CA2761252A1 - Method for manufacturing artificial lightweight aggregate using cold and hot rolling mill sludge - Google Patents
Method for manufacturing artificial lightweight aggregate using cold and hot rolling mill sludge Download PDFInfo
- Publication number
- CA2761252A1 CA2761252A1 CA 2761252 CA2761252A CA2761252A1 CA 2761252 A1 CA2761252 A1 CA 2761252A1 CA 2761252 CA2761252 CA 2761252 CA 2761252 A CA2761252 A CA 2761252A CA 2761252 A1 CA2761252 A1 CA 2761252A1
- Authority
- CA
- Canada
- Prior art keywords
- cold
- lightweight aggregate
- rolling mill
- hot rolling
- mill sludge
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000010802 sludge Substances 0.000 title claims abstract description 65
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 33
- 238000005097 cold rolling Methods 0.000 title claims description 42
- 238000005098 hot rolling Methods 0.000 title claims description 41
- 238000000034 method Methods 0.000 title claims description 32
- 239000000463 material Substances 0.000 claims abstract description 36
- 239000004927 clay Substances 0.000 claims abstract description 31
- 230000005484 gravity Effects 0.000 claims abstract description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 29
- 238000010521 absorption reaction Methods 0.000 claims description 27
- 239000000203 mixture Substances 0.000 claims description 19
- 239000002994 raw material Substances 0.000 claims description 17
- 238000001354 calcination Methods 0.000 claims description 16
- 238000000465 moulding Methods 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 4
- 238000001125 extrusion Methods 0.000 claims description 3
- 238000005453 pelletization Methods 0.000 claims description 2
- 229910000831 Steel Inorganic materials 0.000 abstract description 15
- 239000010959 steel Substances 0.000 abstract description 15
- 239000006227 byproduct Substances 0.000 abstract description 11
- 239000002699 waste material Substances 0.000 abstract description 11
- 239000004088 foaming agent Substances 0.000 abstract description 10
- 238000011109 contamination Methods 0.000 abstract description 2
- 230000007613 environmental effect Effects 0.000 abstract 1
- 239000004567 concrete Substances 0.000 description 17
- 238000009628 steelmaking Methods 0.000 description 13
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 9
- 238000002360 preparation method Methods 0.000 description 7
- 239000000428 dust Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 238000004064 recycling Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 229910001385 heavy metal Inorganic materials 0.000 description 4
- 230000000704 physical effect Effects 0.000 description 4
- 239000010801 sewage sludge Substances 0.000 description 4
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 4
- 239000004568 cement Substances 0.000 description 3
- 238000003912 environmental pollution Methods 0.000 description 3
- 239000000383 hazardous chemical Substances 0.000 description 3
- 238000002386 leaching Methods 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000011449 brick Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000009614 chemical analysis method Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000003795 desorption Methods 0.000 description 2
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000010169 landfilling Methods 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000011368 organic material Substances 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 229910002623 Hg Zn Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 229910052586 apatite Inorganic materials 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- 239000010882 bottom ash Substances 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- VSIIXMUUUJUKCM-UHFFFAOYSA-D pentacalcium;fluoride;triphosphate Chemical compound [F-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O VSIIXMUUUJUKCM-UHFFFAOYSA-D 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- NOTVAPJNGZMVSD-UHFFFAOYSA-N potassium monoxide Inorganic materials [K]O[K] NOTVAPJNGZMVSD-UHFFFAOYSA-N 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Classifications
-
- 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
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/02—Agglomerated materials, e.g. artificial aggregates
- C04B18/027—Lightweight materials
-
- 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
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/18—Waste materials; Refuse organic
-
- 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
- C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B14/02—Granular materials, e.g. microballoons
- C04B14/04—Silica-rich materials; Silicates
- C04B14/10—Clay
-
- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Civil Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Dispersion Chemistry (AREA)
- Treatment Of Sludge (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The present invention relates to a method for producing artificial lightweight aggregates using cold- or hot-rolled mill sludge and clay as a main material. More particularly, the present invention relates to a method for producing artificial lightweight aggregates, in which the aggregates are produced from cold- or hot-rolled mill sludge and clay as a primary material, and the aggregates have an absolute dry specific gravity of 0.8 to 1.5 and an absorptance of 5 to 20%. As the artificial lightweight aggregates according to the present invention use cold- or hot-rolled mill sludge, which is a by-product of the steel industry, as a main material, the necessity of an additional foaming agent is eliminated, and steel wastes are reutilized to increase economical advantages, reduce wastes, and prevent environmental contamination.
Description
METHOD FOR MANUFACTURING ARTIFICIAL LIGHTWEIGHT AGGREGATE
USING COLD AND HOT ROLLING MILL SLUDGE
TECHNICAL FIELD
The present invention relates to a method of manufacturing an artificial lightweight aggregate using cold and hot rolling mill sludge and clay as main raw materials, and more particularly to a method of manufacturing an artificial lightweight aggregate using cold and hot rolling mill sludge and clay as main raw materials, in which the artificial lightweight aggregate has an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%.
BACKGROUND ART
Raw materials containing a foaming agent such as expanded shale and expanded clay are required to manufacture lightweight aggregates from natural materials according to the prior art. Because the quality of lightweight aggregates is determined according to the distribution and content of the foaming agent, securing good-quality raw materials is significantly important for the manufacture of lightweight aggregates. Such raw materials are manufactured only in several countries, but are not manufactured in Korea. Thus, in order to obtain good quality lightweight aggregates, components such as Fe203 and C have been artificially added to raw materials for manufacturing lightweight aggregates. Such components account for a significant portion of the production cost of lightweight aggregates as well as impose many restrictions on the manufacture of lightweight aggregates.
