JP2587486B2 - Manufacturing method of cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a high-grade cement which can exhibit high strength, and is excellent in water tightness and excellent suppression of alkali-aggregate reaction.

[Prior Art] A conventional method for producing cement will be described with reference to FIG.

Coal stone 1, clay 2 and slag 3 such as ferric oxide stored as raw materials in the raw material storage site 4 are dried in the raw material drying plant 5 and then pulverized by the raw material pulverizer. Sorted upper raw material silo and blending silo 7
The mixture is sent to the rotary kiln 10 through a suspension preheater heated by the exhaust gas of the rotary kiln 10 and is sent to the rotary kiln 10 and calcined in a semi-molten state with the coal treated by the coal drying and crushing machine 11 as an auxiliary fuel. It is processed by an attached cooler to become a clinker, and further gypsum 12 is added at a storage place 13.

This mixture of clinker and gypsum is pulverized by a finishing pulverizer 14 and stored in a cement silo 15 to be used as a product cement 16.

[Problems to be solved by the invention]

The cement manufactured by the above-mentioned conventional method has a particle size of 1 to 100 μm (average of 10 to 20 μm), and therefore requires an admixture for high strength development, improvement of water tightness and control of alkali aggregate reaction. In addition, there is a problem that the construction procedure differs depending on the admixture used.

An object of the present invention is to provide a method for producing cement that can solve the problems of the conventional method as described above.

[Means for solving the problem]

The present invention provides a cement production method for producing a product cement by pulverizing and mixing lime, silica, alumina and ferric oxide, and firing and clinking the clinker obtained in a semi-molten state together with gypsum to produce a product cement. A part of the raw materials including the raw material is heated to a temperature higher than the boiling point of silica to generate silica vapor and then cooled to obtain amorphous silica ultrafine particles. It is characterized by being mixed.

(Operation)

In the present invention, the silica vapor is solidified by heating a part of the raw material containing silica to a temperature higher than the boiling point of the silica and cooling it by blowing a cooling gas or the like. Is obtained.

By mixing the ultrafine silica particles with the mixture of the clinker and the gypsum after the finish pulverization treatment, a cement containing the ultrafine particles of amorphous silica can be obtained.

The cement produced in this manner exhibits high strength due to the high reactivity of the amorphous silica and has a function of suppressing the alkali bone reaction. In addition, by mixing ultra-fine particles of non-crystalline silica, high strength and high water tightness are exhibited, and mixing of an admixture is not required in the construction process.

〔Example〕

A first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, limestone 1 as a raw material of lime, clay 2 as a raw material of silica, slag 3 as a raw material of alumina and ferric oxide are stored in respective raw material storage sites 4, The raw material is dried in each raw material drying station 5, crushed by a raw material crusher 6, separated by an air separator 8 and stored in a raw material silo 7 ′. After adjusting the mixing ratio of each raw material in the raw material silo 7 ', the raw material is passed through an air blending silo 7 ", fired in a semi-molten state by a rotary kiln 10 having a suspension preheater, and cooled by a cooler attached thereto. The clinker is stored in the storage 13 where the gypsum 12 is mixed with the clinker. The coal 9 is supplied to the rotary kiln 10 as fuel through a lime drying and crushing machine 11.

In this embodiment, a part of the clay as the silica raw material is processed by the high-temperature processing unit 23. That is, the raw material silo 7 '
A part of the clay that has exited is supplied as a silica raw material 2 'to a high-temperature processing furnace 20 having O ₂ or O ₂ -enriched air equipment, and is heated in the furnace 20 to a temperature higher than the boiling point of silica to generate silica vapor. By cooling with the upper cooling gas and collecting by the ultrafine particle collecting device 21, amorphous silica ultrafine particles having a particle size of 0.3 μm or less can be obtained, and amorphous silica slag in the processing furnace 20. Is obtained. The non-crystalline silica slag 17 is mixed with a mixture of clinker and gypsum in front of the finishing pulverizer 14 and finish pulverized, and the amorphous silica ultrafine particles 22 having a particle size of 0.3 μm or less are subjected to finish pulverization. It is mixed with the material leaving the machine 14 and sent to the cement silo 15.

Further, the exhaust gas from the processing furnace 20 that has exited the ultrafine particle recovery device 21 is blown into the rotary kiln 10, and the exhaust heat thereof is recovered.

Note that the rotary kiln 10 is blown with hot air of, for example, 300 to 350 ° C. and burns lime to raise the internal temperature to 1400 to 1500.
C., a clinker raw material having an average particle size of 30 mm or less is obtained, and this is pulverized by a finishing pulverizer to obtain a mixture of clinker, gypsum and amorphous silica slag having an average particle size of about 40 μm.

The high-temperature processing furnace 20 and the ultrafine particle recovery device 22 in the high-temperature processing section 23 will be described below with reference to FIG.

A part of the above silica material 2 ′ of the clay is conveyed by oxygen or oxygen-enriched air C from O ₂ or O ₂ -enriched air equipment 19 and blown into a high-temperature treatment furnace 20 from a pipe 31 to Pulverized coal fuel A is blown from the enclosed manifold 32, and the boiling point of SiO ₂ (2230 ° C.) in the processing furnace 20 made of a cooling jacket
Combustion at the above temperature of about 2500 ℃.

