Effect of circulating load and classification efficiency on
Significant decrease in circulating load was achieved to obtain very similar product quality Mill ball load can be reduced from 35 per cent to 30 per cent according to simulation results
Significant decrease in circulating load was achieved to obtain very similar product quality Mill ball load can be reduced from 35 per cent to 30 per cent according to simulation results
But for the circulating load we are only interested in that fraction of the crusher output which will pass the 3/4″ screen which is 85 tons That part of the product gradation curve which lies below the 85 percent value represents the gradation of the finished product and 29 tons out of each 85 would be minus ″
Fig 10 illustrates the effect of wear on relative production for the possible size reduction controller candidates CV circulating load SEC power or CSS Results imply that ratio control and SEC control can inherently compensate the long term effect of wear on crusher product PSD whereas load mode and setting mode cannot
The ball mill is the most common ore grinding technology today and probably more than 50% of the total world energy consumption for ore grinding is consumed in ball mills On the other hand high pressure grinding roll HPGR technology is Bond tests were also carried out on standard crushed feed passing mm and mm for comparison
Answer to A copper sulphide ore was crushed and milled in close
Typically the circulating load is calculated based on the oversize material that is returned to the crusher The crushed material is then subjected to fine reduction in a hammer mill Mill product analysis indicates a surface area of 740 m2/kg Calculate the power required to crush 100 ton/hr of an ore if 80% of the feed passes a
The evaluation of breakage tests and survey data revealed the following; the Bond work index obtained for the current ore ranges between kWh/t compared to kWh/t which
The circulating load provides long residence time for the coarser fraction to ensure sulfur elimination Dry grinding of crushed ore using two double rotator mills to obtain 80% passing 74 In general the project philosophy was to use proven technology and equipment where possible to avoid custom engineering and unpleasant surprises
culating load is weighed sufficient fresh minus 6 mesh feed is added to bring the total weight up to that of 700 and the charge is returned to the mill for a secontl grinding period All standard ball mill tests are conductetl at 250 per cent circulating load and the number of revolutions in the mill necessary
Screening is the passing of material through definite and uniform apertures is the only true and accurate means of grading to a required particle size Air separation and hydraulic classification depend upon gravity and particle shape and result in the segregation and retention of material of higher specific gravity and lower surface area irrespective of size
The crusher discharge is screened and the size analysis of the screening product indicated 54% < 2 and 46% >2 The screening efficiency is found to be 85% based on the screen oversize Draw a neat diagram showing the circulating load If the screen efficiency is dependent on the screen undersize calculate the circulating load
In the ore beneficiation process of lead zinc wet grinding circuit is primarily utilized The grinding circuit consists of the following basic components rod mill ball mill and a set of hydrocyclones and sumps [4 39] Prior to passing into the grinding circuit crushing of the ore is initially performed using primary crusher followed by secondary crusher
crushing circuit is tertiary crushed material with a top size of approximately 25 mm This material is drawn from the fine ore bin by a variable speed belt feeder and conveyed to the pilot plant Material with a particle size less than 3 mm is removed from the fresh feed in the primary screen prior to feeding to the HPGR
sample is stage crushed to ½ and the test is run under a 100% circulating load As in the ball mill test the test can also be closed with various sieve sizes but for AG/SAG mill analyses the standard 14 mesh mm sieve is typically used The rod mill work index is computed with an equation very similar to that of the ball
A problem for solving mass balances in mineral processing plants is the calculation of circulating load in closed circuits A family of possible methods for the resolution of these calculations is
This article addresses these problems as a function of the relationships between the major grinding variables circulating load sharpness of size separation new feed rate grinding time energy
The circulating load provides long residence time for the coarser fraction to ensure sulfur elimination Dry grinding of crushed ore using two double rotator mills to obtain 80% passing 74 In general the project philosophy was to use proven technology and equipment where possible to avoid custom engineering and unpleasant surprises
The jaw crusher used is a standard jaw crusher RETSCH BB 100 The gap width is usually set to obtain a product size of 100% − mm at a circulating load of 50% The size reduction ratio should not exceed 1 4 The rod mill is typically operated within the size reduction step 100% α to 100% − 1 mm at a
There is a general consensus within the industry that classification efficiency and circulating load both have a major effect on the efficiency of closed circuit ball mills "The ball mill is the most common ore grinding technology today and probably more than 50% of the total world energy consumption for ore grinding is consumed in ball
Mining is one of Chile s priority economic sectors accounting for 9% of GDP; however there is a low level of technology adoption in decision making in the mining company which results in low production efficiency [] Mining production costs are divided into operating costs mine costs processing costs transport costs plus financial and depreciation costs
The testing system Fig 1 comprises primarily a self designed steel cylinder an AE monitoring system PCI 2 model Physical Acoustic Corporation and a microcomputer controlled electro hydraulic servo testing coal is enclosed in a self designed steel cylinder The charging height and internal diameters of the cylinder are and m