In recent years, researches are in progress to manufacture lightweight aggregates using industrial waste in a cost-effective manner.
In general, steelmaking byproducts include slag (furnace slag and steelmaking slag), sludge (steelmaking sludge, lime sludge, cold and hot rolling mill sludge, ash sludge, wastewater treatment area sludge, and continuous casting sludge), dust (sintered R/EP dust, sintered W/EP dust, lime B/F dust, steelmaking E/P dust, and steelmaking B/F dust) and bottom ashes. Such steelmaking byproducts comprise Si02, A1203r Fe2O3, CaO, MgO, Na2O, K2O, TiO2, P2O5, Cr203r MnO, C and the like, and are recycled in steelmaking processes, but the cold and hot rolling mill sludge is recycled at a significantly low rate, because it contains impurities such as oily components. In Korea, the cold and hot rolling mill sludge is generated in an amount of more than about 200,000 metric tons each year and is mostly landfilled. Also, such cold and hot rolling mill sludge entails a problem in that the chemical components thereof mostly comprise heavy metals which are considerably harmful to the human body, and secondary environmental pollution problems are caused upon the reclamation thereof.
Korean Patent Laid-Open Publication No. 2003-0069692 discloses a method of manufacturing a lightweight aggregate having an apatite crystal structure using wastewater sludge containing phosphate, wherein a steel sludge having an iron content of about 60% is added as a foaming agent in an amount of 5-15% by weight in order to manufacture the lightweight aggregate. However, the above lightweight aggregate manufacturing method encounters a problem in that, when the amount of steel sludge added is more than 15% by weight, the resulting product will have a thick block color which lowers the merchantability of the product, and thus the recycling of the steel sludge is significantly limited.
In addition, Korean Patent Registration No. 662,812 discloses a method for manufacturing an artificial ultra-lightweight aggregate, which comprises adding 20-30 parts by weight of a dry steel sludge to a raw sewage sludge. Since raw sewage sludge has a water content of about 80%, it cannot be molded. To solve this problem, the method disclosed in Korean Patent Registration No. 662,812 aims to make it possible to form the lightweight aggregate by adding the dry steel sludge dried to a water content of about 20-30%, thereby reducing the drying cost of the lightweight aggregate.
USING COLD AND HOT ROLLING MILL SLUDGE
TECHNICAL FIELD
The present invention relates to a method of manufacturing an artificial lightweight aggregate using cold and hot rolling mill sludge and clay as main raw materials, and more particularly to a method of manufacturing an artificial lightweight aggregate using cold and hot rolling mill sludge and clay as main raw materials, in which the artificial lightweight aggregate has an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%.
BACKGROUND ART
Raw materials containing a foaming agent such as expanded shale and expanded clay are required to manufacture lightweight aggregates from natural materials according to the prior art. Because the quality of lightweight aggregates is determined according to the distribution and content of the foaming agent, securing good-quality raw materials is significantly important for the manufacture of lightweight aggregates. Such raw materials are manufactured only in several countries, but are not manufactured in Korea. Thus, in order to obtain good quality lightweight aggregates, components such as Fe203 and C have been artificially added to raw materials for manufacturing lightweight aggregates. Such components account for a significant portion of the production cost of lightweight aggregates as well as impose many restrictions on the manufacture of lightweight aggregates.
In recent years, researches are in progress to manufacture lightweight aggregates using industrial waste in a cost-effective manner.
In general, steelmaking byproducts include slag (furnace slag and steelmaking slag), sludge (steelmaking sludge, lime sludge, cold and hot rolling mill sludge, ash sludge, wastewater treatment area sludge, and continuous casting sludge), dust (sintered R/EP dust, sintered W/EP dust, lime B/F dust, steelmaking E/P dust, and steelmaking B/F dust) and bottom ashes. Such steelmaking byproducts comprise Si02, A1203r Fe2O3, CaO, MgO, Na2O, K2O, TiO2, P2O5, Cr203r MnO, C and the like, and are recycled in steelmaking processes, but the cold and hot rolling mill sludge is recycled at a significantly low rate, because it contains impurities such as oily components. In Korea, the cold and hot rolling mill sludge is generated in an amount of more than about 200,000 metric tons each year and is mostly landfilled. Also, such cold and hot rolling mill sludge entails a problem in that the chemical components thereof mostly comprise heavy metals which are considerably harmful to the human body, and secondary environmental pollution problems are caused upon the reclamation thereof.
Korean Patent Laid-Open Publication No. 2003-0069692 discloses a method of manufacturing a lightweight aggregate having an apatite crystal structure using wastewater sludge containing phosphate, wherein a steel sludge having an iron content of about 60% is added as a foaming agent in an amount of 5-15% by weight in order to manufacture the lightweight aggregate. However, the above lightweight aggregate manufacturing method encounters a problem in that, when the amount of steel sludge added is more than 15% by weight, the resulting product will have a thick block color which lowers the merchantability of the product, and thus the recycling of the steel sludge is significantly limited.
In addition, Korean Patent Registration No. 662,812 discloses a method for manufacturing an artificial ultra-lightweight aggregate, which comprises adding 20-30 parts by weight of a dry steel sludge to a raw sewage sludge. Since raw sewage sludge has a water content of about 80%, it cannot be molded. To solve this problem, the method disclosed in Korean Patent Registration No. 662,812 aims to make it possible to form the lightweight aggregate by adding the dry steel sludge dried to a water content of about 20-30%, thereby reducing the drying cost of the lightweight aggregate.
