Single-stage closed-circuit ball mill pdf

With time, as the hardness of the ore increases with depth in the mine, a second stage ball mill is added. In small milling plants, where simplicity is most essential, it is not economical to use more than single stage crushing, because the steelhead ball or rod mill will take up to 2. Single stage sag sssag mill circuit configurations are a competitive. The australian experience of milling lateritic ore is to use a highaspect ratio mill at the initial stages of operation using a singlestage.

This single stage circuit is chiefly employed for coarse grinding when a product finer than 65. Comparison of comminution circuit energy efficiency using simulation. The apex spigots of the hydrocyclones were changed from 165 mm to 180 mm. The mill discharge from these mills consists of slurry, which goes to the ball mills for further grinding, and coarse pebblesrocks, which are crushed and sent back to the mill. Closed circuit ball mill basics revisited sciencedirect. In ball mill operations the ci rc u lat in g load will vary between 300 % and % depen ding upon the grind required and t ype of m aterial. This singlestage circuit is chiefly employed for coarse grinding when a product finer than 65. Figure 3 is a diagrammatic illustration of this option.

Single stage ball mills single stage balls add to the argument that rotary mills are not ef. Singlestage circuits when finer material is required, a ball mill is used in a closed circuit the feed is ground and then. Ball mill closed circuit henan mining machinery co. Ball mill capacity vs rod mill capacityuntil recently many operators have believed that one particular type of grinding mill had greater efficiency and resulting capacity than some other. Sag mill and a closed circuit ball mill me mining machinery. Single stage circuits when finer material is required, a ball mill is used in a closed circuit the feed is ground and then. Formula for recirculating load of cyclones and mill. The efficiency of the early stages of grinding in a ball mill is much greater than that for formation of ultrafine particles, so ball mills operate most efficiently by making a coarse product, the fine fractions of this then being separated, and the coarse part being returned to the mill inlet. In order to submit information for use of mill operators, we have prepared comparative flowsheets for 50 ton, 100 ton, 200 ton, 350 ton and 550 ton24 hour plants, showing both single and twostage grinding in typical mill flowsheets. Yanacocha singlestage sag mill the bondbarratt singlestage sag model results in the following. The gold extraction is done by leaching process using cyanidation method through a series of stirred.

In multistage abcsabc circuits, the ag or sag mills are in closed circuit with screens and pebble crushers. A schematic of closed circuit, singlestage sag mill. Pdf closed circuit ball mill basics revisited walter valery and. Metallurgical contentopen circuit grindingclosed circuit grindinggrinding circuit process control variablesgrinding operating costs the simplest grinding circuit consists of a ball or rod mill in closed circuit with a classifier. An overview of single stage autogenous and semiautogenous grinding mills brian putland principal metallurgist comminution. Open circuit primary ball mill for wet grinding mini. The slurry and ball charge adheres to the walls of the mill before cascading off at a given angle causing impact and fragmenting the ore nunez f, 2011. Pdf ball mills for fine grinding cement clinker and additives are widely used. Pdf the effect of aspect ratio on the grinding efficiency. The comparison between single stage and double stage grinding has received much attention in the past few years. Modeling and process control article pdf available in cybernetics and information technologies 122 january 2012 with 4,857 reads how we measure reads. This option offers a relatively small foot print and medium capital cost.

If a single stage ball receives material of 80 per cent passing 6 mm and larger, then the bond oversize inef. Analysis of the efficiency of the grinding process in closed circuit ball. A method of c alculating autogenous semiautogenous. A ball mill is a type of grinder used to grind and blend materials for use in mineral dressing. The number of sag mill revolutions required to grind the material to a p.

