JPH03170353A - Production of high-strength cement - Google Patents

Abstract

PURPOSE:To enable coexistence of cement with gypsum having different melting rates by feeding the total amount or part of dihydrate gypsum fed into a closed circuit to a pulverization chamber on the discharge side of a mill or a place between the discharge port of the mill and an inlet of a separator. CONSTITUTION:A clinker is pulverized. In the process, the total amount or part (>=50% based on the total amount) of dihydrate gypsum to be fed is fed to a pulverization chamber on the discharge side of a mill or a place between the discharge port of the mill and an inlet of a separator. Thereby, the residual dihydrate gypsum and the clinker are fed to the pulverization chamber on the feed side of the mill to perform pulverization in a closed circuit. As a result, hemihydrate gypsum having a high dissolution rate, etc., and dihydrate gypsum having a low dissolution rate can be made to coexist in the resultant cement to produce the objective high-strength cement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field] The present invention relates to a method for producing high-strength cement, and in particular to an improved method for supplying and removing gypsum dihydrate during the grinding of clinker for cement. It is.

[Conventional technology J In order to produce cement from talin mill (hereinafter referred to as talinka), a multi-chamber tube mill (often has two chambers) and a separator to classify and separate the cement from this mill are required. Along with Tarinka, Sekigyo is also supplied to the Supply Unit of the Niiki Mill for closed F-way pulverization, and by-product gypsum such as expelled gypsum is often used as gypsum, and these gypsum are mainly It is gypsum dihydrate.

Gypsum with a high dissolution rate in cement (e.g. hemihydrate gypsum)
When gypsum with a low dissolution rate (for example, dihydrate gypsum) coexists, the workability (mobility) of high-strength concrete improves, and the strength development property also improves.

However, according to the conventional method, when dihydrate gypsum is supplied to the feed port of a mill along with the talin force, the dihydrate gypsum is affected by the impact caused by the hard poles of the grinding media in the mill and by the effects of high temperature. As the parts are finely crushed, they become hemihydrate gypsum or a structure similar to hemihydrate gypsum, that is, have a high dissolution rate, and this can lead to major negative effects on quality such as occurrence of false setting and decreased workability.

As a method for producing cement that does not use dihydrate gypsum, which has the above-mentioned drawbacks during pulverization using Talin force, for example, JP-A-57-
Publication No. 205346 discloses a method using insoluble anhydrite or sulfite lime, but it has the disadvantage that it is difficult to use manually and is special compared to the general dihydrate stone. [Problems to be Solved by the Invention] The present invention solves the shortcomings and points of the above-mentioned prior art, and creates a high-strength concrete that can improve the workability of high-strength concrete and improve the strength development while using dihydrate gypsum. Chino is trying to provide a method for producing cement.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a method for producing cement by crushing tarinka for cement in a closed circuit using a multi-chamber tube mill and a separator. All or part of the dihydrate gypsum to be supplied is supplied to the discharge-side crushing chamber of the mill, or between the discharge port of the mill and the inlet of the sebarator, and the remainder of the dihydrate gypsum is supplied to the supply side of the mill. The present invention provides a method for producing high-strength cement, which is characterized in that it is supplied to a grinding chamber.

[Function] In the present invention, the total amount or a portion of dihydrate gypsum (preferably 50% of the total amount) supplied when pulverizing tarinka is used.
% by weight or more) is supplied to the mill discharge-side grinding chamber or between the mill discharge port and the separator inlet. When a portion of the dihydrate gypsum is fed as described above, the remaining dihydrate gypsum is fed to the feed port of the mill along with the talin force.

By supplying water gypsum to the discharge-side grinding chamber of the mill, the above-mentioned effects on dihydrate gypsum are reduced compared to conventional methods, and it remains as dihydrate gypsum, resulting in a faster dissolution rate in the manufactured cement. It is possible to coexist with gypsum, which has a high rate of decomposition, and stone blindness, which has a low rate of decomposition.

When pulverizing tarinka, the temperature of the pulverized product at the mill outlet generally reaches 100-140°C, so
When gypsum dihydrate is supplied from the outlet of the mill to the inlet of the separate lake, which also serves as a cooler for the cement,
Part of the gypsum dihydrate is changed by the heat contained in the crushed product, and the same effect as when supplied to the crushing chamber on the discharge side of the mill can be obtained. When gypsum dihydrate is to be supplied between the outlet of the mill and the inlet of the separator, it is desirable that the gypsum has a small amount of adhering moisture and is thin.