In line with the general concept of the expansion of lightweight aggregates, when lightweight aggregates are calcined, the thermal desorption of organic materials occurs, and gas, carbonic acid, sulfur dioxide and trivalent iron oxide, which are generated by the thermal desorption, are reduced into bivalent iron oxide while they calcine the outer surface of particles surrounding the formed gas. If the gas cannot come out of the calcined surface, the inside of the clay will expand and have somewhat uniform porosity, and thus become lightweight. The above-mentioned method of manufacturing the artificial lightweight aggregate using a combination of the raw sewage sludge and the dry steel sludge, disclosed in the above prior art document, also uses a process similar to this concept. However, about 90% or more of organic materials contained in the raw sewage sludge form many pores during the calcining process, thus making difficult a reduction reaction of Fe2O3, and the surface of the lightweight aggregate is excessively calcined or melted before the expansion process, which makes it significantly difficult to control the calcining process. In addition, it is difficult to ensure the quality uniformity of the manufactured lightweight aggregate.
In Korea, the steel industry accounts for a large portion of the entire industry, and thus waste, including sludge, is generated in large amounts. Such waste is disposed of by, for example, a method of landfilling solid bricks prepared from such waste, and the technology of disposing of such waste remains at a very early stage. Steel sludge and the like which are landfilled without being recycled can contaminate the surrounding environment and can cause serious problems such as soil contamination. Disposal of sludge involves a great deal of cost to increase the production costs, thus weakening the competitiveness of companies.
The above-mentioned patent documents suggest the method of recycling industrial byproducts containing iron, but the suggested method cannot be said to be an ultimate treatment method. Specifically, the disclosed materials serve either as additives for expansion rather than serving to provide main raw materials for the manufacture of lightweight aggregates, or as water-controlling agents during the forming process. Further, the disclosed methods require a process of producing solid bricks, and a pelletizing process, followed by landfilling.
Accordingly, the recycling of the steelmaking byproduct sludge helps to prevent environmental pollution and enhancing national competitiveness, and thus many researches thereon and the positive use thereof are required.
Accordingly, the present inventors have made extensive efforts to recycle steelmaking byproducts and, as a result, have found that, when a cold and hot rolling mill sludge which is a byproduct of the steel industry is used as a raw material for manufacturing a lightweight aggregate, the expansion of the aggregate during a calcining process can be easily controlled, the average calcination temperature of the aggregate can be lowered to greatly save energy, and the recycling rate of steelmaking byproducts can be significantly increased, thereby completing the present invention.
DISCLOSURE OF INVENTION
TECHNICAL PROBLEM
It is an object of the present invention to provide an artificial lightweight aggregate manufactured using a mixture of cold and hot rolling mill sludge and clay which are mixed at a specific ratio, and a method of manufacturing the artificial lightweight aggregate, in order to recycle steelmaking byproducts containing impurities, such as oily components, which make it difficult to recycle the byproducts.
TECHNICAL SOLUTION
To achieve the above objects, in one aspect, the present invention provides an artificial lightweight aggregate which is manufactured using cold and hot rolling mill sludge and clay as main raw materials, and has an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%.
In Korea, the steel industry accounts for a large portion of the entire industry, and thus waste, including sludge, is generated in large amounts. Such waste is disposed of by, for example, a method of landfilling solid bricks prepared from such waste, and the technology of disposing of such waste remains at a very early stage. Steel sludge and the like which are landfilled without being recycled can contaminate the surrounding environment and can cause serious problems such as soil contamination. Disposal of sludge involves a great deal of cost to increase the production costs, thus weakening the competitiveness of companies.
The above-mentioned patent documents suggest the method of recycling industrial byproducts containing iron, but the suggested method cannot be said to be an ultimate treatment method. Specifically, the disclosed materials serve either as additives for expansion rather than serving to provide main raw materials for the manufacture of lightweight aggregates, or as water-controlling agents during the forming process. Further, the disclosed methods require a process of producing solid bricks, and a pelletizing process, followed by landfilling.
Accordingly, the recycling of the steelmaking byproduct sludge helps to prevent environmental pollution and enhancing national competitiveness, and thus many researches thereon and the positive use thereof are required.
Accordingly, the present inventors have made extensive efforts to recycle steelmaking byproducts and, as a result, have found that, when a cold and hot rolling mill sludge which is a byproduct of the steel industry is used as a raw material for manufacturing a lightweight aggregate, the expansion of the aggregate during a calcining process can be easily controlled, the average calcination temperature of the aggregate can be lowered to greatly save energy, and the recycling rate of steelmaking byproducts can be significantly increased, thereby completing the present invention.
DISCLOSURE OF INVENTION
TECHNICAL PROBLEM
It is an object of the present invention to provide an artificial lightweight aggregate manufactured using a mixture of cold and hot rolling mill sludge and clay which are mixed at a specific ratio, and a method of manufacturing the artificial lightweight aggregate, in order to recycle steelmaking byproducts containing impurities, such as oily components, which make it difficult to recycle the byproducts.
TECHNICAL SOLUTION
To achieve the above objects, in one aspect, the present invention provides an artificial lightweight aggregate which is manufactured using cold and hot rolling mill sludge and clay as main raw materials, and has an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%.
In another aspect, the present invention also provides a method for manufacturing an artificial lightweight aggregate having an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%, the method comprising the steps of: (a) mixing 5-90 parts by weight of a cold and hot rolling mill sludge and 10-120 parts by weight of clay; (b) molding the mixture; (c) drying the molded material; and (d) calcining the dried material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart showing a process of manufacturing an artificial lightweight aggregate according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Other features and embodiments of the present invention will be more apparent from the following detailed descriptions and the appended claims.
In one aspect, the present invention is directed to an artificial lightweight aggregate which is manufactured using cold and hot rolling mill sludge and clay as main raw materials, and has an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart showing a process of manufacturing an artificial lightweight aggregate according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Other features and embodiments of the present invention will be more apparent from the following detailed descriptions and the appended claims.
