JPS63291838A - Production of ultrafine powder from granulated slag - Google Patents

Abstract

PURPOSE:To enable reduction in power consumption and installation size by classifying fine powder in the first-stage milling into crude particles, fine particles and ultrafine particles and milling the fine particles into ultrafine particles in the second-stage milling. CONSTITUTION:The starting slag granules is subjected to the first-stage milling with crushing mill 3 and fine powder is collected. The fine powder is sent into silo 8 and stored. Most of the powder is taken out for mixing with cement. A part of the fine powder is fed to the primary classifier 15 and the fine powder from the bottom of the classifier 15 is sent back to mill 3 and silo 8 and milled again. In the meantime, the fine powder from the top of the classifier 15 is fed to the secondary classifier 17. A part of crude fine powder therefrom is crushed with the crusher 22 and sent back to the classifier 17. Ultimately, ultrafine powder is sent from the classifier 17 to collector 23 where the final product is collected. The exhaust gas from the collector is sent back to the crusher 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing ultrafine powder useful for glass cement, water-stopping agents, etc. using granulated blast furnace slag as a raw material.

[Conventional technology]

Conventionally, there have been two methods for producing ultrafine powder: ■ A method in which granulated blast furnace slag is directly crushed in an ultrafine mill to obtain ultrafine powder, and ■ A method in which granulated granulated blast furnace slag is further crushed to obtain ultrafine powder for use in cement admixtures. be.

[Problem that the invention seeks to solve]

However, in the method (2) above, since both fine powder with relatively large particle size and fine powder with small particle size are crushed, the crushing efficiency is low, power consumption is large, and cost is high. In addition, in the method (2), as in the case (2), particles with a coarse particle size are used as raw materials, resulting in high power consumption and large equipment capacity.

Therefore, the main object of the present invention is to provide a method for producing ultrafine powder that reduces the load on a crusher and reduces costs.

[Means for solving problems]

Means for solving the above problems and achieving the object of the present invention is that when producing ultrafine powder from granulated blast furnace slag, the granulated slag is first pulverized to obtain a fine powder, and then the fine powder is first classified. The fine powder obtained after removing coarse particles is sieved into ultra-fine powder and coarse-fine powder using a secondary classifier. It is characterized in that it is pulverized to produce ultrafine powder.

[For production]

In the present invention, after the granulated blast furnace slag is primarily pulverized, it is sieved by a secondary classifier, and the sieved product is further separated by a secondary classifier into relatively coarse fine powder and ultrafine powder that can be used as a product as it is,
Since only this coarse fine powder is subjected to secondary grinding using a grinding mill, the amount of secondary grinding is reduced, and therefore grinding efficiency is extremely improved, power consumption can be reduced, and equipment capacity can be reduced.

[Specific structure of the invention]

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows a specific example of the method of the present invention, which roughly consists of a first stage of a fine powder manufacturing process and a second stage of an ultrafine powder manufacturing process. In the figure, granulated slag as a raw material is first put into a hopper 1, then fed through a quantitative feeder 2 into a vertical roller mill 3 having a plurality of helical or conical rolls, where the granulated slag is primarily pulverized. The hot air from the hot air generating furnace 4 is carried by the hot air flow and sent to the collector 5 and exhausted by the fan 6, while the fine powder is collected. Next, this fine powder is introduced into a silo 8 by a conveyor 7, and after being stored once, most of it is transferred to a lorry car 9 as a product for use in cement mixtures, etc.
Then, it is carried out. A portion of the fine powder is discharged from the cut-out valve 10 and fed into the hopper 12 via the conveyor 11.

Next, a fixed amount is sent to the conveyor 14 by the fixed amount feed V-XS, and is supplied to a primary classifier 15 such as a dry air classifier that obtains airflow using a fan, and is subjected to negative classification. In this classification, it is preferable to classify based on 5 to 8 μm.

The coarse powder discharged from the bottom of the primary classifier 15 is returned to the vertical roller mill 3 and the silo 8 for re-pulverization treatment, while the fine powder discharged from the top of the -grade classifier 5 is processed using an elbow jet classifier, etc. is supplied to the secondary classifier 17. In the secondary classifier 17, the primary and secondary air from the fan 16 and fine powder are sent and classified while being carried on the air flow. A part of the fine powder thus obtained (coarse fine powder) is filtered into bag filter-1.
After passing through a hopper 19 having a 8-inch hopper 19, a metering feeder 20, and a conveyor 21, a crusher 22 such as a vertical roller mill performs secondary crushing, and then the raw material is returned to a secondary classifier 17. The ultrafine powder that has finally been ultrafinely divided is transferred from the secondary classifier 17 to the collector 23, where it is collected and made into an ultrafine powder that is a product.

