Academic literature on the topic 'Self-grinding mills'

The necessity of improving technological operations in the processing of mineral raw materials and the use of energy-efficient grinding equipment is substantiated. The technical and technological benefits of vertical dynamic autogenous grinding mills are given. They are based on a method of self-grinding of the material, which allows to reduce the specific energy consumption. The technical advantages of the MKAD system mills, the structural schemes of which have an indifferent group are explained. Since the mills of this system additionally use so-called “circulating” energy, depending on the degree of deformation of the drive motor shaft, it is necessary to study the effect of kinematic mismatch of closed-circuit branches on the specific energy consumption of grinding. The graphic dependences of kinematic discrepancy effect on the specific energy consumption of grinding in the MKAD system mills are presented.

In this work complex investigations of the abrasing wear of lining of self-grinding mills (semiautogenous grinding mills) are carried out with the obtaining of mathematical models of wear-abrasing of elevators in terms of height, weight, volume and worn-out area. In particular, according to the location and nature of the abrasing wear processes, the liner-lifters mill self-grinding are identified in three typical groups. During 1 year, in the conditions of Ingulets GOK, the monitoring of the abrasing wear of selected groups of lifters of self-grinding mills was performed. On the basis of the experimental data calculationed in the Microsoft Office Excel program, a set of mathematical models of lifter abrasing wear was obtained in terms of height, weight, volume and worn-out area. The obtained dependencies are recommended for prediction of abrasing wear of lining and necessary frequency of replacement of inserts-lifters. In addition, the research of wear of lining made of cast iron RF–4, showed a significant reduction in their abrasing wear compared with steel 110G13L. Thus, it has been shown that the selection of liner-lifters materials can reduce the inter–repair period by 3 times or more (replacement of worn-out lifters). A comparison of the actual picture of the abrasing wear of elevators and Simulation Statics simulated result (using SolidWorks) stresses shows the convergence of the arrangement of the zones of maximum stresses and the maximum abrasing wear of the lining. Investigation of the influence of the stressed state of lining plates on the intensity of their abrasing wear – a promising direction for further research.

For the on-line measurement of stress and energy distributions inside ball mills, two types of self-contained, autonomous grinding balls with fully integrated piezo-electric sensors and data-processing electronics are developed and fabricated. The basic model is designed for batchwise experiments on ball mills, where data registered in electronic memories are read out through cable connections to a processing circuit. The improved model contains additional data modulation circuits with a VHF microtransmitter, allowing on-line data retrieval. For the purpose of circuit miniaturization, hybrid and surface mount techniques (SMT) have been utilized. The instrumented balls are identical in size, mass and surface characteristics to the normal grinding balls, with the minimum outer diameter being 40 mm. Systematic experiments have shown that they are fully applicable in a realistic grinding environment where grinding media are presented. In addition to ball mill applications, the developed integration and measuring technique is generally suited for on-line data registration on free-moving objects or other industrial applications where accessibility of the measurand is insufficient.

This article presents the results of theoretical and experimental studies on the processes of destruction ore in wet self-grinding mills under the influence of the aquatic environment on it. The equivalent circuit for determining the stress-strain state of a large piece (ball) exposed to the load at an angle of repose of the material in motion are justified. A uniformly distributed pressure acts on the body of arbitrary shape, depending on the hydrostatic pressure of the pulp inside the drum and the force of hydrodynamic resistance). It is assumed that a large piece has the shape of a sphere with a uniform structure, but in some of its parts there are cavities filled with an incompressible fluid. Under the action of these forces inside the cavity wedging effects of water occur, the effect of which on the strength ores depends on the expansion force and the angle of the micro crack. The experimental researches are done under laboratory and industrial conditions. It was established that the disintegration of kimberlitic ore in MMC is significantly influenced by the characteristics of the aquatic environment pH and Eh, the values of which vary from 3.2 to 7.0 and from -500 to +1020 mV.

