Mechanical Characteristics Analysis of Grinding Plate of Food Waste Grinding Mill Based on ANSYS Workbench

Food waste accounts for 30% - 50% of domestic waste, and its centralized treatment is difficult. For commercial places with large production of food waste, it is a better way to use grinding mill to crush food waste and then discharge it into sewer. The mechanical properties of grinding plate are the decisive factors affecting the performance of grinding mill. In this paper, the static analysis and modal analysis of the grinding plate of commercial grinding mill are carried out. The results show that: under the rated load, the maximum equivalent stress of grinding hammer is 83.4mpa, the maximum equivalent stress of cutter head is 77.6mpa, which meets the design requirements, but the stress is relatively concentrated. The lowest modal vibration frequency of the lapping plate is 456.2hz, and the lapping plate will not have resonance damage under normal conditions.

Control of Sulfide Oxidattion and its Effect in Galena Flotation

Pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS) and galena (PbS) generate hydrogen peroxide (H2O2) when placed in water, that pyrite the most amount of H2O2. The order of these minerals for generate of H2O2 in presence water is pyrite > chalcopyrite > sphalerite > galena. In the previous research, the methods of generation of H2O2 in the grinding mill have been studied but its effect on the oxidation of pulp components and hence in deteriorating the concentrate grade and recovery in flotation has not been explored yet. In this study, some parameters investigated to control the deleterious effects of H2O2 in flotation. The data from experimental have been attached by using MODDE 9 software for 6 parameters consist of composition of water, grinding media, particle size, pH, adding collector among the grinding, adding depressant. Finally, the optimize condition has been achieved: particle size 75 μ, process water, adding all collector, without depressant and pH 10. These changes in flotation response of sulphides have been discussed and explained with the formation of H2O2 quantitatively and the results are presented and discussed in terms of H2O2 generation vis-à-vis concentrate grade and recovery in flotation.

On the problem of control over the primary grinding mill ball charging

Considering the fact that the costs related to grinding balls and electric power account for a significant share of operational costs incurred by concentrator plants, this paper highlights the relevance of using an optimized ball charge. The paper considers a conventional approach to ball charging, which involves doing calculations on the basis of a given throughput. The latter serves as a parameter for the specific ball consumption rate approval procedure. At the same time, no consideration is given for the ball wear rate as a parameter defining the grinding performance. It is noted that the ball charge dynamics can be analyzed based on the noise produced by the mill, or the vibroacoustic parameters of the mill. The paper examines some vibro-acoustic ball charge analysis techniques utilized by both domestic and international service providers. It is noted that in all these cases the technique uses just one physical parameter, which is not enough to monitor the total mill load. The VAZM-1M analyzer developed by Soyuztsvetmetavtomatika JSC analyzes and calculates an integral amplitude of the mill vibro-acoustic field. This ensures that all components of the grinding process are taken into account. The paper takes a detailed view of the findings obtained upon analysis of the primary grinding mill ball charge. The work was carried out at the Erdenet concentrator plant as part of contractual scope. A number of different ball charge options was considered, and is it noted that none of the options can resolve this problem completely. The authors describe a possibility to monitor the mill process load with the help of the VAZM-1M analyzer. The authors also analyzed the experiments that aimed at identifying the grinding parameters governed by the mill ball charge. It is shown that the VAZM-1M analyzer gives adequate readings of any ball charge deviations. The mill spectrum registered by the VAZM-1M analyzer contains a resonance peak, which is believed to correlate as a small mill ball charge spectrum. In this regard, a plan of further research was drafted that relies on the use of the VAZM-1M analyzer. The aim is to identify an exact frequency band that would adequately correlate with the mill ball charge.

Autogenous grinding mill process control practices

This paper considers pre-requisite conditions for developing grinding mill control systems and describes the main problems of control and existing constraints. The author selected a set of grinding equipment that consists of autogenous grinding mills and ball mills. The paper considers the selected mill types as control objects. It is shown that there exists a good correlation between the mill charge and its acoustic and vibration noise. The paper examines the relationship between the level of vibroacoustic noise and the mill motor power draw and defines what can be considered an extreme dependence, as well as the conditions in which a stable operation of the automatic system can be maintained excluding the mill overload mode. The paper specifies what hardware and software means would be necessary to implement such system and describes the mill charge analyzer VAZM-1M developed by Soyuztsvetmetavtomatika that was selected for this application. The author looks at certain downsides typical of the conventional control scheme when the head mill feed rate changes as the mill motor power draw changes without allowing for changing physical and mechanical properties of the ore material. The author also considers the capability of the VAZM-1M analyzer in terms of mill load estimation accuracy. This laid the basis for developing mill protection and optimization algorithms for the AG and Ball Mill comminution circuit. The paper features a block diagram of the control algorithm and its brief description. The algorithm consists of blocks, which are responsible for the following actions: they receive key process parameters from the process control system database, check them for validity, perform initial processing and filtering; after that they analyze the trends of the measured parameters and analyze if an overload condition is probable. As decided by the mill operator, the ore flow rate can be adjusted. The paper describes a case study of running an AG mill control system on the basis of the above described algorithm and using the VAZM-1M analyzer. It is noted that this algorithm can be implemented both as an adviser for the operator and for automatic control of the mill when running in overload mode.