Further, the exhaust gas from the collector 23 is returned to the crusher 22 by a fan 24.

In addition to the above-mentioned types, commercially available ones can be used as the secondary classifier 15 and the secondary classifier 17.

Next, the advantages of the present invention described above will be explained in more detail by comparing them with the conventional method using the processing flows shown in FIGS. 2 and 3. As shown in Figure 2, conventionally, when producing fine powder and ultra-fine powder from granulated slag, it was common to directly produce them from granulated slag using dedicated mills for fine powder and ultra-fine powder. there were.

That is, in FIG. 2(a), for example, granulated slag 100
0kg to average Blaine value s, ooo ultrafine powder 1000
kg, but in this case, the average power consumption (excluding classifier and fan power) was 82.4 KWH/l. Further, as shown in FIG. 2(b), the power used when producing 1000 kg of fine powder with a Blaine value of 4.210 from 1000 kg of granulated water was 28.4 WH/t. Therefore, in the conventional method, ultrafine powder and fine powder are prepared in a special mill, each with 1. The total power required to produce 1.0 tons of ultrafine powder and 1.0 ton of fine powder is 82.4 + 28.4 and 11 = 110.8.
KWl (was.

Next, in the method of the present invention, as shown in Fig. 3, 1,000 kg of granulated slag is first ground into fine powder (plain value -
200). The power consumption for this crushing is 28゜4
KWH/l. Next, this fine powder is classified into particle sizes of 7.8 microns or more and those smaller than 7.8 microns. Fine powder 615k with a particle size of 7.8μ or more
Assigning power consumption to g is 0.615t x 28.
4 H/1-17.47 H 1 ((A).Then, this fine powder was crushed again and the product had a Blaine value of 421.
0 mm615 kg was obtained. The power consumption at this time is 2
2.5KWH/lX0.615t=13.84KWH(
B). Therefore, the total power consumption in this fine powder production is 31.31KWH1 power consumption is 31.31K
WH10,615t = 50.91KWH/l.

On the other hand, 385 kg of fine powder 4 with a particle size of less than 7.8μ can be obtained, but the power consumption to obtain fine powder 1 (28.4 KWH/
When t) is allocated to the production of fine powder 4, the power consumption is 0.38
5t x 28.4KWH/l = 10.93 and H (
C). Next, this fine powder 4 is classified (secondary classification) into particles with a particle size of less than 2.8 μm and particles with a particle size of 2.8 or more. Ultrafine powder 5 is 92 as a product with a particle size of less than 2.8μ
kg was obtained. In addition, fine powder 6 with a particle size of 2.8μ or more is 293
kg was obtained, and this was crushed again in a small mill to obtain ultrafine powder 7 with a Blaine value of 8,000. The electric power for this re-shredding is 24.
Since it is 45KWH/l, the power consumption is 24.45KWH
/lxO,293t=7.16KIIH(D). Therefore, the power required to produce ultrafine powder is (C) + (D)
= 18.09KWH and the electricity consumption rate is 1B, 09KW
H10,385t = 46.99KWH/l.

Therefore, by the method of the present invention, ultrafine powder 1. The total power required to produce 1.0t of fine powder is 50.91 + 46.99K
WH=97.4KWH.

From the above, ultrafine powder 1. Ot, fine powder 1. It has been revealed that the total power consumption required for manufacturing Ot is 110.8 KWFl in the conventional method, while it is 97.9 KWH in the present invention, which is extremely low power consumption.

〔Effect of the invention〕

As described above, according to the present invention, only fine powder with a small particle size is passed through the pulverizer through primary classification and secondary classification, so the capacity of the pulverizer can be reduced, power consumption can be reduced, and related equipment can be made smaller. equipment costs become cheaper.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing a specific example of the method of the present invention, FIG. 2 is a process flow diagram of the conventional method, and FIG. 3 is a process flow diagram of the method of the present invention. 3... Grinding mill (vertical roller mill, etc.), 8... Silo, 15... Secondary classifier, 17... Secondary classifier, 2
2...Crusher, 23...Collector.

Claims (1)

[Claims] (1) When producing ultrafine powder from granulated blast furnace slag, the granulated slag is first pulverized to obtain a fine powder, and then the fine powder is classified and sieved using a primary classifier to remove coarse particles. The water is characterized in that the fine powder is sieved into ultrafine powder and coarse fine powder using a secondary classifier, the ultra fine powder is made into a product as it is, and the coarse fine powder is secondarily crushed using a grinding mill to produce ultra fine powder. A method for producing ultrafine crushed slag powder.