In the processing furnace 20, a high-temperature combustion occurs by forming a flame D,
It becomes vapor E of mineral substance mainly composed of SiO ₂ in clay,
The gas is guided to the outside-furnace duct 40 together with the combustion gas. At this time, on the inner wall of the processing furnace 20, the mineral substance which is the non-evaporable component (Al ₂ O ₃ , CaO, etc.) in the clay and a part of SiO ₂ not reaching the boiling point are melted and adhered to form a heat insulating layer 36, Keep high temperature inside. At this time, the non-evaporated portion is melted and falls along the furnace wall, becomes amorphous silica slag 17, is cooled and crushed by the cold water V in the lower water tank 38, and is taken out from the outlet 39 as small pieces 17 ',
As described above, it is sent to the front (upstream side) of the finishing crusher 14 and is mixed with the mixture of clinker and gypsum.

On the other hand, the fuel gas containing the vapor E mainly composed of SiO ₂ is mixed with the air F blown out from the cooling air nozzle 41 provided at the outlet of the furnace, and the temperature is reduced to 400 ° C. at a stroke.

In the combustion gas G thus cooled, the mineral substance vapor solidifies, and at this time, non-crystalline fume H mainly composed of ultrafine SiO ₂ is generated. The combustion gas G containing the fume H is guided to a bag filter 44 of an ultrafine particle recovery device 22 provided at the rear of the duct 40, and the fume H is collected as ultrafine particles 22 of amorphous silica, and Type valve
It is removed by 45 and mixed with the material exiting finish crusher 14 as described above. The combustion gas from which fume H has been removed is supplied to the rotary kiln 10 by the fan 36 through the exhaust duct 37.

Experimental results show that SiO ₂ : 66%, Al ₂ O ₃ : 13.9%, other Fe ₂ O ₃ ,
From the clay containing CaO, MgO, etc., ultrafine amorphous silica particles having an average particle diameter of 0.3 μm or less as a main component of SiO ₂ can be produced, and SiO ₂ : 53.9%, Al ₂ O ₃ : 31.2 %, Fe ₂ O ₃ : 7.9
%, Other amorphous silica slag consisting of CaO and MgO was obtained.

In the present embodiment, as described above, a part of the clay as the silica raw material is processed by the high-temperature processing section 32, and the amorphous silica slag generated in the high-temperature processing section 23 is clinker and plastered by the finish crusher 14. Average particle size with mixture of 40μ
0.3 μm obtained in the high-temperature processing section 23
By mixing ultrafine particles of amorphous silica having a particle size of m or less, a cement containing a high content of amorphous silica can be obtained. Since amorphous silica has high reactivity, high strength can be exhibited and a function of suppressing alkali-aggregate reaction can be imparted to cement.

In addition, in the manufactured cement, ultra-fine particles of amorphous silica are mixed, and in the manufactured cement, high strength and high watertightness are expressed, and also, an admixture is mixed in the cement working process. Eliminates the need.

Furthermore, the production cost can be reduced by introducing the high-temperature exhaust gas 18 generated in the high-temperature processing furnace 20 from which the silica ultrafine particles are separated into the rotary kiln 10 for heat recovery. The fuel for the high-temperature processing furnace 20 is coal or gas (LNG, LP) as fuel in a cement plant.
G, COG, etc.) and heavy oil.

 A second embodiment of the present invention will be described with reference to FIG.

In this embodiment, limestone 1, clay 2 and slag 3 are supplied to a raw silo 7 'through a common raw material storage 4, a raw material dryer 5, a raw material crusher 6, and an air separator 8, and the raw silo 7'
A portion of the limestone, clay and slag 3 coming out of the furnace is used as a silica raw material 2 ', and a high-temperature treatment section similar to that in the first embodiment.
23, except that the remainder is supplied to the rotary kiln 10 via the air blending silo 7 ".

In FIG. 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals.

Also in this example, as in the first example, the particle size is 0.
Ultra-fine particles 22 of amorphous silica of 3 μm or less and amorphous silica slag 17 are obtained in the high-temperature processing furnace 20 and the ultra-fine particle recovery device 21.
Behind and forward of the 14 are mixed into the mixture of clinker and gypsum.

In this embodiment, the same operation and effect as those of the first embodiment can be obtained.

It goes without saying that the device used in the present invention is not limited to those in the above embodiments.

〔The invention's effect〕

As described above, according to the present invention, high strength can be expressed, high-grade cement having high watertightness and alkali-aggregate reaction inhibitory action can be manufactured by the manufacturer, and mixing of the admixture at the construction site, There is no need for adjustment, and a unified construction method is possible. Thus, it is possible to solve problems such as a reduction in construction cost, a variation in strength of concrete or the like due to a variation in construction procedures, and a suppression of performance.

[Brief description of the drawings]

FIG. 1 is a process flow diagram of a first embodiment of the present invention, FIG. 2 is a schematic diagram of a high-temperature processing section in the same embodiment, FIG. 3 is a process flow diagram of a second embodiment of the present invention, FIG. 4 is a process flow chart of a conventional cement production method. 1 ... limestone, 2 ... clay, 2 '... silica raw material, 3 ... slag, 10 ... rotary kiln, 12 ... gypsum, 14 ... finishing crusher, 16 ... product cement, 17 ... amorphous Silica slag, 18 …… Exhaust gas, 19 …… O ₂ or O ₂ enriched air equipment, 20
…… High temperature processing furnace, 21… Ultra fine particle recovery device, 22 …… Amorphous silica ultra fine particles, 23 …… High temperature processing unit, 32 …… Manifold, 38
…… water tank, 41 …… cooling air nozzle, 44 …… bug filter.

Claims (1)

(57) [Claims] 1. A method for producing a cement product, comprising the steps of: pulverizing and mixing coal, silica, alumina and ferric oxide, and firing and clinking the clinker obtained in a semi-molten state together with gypsum to produce a product cement. A part of the raw material containing is heated to a temperature higher than the boiling point of silica to generate silica vapor and then cooled to obtain amorphous silica ultrafine particles. A method for producing cement, which comprises mixing.