Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/20—Silicates
  • C01B33/24—Alkaline-earth metal silicates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/18—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing mixtures of the silica-lime type
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B7/00—Hydraulic cements
  • C04B7/345—Hydraulic cements not provided for in one of the groups C04B7/02 - C04B7/34
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B7/00—Hydraulic cements
  • C04B7/345—Hydraulic cements not provided for in one of the groups C04B7/02 - C04B7/34
  • C04B7/3453—Belite cements, e.g. self-disintegrating cements based on dicalciumsilicate
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding

Definitions

• the present invention mainly relates to a method for producing ⁇ -2CaO ⁇ SiO 2 that can be used as a cement material.
• 2CaO ⁇ SiO 2 As the 2CaO ⁇ SiO 2 , ⁇ type, ⁇ type, ⁇ type, and the like are known. Of these, ⁇ -type and ⁇ -type are stable at room temperature. The ⁇ type is known as one of the ingredients of Portland cement, and it is weak but hydraulic. On the other hand, although the ⁇ type does not have hydraulic properties, it has a high carbonation activity and has recently been found to be useful as a cement admixture. As described above, 2CaO ⁇ SiO 2 has been found to be used by utilizing the characteristics of both ⁇ -type and ⁇ -type, so if a method for controlling the crystal form of 2CaO ⁇ SiO 2 can be established, it will be industrially applied. It is beneficial.
• Non-patent Document 1 Non-patent document 2
• Non-patent document 3 Non-patent document 3
• Patent Document 1 ⁇ -2CaO ⁇ SiO 2
• Patent Document 2 ⁇ -2CaO ⁇ SiO 2
• the present invention provides a method for producing ⁇ -2CaO ⁇ SiO 2 that has high whiteness, does not contain harmful substances, does not inhibit the setting and hardening of cement, can reduce energy costs during firing, and has a high yield. To do.
• the present inventors have found that the slaked lime raw material and the siliceous raw material that are by-produced after generating acetylene from calcium carbide contain a trace amount of alkali components, but CaO / SiO 2. It has been found that ⁇ -2CaO ⁇ SiO 2 is produced by adjusting the total alkali amount in the raw material mixture by adding an alkali component to the raw material mixture depending on the molar ratio range. Moreover, it was found that ⁇ -2CaO ⁇ SiO 2 obtained by this method has high carbonation activity, high whiteness, no harmful substances, and is useful without inhibiting the setting and hardening of cement.
• the inventors of the present invention have made intensive efforts and have a high carbonation activity, high whiteness, no harmful substances, and inhibit cement setting and hardening with respect to the production method of ⁇ -2CaO ⁇ SiO 2.
• the inventors have found that the energy cost during firing can be reduced and that the production method of ⁇ -2CaO ⁇ SiO 2 is high, and the present invention has been completed.
• the present invention has the following gist. 1. And slaked lime material by-produced after reacting the calcium carbide and water to generate acetylene and siliceous material, a raw material mixture was blended, and CaO / SiO 2 molar ratio of 1.6 to 2.0 The total alkali amount is 0.05 mass% to 1.00 mass%, or the CaO / SiO 2 molar ratio is more than 2.0 and 2.4 or less, and the total alkali amount is 0.50 mass% or less. adjusted the raw material mixture, ⁇ -2CaO ⁇ SiO 2 of production method and firing at a firing temperature 1300 ⁇ 1600 ° C. at a rotary kiln as. 2. 2.
• the slaked lime raw material is CaO 71-74% by mass, ignition loss (LOI) 23-25% by mass, SiO 2 0.5-1.5% by mass, Fe 2 O 3 0.2-0.35. % By mass, Al 2 O 3 by 0.3 to 0.7% by mass, MgO by less than 0.2% by mass, Na 2 O and K 2 O by less than 0.1% by mass, and SO 3 by 1.
• the obtained ⁇ -2CaO ⁇ SiO 2 has a high carbonation activity, a high whiteness, and does not inhibit the setting and hardening of the cement.
• the energy cost can be reduced and the yield is high.
• ⁇ -2CaO ⁇ SiO 2 referred to in the present invention is a kind of dicalcium silicate 2CaO ⁇ SiO 2 among the compounds mainly composed of CaO and SiO 2 .
• the dicalcium silicate 2CaO ⁇ SiO 2 includes ⁇ type, ⁇ prime type, ⁇ type, and ⁇ type.