In one aspect, the present invention is directed to an artificial lightweight aggregate which is manufactured using cold and hot rolling mill sludge and clay as main raw materials, and has an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%.
In another aspect, the present invention is also directed to a method for manufacturing an artificial lightweight aggregate having an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%, the method comprising the steps of: (a) mixing 5-90 parts by weight of a cold and hot rolling mill sludge and 10-120 parts by weight of clay; (b) molding the mixture; (c) drying the molded material; and (d) calcining the dried material.
As used herein, the term "cold and hot rolling mill sludge" means a sludge containing large amounts of heavy metals, which is generated in cold and hot rolling processes in a steel mill.
The artificial lightweight aggregate according to the present invention is manufactured using steel waste such as a cold and hot rolling mill sludge. It does not require a separate foaming agent, because chemical components, such as Fe2O3 and C, which are contained in large amounts in the cold and hot rolling mill sludge, serve as the key foaming agents during calcination of the lightweight aggregate as shown in the following chemical equations:
Fe2O3 + C 2FeO + CO T ...... (1) 3Fe2O3 + C 2Fe3O4 + CO T ...... (2) 3Fe2O3 2Fe3O4 + 1/2 CO T...... (3) Thus, the present invention can solve the problems associated with the insufficient foaming components of raw materials which could not provide lightweight aggregates. At the same time, according to the present invention, the lightweight aggregate is manufactured using steelmaking waste which has been landfilled, and the manufactured lightweight aggregate is used as a raw material for high-value-added construction materials. Thus, the present invention significantly contributes to reducing environmental pollutants which become social problems.
In one embodiment of the present invention, the artificial lightweight aggregate is manufactured by mixing 5-90 parts by weight of the cold and hot rolling mill sludge with 10-120 parts by weight of clay, molding the mixture and calcining the molded material in an electric furnace at 1100-12001C . The manufactured artificial lightweight aggregate showed an absolute dry specific gravity of 1.0-1.5 and a water absorption rate of 5-10%.
In another embodiment of the present invention, the artificial lightweight aggregate is manufactured by mixing 5-90 parts by weight of the cold and hot rolling mill sludge with 10-120 parts by weight of clay, primarily molding the mixture using an extrusion molding machine, cutting the molded material, secondarily molding the cut molded material, and calcining the secondarily molded material in a rotary kiln at 950-1100C. The manufactured artificial lightweight aggregate showed an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 12-20%, and no heavy metals were detected in the artificial lightweight aggregate as can be seen from the results of measuring the leaching of hazardous substances.
Such lightweight aggregates having various specific gravities can be used in a wide range of applications, including structural materials in the construction and civil engineering field, noise-reducing materials for buildings, humidity-controlling materials for buildings, and horticultural applications.
Hereinafter, the present invention will be described in further detail with reference to examples. It will be obvious to those skilled in the art that these examples are illustrative purposes only and are not to be construed to limit the scope of the present invention.
EXAMPLES
Example 1: Measurement of chemical components of raw materials The chemical components of red clay (Asan Industrial Co., Ltd., Hongsung, Chungcheongnam-do, Korea) and a cold-and hot rolling mill sludge (Posco Co., Ltd., Korea) required to manufacture an artificial lightweight aggregate were measured according to the chemical analysis and testing method of KS L
4007 (chemical analysis method of clay).
As a result, as shown in Table 1 below, the cold and hot rolling mill sludge had a Fe2O3 content of 70% or more and an unburned carbon content of 10% or more, and such components (Fe2O3 and carbon) can provide sufficient amounts of foaming agents during the calcinations process.
[Table 1]
Type Ig Si02 A1203 Fe2O3 CaO MgO Na2O K2O TiO2 ZrO2 P2O5 Cr2O3 MnO C
loss Red 9.0062.1016.81 6.20 0.511.160.812.350.77 - 0.09 - - -clay Cold and hot rolling8.61 1.26 5.13 70.220.820.040.010.010.02 - 0.850.130.2312.69 ill sludge Example 2: Manufacturing of lightweight aggregate using cold and hot rolling mill sludge In Experimental Example 1, 10 parts by weight of a cold and hot rolling mill sludge was mixed with 90 parts by weight of clay, and the mixture was crushed and kneaded. Then, the resulting material was manually formed into a pellet shape and calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.48 and a water absorption rate of 9.48%.
In Experimental Example 2, 20 parts by weight of a cold and hot rolling mill sludge was mixed with 80 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.40 and a water absorption rate of 8.64%.
In Experimental Example 3, 30 parts by weight of a cold and hot rolling mill sludge was mixed with 70 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.46 and a water absorption rate of 9.05%.
In Experimental Example 4, 40 parts by weight of a cold and hot rolling mill sludge was mixed with 60 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.08 and a water absorption rate of 9.59%.
In Experimental Example 5, 50 parts by weight of a cold and hot rolling mill sludge was mixed with 50 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.16 and a water absorption rate of 7.44%.
In Experimental Example 6, 60 parts by weight of a cold and hot rolling mill sludge was mixed with 40 parts by weight of clay, and the mixture was molded in the same manner as Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.23 and a water absorption rate of 4.48%.
In Experimental Example 7, 70 parts by weight of a cold and hot rolling mill sludge was mixed with 30 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.11 and a water absorption rate of 5.79%.
