scholarly journals A Comparative Study of Energy Efficiency in Tumbling Mills with the Use of Relo Grinding Media

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 735
Author(s):  
Nikolay Kolev ◽  
Petar Bodurov ◽  
Vassil Genchev ◽  
Ben Simpson ◽  
Manuel G. Melero ◽  
...  

An evaluation of Relo grinding media (RGM, Reuleaux tetrahedron-shaped bodies) performance versus standard grinding media (balls) was made through a series of grinding tests, including a slight modification of the standard Bond test procedure. Standard Bond tests showed a reduction in the Bond ball mill work index (wi) of the mineral sample used in this study when using Relo grinding media. The modified Bond test procedure is based on using the standard Bond ball work index test but changing the circulating loads (350%, 250%, 150%, 100%). The comparative tests with RGM were carried out at the same number of revolutions as the grinding tests with balls at respective circulating load. The RGM charge yielded a 14% higher net undersize product than balls, which hints at improving energy efficiency and the potential for significant mining industry benefits.

2014 ◽  
Vol 67 (3) ◽  
pp. 311-316
Author(s):  
Eduardo Nozawa Caetano de Araujo ◽  
Homero Delboni Jr.

Tumbling mills are often taken as the object of optimization studies because they are a type of equipment that consume large amounts of energy. Among the current available resources to conduct such studies, mathematic modelling presents great efficiency due to its low cost, speed and reliability. The total charge and grinding media charge are very important variables to conduct modelling exercises that aim at power draw and product size distribution forecasting. However, the common measurement methods require people entering the equipment, which carries a number of adversities related to confined spaces. In this regard, this paper presents the development of a method and the prototype of a device able to measure tumbling mill charges, quickly, precisely, with low cost and, above all, ensuring safety. The result of this work is a method that allows equivalent or superior precision in comparison to the existing methods, whose main aspect is to eliminate the requirement of people entering dangerous environments, such as tumbling mills.


Author(s):  
David Konstantin Tilcher ◽  
Michael Pöhler ◽  
Paul Uwe Thamsen

Abstract During the development of sewage pumps their functionality and efficiency have been continuously improved. Different impeller types have been developed; types to reduce clogging, types for associated maintenance during the various stages of the wastewater transport system, and types to increase the efficiency of the pumps. In the current market, energy requirements and efficiency play an increasingly important role. The design of pump impellers with the aim of improving efficiency may increase the susceptibility of clogging. So far there is no test describing both the energy efficiency and the wastewater pumping functionality. Operators can only describe in tenders, a desired efficiency and the indication of plausible experience with respect to the impeller geometry: the impeller shape and the ball passage. It is generally assumed that the susceptibility of clogging can be derived from the impeller shape and the ball passage (or freely passable space). Under this assumption, the vortex impeller should have the lowest susceptibility to clogging. With single and dual-channel impellers, accordingly, the largest possible ball passage points to a low susceptibility of clogging. Both, the hydraulically disadvantageous form of the vortex impeller and an enlargement of the ball passages beyond the hydraulic requirements leads to a significant reduction of efficiency. Generally, it is inferred from these circumstances that clog-free pumps are associated with low efficiency. This assumption, which is also found in the literature, requires a uniform test procedure for the objective assessment of the clogging behavior of sewage pumps. Such a test did not exist. At the Chair of fluid system dynamics, TU Berlin a test stand was developed to examine such assumptions to investigate the functionality and the clogging behavior of sewage pumps. More than 30 different wastewater pumps were tested in this procedure. The results may suggest a correlation between the susceptibility to clogging and the shape of the impeller or ball passage of various sewage pumps. Based on investigations already carried out at the Chair of fluid system dynamics, TU Berlin, the following conclusions are drawn from the measurements: • the superordinate impeller form (Vortex, Channel, etc.) gives no evidence about the susceptibility to blockages, • the ball passage does not indicate the susceptibility to blockages. From these observations it can be deduced: • a sewage pump with an appropriate efficiency may have a low susceptibility to clogging. It can therefore be concluded that the ball passage and the type of impeller are not appropriate parameters to characterize the functional performance of a sewage pump.