• the present invention relates to ⁇ -type dicalcium silicate.
• the slaked lime raw material (calcium hydroxide raw material) byproduced after making calcium carbide and water react and generating acetylene is used.
• ⁇ -type 2CaO ⁇ SiO 2 is obtained.
• ⁇ -2CaO ⁇ SiO 2 of the present invention cannot be obtained.
• the component of slaked lime produced as a by-product after the reaction of calcium carbide with water to generate acetylene is about 71 to 74% of CaO on the basis of oxides after heat treatment of the slaked lime produced as a by-product.
• MgO is less than 0.2%, Na 2 O and K 2 O are both less than 0.1%, and SO 3 is contained in an amount of about 1.0 to 1.5%.
• a siliceous raw material (SiO 2 raw material) is used in addition to a slaked lime raw material (CaO raw material) produced as a by-product after generating acetylene by reacting calcium carbide and water.
• the siliceous raw material (SiO 2 raw material) is not particularly limited, but silica fine powder, silica fume, diatomaceous earth, fused silica dust, and the like can be used.
• silica fine powder silica fume, diatomaceous earth, fused silica dust, and the like can be used.
• the presence of impurities is also preferable.
• SiO 2 raw material a high-purity siliceous raw material
• SiO 2 raw material a slaked lime raw material by-produced after reacting calcium carbide and water to generate acetylene, ⁇ -2CaO - it is possible to obtain a SiO 2.
• the total alkali amount means the content (mass%) of Na 2 O, K 2 O, and Li 2 O contained in the raw material mixture.
• the alkaline substance is not particularly limited, but potassium carbonate, sodium carbonate, or the like can be used.
• the heat treatment method is not particularly limited.
• a rotary kiln, an electric furnace, a tunnel furnace, a shaft kiln, a fluidized bed incinerator, etc. can be used. Above all, it is necessary to select a rotary kiln from the viewpoint of continuous operation and cost performance.
• the calcination temperature is 1300 ° C. to 1600 ° C., preferably 1400 ° C. to 1550 ° C., more preferably 1450 to 1550 ° C. If it is less than 1300 ° C., the efficiency may be deteriorated or it may be burnt. If it exceeds 1600 ° C., it will not only melt and become difficult to operate, but it may be easily coated and the yield may be reduced. .
• the firing temperature here is the maximum temperature, and in the case of a rotary kiln, it is the temperature in the firing zone.
• the CaO / SiO 2 molar ratio of the raw material mixture it is necessary to adjust the CaO / SiO 2 molar ratio of the raw material mixture to 1.6 to 2.4.
• the total alkali amount needs to be 0.05% or more and 1.00% or less, and preferably 0.10% or more and 0.95% or less.
• the CaO / SiO 2 molar ratio of the raw material mixture is adjusted to 2.0 to 2.4 or less, the total alkali amount needs to be 0.50% or less, and should be 0.40% or less. Is preferable, and may be 0%.
• the particle sizes of the slaked lime raw material and the siliceous raw material are preferably prepared so that the 150 ⁇ m pass rate is 90% or more, and more preferably prepared so that the 100 ⁇ m pass rate is 90% or more. If the particle size of the raw material is not fine within the above range, the purity of ⁇ -2CaO ⁇ SiO 2 tends to deteriorate. Specifically, free lime and insoluble residue increase.
• the present invention it is preferable to granulate the prepared raw material mixture.
• the formation reaction of ⁇ -2CaO ⁇ SiO 2 is facilitated, energy costs can be reduced, and purity is increased.
• the shape after granulation is not particularly limited, but a spherical shape is preferred when firing in a rotary kiln.
• the size of the granulated product is not particularly limited, but the diameter is preferably 1 cm to 10 cm, more preferably 3 cm to 7 cm.
• Granulation is an operation of forming the prepared raw material mixture into a dumpling shape.
• Examples of this method include a method in which a raw material mixture and water are put into a disc-shaped rotary drum and granulated, and a method using a so-called pelletizer in which the raw material mixture is put in a mold and pressure-molded.
• the amount of water used for granulation is preferably 10 to 30%, more preferably 15 to 25% in terms of the mass ratio of the water / raw material mixture. If the amount of water used is less than 10%, the granulated raw material mixture tends to collapse, and the raw material mixture may be collected to reduce the yield, or the firing reaction may not proceed sufficiently during firing in a rotary kiln.