The effect of a simultaneous change in the degree of filling a chamber with load κbr and in the content of the crushed material κmbgr on the efficiency of the self-oscillatory grinding process has been estimated. Using a method of numerical modeling based on the results of experimental visualization of the flow has helped establish an emergent dynamic effect of the sharp increase in the self-oscillatory action of two-faction loading at a joint reduction in κbr and κmbgr. A significant decrease in the passive quasi-solid loading motion zone has been detected, as well as an increase in the active pulsation zone and a growth of dilatancy. The manifestation of the effect is enhanced by the simultaneous interaction of increasing the scope of self-oscillations and weakening the coherent properties of particles in a loose large fraction under the influence of the particles of fine fraction. A significant decrease in the values of the inertial loading parameters has been established: maximum dilatancy υmax, the relative scale of self-oscillations ψRυ, the maximum share of the active part of κfammax, and the generalized complex degree of dynamic activation Ka. A 2.65-time growth of υmax was detected, ψRυ increased by 5 times, κfammax ‒ by 4.36 times, Ka ‒ by 18.4 times, at a joint decrease in κbr from 0.45 to 0.25, in κmbgr ‒ from 1 to 0. The synergistic technological effect of a sharp decrease in the specific energy intensity Еo/Еs has been established, as well as an increase in the relative performance Co/Cs in the self-oscillatory grinding, due to a significant increase in the dynamic action of loading, which is exacerbated by the joint interaction of reduced κbr and κmbgr. The process of the self-oscillatory grinding of cement clinker has been investigated. A 62 % reduction in Еo/Еs and a 125 % increase in Co/Cs were detected at a joint decrease in κbr from 0.45 to 0.25, in κmbgr ‒ from 1 to 0.125. The established effects make it possible to substantiate the parameters for the energy-efficient self-oscillatory process of grinding in tumbling mills with a conventional structure

Introduction. Currently used grinding machines, among which drum mills are the most widely used, have a low efficiency, are bulky, are characterized by low specific productivity, significant consumption of steel for grinding bodies and lining, high noise level, and high energy consumption of the grinding process. The most promising devices of a new type that can effectively perform grinding operations at high technological rates are centrifugal mills. The centrifugal mill developed at SKGMI operates on the principle of self-grinding of pieces and particles of crushed mineral raw materials, when they collide and RUB in a mobile toroidal flow formed when the material moves between a rotating Cup-shaped rotor, a fixed body and the overlying layers of the crushed material. Grinding occurs due to the appearance of a gradient of particle velocities over the working body, due to their impact and, to a greater extent, abrasion. The tests of these mills for grinding various materials have shown high efficiency in operation, but until now, the issues of determining the physical and mechanical properties of the crushed material based on the establishment of the particle opening mechanism remain unresolved. The purpose of the tests. Determination of the physical and mechanical properties of the crushed material in a centrifugal mill based on the establishment of the particle opening mechanism. Test procedure. To solve this problem, a vertical centrifugal mill MC-600 with a rotor diameter of 600 mm was used. Tests of the centrifugal mill were carried out according to the following method. The speed of rotation of the rotor was 4.8 and 8.4 s-1, the height of the material column above the rotor was at the level of 250 and 350 mm; 6 radial ribs were installed in the rotor cavity of the mill. The time of each test was 4 hours. The tests were repeated 3–5 times for each mode of operation of the mill. Quartz was used as a reference material for determining the relative pulverizability coefficient. The research was carried out in the production conditions of the Izhevsk machinebuilding plant during the regeneration of spent molding quartz mixtures. Pieces of a liquid-glass mixture based on quartz sand with strength of 1.3 MPa and 4.25 MPa were used as the crushed material. The crushed material was dispersed according to the standard method for each hour of operation of the mill. Samples were taken in the size class -0.200 + 0.074 mm for their fractional analysis by size. Test result. 1. It was Found that the maximum productivity of a centrifugal mill when grinding pieces of material with a strength of 1.3 MPa was achieved with a loading weight of 90–100 kg, and with a strength of 4.25 MPa – 100–110 kg, which indicates the need to create an increased normal pressure of the layers of crushed material located above the mill rotor. It was found that the maximum productivity of a centrifugal mill when grinding pieces of material with a strength of 1.3 MPa and a rotor rotation frequency of 8.4 s-1 was 13.16 t/h, and when grinding pieces of material with a strength of 4.25 MPa – 10.0 t/h. 2. The Dependence of power consumption on the weight of the mill load and the rotor speed increases when the load weight is more than 100 kg. 3. The Highest fraction content of class -0.4 +0.16 mm is 72.14 %, and the content of class -0.074 mm is 3.9 %, i.e. there is no re-grinding of the source material. 4. The specific productivity of the centrifugal mill for the newly formed calculated size classes -0.074 mm and -0.200 mm was 1.28 t/h and 13.0 t/h, respectively. 5. Microscopic study of anshlifov showed that quartz grains in the crushed material mostly have a rounded shape, on average 90–95 % of the grains. In the initial material, about 90% of quartz joints with a binder, and in the crushed material, the number of joints does not exceed 3–5%. Thus, the degree of expansion of quartz reaches to 0.87. Conclusions. The paper presents the results of studies of a centrifugal mill in the conditions of the Izhevsk machinebuilding plant when grinding quartz-containing products. The physical and mechanical properties of the crushed material that significantly affect the efficiency of grinding are determined. The mechanism of the disclosure particles of quartz, which is primarily the mineral content of many ores and defined particle size obtained by grinding. At the same time, it was found that a large yield of thin classes significantly reduces the efficiency of further technology.

