JPH03218952A - Method for producing granulated slag powder - Google Patents

Abstract

PURPOSE:To obtain powder of water granulated slag having high hydraulic property with low consumption of electric power by predrying water granulated slag to a specified water content or below, crushing and drying the predried slag with a roller mill having drying function. CONSTITUTION:Water granulated slag is predried to <=10wt.% water content, crushed and dried with a roller mill having drying function. When triethanolamine, diethanolamine or diethylene glycol is added to the predried water granulated slag and this slag is crushed and dried with the roller mill having drying function, the consumption of electric power at the time of crushing is effectively reduced and the hydraulic property of the resulting powder of water granulated slag is effectively improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing granulated slag powder using a roller mill, and more specifically, it relates to a method for producing granulated slag powder with low power consumption and high hydraulic hardness. Relating to a method of manufacturing.

[Conventional technology]

Granulated slag powder is obtained by pulverizing blast furnace slag, which is a by-product when producing pig iron in a blast furnace, by quenching and crushing it with water, and is widely used as a hydraulic material such as a mixed material for blast furnace cement. It is being

Tube mills and roller mills are used to grind granulated slag, but roller mills are superior in terms of power consumption and the ability to dry and grind at the same time, and have been widely developed in recent years. (Unexamined Japanese Patent Publication No. 62-216, 6
49, JP-A-63-166, 444).

[Problem to be solved by the invention]

However, when the present inventors investigated the hydraulic properties of granulated slag powder crushed with a roller mill and granulated slag powder crushed with a tube mill, they found that using granulated slag with the same component composition as raw materials, the hydraulic properties were the same. It was found that when ground to a Blaine specific surface area of

Therefore, the present inventors conducted intensive research to solve such problems and found that when producing granulated slag powder using a roller mill, the water content of the granulated slag used as a raw material during pulverization is The present invention was completed based on the discovery that power consumption is closely related to the hydraulic properties of granulated slag powder.

An object of the present invention is to provide a method for producing granulated slurry powder with high hydraulic hardness with low power consumption.

[Means to solve the problem]

That is, the present invention is a method for producing granulated slag powder, which is characterized in that granulated slag is pre-dried to a water content of 10% by weight or less, and then pulverized and dried using a roller mill with a drying function. Furthermore, the present invention is characterized in that after pre-drying the granulated slag to a water content of 10% by weight or less, triethanolamine, diethanolamine or diethylene glycol is added, and the granulated slag is pulverized and dried using a roller mill having a drying function. This is a method for producing granulated slag powder.

The present invention will be explained in detail below.

The granulated slag used in the present invention is made by quenching and crushing molten blast furnace slag, which is a by-product when producing pig iron in a blast furnace, with water, and contains components such as calcium oxide, silicon dioxide, aluminum oxide, and magnesium oxide. contains. This material is pulverized, dehydrated, piled up outdoors, stored, and used one after another. Therefore, when used, it contains more than 10% water.

In the present invention, the granulated slag is predried to a moisture content of 10% by weight or less, preferably 5 to 10% by weight, and then pulverized and dried using a roller mill having a drying function. If the moisture content of the pre-dried granulated slag is high, the hydraulic properties of the obtained granulated slag powder will decrease, and if it is too low, the power consumption during pulverization will tend to increase. Also, if triethanolamine, diethanolamine or diethylene glycol is added when crushing pre-dried granulated slag,
The power consumption during pulverization is reduced, and the hydraulic properties of the resulting granulated slag powder are improved. In addition, when grinding with the addition of triethanolamine, diethanolamine or diethylene glycol, the water content of the granulated slag is 2 to 2.
Pre-drying to IQ weight % is preferred.

Drying of the granulated slurk' can be done using a normal dryer such as a rapid dryer or rotary dryer.

Roller mills used to grind pre-dried granulated slurry include vertical centrifugal force roller mills and vertical spring roller mills, which are equipped with an air classifier inside the machine, and classify while blowing warm air or air into the mill. , pulverization, and drying methods, and those described in JP-A-63-166,444 and JP-A-62-2T6,649 can be used. Normally, when grinding raw materials with a high moisture content, drying can be performed simultaneously with the grinding by blowing hot air into the mill.

In the present invention, pre-dried granulated slag is pulverized, so depending on the degree of pre-drying, it can be pulverized while blowing cold air at a temperature of 70°C or less, or it can be pulverized while blowing hot air.

The granulated slag powder obtained by the present invention has a characteristic that the loss on ignition is small and the pH of the liquid dispersed in water is high. usually,
Loss on ignition at 700°C is 0.5% by weight or less, preferably 0
．． It is 3% by weight or less. Further, the pH of a liquid obtained by dispersing 10 parts by weight in 100 parts by weight of distilled water is 1) or higher.

This loss on ignition and pI-{ are closely related to the calcium carbonate content derived from water in the granulated slag and carbon dioxide in the pulverizing atmosphere. Crushed slag powder has low hydraulic properties.

The granulated slag powder obtained by the present invention has high hydraulic properties and is suitable as a raw material for slag cement. Examples of slag cement include blast furnace cement obtained by blending with talinkar powder and gypsum, and slag cement obtained by blending hardening stimulants such as alkali metal and alkaline earth metal hydroxides, carbonates, and silicates. Yes, when used as a binding material for mortar or concrete, a molded product with high strength can be obtained.

