DK2407244T3

DK2407244T3 - A process for the comminution of material with a tube mill

Info

Publication number: DK2407244T3
Application number: DK11166409.0T
Authority: DK
Inventors: Günter Guse
Original assignee: Thyssenkrupp Ind Solutions Ag
Priority date: 2010-06-16
Filing date: 2011-05-17
Publication date: 2015-10-12
Also published as: EP2407244A3; CN102284323A; EP2407244A2; DE102010017394A1; CN102284323B; ES2547335T3; EP2407244B1

Description

Method for comminution of material by a tube mill Description

The invention relates to a method for the comminution of grist with the aid of a tube mill, which has at least one first and at least one second grinding chamber and a central output as well as a separator.

Described in DE-A1-43 03 987 is a tube mill, which is characterized by a first grinding chamber configured as a deagglomeration drum and a plurality of further grinding chambers arranged sectionally and in parallel to the axis of rotation. Provided, according to one illustrative embodiment, between the deagglomeration drum and the sectional grinding chambers is a central output, which is connected to a separator. The grist is first added to the deagglomeration drum and then makes its way via the central output into the separator, whereby any coarse material is fed back to the sectional grinding chambers. This grinding method is characterized by a low overall energy requirement, because comminution work is assured at all times in the sectionally arranged grinding chambers. The respective "unbalance moments" in this tube mill are also minimized in any rotational position of the mill, which also contributes to reducing the specific energy requirement. DE 29 28 939 A1 describes a method for grinding different grists to their respective required grinding fineness, whereby neither the different grists, nor the gases in contact with the grists are mixed together. A rotary tube mill with two grinding chambers that are completely separate from one another finds an application here, whereby the rotary tube mill can also be a component part of a circulation-separator-grinding plant, whereby each of the grists that are discharged separately from one another from the two grinding chambers are supplied to a separate separator.

The invention has as its object to propose a method for the comminution of grist by means of a tube mill as well as a separator, which permits the more efficient grinding of at least one first and one second fresh goods component, whereby the first fresh goods component is easier to grind than the second, and the second fresh goods component is more abrasive than the first.

According to the invention, this object is accomplished by the characterizing features of Claim 1.

The method for the comminution of grist according to the invention uses a tube mill with at least one first and one second grinding chamber and a central output as well as a separator, whereby a. grist is used, which has at least one first and one second fresh goods component, whereby the first fresh goods component is easier to grind than the second, and the second fresh goods component is more abrasive than the first, b. the first fresh goods component is added to the first grinding chamber, where it is comminuted under the influence of grinding balls and is discharged via the central output, c. the grist discharged from the first grinding chamber is supplied to the separator, d. the second fresh goods component together with coarse material from the separator is supplied to the second grinding chamber, where it is ground under the influence of grinding balls and is discharged via the central output, e. the grist discharged from the second grinding chamber is supplied to the separator, and f. the fine material from the separator is extracted in the form of a finished product.

This method can be used advantageously in particular for the manufacture of cement. The grist required for this purpose as a rule contains a relatively large proportion of relatively easy-to-grind limestone (first fresh goods component) and a smaller proportion of relatively hard-to-grind sand (second fresh goods component).

The limestone is usually pre-comminuted in so-called material bed roller mills and in the process forms agglomerates. The sand component, for example granulated blast furnace slag, already has a fine-grained structure at the point of entry into tube mills and is usually added to the first grinding chamber together with the limestone component. Because of its smaller granulation, this second component arrives at the central output without significant comminution and is supplied from there to the separator, where it is separated out as a coarse material and is added to the second grinding chamber for comminution. In the previous grinding method, the second grinding component passes through the separator for the first time without being subjected to substantial grinding. Nevertheless, it does cause corresponding wear to the separator.

This is prevented by the separate addition, according to the invention, of the second fresh goods component into the second grinding chamber, and in this way the second fresh goods component is already subjected to effective comminution in the course of its first passage through the grinding chamber, before it arrives at the central output and is supplied to the separator. The circulation factor for the second fresh goods component is reduced, and the total wear is minimized, in this way, with the result that the milling is more efficient.

It is already known in tube mills with two grinding chambers for aggregates, such as gypsum, to be added directly to the second grinding chamber, although in this case the fresh goods component is not a more difficult-to-grind and more abrasive material in the sense of the invention.

Further embodiments of the invention are the subject-matter of the dependent claims.

According to a further embodiment of the invention, grinding balls which are made of different materials are used in the first and second grinding chambers. In particular metal grinding balls, in particular steel balls, are thus able to find an application in the first grinding chamber, and non-metal grinding balls, in particular ceramic balls in the second grinding chamber.

If the method for the manufacture of cement is used, in particular calciferous material is added to the grinding chambers as the first fresh goods component, and sand is added as the second fresh goods component.