[Table 2]
Comparison of specific gravity and water absorption rate between lightweight aggregates manufactured in electric furnace Cold and hot Absolute Water Type rolling mill clay dry absorption sludge specific rate(%) gravity Experimental 10 90 1.48 9.48 Example 1 Experimental 20 80 1.40 8.64 Example 2 Experimental 30 70 1.46 9.05 Example 3 Experimental 40 60 1.08 9.59 Example 4 Experimental 50 50 1.16 7.44 Example 5 Experimental 60 40 1.23 4.48 Example 6 Experimental 70 30 1.11 5.79 Example 7 Table 2 above shows the absolute dry specific gravity and water absorption rate of the lightweight aggregates manufactured according to Experimental Examples 1 to 7. The physical properties of the lightweight aggregates using the mixtures of the cold and hot rolling mill sludge and clay were compared with each other, and as a result, the lightweight aggregates manufactured in the Experimental Examples all had an absolute dry specific gravity of 1.5 or less and a water absorption rate of 10% or less.
Example 3: Comparison of physical properties between lightweight aggregates manufactured in mass production process In Experimental Example 8, 30 parts by weight of a cold and hot rolling mill sludge was mixed with 70 parts by weight of clay, and the mixture was crushed and kneaded. The resulting material was primarily molded in an extrusion molding machine equipped with a mold having a plurality of perforated circular holes having a diameter of 5-11 mm. The molded material was cut to a specific length using a rotating cutter and was transferred to a rotating drum in which the molded material was in turn secondarily molded into a pellet shape. Next, the secondarily molded material was dried, and then calcined in a rotary kiln at about 1000C. The manufactured lightweight aggregate had an absolute dry specific gravity of 1.44 and a water absorption rate of 13.98%.
In Experimental Example 9, 40 parts by weight of a cold and hot rolling mill sludge was mixed with 60 parts by weight of clay, and the mixture was molded according to the method of Experimental Example 8. The molded material was dried, and then calcined in a rotary kiln at about 1000 C. The manufactured lightweight aggregate had an absolute dry specific gravity of 1.29 and a water absorption rate of 15.76%.
In Experimental Example 10, 50 parts by weight of a cold and hot rolling mill sludge was mixed with 50 parts by weight of clay, and the mixture was molded according to the method of Experimental Example 8. The molded material was driedm, and then calcined in a rotary kiln at about 1000 C. The manufactured lightweight aggregate had an absolute dry specific gravity of 0.90 and a water absorption rate of 19.80%.
The absolute dry specific gravity and the water absorption rate of the artificial lightweight aggregates manufactured according to the above Experimental Examples were measured according to KS F 2503 (testing of density and water absorption rate of coarse aggregate).
[Table 3]
Comparison of physical properties between lightweight aggregates manufactured in rotary kiln Cold and hot Absolute Water rolling mill clay dry absorption sludge specific rate(d) gravity Experimental 30 70 1.44 13.98 Example 8 Experimental 40 60 1.29 15.76 Example 9 Experimental 50 50 0.90 19.80 Example 10 Table 3 above shows the absolute dry specific gravity and water absorption rate of the lightweight aggregates manufactured according to Experimental Examples 8 to 10. The physical properties of the lightweight aggregates manufactured in the above Experimental Examples showed that the absolute dry specific gravity thereof is less than 1.5.
In particular, in case of Experimental Example 10, the lightweight aggregate showed an absolute dry specific gravity of 0.90, which is considerably low. This makes it possible to manufacture a general structural lightweight aggregate as well as an untra-lightweight aggregate which can be used for non-structural concrete As such, the fact that lightweight aggregates having various specific gravities can be manufactured means that they are not limited to structural materials in the construction and civil engineering field, but can be used in a wide range of applications, including partition panels and noise-reducing materials for buildings, humidity-controlling materials for buildings, and horticultural applications In addition, the leaching of hazardous substances of the lightweight aggregate manufactured according to Experimental Example 10 was measured by a waste processing test method, and no heavy metals were detected in the artificial lightweight aggregate as can be seen from Table 4 below.
[Table 4]
Type The leaching of hazardous substances(mg/L) Pb Cd Cr Cu As Hg Zn Ni Experimental Example 10 lightweight none none none none none none none none aggregate Example 4: Measurement of compressive strength of concrete using lightweight aggregate comprising cold and hot rolling mill sludge Concrete was manufactured using the lightweight aggregate manufactured according to the present invention, and then the compressive strength thereof was measured.
Preparation Example 1 in Table 5 below is concrete manufactured using lightweight aggregate 1 of Experimental Example 9. Concrete specimens were manufactured according to KS F 2403 (method for manufacturing specimens for testing strength of concrete) and cured, and then the compressive strengths thereof were measured according to KS F 2405 (test method for compressive strength of concrete).
In the meantime, for comparison with Preparation Example 1, Comparative Example 1 in Table 5 is general crushed aggregate (Gwangcheon-eup, Hongseong-gun, Chungcheongnam-do, Korea) used in conventional concrete. Concrete was manufactured using the aggregates of Comparative Example 1 in the same manner as in Preparation Example 1, and the compressive strengths thereof were measured in the same manner as in Preparation Example 1.
As a result, as shown in Table 5 below, when the concrete of Comparative Example 1 comprising conventional crushed aggregate was compared with the lightweight aggregate concretes of Preparation Example 1 comprising a cold and hot rolling mill sludge, the crushed aggregate concrete of Comparative Example 1 had a compressive strength of 23.0 N/m.m2, whereas the artificial lightweight aggregate concrete of Preparation Example 1 comprising the cold and hot rolling mill sludge showed a compressive strength of 23.5.0 N/mm2, which was similar to or slightly higher than that of conventional crushed aggregate concrete. In addition, when the materials used and the mixture ratio thereof are reviewed, the amount of cement used when manufacturing concrete using the general crushed aggregate is 330 kg/m3 whereas the amount of cement used when manufacturing concrete using the artificial lightweight aggregate is 315 kg/m3. Thus, it was determined that the manufacturing cost of the concrete could be reduced.