Whether the supply position of dihydrate gypsum is to be placed in the discharge-side crushing chamber of the mill or between the mill discharge port and the separator inlet, and the amount of dihydrate gypsum supplied to this position is the total amount of dihydrate gypsum to be added. Whether it is used or not is determined appropriately depending on the temperature of the talin force used, the fineness of the cement to be manufactured, the swampiness of the pulverized product of the mill, the moisture content of the dihydrate gypsum used, the coarseness, etc.

The form of gypsum in the cement produced by the present invention, for example, dihydrate gypsum, hemihydrate gypsum, and the amount present are
Observation can be made by line diffraction, preferably by diffraction of the salicylic acid methanol treatment residue of cement.

Furthermore, in addition to dihydrate gypsum, type II anhydrite can be used to provide the same actions and effects as dihydrate gypsum.

[Jitsugo J Example 1 A closed-circuit grinding device consisting of a two-chamber multi-chamber tube mill and a separator for classifying the grinding product of the mill is used, and talin force is supplied to the grinding chamber on the supply side of the mill, and the discharge of the mill is Cement was produced by blowing and supplying gypsum, a by-product of waste removal, as dihydrite into a side crushing chamber with compressed air. The SO3 content of cement is 2.0% by weight, and the particle size is 3400 crn in Blaine value.
The target was '/g.

The manufactured cement was used as coarse aggregate using No. 5 crushed stone from Ryogami (specific gravity 2.67, roughness rate 6.9 2 1) and No.
The same weight of crushed stone (specific gravity 2.69, coarse grain ratio 6.21) was mixed and used, and Kisarazu mountain sand (specific gravity 2.61.
Granule rate 2. Using 9 6 1, the unit cement amount is 4
50kg/rn', high performance water reducing agent "Mighty 150"
J (manufactured by Kao Corporation) was added at a rate of 1.2% by weight based on the cement, and the concrete was kneaded and formed with a target slump value of 10 cm.

The compacts were subjected to steam curing (t70''C, 3 hours) and standard water curing (28 days), and then the compressive strength was determined by i'.

As Comparative Example 1, the entire amount of trihydrate was supplied to the mill {I11
The test was carried out in the same manner as in Example 1, except that the cement was supplied to the crushing chamber.The cement according to Example 1 showed a small hemihydrate-containing peak and an obvious dihydrate H peak in X-ray diffraction. On the other hand, in Comparative Example 1, only the peak of gypsum hemihydrate was detected.

The results of the concrete test are shown in Table 1.7 Note that when using the same cement ratio, the cement according to Actual Example 1 had better slump development than the cement according to Comparative Example 1.

Example 2 Using the same closed-circuit crushing device as used in Practical Example 1, removed dihydrate gypsum with less adhering moisture was used, and the entire amount was placed between the mill outlet and the separator. Cement was produced by supplying it to the bottom of a packed elevator. The SOa content of the cement was set at 2.0% by weight, and the particle size was set at a Blaine value of 3350 crn'/g. Concrete tests were conducted on the manufactured cement in the same manner as in Example 1.

As Comparative Example 2, a test was carried out in the same manner as in Example 2, except that the entire amount of gypsum dihydrate was supplied to the supply-side crushing chamber of the mill.

In the cement according to Example 2, a small peak of gypsum hemihydrate and a large peak of gypsum dihydrate were detected in X-ray diffraction, whereas in the cement according to Comparative Example 2, only a peak of gypsum hemihydrate was detected.

The results of the concrete test are also listed in Table 1.

[Effects of the Invention] According to the present invention, it is possible to coexist in cement, for example, gypsum hemihydrate, which has a fast dissolution rate, and gypsum dihydrate, which has a slow dissolution rate, thereby making it possible to manufacture high-strength cement. Ta.

Out wish teenager Reason People Mitsubishi Mining Cement Co., Ltd.

Claims (1)

[Claims] 1. When manufacturing cement by pulverizing clinker for cement in a closed circuit using a multi-chamber tube mill and a separator, all or part of the dihydrate gypsum supplied into the closed circuit is pulverized on the discharge side of the mill. A method for producing high-strength cement, characterized in that the gypsum dihydrate is supplied between a chamber or an outlet of the mill and an inlet of the separator, and the remainder of the gypsum dihydrate is supplied to a grinding chamber on the feed side of the mill.