It is particularly advantageous in the manufacture of white cement for ceramic balls to be used in the second grinding chamber, since these do not cause the abrasion of iron and chromium that is prejudicial to the end product in the course of the grinding operation. The grinding operation in the first grinding chamber, in which steel balls are used, is comparatively small in its extent and accounts for less than approx. 30 % of the entire grinding capacity. Since only the easier-to-grind fresh goods component is added in the first grinding chamber, the abrasion of iron and chromium caused at that point remains within limits. The more abrasive and more difficult-to-grind fresh goods component is added directly to the second grinding chamber and thus comes into contact only with the ceramic balls, of which the abraded material consists predominantly of silicon and does not contain any iron or chromium.

It has emerged in the course of the trials on which the invention is based that particularly efficient comminution can be achieved if the grinding balls that are used in the first grinding chamber have a weight of at least 1.8 times that of the grinding balls of the second grinding chamber.

It is further proposed that the grinding balls that are used in the first grinding chamber have a diameter of at least 1.0 times that of the grinding balls of the second grinding chamber. Furthermore, the weight ratio of the first to the second fresh goods component preferably lies within a range of 80-95 %.

Further embodiments and advantages of the invention are explained in more detail on the basis of the following description and the drawing. A plant for the implementation of the method according to the invention is illustrated schematically in the drawing. This consists essentially of a tube mill 1 having a first grinding chamber 2 and a second grinding chamber 3 as well as a central output 4. A separator 5 is also provided. Each of the two grinding chambers 2, 3 has suitable feed devices for adding a fresh goods component 6 into the first grinding chamber 2 or a second fresh goods component 7 into the second grinding chamber 3. The central output 4 is connected to the separator 5 via a suitable conveyor device 8, for example a bucket conveyor, which may be a dynamic separator.

The fine material 9 from the separator 5 is extracted in the form of a finished product, whereas the coarse material 10 is supplied to the second grinding chamber 3 together with the second fresh goods component 7. Only a small proportion of the coarse material can be assigned to improve the flow characteristics and the level control of the first grinding chamber 2, as indicated by the broken line.

Grinding balls are present in both grinding chambers, whereby steel balls are used in the first grinding chamber and ceramic balls are used in the second grinding chamber. During operation, the first fresh goods component 6 is added to the first grinding chamber 2, where it is comminuted by contact with the steel balls and then makes its way via the central output 4 and the conveyor device 8 into the separator. The coarse material 10 from the separator 5 is added to the second grinding chamber 3 together with the second fresh goods component 7. The material that is comminuted there likewise makes its way via the central output 4 and the conveyor device 8 into the separator 5, where it is separated into finished material 9 and coarse material 10.

In the manufacture of cement, in particular white cement, calciferous material as the first fresh goods component 6 and sand as the second fresh goods component 7 are supplied to the grinding chambers 2 and 3. The more difficult-to-grind and more abrasive sand thus comes into contact only with the ceramic balls that are present in the second grinding chamber 3. The principal comminution takes place in this grinding chamber, which occurs predominantly as attrition grinding. The material abraded from ceramic balls substantially consists of silicon and contains no iron or chromium, which would be prejudicial to the manufacture of white cement.

The separated fresh goods components thus not only ensure more efficient grinding, but also permit the highly advantageous manufacture of white cement.

Claims

A method of comminuting paint by means of a tube mill (1) having at least a first and at least a second painting chamber (2, 3) and a central outlet (4) and a separator (5), wherein a. and a second baggage component (6, 7) is used, whereby the first baggage component (6) is easier to grind than the second, and the second baggage component (7) is more abrasive than the first, b. the first baggage component (6) is fed to it. first grinding chamber (2) is comminuted under the influence of grinding balls and discharged via the center outlet (4), c. The grinding material discharged from the first grinding chamber (2) is fed to separator (5), d. 10) from the separator (5) is fed to the second grinding chamber (3), comminuted under the influence of grinding balls and discharged via the center outlet (4), e. material (9) from the separator (5) is extracted as f honest product.

Method according to claim 1, characterized in that paint balls made of different materials are used in the first and second paint chambers (2, 3).

Method according to claim 2, characterized in that metal grinding balls, especially steel balls, are used in the first grinding chamber (2) and non-metallic grinding balls, especially ceramic balls, are used in the second grinding chamber (3).

Method according to claim 1, characterized in that calcareous material is applied to the grinding chambers (2, 3) as the first fresh material component (6) and sand is applied as the second fresh material component (7).

Method according to claim 1, characterized in that grinding balls weighing at least 1.8 times the weight of the grinding balls in the second grinding chamber (3) are used in the first grinding chamber (2).

Method according to claim 1, characterized in that grinding balls having a diameter of at least 1.0 times the diameter of the grinding balls in the second grinding chamber (3) are used in the first grinding chamber (2).

Process according to claim 1, characterized in that the weight ratio of the first to the second fresh goods component (6, 7) is in the range of 80% to 95%.