Particle size reduction screening and size analysis Objective some grinding media are rotated on a common machine frame It is used for small batches of place in ball pebble or rod mills The efficiency of wet grinding can be higher than that for dry grinding but wear of equipment is also higher Grinding is the last stage of the comminution process The particles are reduced from a maximum upper feed size of 3/8 inch to some upper limiting product size ranging between 35 mesh and 200 mesh A rod mill uses rods as a grinding medium Length to diameter ratio is between 1 5 and 2 5

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Rod mill Rod mills are very similar to ball mills except they use long rods for grinding media The rods grind the ore by tumbling within the the mill similar to the grinding balls in a ball mill To prevent the conditions leading to rod charge tangling the length to diameter ratio is maintained at 1 4 to 1 6

The primarily used equipment in crushing are-jaw crushers gyratory crushers and cone crushers whereas rod mills and ball mills closed circuited with a classifier unit are generally employed for grinding purposes in a mineral processing plant Crushing is a dry process whereas grinding is generally performed wet and hence is more energy

Bond Rod Mill Work Index RWi kWh/t 18 1 Table 1 Example of AG/SAG Ball Mill Circuit Wio Calculations [1] [2] ABstrAct Optimum use of power in grinding both in terms of grinding efficiency and use of installed capital can have a large effect on profitability Mill operators have long used operating work indices to evaluate grinding circuit

Other names Grinding mill Related items Mortar and pestle Expeller Extruder Uses Grinding Inquire Now rod mill grinding media to feed ratio The rods grind the ore by tumbling within the mill similar to the grinding balls in a ball mill To prevent the conditions leading to rod charge tangling the length to diameter ratio is maintained at 1 4 to 1 6

Select mill feed material Specify material grindability index Mill feed material Shale ash Raw charge from chalk clay blast furnace slag and limestone Boiler slag Granulated blast furnace slag Dry clay Quartz sand Anthracite Coal Brown coal Magnesite Cement clinker Field spar Limestone earth marl Talc Charge material from limestone and clay

AMIT 135 Lesson 8 Rod Mills – Mining Mill Operator Training

8 1 Introduction Tubular tumbling mills loaded with rods as the grinding media are used for primary grinding of rocks and minerals Rods are placed parallel to the length of the mill their length being about 150 mm shorter than the inside length of mills

The grinding circuit is the largest capital investment of your processing plant Depending on the grindability of your orebody abrasion will cause a certain amount of deterioration to the steel media and liners in your circuit The Abrasion test will allow you to quantify this and design accordingly

rod or coarse sieve and record measurements • Examine the feed measure the largest lump either with a meter rod or coarse sieve as the case may be and record it • Feed the machine and crush the entire sample • Perform sieve analysis on the product by using coarse sieve set as given in 1 2 • Calculate the reduction ratio of the machine

A rod mill uses steel rods as the grinding media in tumbling mills is an efficient means to feed ball mills a product finer than could be made in a crusher but coarser than could be made in a ball mill The principal use for rod mills which were invented to make ball mill feed in a wet-grinding rod mill-ball mill

BWI is a measure of resistance of the material to grinding in a rod mill The BWI of the petcoke depends on the type of crude being processed (generally BWI is directly related to the metal content in the crude) Thereby one of the major issues with the operation of the rod mill may be the dynamically changing BWI of the feed to the mill

2 MODELLING THE SPECIFIC GRINDING ENERGY AND BALL-MILL SCALEUP Ball-mill scale up (Bond's Law)Data zBond work index w i zFeed D f and product d size (both 80% cumulative passing) Result The specific grinding energy w Mill power draw P = wT where T the mill capacity Mill dimensions (from Tables or charts)

AMIT 135 Lesson 8 Rod Mills – Mining Mill Operator Training Mill Characteristics (length diameter rotation speed lifters) Feed Characteristics (work index) Reduction Ratio Under given load and particle size requirement capacity is a function of mill length and diameter Q = kLD 2+N

One long reason The crushing ratio of the rod mill is 16 1 to 30 1 The basic grinding step of most overseas plants is composed of a pulverizer a rod mill and a ball mill In the concentrating plant in China the rod mill is rarely used The ball mill's ore distribution size is high resulting in energy consumption grinding media consumption

An Efficient and Simple Multiple Criteria Model for a

An Efficient and Simple Multiple Criteria Model for a Grinding Circuit Selection Based 75 Also to use MOORA method under uncertainty Stanujkic et al (2012a 2012b) pro-posed a Grey extension of MOORA method The MOORA method as well as its extension MULTIMOORA method can be men-tioned as the prominent and often used MCDM methods

media shape and mill power The objective of this dissertation was to investigate how media shape affects grinding Ball size distribution inside an industrial mill was analysed in terms of shapes and sizes Load behaviour mill power and breakage as affected by media shapes were studied in a pilot laboratory mill An inductive proximity probe

However fine grinding increased the amount of liberated copper method of regrinding of the CIL feed followed by copper flotation was developed as an mineral dissolution free cyanide is oxidised to cyanate if the reduction of Cu laboratory batch rod mill with inert grinding media

Rod mills are very similar to ball mills except they use long rods for grinding media The rods grind the ore by tumbling within the mill similar to the grinding balls in a ball mill To prevent the conditions leading to rod charge tangling the length to diameter ratio is maintained at 1 4 to 1 6

Rod mills accept feed up to about 50 mm (2 in ) and produce a product in the size range of 3000 to 270 mm (4 to 35 mesh) Rod mill is widely applied in metal and nonmetal mine water conservancy glass and construction materials industries mainly suitable for grinding various ores

grinding mills? The use of small grinding media (5 - 12 mm) called Millpebs in regrind mills proved that fi ner grinding can be achieved at lower energy consumption In ball mills energy savings vary from 10 per cent to 40 per cent compared to 25 mm media A regrind ball mill with a mix of small grinding media

The structure of the rod mill The rod mill is the center drive center discharge both ends of the mill by the main bearings supporting four Warehouse Diaphragm plate mill built the cylinder separated for four positions quartz grinding machine first positions filled with grinding media steel bars so called rod