. Often, the ball used in ball mills is oversize “just in case”. Well, this safety factor can cost you much in recovery and/or mill liner wear and