The result of many years research of the university scientific community in the field of topical issues of complex processing of natural and man-made mineral raw materials was the creation of a scientific school “Dynamics of working bodies of machines and equipment for fine grinding of rocks” under the leadership of Professor Dmitrak Yu. V. Research results. The dynamic parameters of the grinding bodies are determined directly in the mill grinding chamber which ensure the contactless transmission of information from the grinding ball to the receiving device. A new method of materials self-grinding and the design of a vertical centrifugal mill based on it has been developed. The mill tests during the grinding waste from the production of ceramic products (the battle of insulators, crushed mullite bricks) showed high efficiency and prospects. The tests of a laboratory vibrating mill with one grinding chamber and a rotor diameter of 250 mm for grinding dolomite were carried out. The experiments have shown the possibility of creating vibrating mills for solid materials grinding. In the development of the work of I. N. Plaksin on the flotation of ores with the jet movement of products in the scheme tested by him together with employees in the conditions of the Tekeli processing plant, the modes of joint processing of ores and gold placers were developed at the NCIMM (GTU). It was established that with the unprofitable individual development of alluvial gold mining waste, a positive economic effect can be obtained through their joint processing with ore gold reserves by fine-tuning the concentrate extracted from man-made raw materials by gravitational enrichment methods at a stationary processing plant. It is proved that the addition of the gravitational technology of alluvial gold extraction by flotation methods provides an increase in annual gold production by ~38 % due to the additional extraction of “resistant” forms of gold for gravitational methods. It has been proved in laboratory conditions that the waste slag of the Copper plant of “Ltd. MMP Norilsk Nickel” can be disposed of by joint processing with the ore of current production. It is established that the technology development using metal leaching is promising for the development of Sadonsky plant deposits.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.13.07 – Автоматизація процесів керування. ДВНЗ “Національний гірничий університет”. Дніпропетровськ, 2013.
Диссертация на соискание ученой степени кандидата технических наук по специальности 05.13.07 – Автоматизация процессов управления. – ГВУЗ “Национальный горный университет”. Днепропетровск, 2013.
Ph D. thesis on the 05.13.07 specialism area – Automation of control processes. SHEI “National Mining University”. Dnipropetrovsk, 2013.
Дисертація присвячена рішенню актуальної наукової задачі – автоматизації процесів управління технічним станом конструктивних елементів броні футеровки барабанних млинів мокрого самоподрібнення шляхом застосування моментной ідентифікації у якості інформаційного засібу автоматизації на основі встановлення нових закономірностей формування моментних характеристик та їх спектрів сигналів активної потужності привідного електродвигуна барабанного млина. Вирішення цієї задачі дозволяє підвищити ефективність подрібнення за рахунок підтримки броні барабана в технологічно раціональному стані, підвищити продуктивність та надійність процесу подрібнення, знизити ресурсні і енергетичні витрати. Науково обґрунтовані інформаційне забезпечення, функціонально- алгоритмічні структури та програмне забезпечення до систем автоматичного контролю і регулювання процесів зносу конструктивних елементів броні футеровки барабанних млинів. Результати роботи впроваджені в проектній документації і можуть бути використані на залізорудних збагачувальних фабриках у гірничо-металургійній промисловості.
Диссертация посвящена решению актуальной научной задачи – автоматизации процессов управления техническим состоянием конструктивных элементов брони футеровки барабанных мельниц мокрого самоизмельчения путем применения моментной идентификации в качестве информационного средства автоматизации на основе установления новых закономерностей формирования моментных характеристик и их спектров сигналов активной мощности приводного электродвигателя барабанной мельницы. Решение этой задачи позволяет повысить эффективность измельчения за счет поддержания брони футеровки барабана в технологически рациональном состоянии, повысить производительность, надежность процесса измельчения, снизить ресурсные и энергетические затраты. Установлено, что для энергоинформационных сигналов активной мощности потребляемой приводными электродвигателями БМ ММС 70*23 фильтрация фрикативных составляющих полностью выполняется уже на третьем уровне моментной иерархии, что обусловливает из этого уровня повышение точности определения периодических составляющих. Установлено, что впервые примененные в работе числовые оценки тесноты статистических моментних связей случайных значений энергоинформационных сигналов потребляемой активной мощности барабанных мельниц являются новыми знаниями по всем основным признакам и могут быть использованы как информационные естества при формировании предметных областей систем интеллектуальной поддержки принятия решений для задач автоматизации процессов управления БМ в условиях неопределенности состояния последних. Использование раскрытых закономерностей технологических и технических параметров процесса измельчения через аппроксимирующие функции регрессии условных математических ожиданий определило возможность представления БМ в разных режимах через линейные и нелинейные модели. Впервые установлено, что показатели информационных характеристик, в виде количества и характера экстремумов моментних функций, что используют центральные моменты парных степеней подобные, однако при увеличение степени повышается чувствительность моментной функции, что дает дополнительную информацию для увеличения точности идентификации. Информационные характеристики моментних функций, что используют центральные моменты непарных степеней аналогично подобны. Установлено, что расширение информационного обеспечения автоматизации процессов управления БМ за счет использования моментних функций степеней, больше четвертого порядка для парного ряда и пятого порядка для непарного ряда не дает существенного прироста информации при идентификации технологических состояний барабанных мельниц Установлены числовые зависимости характеристик экстремумов спектральных оценок моментных функций непрерывных случайных сигналов активной мощности потребляемой приводными электродвигателями барабанных мельниц ММС 70*23 при разных технологических состояниях по заполнению барабана измельчаемой рудой. Впервые установлено, что автоматизация процесса измельчения в барабанных мельницах на основе метода интеллектуальной идентификации нелинейных объектов нечеткими базами знаний обеспечивает в пределах допустимой достоверности выполнение оперативного контроля степени износа брони барабана, что позволяет повысить точность и надежность определения предаварийных и аварийных ситуаций в барабанных мельницах. Разработанное информационное и программное обеспечение направлено на сбор, сохранение и использование знаний, с целью решения прикладных задач интеллектуальной идентификации и принятия решений относительно оперативных состояний барабанных мельниц. Программа содержит все экранные формы, необходимые для настройки экспертной системы. Основные научные положения и результаты работы приняты к внедрению в проект ОАО Проектное и проектно-конструкторский институт «Металлургавтоматика» при проектировании автоматизации секции 10, 12 РОФ-2 ОАО «Арселор Миттал Кривой Рог» (проект № 0476).
The thesis is devoted to solving such a relevant scientific problem as automation of control of structural components of coating armour of drum mills of wet self-grinding through moment identification as information technique of automation based on identification of new laws of moment characteristics forming as well as their spectra of active power of the drum mill drive motor. The problem solving helps to improve grinding efficiency owing to keeping armour of a drum in technologically rational conditions. That will help to improve efficiency as well as reliability of grinding process, and to reduce both resource and power consumption. Data support, functional and algorithmic structures are scientifically grounded as well as software for the systems of automatic control and control of wear of structural elements of drum mills coating armour. The results are implemented in project documents; they can be applied at iron-ore preparators of ore mining and smelting industry.