[For production]

According to the findings of the present inventors, when pulverizing granulated slag with a moisture content of more than 10% by weight using a roller mill, if the granulated slag is pulverized while being dried by blowing hot air into the mill, the water content in the granulated slag will be reduced. The action of this and the carbon dioxide gas in the hot air generates calcium carbonate crystals that have no hydraulic properties, reducing the hydraulic properties of the granulated slag powder. However, if the water content in the granulated slag is pre-dried to 10% by weight or less and the granulated slag is pulverized, even if combustion exhaust gas with a high carbon dioxide concentration is used as the hot air, the hydraulic properties will decrease. The degree of is small.

〔Example〕

Examples of the present invention will be described below.

Example 1 Dry granulated slag with a basicity of 1.85 and a water content of 12% by weight was dried using a dryer at a temperature of 1) 0°C to reduce the water content to about 0% by weight. Using a Roche type roller mill, the Blaine specific surface area was reduced to approximately 4,000 cr while blowing air at a temperature of approximately 20°C.
The granulated slag powder of the present invention was obtained by pulverizing the powder under conditions of t/g or approximately 6.000 ci/g.

In addition, as a comparative example, granulated slag with a water content of 12% by weight was prepared using a Roche type roller mill, and while blowing hot air at a temperature of 130 to 150°C with a carbon dioxide concentration of 1%, the Blaine specific surface area was increased to approximately 4,000 cnf. /g or about 6,
The granulated slag powder was pulverized under the conditions of 000cnf/g to obtain granulated slag powder.

Blaine specific surface area 3 for each 50 parts by weight of granulated slag powder
, 47 parts by weight of clinker powder of 200 crl/g and 3.5 parts by weight of gypsum trihydrate were mixed to make blast furnace cement B.
A seed was produced, and a mortar strength test of the obtained blast furnace cement type B was conducted according to JIS-R5201.

The loss on ignition of each granulated slag powder, the pH of the liquid obtained by stirring 10 parts by weight of each granulated slag powder with a stirrer for 60 minutes in 100 parts by weight of distilled water, and the age of each blast furnace cement B type from 3 days to 28 days.
Indicates the mortar compressive strength in days.

Table 1 Example 2 Granulated slag with a water content of about 15% by weight was dried using a dryer at a temperature of 1) 0°C to reduce the water content to 0%, 4.8%, 8. Dry granulated slag containing 7% by weight, 9.5% by weight or 12.1% by weight is heated using a Roche type roller mill by blowing hot air at a temperature of 130 to 150°C until the Blaine specific surface area is approximately 9,000c.
The granulated slag powder of the present invention was obtained by pulverization under the conditions of nf/g.

A type B blast furnace cement was produced in the same manner as in Example 1, and a mortar strength test was conducted.

Table 2 shows pre-dried granulated slag (dried granulated slag).
Moisture content, ignition loss of granulated slag powder and distilled water 10
The pH of the liquid obtained by stirring and dispersing 10 parts by weight of 0 parts by weight with a stirrer for 60 minutes and the mortar compressive strength at 3 and 7 days of age for each blast furnace cement type B are shown.

Table 2 Example 3 Granulated slurry with a moisture content of 12% by weight was dried using a dryer at a temperature of 1) 0°C to reduce the moisture content to approximately 9%.
Dry granulated slurry made into % by weight was processed using a Rossier-type roller mill, using triethanolamine as a grinding aid and blowing air at a temperature of 130 to 150°C, roller pressing force 4.7 t/roller, feed amount 70 kg. /
time, table rotation speed 60 times/min, separator rotation speed 1
, 250 times/min, and an air flow rate of 1) m/min to obtain granulated slag powder.

Blast furnace cement type B was produced in the same manner as in Example 1, and a mortar strength test was conducted.

The amount of triethanolamine (TEA) used per 100 parts by weight of pre-dried granulated slag, the Blaine specific surface area of each granulated slag powder, the loss on ignition, and 10 parts by weight per 100 parts by weight of distilled water using a stirrer. Table 3 shows the pH of the dispersed liquid after stirring for 60 minutes and the mortar compressive strength of each type B blast furnace cement.

These results show that granulated slag powder produced with triethanolamine added as a grinding aid has the same hydraulic hardness as granulated slag powder produced without using a grinding aid, even though the Blaine specific surface area is small. It turns out that it has.

Table 3 [Effects of the Invention] According to the present invention, granulated slag powder with high hydraulic hardness can be produced using a roller mill with less power consumption.

Claims (3)

[Claims] (1) A method for producing granulated slag powder, which comprises pre-drying granulated slag to a water content of 10% by weight or less, and then pulverizing and drying it using a roller mill with a drying function. (2) A method for producing granulated slag powder, which comprises pre-drying granulated slag to a moisture content of 5 to 10% by weight, and then pulverizing and drying it using a roller mill with a drying function. (3) Granulated slag characterized by pre-drying the granulated slag to a moisture content of 10% by weight or less, adding triethanolamine, diethanolamine or diethylene glycol, and pulverizing and drying using a roller mill with a drying function. Method for producing slag powder.