SU948438A1

SU948438A1 - Grinding charge for drum mills

Info

Publication number: SU948438A1
Application number: SU802916895A
Authority: SU
Inventors: Александр Андреевич Яценко; Владимир Хрисанович Денисов; Валерий Владимирович Песков; Игорь Михайлович Кравец; Вячеслав Александрович Цукерман
Priority date: 1980-02-15
Filing date: 1980-02-15
Publication date: 1982-08-07

Description

Изобретение относитс к области измельчени полезных ископаемых и других материалов при их промышленной переработке.The invention relates to the field of grinding minerals and other materials during their industrial processing.

Областью применени изобретени вл етс тонкое и особо тонкое измельчение Мстериалов, при котором содержание класса - 0,071 мм в конечном продукте должно быть выше 60%,The field of application of the invention is the fine and extremely fine grinding of Msterials, in which the content of the class is 0.071 mm in the final product should be above 60%,

Известна мелюща загрузка дл барабанных мельниц, имеюща шарообразную форму, она выполнена с шестью симметрично расположенными сферическими впадинами с радиусом кривизны, равным или большим радиуса самого мелющего тела П.Known grinding load for drum mills, having a spherical shape, it is made with six symmetrically arranged spherical depressions with a radius of curvature equal to or greater than the radius of the grinding body P.

Анализ формы данных тел и способов их взаимной укладки показывает на отсутствие возможности полного совмещени выпуклостей одних тел со впадинами других, что не позвол ет реализовать предполагаемый эффект в полной мере. Вместе с этим данные тела в св зи с их сложной формой (6 сферических впадин и 8 шарообразных выступов , сопр гающихс между собой) не могут быть изготовлены высокопроизводительным промышленным (например, прокаткой ) способом.The analysis of the shape of these bodies and the methods of their mutual stacking shows that it is impossible to completely combine the convexities of some bodies with the depressions of others, which does not allow one to realize the intended effect to the full. At the same time, these bodies, in connection with their complex shape (6 spherical depressions and 8 spherical protrusions mating with each other) cannot be made by a high-performance industrial (for example, by rolling) method.

Наиболее близким техническим решением вл етс мелюща загрузка дл барабанных мельниц, включающа шаЕы 23 ,The closest technical solution is a grinding load for drum mills, including STEPS 23,

Недостатком мелющей загрузки вл етс низка эффективность процесса измельчени в св зи с тем, что шары соприкасаютс только в одной точке.The disadvantage of the grinding load is the low efficiency of the grinding process due to the fact that the balls are in contact only at one point.

Целью изобретени вл етс повы10 шение эффективности процесса измельчени путем увеличени плотности уклсщки загрузки.The aim of the invention is to increase the efficiency of the grinding process by increasing the density of the load box.

Указанна цель достигаетс тем, что мелюща загруз.ка дл барабанных This goal is achieved by grinding mills as drum drums.

15 мельниц, включающа шары, снабжена дополнительными мелющими телами в виде многогранников, грани которых образованы вогнутыми сферическими поверхност ми, причем количество мно20 гогранников составл ет 15-70% общего количества мелющей загрузки.15 mills, including balls, are provided with additional grinding bodies in the form of polyhedra, the faces of which are formed by concave spherical surfaces, and the number of polyhedrons is 15-70% of the total number of grinding load.

На фиг,1 изображена взаимна упаковка мелющей загрузки в аксонометрии,на фиг.2 - то же, в поперечном се25 чении; на фиг. 3 - экспериментальные кривые кинетики измельчени .Fig. 1 shows the mutual packing of the grinding load in axonometric view, in Fig. 2, the same in the cross section; in fig. 3 — experimental grinding kinetics curves.

Claims

FIG. Figure 1 shows the elementary cube of spatial packaging of a mixture of balls 1 and polyhedra 2 for the case of face-centered cubic packaging of balls. This type of packaging belongs to the simplest types, i.e., most likely with the static nature of the movement of the balls in the mill. The gaps between the balls 1 are filled with polyhedra 2, and for this type of packing of balls and the conditional conditions for constructing a model, all the polyhedra must be in the shape of a cube. Each cube with its concave faces is in contact with six balls symmetrically about its hugs, each ball with six cubes symmetrically surrounding it. The gaps between cubes and balls are shaped like a slowly widening gap. The package shown has a high density, an area of contacts between the bodies, and symmetry that allows rotations by 90 ° with respect to any edge a of the elementary cube of spatial packing. Figure 2 shows the cross section of one layer of laying balls 1 and cubes 2. The dotted line highlights the face of the one shown in FIG. 1 cube of spatial packaging. The simplest type of ball stacking is hexagonal packaging. In this case, two kinds of voids are formed between the balls; a tetrahedron (tetrahedron) can be inscribed into one of them, an octahedron (octahedron) into the other. These types of Taie polyhedra can be used as grinding bodies mixed with balls (the calculations of dimensional, weight and quantitative ratios in this application are not given). However, as practice shows, the most likely structure for laying balls with their statistical (random) character of relative motion is the face-centered cubic structure described above. This is confirmed by the following observations. In practice, during the operation of prolific drum mills, when balls are worn, the formation of a part of scrap (worn balls) is observed in the form of a polyhedron; The size of these cubes is 2-3 times smaller than the size of balls that are reloaded into a mill. It follows that under the conditions of the grinding process in a drum mill, part of the grinding bodies, when worn, naturally tend to acquire a form in which the entire grinding environment would tend to increase the surface of mutual contact and the packing density of the bodies. The number of cubes formed is small to (3-5%) against the value of 50% calculated by the authors of the total number of grinding bodies. The total weight of the balls, the size of which decreases with wear by 2-3 times from the maximum, is 12 and 5%, respectively, of the total weight of the balls in the mill. Since balls of this size, from which the required cubes can be formed in the mill, are few, the number of cubes, respectively, does not reach the optimal size. The following peculiarity of the formation of cubes is also noted: in stage I mills with large raw material, they have rounded edges and tops, i.e. they retain the remnants of the ball shape; in the mills of the subsequent stages, as the NKpa size of grinding bodies and particles of the comminuted material decreases, their faces and tops become sharp. This natural process of the formation of polyhedra with the wear of part of the balls confirms the correctness of the premise that the grinding medium for fine grinding in the drums of the mills should consist of a mixture of bodies of two different shapes, one of which is a ball, the other is a polyhedron with concave surfaces. In this case, the maximum possible contact surface and packing density of grinding bodies is ensured. The invention of the grinding load for drum mills, including balls, characterized in that to increase the efficiency of the grinding process by increasing the packing density of the load, the latter is equipped with additional grinding bodies in the form of polyhedra, whose faces are formed by concave spherical surfaces, and the number of polyhedra is em 15-70% of the total grinding load. Sources of information taken into account in the examination 1. The author's certificate of the USSR 376117, CL, 02 C 17/22, 1971.

2. Ilevich A.P. Equipment plants silicate industry. M.,. Gosstroyizlat, 1958, p. 237 (prototype)

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