In this work complex investigations of the abrasing wear of lining of self-grinding mills (semiautogenous grinding mills) are carried out with the obtaining of mathematical models of wear-abrasing of elevators in terms of height, weight, volume and worn-out area. In particular, according to the location and nature of the abrasing wear processes, the liner-lifters mill self-grinding are identified in three typical groups. During 1 year, in the conditions of Ingulets GOK, the monitoring of the abrasing wear of selected groups of lifters of self-grinding mills was performed. On the basis of the experimental data calculationed in the Microsoft Office Excel program, a set of mathematical models of lifter abrasing wear was obtained in terms of height, weight, volume and worn-out area. The obtained dependencies are recommended for prediction of abrasing wear of lining and necessary frequency of replacement of inserts-lifters. In addition, the research of wear of lining made of cast iron RF–4, showed a significant reduction in their abrasing wear compared with steel 110G13L. Thus, it has been shown that the selection of liner-lifters materials can reduce the inter–repair period by 3 times or more (replacement of worn-out lifters). A comparison of the actual picture of the abrasing wear of elevators and Simulation Statics simulated result (using SolidWorks) stresses shows the convergence of the arrangement of the zones of maximum stresses and the maximum abrasing wear of the lining. Investigation of the influence of the stressed state of lining plates on the intensity of their abrasing wear – a promising direction for further research.