JPS5855098B2 - How to produce a set for portland cement from a discharged set - Google Patents

Description

[Detailed Description of the Invention] The present invention provides flue gas desulfurization Ceracola (hereinafter referred to as exhaust desulfurization Ceracola).
The present invention relates to a method for producing ceracola that further retards the setting of Portland cement.

Ceracola is generally used as a setting retardant for Portland cement (hereinafter referred to as cement), but the optimal amount of Ceracola for Portland cement varies depending on the chemical components of the cement, especially the 3CaO/Al2O3 content and fineness. When producing cement industrially, the amount of Ceracola added is considerably lower than this optimum amount.

The reason for this is that when the amount of Ceracola added to cement increases, when cement clinker and Ceracola are crushed in a crusher, Ceracola is dehydrated due to the heat generated and semi-hydrated Ceracola grows, resulting in false coagulation during cement irrigation. This is because such phenomena occur.

Therefore, in order to add Ceracola close to the optimum amount in terms of 803, it is possible to replace a part of Ceracola with ■-type anhydrous ceracolla in order to prevent the formation of semi-hydrated ceracolla. This is uneconomical because tank transportation equipment must be provided.

The inventors of the present invention have noticed that a large amount of removed Ceracola has been produced as a by-product in recent years, and have conducted various studies in an attempt to produce Ceracola suitable for cement use from this removed Ceracola.

Since the expelled ceracola is obtained as a wet powder, if it is not used as is, transportation and handling problems will occur.

Furthermore, if this were to be dried using the conventional method, a large amount of heat would be required and it would be uneconomical.

In order to avoid this, if you want to make Ceracola pellets by rapidly heating them in contact with high-temperature gas and drying them, making them semi-hydrated Ceracola and/or soluble anhydrous Ceracola, and then hydrating them to make Ceracola pellets, the crystal lattice can be formed by rapid heating. Since extremely irregular semi-hydrated ceracola and soluble anhydrous ceracola are formed, the rate of water utilization during granulation becomes extremely high, making it impossible to produce granules of a certain size.

Therefore, the inventors of the present invention have attempted to produce Ceracola for use as a retarder for cement, which can be added to cement to prevent the occurrence of false setting while avoiding the troubles mentioned above during granulation. The firing conditions were determined using the following equipment.

In the figure, the wet drained Ceracola is charged from the charging pipe 2 near the bottom of the firing furnace 1, which is a cylindrical or rectangular cylinder with a conical lower part. 3, the discharged Ceracola is instantaneously dried and dehydrated.

The dehydrated Ceracola then rises in the conduit 4 along with the high-temperature gas introduced, and is led to the cyclone 6 through the connecting pipe 5, where the low-phosphorus gypsum and gas are separated, and the Ceracola is discharged. The gas is collected through a pipe 7 and exhausted through an exhaust pipe 8.

As shown in the figure, the temperature of the high-temperature gas was varied in the ■ furnace, and the relationship between the amount of ■-shaped gas in the ceracola and the cyclone inlet temperature was tested for the collected burnt gas, and the results were as shown in Figure 2. I got it.

From this result, when the temperature of the high-temperature gas is set to 1000'C or higher and the moist drained Ceracola is baked, the temperature at the cyclone inlet increases as the temperature increases, and the amount of ■ type snails in the formed sintered snails increases. It is recognized that

Next, when the Cerakola obtained in this test was put into a granulator and granulated, the amount of ■-shaped gypsum in the baked gypsum was 10
〜40%, it can be granulated, and the granulated product has 30%
The strength after minutes was as follows.

The strength is the result of measuring granules with a diameter of 15 mm.

■Type Setsukola content (correspondence) in low phosphorus Setsukou 0.5 21.8 30.4 39.6 Compressive strength +; 7/c/? L 28.1 25.6 22.3 8.6 If the content of ■-type slag exceeds 40φ, the strength of the granulated product will decrease, which is undesirable.
This is undesirable because it reduces the effect of the mold on the cement.

The present invention is a method based on these findings, in which wet and depleted Ceracola is charged into a firing furnace and brought into direct contact with high-temperature gas to instantly dry and dehydrate the dehydrated Ceracola, resulting in low phosphorous Ceracola. In the recovery method, the temperature of the high-temperature gas is
~1300℃, and the temperature at the inlet of the grilled collector is 1.
A method for producing gypsum for Portland cement from expelled ceracola, which is characterized by adjusting the temperature to 60 to 290°C.

According to the present invention, 10 to
40%, and the remainder consists of semi-aqueous Ceracola and soluble ■-type Ceracola. As a result, it instantly dries and dehydrates and becomes a ■-type gypsum, but before the inside of the ceracola becomes a It is thought that this is because it becomes a mixture of Setsukou.

According to the present invention, it is possible to reduce the amount of phosphorus in a wet drained Ceracola using high-temperature gas in a short time, and the amount of gas per unit weight of Ceracola is reduced, so that the sintering equipment can be made smaller. Thermal energy efficiency also improves.

In addition, the produced low-phosphorus sessile can be easily granulated in the same way as in the case of conventional semi-hydrated Ceracola, and the granules are added to cement clinker in an excess amount compared to the case of conventional semi-hydrated Ceracola granules. The initial strength can be increased and the drying shrinkage of the cured product can be reduced.

Example: 9 pieces of free moisture were removed from Ceracola in a kiln (300 mm square, 4 m high) equipped with a conduit (300 mm square, 4 m high) in the same shape as the one used in the experiment.
At the same time, hot gas at 1100'C was charged at a rate of 1400 kp/hr to the bottom of a 500° square, 2 m high
The fired Ceracola was introduced into a collector (1.2 m in diameter and 2.5 m in height) with hot gas, and the temperature at the inlet of the collector was adjusted to 260°C. Low phosphorus snails were obtained from the collector.

30.2% of the ■-type setsukou among the ■-yaki setsukou obtained.
Hemihydrate Ceracola is s%, TNN type Ceracola is 64.8%, and can be easily granulated with a pan pelletizer, and the strength of the granulated product is 22.5 kg/cri on average when the diameter is 15 mm.
It was t.

The ceracola granulated in this way is pulverized with Portland cement clinker to prepare Portland cement, and the physical properties of this cement and the conventional cement (using only dihydric sessile, which does not contain ■ type sessile) The following results were obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the sintering system used in the low phosphorus test of the present invention. In addition, FIG. 2 graphically shows the results of the firing test.

Claims (1)

[Scope of Claims] 1. In a method for collecting Ceracola with low phosphorus content by introducing and dispersing wet and drained Ceracola into a high-temperature, high-velocity gas stream ejected from the lower part of a kiln, and instantly drying and dehydrating it. ,
A method for producing slag for Portland cement from discharged ceracola, characterized by adjusting the temperature of high-temperature gas to a range of 1000 to 1300°C and the temperature at the inlet of a scorching slag collector to 160 to 290°C. 2. Charge the moist drained Ceracola to the bottom of a cylindrical kiln with a conical lower part, and introduce high temperature gas from the bottom at a position lower than the Ceracola charging point to reduce the phosphorus content of the drained Ceracola. A method for producing slag for portland cement from the expelled ceracola according to claim 1.