[Table 5]
Materials used and the mixture Compressive Type ratio(kg/m3) Type of strength(N/m cement Fine Coarse S/A aggregate m2 aggregateaggregate(o) /C(%) Comparative 330 811 918 47 55 Crushed 23.0 Example 1 aggregate Preparation 315 827 520 47 55 Ecological 23.5 Example 1 lightweight aggregate Accordingly, the artificial lightweight aggregate manufactured according to the present invention uses, as a main raw material, the cold and hot rolling mill sludge containing, in large amounts, chemical components such as Fe2O3 and C serving as foaming agents, thus making easy a reduction reaction of Fe203r so that since the expansion of the aggregate during a calcining process can be easily controlled, a separate foaming agent is not required. In addition, the average calcination temperature of the aggregate is 1000'C, which is lower by about 100-200 C than an existing calcination temperature to greatly save energy.
Further, since the cold and hot rolling mill sludge is used in an amount of more than 50% as a main raw material of the lightweight aggregate, the recycling rate thereof can be remarkably increased.
Although the present invention has been described in detail with reference to the specific features, it will be apparent to those skilled in the art that this description is only for a preferred embodiment and does not limit the scope of the present invention. Thus, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof.
INDUSTRIAL APPLICABILITY
The artificial lightweight aggregate according to the present invention is manufactured using, a main raw material, cold and hot rolling mill sludge, i.e., a steelmaking byproduct in the steel industry, so that a separate foaming agent is not needed, steel wastes can be recycled to ensure high economic efficiency, and wastes can be reduced to solve environmental pollution problems.
As used herein, the term "cold and hot rolling mill sludge" means a sludge containing large amounts of heavy metals, which is generated in cold and hot rolling processes in a steel mill.
The artificial lightweight aggregate according to the present invention is manufactured using steel waste such as a cold and hot rolling mill sludge. It does not require a separate foaming agent, because chemical components, such as Fe2O3 and C, which are contained in large amounts in the cold and hot rolling mill sludge, serve as the key foaming agents during calcination of the lightweight aggregate as shown in the following chemical equations:
Fe2O3 + C 2FeO + CO T ...... (1) 3Fe2O3 + C 2Fe3O4 + CO T ...... (2) 3Fe2O3 2Fe3O4 + 1/2 CO T...... (3) Thus, the present invention can solve the problems associated with the insufficient foaming components of raw materials which could not provide lightweight aggregates. At the same time, according to the present invention, the lightweight aggregate is manufactured using steelmaking waste which has been landfilled, and the manufactured lightweight aggregate is used as a raw material for high-value-added construction materials. Thus, the present invention significantly contributes to reducing environmental pollutants which become social problems.
In one embodiment of the present invention, the artificial lightweight aggregate is manufactured by mixing 5-90 parts by weight of the cold and hot rolling mill sludge with 10-120 parts by weight of clay, molding the mixture and calcining the molded material in an electric furnace at 1100-12001C . The manufactured artificial lightweight aggregate showed an absolute dry specific gravity of 1.0-1.5 and a water absorption rate of 5-10%.
In another embodiment of the present invention, the artificial lightweight aggregate is manufactured by mixing 5-90 parts by weight of the cold and hot rolling mill sludge with 10-120 parts by weight of clay, primarily molding the mixture using an extrusion molding machine, cutting the molded material, secondarily molding the cut molded material, and calcining the secondarily molded material in a rotary kiln at 950-1100C. The manufactured artificial lightweight aggregate showed an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 12-20%, and no heavy metals were detected in the artificial lightweight aggregate as can be seen from the results of measuring the leaching of hazardous substances.
Such lightweight aggregates having various specific gravities can be used in a wide range of applications, including structural materials in the construction and civil engineering field, noise-reducing materials for buildings, humidity-controlling materials for buildings, and horticultural applications.
Hereinafter, the present invention will be described in further detail with reference to examples. It will be obvious to those skilled in the art that these examples are illustrative purposes only and are not to be construed to limit the scope of the present invention.
EXAMPLES
Example 1: Measurement of chemical components of raw materials The chemical components of red clay (Asan Industrial Co., Ltd., Hongsung, Chungcheongnam-do, Korea) and a cold-and hot rolling mill sludge (Posco Co., Ltd., Korea) required to manufacture an artificial lightweight aggregate were measured according to the chemical analysis and testing method of KS L
4007 (chemical analysis method of clay).
As a result, as shown in Table 1 below, the cold and hot rolling mill sludge had a Fe2O3 content of 70% or more and an unburned carbon content of 10% or more, and such components (Fe2O3 and carbon) can provide sufficient amounts of foaming agents during the calcinations process.
[Table 1]
Type Ig Si02 A1203 Fe2O3 CaO MgO Na2O K2O TiO2 ZrO2 P2O5 Cr2O3 MnO C
loss Red 9.0062.1016.81 6.20 0.511.160.812.350.77 - 0.09 - - -clay Cold and hot rolling8.61 1.26 5.13 70.220.820.040.010.010.02 - 0.850.130.2312.69 ill sludge Example 2: Manufacturing of lightweight aggregate using cold and hot rolling mill sludge In Experimental Example 1, 10 parts by weight of a cold and hot rolling mill sludge was mixed with 90 parts by weight of clay, and the mixture was crushed and kneaded. Then, the resulting material was manually formed into a pellet shape and calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.48 and a water absorption rate of 9.48%.
In Experimental Example 2, 20 parts by weight of a cold and hot rolling mill sludge was mixed with 80 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.40 and a water absorption rate of 8.64%.
In Experimental Example 3, 30 parts by weight of a cold and hot rolling mill sludge was mixed with 70 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.46 and a water absorption rate of 9.05%.
In Experimental Example 4, 40 parts by weight of a cold and hot rolling mill sludge was mixed with 60 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.08 and a water absorption rate of 9.59%.