• the granulated raw material mixture when the usage-amount of water exceeds 30%, the granulated raw material mixture will become watery, it will be easy to collapse
• the raw material mixture since the raw material mixture contains a large amount of water, it requires a large amount of firing energy to evaporate the mixture, which is uneconomical and increases the environmental burden, which is not preferable.
• magnesia-spinel system or a high-purity alumina system when firing is performed, it is preferable to use a magnesia-spinel system or a high-purity alumina system as a brick in the firing zone.
• silica-alumina brick or magnesia brick is used instead of magnesia-spinel or high-purity alumina, it becomes difficult to stably produce ⁇ -2CaO ⁇ SiO 2 , and ⁇ -2CaO ⁇ SiO 2 In some cases, the mixing of these becomes significant.
• examples of the magnesia-spinel brick and the high-purity alumina brick include JIS R 2302 magnesia brick and JIS R 2305 high-alumina refractory brick.
• the cooling operation is performed after the heat treatment, but the cooling conditions are not particularly limited, but a special rapid cooling operation may not be performed.
• a method according to the general cooling conditions of Portland cement clinker may be used. For example, after firing in a rotary kiln, cooling may be performed through a cooler or the like in an atmospheric environment.
• Example 1 Various slaked lime raw materials and siliceous raw materials were prepared so that the CaO / SiO 2 molar ratio was 1.6 to 2.4.
• This blended raw material mixture was granulated into a spherical shape (diameter 4 cm) with a granulator. At this time, 20% of water was added to the powder.
• the granulated product was heat-treated with a rotary kiln. The firing temperature was 1450 ° C. as the firing temperature of the burner. Note that magnesia-spinel brick was used as the brick in the fired zone. As a result of analyzing the obtained fired product, it was as shown in Table 1.
• Raw material of slaked lime slaked lime produced as a by-product after generating acetylene by reacting calcium carbide and water, based on oxides after heat treatment of the slaked lime produced as a by-product, 73.1% CaO, 0.07% MgO , Al 2 O 3 is 0.55%, Fe 2 O 3 is 0.28%, SiO 2 is 0.95%, SO 3 is 1.31%, Na 2 O is 0.03%, K 2 O is 0.02%, loss on ignition is 23.80%. 150 ⁇ m passage rate 99.5%, 100 ⁇ m passage rate 96.9%.
• Siliceous material Silica fine powder, commercially available, SiO 2 is 97.05%, Al 2 O 3 is 1.89% Na 2 O is 0.06% K 2 O is 0.14%, ignition Weight loss is 0.49%, average particle size is 7.8 ⁇ m, 150 ⁇ m passage rate is 100%, 100 ⁇ m passage rate is 100%.
• Water tap water Baking zone brick: magnesia-spinel brick, MgO content 80% and Al 2 O 3 content 20%.
• Rotary kiln Outer outer diameter 1m, Outlet outer diameter 1.2m, Length 25m
• ⁇ Measurement method> Compound identification: The compound was identified by powder X-ray diffraction. Color observation: The degree of whiteness is determined visually. Observe in a room with an illuminance of 200 lux, and observe the whiteness of the powder prepared to a brain specific surface area of 3000 ⁇ 100 cm 2 / g. In the case of white, ⁇ , in the case of yellow, ⁇ , and in the case of brown, X.
• Example 2 It carried out similarly to Experimental example 1 except having added potassium carbonate and having changed the total amount of alkalis as shown in Table 2 with respect to the raw material mixture. The results are shown in Table 2.
• Example 3 The experiment was performed in the same manner as in Experimental Example 1 except that the firing temperature was changed as shown in Table 3. The results are shown in Table 3.
• Example 4 The experiment was performed in the same manner as in Experimental Example 1 except that the bricks in the fired zone were changed as shown in Table 4. The results are shown in Table 4. ⁇ Materials used> High purity alumina brick: Al 2 O 3 content is 95% or more. Silica-alumina brick: SiO 2 content 30% and Al 2 O 3 content 70%.
• the carbonation activity is high, the whiteness is high, the setting hardening of the cement is not inhibited, the energy cost at the time of firing can be reduced, and the yield is also increased. Since it is a high production method of ⁇ -2CaO ⁇ SiO 2 , it can be widely used in the cement field and the like.

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• 2013
  • 2013-06-06 WO PCT/JP2013/065731 patent/WO2014002727A1/ja active Application Filing
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