SU1079288A1 - Method of milling cement - Google Patents

Abstract

A METHOD FOR GRINDING 1 SCHEME, including grinding of clinker with additives and grains separated in a separator in a pipe mill, by feeding clinker with additives to a coarse zone, and crumbs to a fine grinding zone, characterized in that, in order to increase the grinding efficiency, particles the grains are fed with compressed air to the fine grinding zone through the coarse zone, together with them at the entrance to the mill an initial speed of 0.5-25 m / s, and the air flow rate is directly proportional to the quantity and inversely proportional to the average particle size .

Description

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CfHif.t ONZH The invention relates to a grinding technique, and more specifically to a cement grinding method, and can be used in cement production, power engineering, heating and other industrial sectors. There is a known method for grinding cement, including grinding clinker with additives and separated grains in a pipe mill. By feeding the clinker with additives and grains to the beginning of the coarse grinding zone Ci 3. A disadvantage of the known method is the low grinding efficiency caused by the coarse grinding zone being overloaded by particles of grains, requiring only fine grinding. As a result, the required level of grinding of the clipper with additives is not provided, and the grains are regrind, which is accompanied by additional power consumption. The closest to the invention is a method that includes grinding the clinker with additives and grains separated in a separator in a tube mill by feeding a linker with additives to the coarse zone, and grains to the fine grinding zone p}. This method provides some increase in grinding efficiency in comparison with the above, by achieving a larger correspondence of the size of fine bodies to the size of particles of the material being ground. However, the effectiveness of grinding using this method is still small due to the size of coarse and fine grinding zones that are strictly regulated by the chamber lengths. and the impossibility of ensuring a consistent and optimal correspondence between the amount and size of clinker particles with additives, the amount and size n grits with one item and Rhone dpinoy zones coarse and fine grinding, The size of the grinding bodies in said zones - the other. The purpose of the invention is to increase the grinding efficiency. This goal is achieved by the fact that according to the cement grinding method, which includes grinding the clinker with additives and grains separated in a separator in a tube mill, learn clinker with additives to the gravel zone and grains to the fine grinding zone, particles of the grains are fed with compressed air to the fine grinding zone through the coarse zone, together with them, at the entrance to the mill, an initial velocity of 0.5-25 m / s, with the air flow rate being directly proportional to the quantity and inversely proportional to the average particle size of the grains. FIG. 1 schematically shows a mill, a longitudinal section; figure 2 - section aa in figure 1. The essence of the method is the following. The clinker with additives enters the beginning of the mill and is crushed first by large small bodies in the coarse grinding zone in section 1. As the average size decreases, the grinding product of the clinker moves to the fine grinding zone, to section II, where it is crushed by small grinding bodies. A change in the size of the maxillary bodies along the length of the mill is both sintered, as a rule, using a sorting armor. The flow of grit separated in the separator, as well as the clinker, is fed to the beginning of the mill. But it is directed by compressed air along the axis of the mill, mainly outside the movement profile of the charge-material load, together with the particles of the grit, the initial velocity of 0.5-25 m / s. The specific speed is adopted such that the grit particles fall into the fine grinding zone. The boundary between the coarse and fine grinding zones is the point along the length of the mill, at which the average particle size of the ground clinker is equal to the average particle size of the nib. Since the feeding of the grains through the coarse grinding zone is carried out outside the profile of the charmer loading, the grains particles do not interfere with the grinding of large granules of clinker, and when they fall into the area of the fine grinding zone, they are crushed with small grinding bodies that correspond to this average particle size of the grains, which results Both increase the efficiency of grinding. At a particle velocity of less than 0.5 m / s, they go directly to the beginning of the mill, i.e. at the beginning of the coarse grinding zone, and the grinding process is ineffective. At a speed of more than 25 m / s, the particles of the grit, by air flow without grinding, penetrate to the end of the fine grinding zone practically without being crushed, and the grinding process is also ineffective. Only in the velocity range of the grit particles at the beginning of the mill 0.5–25 m / s, they are fed to the mill site, where the particles of clinker and additives corresponding to the average particle size of the grit are ground. to the beginning of the fine grinding zone. The magnitude of the specified speed range was determined experimentally, based on the fact that the speed of the grains at the end of their path through the coarse grinding zone to the start of fine grinding as a result of their resistance to movement in the mill was zero. The specific speed required is determined by the grindability of the clinker and the average particle size of the grains. With the same grindability of clinker and grit, the required speed is inversely proportional to the average particle size of the grit, ie the larger the grit, the slower it needs to be fed and the closer to the entrance, the mill will flow to . If the grindability of the grains is more difficult than of the clinker, the feed speed to the mill is required to decrease even more; if the grindability of the grains is lighter than the clinker, the feed rate to the mill is required to grow. When the grains are fed to the beginning of the mill with compressed air through a pipeline, the necessary velocity of the particles is provided by using 88 in the final section of the pipeline of the appropriate diameter. The relationship between the required particle velocity of the grain and the diameter of the pipeline for grain, made by industrial centrifugal separators of cement mills, was determined experimentally. With a pipeline diameter of 250 mm, the particle velocity is 0.5 m / s with a diameter of 100 mm 7.5 m / s, and with a diameter of 20 mm 25 m / s. By installing a pipeline of the appropriate diameter, a coarse adjustment of the feed rate of the grains to the mill is provided. In the process of grinding, due to fluctuations in the grinding of clinker and the operating mode of the separator, a periodic change in the number and average particle size of the grains is possible. With a change in the average size of particles of grit, the regulation of their supply to the initial part of the fine grinding zone is provided additionally by changing the compressed air flow rate of the pneumatic feed inversely proportional to the average particle size. With an increase in the average particle size, they are fed to the section of the mill close to its entrance, and when they decrease, to the section of the mill close to the exit from it. In the case of I31.1eni quantity. the grains supplied to the grinding in the mill, the flow rate of compressed air of the pneumatic feed vary directly in proportion to the quantity of the grain, i.e. as the amount of grains supplied increases by increasing the air flow rate, it is fed further along the length of the mill, and as it decreases, closer to the entrance to the mill. As a result, effective grinding of clinker in the free zone of the grains is provided, as well as optimal conditions for grinding the grains themselves.

Claims (1)

METHOD OF GRINDING CEMENT, incl. for grinding clinker with additives and grains separated in the separator in a tube mill by feeding clinker with additives into the coarse zone, and grains into the fine grinding zone, characterized in that in order to increase grinding efficiency, the grains are fed with compressed air to the fine grinding zone through the coarse zone, informing them at the entrance to the mill the initial velocity is 0.5-25 m / s, and the air flow rate is directly proportional to the quantity and inversely proportional to the average size of the grains. , SU ..., 1079288