·The feed to a crusher should not contain an excessive amount of fine material; this could be stated a little more definitely by saying that it should not contain an excessive amount of material smaller than the crusher product size Just what constitutes an excessive amount depends of course upon several factors chief among which are the design of the
·This model is a quantitative relation between feed size distribution and product size distribution in comminution systems It has been widely accepted To construct a mathematical model to relate product and feed sizes where the crusher feed contains a proportion of particles which are smaller than the closed set and hence will pass through
·size decreases Nikolov 2002 2004 presented a model for the particle size distribution of material crushed by hammer or VSI crusher expressed as a function of the crusher rotor radius and angular velocity the feed rate and the feed size distribution In the model of Bengtsson and Evertsson 2008 typical parameters of mass flow and absolute
·Morrell 2004a Morrell 2004b Morrell 2008 Morrell 2009 Morrell 2010 Bond and Wang 1950 developed an empirical model by correlating the comminution energy with 80% passing size of the feed coal and the product which was based on the Bond s law 5 e = M i K x 2 80 n x 2 x 1 80 n x 1 where M i and K are constants x 1 80 and x 2 80 are the 80%
·Comminution by gyratory crusher is the first stage in the size reduction operation in mineral processing In the copper industry these machines are widely utilized and their reliability has
·Figure 5 page I 195 shows the fluctuation in crusher feed size that can I 195 occur over a relatively short period The similar % coarse values recorded by the WipFrag feed cameras at both crushers confirms the reproducibility of the measurements as well as the consistency of ore blending ahead of the crushers 0 5 10 15 20 25 30
·The reduction ratio is driven by the Crusher Close Side Setting The actual minimum safe closed side setting of a crusher will vary somewhat for any given crushing machine depending upon the character of the material the amount of fines in the feed and whether the crusher is being operated under choke feed or regulated feed conditions It is
·80 µm of the circuit feed x 2 = P 80 µm of the circuit product M ih = HPGR ore work index and is provided directly by SMC Test ® A Specific Energy Correction for Size Distribution W s Implicit in the approach described in this paper is that the feed and product size distributions are parallel and linear in log log space
·"Comminution represents a significant part of mineral processing plant operating costs Yet autogenous AG or semi autogenous grinding mills SAG are difficult to control because of disturbances like feed size distribution and rock hardness AMIRA within project GeMIII developed a comminution index from laboratory crusher data The index correlated
·Mineral liberation and size reduction are the most critical steps before mineral separation Several investigations showed that mineral liberation degree could be affected by ore texture and/or
·Comminution Comminution or size reduction can be accomplished dry or wet 2 Sizing Process Feed Size Product size 1 Coarse Crushing ROM 150 4cms cm Gape is defined as the distance between the jaw plates at the feed opening end 10 The Blake crusher has a varying discharge opening This distance between the jaws in
The JK Drop Weight Test is a single particle breakage test across 15 size/energy combinations Sample requirements The minimum sample required to provide sufficient particles for testing is 100 kg of crushed rock in the 63 mm size range JKTech can prepare a sample to the specified size range from a larger amount if required
In this study the effects of three different choke feed level 1/1 1/2 and 1/4 and four different effective reduction ratios 5 10 and 20 depend on the capacity of the crusher of the
·For wet grinding in the finer size ranges wet classifiers and/or cyclones are employed generally to make a size separation from 20 mesh down to 325 mesh Under dry grinding conditions air classifiers are used to make the size classification Single stage grinding may be defined as grinding original feed to finished size in a single mill
·The size reduction process of rocks in cone crushers is one of the most important issues particularly for the secondary and tertiary stages of crushing operations In this study 17 different rock types were considered for the evaluation of their size reduction variations that occurred in a laboratory scale cone crusher Based on several mineralogical physico
·Due to their significant influence on feed size distributions two blasting parameters burden and spacing were considered The crusher parameters that affect energy consumption were also
·In this study the effects of three different choke feed level 1/1 1/2 and 1/4 and four different effective reduction ratios 5 10 and 20 depend on the capacity of the crusher of the
·Primary crushing is the first stage in the comminution process and involves breaking down large rocks into smaller pieces of a size that can be handled by the downstream machinery The purpose of primary crushing is to reduce the size of the material to a level that can be handled by the secondary and tertiary crushers Types of Primary Crushers
When the SAG mill feed size dropped to when there is excessive water in the feed The crusher may be run at 12mm or 20mm and still vibrations are present four target final comminution
·Comminution circuits generally have a coarse ore stockpile after the primary crusher to decouple the relatively uneven mined ore supply from the downstream comminution and concentrator circuits
·comminution stages covered by the circuit option chosen by the user The ROM P80 is the feed to the circuit primary crusher feed and this has been fixed at 450mm The reason for fixing this is that often users do not know what the value is and hence it was decided to use a typical value from SMC Testings data base
·The relationship between the input energy and the particle size of the feed that provides a particular product size from the comminution device can be mathematically described by Equation [1] [1] where dE is an infinitesimal change in specific energy dL is an infinitesimal size change L is the particle size k is a constant