In Experimental Example 5, 50 parts by weight of a cold and hot rolling mill sludge was mixed with 50 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.16 and a water absorption rate of 7.44%.
In Experimental Example 6, 60 parts by weight of a cold and hot rolling mill sludge was mixed with 40 parts by weight of clay, and the mixture was molded in the same manner as Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.23 and a water absorption rate of 4.48%.
In Experimental Example 7, 70 parts by weight of a cold and hot rolling mill sludge was mixed with 30 parts by weight of clay, and the mixture was molded in the same manner as in Experimental Example 1. The molded material was calcined in an electric furnace at about 1150 C. The lightweight aggregate manufactured according to this Experimental Example showed an absolute dry specific gravity of 1.11 and a water absorption rate of 5.79%.
[Table 2]
Comparison of specific gravity and water absorption rate between lightweight aggregates manufactured in electric furnace Cold and hot Absolute Water Type rolling mill clay dry absorption sludge specific rate(%) gravity Experimental 10 90 1.48 9.48 Example 1 Experimental 20 80 1.40 8.64 Example 2 Experimental 30 70 1.46 9.05 Example 3 Experimental 40 60 1.08 9.59 Example 4 Experimental 50 50 1.16 7.44 Example 5 Experimental 60 40 1.23 4.48 Example 6 Experimental 70 30 1.11 5.79 Example 7 Table 2 above shows the absolute dry specific gravity and water absorption rate of the lightweight aggregates manufactured according to Experimental Examples 1 to 7. The physical properties of the lightweight aggregates using the mixtures of the cold and hot rolling mill sludge and clay were compared with each other, and as a result, the lightweight aggregates manufactured in the Experimental Examples all had an absolute dry specific gravity of 1.5 or less and a water absorption rate of 10% or less.
Example 3: Comparison of physical properties between lightweight aggregates manufactured in mass production process In Experimental Example 8, 30 parts by weight of a cold and hot rolling mill sludge was mixed with 70 parts by weight of clay, and the mixture was crushed and kneaded. The resulting material was primarily molded in an extrusion molding machine equipped with a mold having a plurality of perforated circular holes having a diameter of 5-11 mm. The molded material was cut to a specific length using a rotating cutter and was transferred to a rotating drum in which the molded material was in turn secondarily molded into a pellet shape. Next, the secondarily molded material was dried, and then calcined in a rotary kiln at about 1000C. The manufactured lightweight aggregate had an absolute dry specific gravity of 1.44 and a water absorption rate of 13.98%.
In Experimental Example 9, 40 parts by weight of a cold and hot rolling mill sludge was mixed with 60 parts by weight of clay, and the mixture was molded according to the method of Experimental Example 8. The molded material was dried, and then calcined in a rotary kiln at about 1000 C. The manufactured lightweight aggregate had an absolute dry specific gravity of 1.29 and a water absorption rate of 15.76%.
In Experimental Example 10, 50 parts by weight of a cold and hot rolling mill sludge was mixed with 50 parts by weight of clay, and the mixture was molded according to the method of Experimental Example 8. The molded material was driedm, and then calcined in a rotary kiln at about 1000 C. The manufactured lightweight aggregate had an absolute dry specific gravity of 0.90 and a water absorption rate of 19.80%.
The absolute dry specific gravity and the water absorption rate of the artificial lightweight aggregates manufactured according to the above Experimental Examples were measured according to KS F 2503 (testing of density and water absorption rate of coarse aggregate).
[Table 3]
Comparison of physical properties between lightweight aggregates manufactured in rotary kiln Cold and hot Absolute Water rolling mill clay dry absorption sludge specific rate(d) gravity Experimental 30 70 1.44 13.98 Example 8 Experimental 40 60 1.29 15.76 Example 9 Experimental 50 50 0.90 19.80 Example 10 Table 3 above shows the absolute dry specific gravity and water absorption rate of the lightweight aggregates manufactured according to Experimental Examples 8 to 10. The physical properties of the lightweight aggregates manufactured in the above Experimental Examples showed that the absolute dry specific gravity thereof is less than 1.5.
In particular, in case of Experimental Example 10, the lightweight aggregate showed an absolute dry specific gravity of 0.90, which is considerably low. This makes it possible to manufacture a general structural lightweight aggregate as well as an untra-lightweight aggregate which can be used for non-structural concrete As such, the fact that lightweight aggregates having various specific gravities can be manufactured means that they are not limited to structural materials in the construction and civil engineering field, but can be used in a wide range of applications, including partition panels and noise-reducing materials for buildings, humidity-controlling materials for buildings, and horticultural applications In addition, the leaching of hazardous substances of the lightweight aggregate manufactured according to Experimental Example 10 was measured by a waste processing test method, and no heavy metals were detected in the artificial lightweight aggregate as can be seen from Table 4 below.
[Table 4]
Type The leaching of hazardous substances(mg/L) Pb Cd Cr Cu As Hg Zn Ni Experimental Example 10 lightweight none none none none none none none none aggregate Example 4: Measurement of compressive strength of concrete using lightweight aggregate comprising cold and hot rolling mill sludge Concrete was manufactured using the lightweight aggregate manufactured according to the present invention, and then the compressive strength thereof was measured.
Preparation Example 1 in Table 5 below is concrete manufactured using lightweight aggregate 1 of Experimental Example 9. Concrete specimens were manufactured according to KS F 2403 (method for manufacturing specimens for testing strength of concrete) and cured, and then the compressive strengths thereof were measured according to KS F 2405 (test method for compressive strength of concrete).
In the meantime, for comparison with Preparation Example 1, Comparative Example 1 in Table 5 is general crushed aggregate (Gwangcheon-eup, Hongseong-gun, Chungcheongnam-do, Korea) used in conventional concrete. Concrete was manufactured using the aggregates of Comparative Example 1 in the same manner as in Preparation Example 1, and the compressive strengths thereof were measured in the same manner as in Preparation Example 1.
