Synthesis, identification and thermal behavior studies of nanoparticles cobalt (II) bromide has been studied in this research. Cobalt (II) bromide was synthesized by planetary high-energy ball mill. The general formula of this compound is CoBr2.6H2O. The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy and also Size and structure of synthesized nanoparticles were studied by analyzing X-ray diffraction and morphology of surface and structure of synthesized nanoparticles were studied by scanning electron microscopy. This compound has many applications in mineral synthesis as a catalyst. The nanoparticles of CoBr2.6H2O synthesized with smaller size of 35 nm, and its SEM images show that the morphology of particles surface is as like as layer. Also, the thermal behavior of these nanoparticles is considered by using of DTA /TGA thermal analysis.

In this work, the ball-end mill machining has been analyzed and a model based on mechanics of metal cutting is developed. This model is used for prediction of the cutting forces in ball-end milling from fundamental data. The cutting edge in this model is considered as a series of infinitesimal elements and the oblique cutting process with these elements has been analyzed as orthogonal cutting process. Cutting forces result from the summation of cutting forces on these elements. The results have been compared with the experiments on machining 1045 steel and Al4Ti6V and show relatively good agreements.

The aim of this research work was to investigate on the ball filling estimation of Miduk semiautogenous (SAG) Mill via an utilized method. Miduk copper concentrator is located in Kerman Province, Iran, and its size reduction stage includes one gyratory crusher which feeds one SAG mill (9.75 dia. (m) *3.88 length (m)) following two parallel ball mills (5dia. (m) *7lenght (m)). After SAG mill, a trommel screen produces two over and under size materials which the oversize part is circulated into SAG mill and undersize reports to hydrocyclone for further process. Ball filling identify was implemented in this work using mill`s load sampling and ball abrasion test.These methods could estimate ball filling variation with easy, undeniable, and useful tests. Also, these tests have shown the digression of operating ball filling amount and its manual designed. To make more homogenous load, mill load samplings were carried out from 6 points after whirling the mill via inching motor. Acquired load sampling results were compared with ball abrasion tests. Ball abrasion tests were calculated for 3 different conditions include maximum, average, and minimum ball abrasion. However, the calculated maximum and minimum conditions never occurred. However, these are just for obtaining to ball filling variation in the mill. The results obtained from this work show, the ball filling percentage variation is between 1.2– 3.7% which is lower than mill ball filling percentage, according to the designed conditions (15%). In addition, acquired load samplings result for mill ball filling was 1.3%.

It is always attempted to reduce the costs of comminution in mineral processing plants. One of the difficulties in size reduction section is not to be designed properly. The key factor to design size reduction units such as crushers and grinding mills, is ore’s work index. The work index, wi, presents the ore grindability, and is used in Bond formula to calculate the required energy. Bond has defined a specific relationship between some parameters which is applied to calculate wi, which are control screen, fine particles produced, feed and product d80.In this research work, a high grade copper sample from Miduk copper concentrator was prepared, and its work index values were experimentally estimated, using different control screens, 600, 425, 212, 150, 106 and 75 microns. The obtained results from the tests showed two different behaviors in fine production. According to these two trends the required models were then defined to present the fine mass calculation using control screen. In next step, an equation was presented in order to calculate Miduk copper ore work index for any size. In addition to verify the model creditability, a test using 300 microns control screen was performed and its result was compared with calculated ones using defined model, which showed a good fit. Finally the experimental and calculated values were compared and their relative error was equal to 4.11% which is an indication of good fit for the results.

COMSIM has been developed in Excel spreadsheet to simulate industrial grinding circuits that consist of ball mills and hydrocyclone. In this software Population Balance Model (PBM) has been used for simulating ball mill performance. In this model, the required parameters are mean Retention Time Distribution (RTD) of particles inside the ball mill, selection function and breakage function. Also, for simulating hydrocyclone performance two empirical models, Plitt and Nageswararao models have been used. These two models predict performance based on hydrocyclone geometry and inlet pulp characterisation.This package allows simulation of circuits consist any layout configuration of ball mills and hydrocyclones. Data obtained from the simulator are compared with measured data from the plant. This reliable performance of the simulation software. Easy handling of input and output, validation of input data, multiple displays of various flows and graphical representation of the results constitute the characteristics of this user friendly similuator.

The mill shell liner type, rotation speed and the amount of its loading are the key factors influencing the charging behavior, consequently the comminution mechanism. In this paper, the milling operation of industrial ball mills using the Discrete Element Method (DEM) is investigated. First, an industrial scale ball mill with a Smooth liner type is simulated. Then, by changing liner type, i. e. Wave, Rib, Ship-lap, Lorain, Osborn, and Step liners, six other independent simulations are performed. Effects of mill shell liner type on charge shoulder, toe, impact, and head points, also on head height and impact zone length as well as on the creation of cascading, cataracting, and centrifuging motions for balls at two different mill speeds, i. e. 70% and 80% of its critical speed (NC) are evaluated. Also, in order to validate simulation results, a laboratory-scale mill is simulated. The results indicate that the charge heads are respectively about 240. 13, 283. 40, 306. 47, 278. 12, 274. 42, 274. 42, and 278. 12 cm at the simulations performed with Smooth, Wave, Rib, Ship-lap, Lorain, Osborn, and Step liners at 70% of NC. The corresponding values at 80% of NC are as follows: 256. 08, 264. 56, 313. 54, 298. 45, 313. 54, 311. 60, and 283. 40 cm. On the other hand, the impact zone lengths are respectively about 33. 14, 22. 11, 38. 63, 35. 86, 38. 63, 38. 63, and 49. 59 cm at the simulations performed with the above-mentioned liners at 70% of NC. The corresponding values for impact zone lengths at 80% of NC are as follows: 35. 86, 27. 63, 49. 59, 38. 63, 33. 14, 52. 32, and 41. 38 cm. Comparison of the simulations related to the laboratory scale mill with experimental results demonstrates a good agreement that validates the DEM simulations and the software used.

Tumbling mill liners transfer the energy to the mill charge and have a significant effect on the load behavior. A plant audit at the Sarcheshmeh copper complex indicted that due to the inappropriate design of ball mills liners, the liners wear and tear increased and the grinding efficiency decreased. With the objective of investigating the design of initial, current and proposed liners, charge trajectory was simulated by the GMT and KMPCDEM software packages. It was observed that the charge impact point for the current liners design was above the toe and on the shell liners. By simulation it was found that increasing the liner lifter face angle from 0 to 15° and the lifter height from 18 to 21cm could decrease the difference between the impact point and the toe and direct ball impacts to liners. Given the promising results, the new liners were designed, constructed and installed in ball mill 4. The result of sampling for a period of one liner life indicated that the amount of particles smaller than 75 microns in ball mill 4 product (with proposed design) compared with ball mill 3 (with current design) increased by 2. 5% and the liners life of the first half and second half increased by 18% and 20%, respectively.