Energy ◽  
2018 ◽  
Vol 163 ◽  
pp. 546-554 ◽  
Author(s):  
A.J.H. Nel ◽  
J.C. Vosloo ◽  
M.J. Mathews

2020 ◽  
Vol 59 (3) ◽  
pp. 131-139
Author(s):  
Nikolay Maksimovich SUSLOV ◽  
◽  
Stanislav Alekseevich CHERNUKHIN ◽  
Dmitriy Nikolaevich SUSLOV ◽  
◽  
...  

Relevance of the work. Reducing the cost of mining in the course of open pit mining has always been considered one of the important tasks in the mining industry; it allows to reduce the cost of the extracted ore. When developing quarries, the most costly work, in which there is no direct mining, is the overburden of waste rocks. The method of stripping operations is one of the most efficient and highly productive, which uses a non-transport technology with a walking dragline excavator. Moving such powerful machines is energy-intensive and affects the efficiency of the machine as a whole, therefore, the modernization of the walking mechanism will increase the energy efficiency of the excavator and ultimately reduce the cost of mining. The most common mechanism for moving such machines is a hydraulically driven three-bearing mechanism. This paper describes the proposed modernization of such a walking mechanism, which makes it possible to get rid of two main disadvantages, namely, the lack of energy recuperation of the lifted machine along the path and the dragging of the base edge against the ground, which creates additional resistance to movement. The installation of hydraulic accumulators in the hydraulic system of the drive of the movement of the machine will allow accumulating the energy of the machine raised above the ground when walking, and the introduction of an additional support shoe into the support base of the machine will get rid of dragging the base. In general, the presented modernization of the mechanism will reduce the energy consumption of moving a dragline excavator with a three-bearing walking mechanism with a hydraulic drive and, ultimately, reduce the cost of mining. Purpose of the work: to improve the efficiency of the dragline as a whole by increasing the energy efficiency of its movement. Objectives: consider design changes to reduce the energy cost of moving the dragline. Results. A variant of adding a support shoe into the walking mechanism is considered, which makes it possible to eliminate the friction of the base against the rock along the path by completely separating the base from the ground. Calculations of energy consumption of mechanisms for different types of draglines with the existing and proposed mechanism are carried out. Conclusions, application of results. The calculations given in this paper allow us to conclude about the effectiveness of the changes made to the design of the walking mechanism. The proposed mechanism allows you to significantly reduce the cost of moving and get rid of the disadvantages inherent in the existing mechanism.


Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1280
Author(s):  
Ngonidzashe Chimwani

The attainable region (AR) is an optimization method adopted for use in comminution to achieve different objective functions, which all converge to optimising the production of the desired particle size distributions for downstream processes. The technique has so far mostly been used to optimise the breakage of particles in tumbling mills. It achieved the desired purpose by unveiling all possible outcomes derived from a combination of operational parameters that are bound by trajectories showing the limitations of a system. The technique has given the scientific community lenses to see the behaviour of different parameters in ball mills otherwise known as the black boxes due to their concealing nature. Since its inception, the AR technique has been applied to data obtained from the laboratory tests and simulated industrial mills and the results sometimes contradict or confirm the conventional milling practices in the industry. This makes the already conservative mining industry sceptical about its adoption. This review thus assesses the milestone covered as far as the AR development in comminution is concerned. It also helps to clarify the sources of the discrepancies between the AR results and the conventional knowledge concerning the optimisation of ball mill operational parameters.


2020 ◽  
Vol 176 ◽  
pp. 261-270
Author(s):  
Abdellah Chehri ◽  
Rachid Saadane ◽  
Nadir Hakem ◽  
Hasna Chaibi

1984 ◽  
Vol 2 (2) ◽  
pp. 123-141 ◽  
Author(s):  
E.D. Dickens

Experimental Oxygen Index data taken on plasticized poly(vinyl chloride) systems which consisted of just poly(vinyl chloride) resin, PVC, and plasticizer are shown to obey a simple two-parameter equation for plasticizer loadings above 15 weight percent. The empirical equation is further tested using data for similar plasticized PVC compounds based on large number of commercial plasticizers and plasticizer blends. One parameter used in the equation is the Oxygen Index of the pure plasticizer determined using a simple modification of the standard Oxygen Index test procedure. The other parameter is shown to have essentially the same value for all the plasticizers tested. A detailed deriva tion of the empirical model is provided using published flame spread models adapted for the Oxygen Index test. Predictions of the Oxygen Index for the two-component (ideal) plasticized PVC compounds are within 2-3% of the ex perimentally measured values.


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