Single stage selection criteria the decision to go single stage or two stage grinding is generally dictated by the product required. Powerbased modelling of singlestage ag and sag mill circuits. Mill circulating load formula screen gold vibrating screen calculation of circulating load screen get pricesirculating load calculation made in a mill is plant includes one sag mill in a closed circuit with a vibrating screen and one ball mill with a size classification ecessary to calculate the proportion of each mills energy f ball mills. In multi stage abcsabc circuits, the ag or sag mills are in closed circuit with screens and pebble crushers. The high unit capacity sag millball mill circuit is dominant today and has contributed toward substantial savings. Characteristics of open and closedcircuit grinding systems. As illustrated in figure 3, rod mill discharge and ball mill discharge are combined in the same sump and pumped to the cyclones. The effect of aspect ratio on the grinding efficiency of open and closed circuit agsag mills. Pdf toward a simple approach determining single stage sag. Closed circuit grinding vs open circuit grinding 911 metallurgist. Ball mills are used primary for single stage fine grinding, regrinding, and as. The simplest grinding circuit consists of a ball or rod mill in closed circuit.

The first two types may be called singlestage operation, while the last two are twostage operations. The ground product for the laboratory sag mill is then submitted to the bond ball mill work index test. With time, as the hardness of the ore increases with depth in the mine, a secondstage ball mill is added. The australian experience of milling lateritic ore is to use a highaspect ratio mill at the initial stages of operation using a single stage circuit. If included, the use of a single stage mill is likely to be inappropriate. If determined to be reasonably powerefficient, single stage sag milling is likely to be the most profitable grinding circuit. The aim of the present study was to optimise operating parameters i.

The closed circuit operation started in april 2008 along with smaller, 16 inch 400 mm cyclones instead of the previous 20 inch 508 mm cyclones. Optimizing your sag mill operation international mining. Single stage open circuit rod mill this circuit comprises a single stage rod mill operating in open circuit. Ball vs rod mill conversionthe correct grinding mill depends so much upon the particular ore being treated and the product desired, that a mill must have maximum flexibility. A schematic of closed circuit, single stage sag mill flowsheet is shown in figure 2. Discharge fo oversize return sands primary milldc classifier finished product open circuit or single stage f advantages of closed circuit. The laboratory benchscale sag mill reproduces operating conditions of a commercial sag mill, in a closed circuit dry grinding environment. Cement mill open closed circuit rod mill in closed circuit with a classifier the flow sheet is shown into an open circuit grinding system and a mill. The twostage circuit includes a transfer size of agsag product that becomes the feed to the closedcircuit ball mill. Difference between open circuit and close circuit ball mill. Apr 15, 2004 the characteristic differences between open and closedcircuit grinding systems were examined via the use of a continuous vibration ball mill and a blade type classifier. One of the main reasons for this significance is the importance of these.

Aug 15, 2017 in ball mill operations the ci rc u lat in g load will vary between 300 % and % depen ding upon the grind required and t ype of m aterial. The ball mills typically operate in a closedcircuit configuration with. In case of continuously operated ball mill, the material to be ground is fed from the batch and continuous operation, similarly it is suitable for open as well as closed circuit create a book download as pdf printable version. To design or optimize a comminution circuit, one needs. A method of c alculating autogenous semiautogenous grinding. This singlestage circuit is chiefly employed for coarse grinding when a product finer than 65 mesh is not required, but it can be adapted for fine grinding by substituting a bowl. This singlestage circuit is chiefly employed for coarse grinding when a. For the same median diameter of the product, the rate of powder production in the closedcircuit is about 5% higher than that of the opencircuit. An industrial ball mill operating in closedcircuit with hydrocyclones was studied by five sampling surveys. The australian experience of milling lateritic ore is to use a highaspect ratio mill at the initial stages of operation using a singlestage circuit. Over the years, ball mill circuits closed with cyclones have become an industry standard, and since the early days, it has been recognised that classification efficiency and circulating load both have a major effect on the efficiency of closed circuit grinding i.

Twostage singlecircuit of tsg with a tube ball mill under pregrinding and. Simplified grinding mill circuit models for use in process control by johan derik le roux submitted in partial ful. This means a closed circuit single stage ag sag mill can operate at a reasonable ef ciency if the. Mar 12, 2015 figure 3 is a diagrammatic illustration of this option. The simplest grinding circuit consists of a ball or rod mill in closed circuit with a classifier. The former is equipped with a reverseconfigured ball mill closed grinding circuit, while the latter is equipped with ball mills under a direct closed circuit. The gold extraction is done by leaching process using cyanidation method through a series of stirred tanks. Grinding, semiautogenous grinding, sag, ball mill, energy, efficiency, greenhouse gas, ghg.