As a result, as shown in Table 5 below, when the concrete of Comparative Example 1 comprising conventional crushed aggregate was compared with the lightweight aggregate concretes of Preparation Example 1 comprising a cold and hot rolling mill sludge, the crushed aggregate concrete of Comparative Example 1 had a compressive strength of 23.0 N/m.m2, whereas the artificial lightweight aggregate concrete of Preparation Example 1 comprising the cold and hot rolling mill sludge showed a compressive strength of 23.5.0 N/mm2, which was similar to or slightly higher than that of conventional crushed aggregate concrete. In addition, when the materials used and the mixture ratio thereof are reviewed, the amount of cement used when manufacturing concrete using the general crushed aggregate is 330 kg/m3 whereas the amount of cement used when manufacturing concrete using the artificial lightweight aggregate is 315 kg/m3. Thus, it was determined that the manufacturing cost of the concrete could be reduced.
[Table 5]
Materials used and the mixture Compressive Type ratio(kg/m3) Type of strength(N/m cement Fine Coarse S/A aggregate m2 aggregateaggregate(o) /C(%) Comparative 330 811 918 47 55 Crushed 23.0 Example 1 aggregate Preparation 315 827 520 47 55 Ecological 23.5 Example 1 lightweight aggregate Accordingly, the artificial lightweight aggregate manufactured according to the present invention uses, as a main raw material, the cold and hot rolling mill sludge containing, in large amounts, chemical components such as Fe2O3 and C serving as foaming agents, thus making easy a reduction reaction of Fe203r so that since the expansion of the aggregate during a calcining process can be easily controlled, a separate foaming agent is not required. In addition, the average calcination temperature of the aggregate is 1000'C, which is lower by about 100-200 C than an existing calcination temperature to greatly save energy.
Further, since the cold and hot rolling mill sludge is used in an amount of more than 50% as a main raw material of the lightweight aggregate, the recycling rate thereof can be remarkably increased.
Although the present invention has been described in detail with reference to the specific features, it will be apparent to those skilled in the art that this description is only for a preferred embodiment and does not limit the scope of the present invention. Thus, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof.
INDUSTRIAL APPLICABILITY
The artificial lightweight aggregate according to the present invention is manufactured using, a main raw material, cold and hot rolling mill sludge, i.e., a steelmaking byproduct in the steel industry, so that a separate foaming agent is not needed, steel wastes can be recycled to ensure high economic efficiency, and wastes can be reduced to solve environmental pollution problems.
Claims (5)
1. An artificial lightweight aggregate which is manufactured using cold and hot rolling mill sludge and clay as main raw materials, and has absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%.
2. A method for manufacturing an artificial lightweight aggregate having an absolute dry specific gravity of 0.8-1.5 and a water absorption rate of 5-20%, the method comprising the steps of:
(a) mixing 5-90 parts by weight of a cold and hot rolling mill sludge and 10-120 parts by weight of clay;
(b) molding the mixture;
(c) drying the molded material; and (d) calcining the dried material.
(a) mixing 5-90 parts by weight of a cold and hot rolling mill sludge and 10-120 parts by weight of clay;
(b) molding the mixture;
(c) drying the molded material; and (d) calcining the dried material.
3. The method according to claim 2, characterized in that the molding of step (b) is a pelletizing molding or an extrusion molding.
4. The method according to claim 2, characterized in that the calcining of step (d) is performed in an electric furnace or a rotary kiln.
5. The method according to claim 2, characterized in that the calcining of step (d) is performed at 950-1200° C.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2009-0018020 | 2009-03-03 | ||
| KR20090018020A KR101165395B1 (en) | 2009-03-03 | 2009-03-03 | Method for Manufacturing Lightweight Aggregate Using Hot Rolling Mill Sludge and Cold Rolling Mill Sludge |
| PCT/KR2010/001329 WO2010101412A2 (en) | 2009-03-03 | 2010-03-03 | Method for producing artificial lightweight aggregates using cold- or hot-rolled mill sludge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2761252A1 true CA2761252A1 (en) | 2010-09-10 |
Family
ID=42710117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2761252 Abandoned CA2761252A1 (en) | 2009-03-03 | 2010-03-03 | Method for manufacturing artificial lightweight aggregate using cold and hot rolling mill sludge |
Country Status (5)
| Country | Link |
|---|---|
| KR (1) | KR101165395B1 (en) |
| CN (1) | CN102414141A (en) |
| AU (1) | AU2010220974A1 (en) |
| CA (1) | CA2761252A1 (en) |
| WO (1) | WO2010101412A2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108863426A (en) * | 2018-07-10 | 2018-11-23 | 黄河三角洲京博化工研究院有限公司 | A kind of super light ceramisite of the greasy filth containing cold rolling and preparation method thereof |
| KR102363677B1 (en) | 2020-12-24 | 2022-02-15 | 한갑수 | The light weight aggregate and the manufacturing method thereof using clay and silica |
| KR20240138028A (en) | 2023-03-09 | 2024-09-20 | 권만수 | Manufacturing method and manufacturing apparatus for ferrous sulfate using bauxite residue |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61163152A (en) * | 1985-01-14 | 1986-07-23 | 宇部興産株式会社 | Manufacture of artificial lightweight aggregate |
| JP2883881B2 (en) * | 1994-12-27 | 1999-04-19 | 鐵男 中村 | Artificial lightweight aggregate and manufacturing method thereof |
| CN1109850A (en) * | 1995-01-25 | 1995-10-11 | 北京市环境卫生科学研究所 | Method for producing haydite from refuse or mud |
| CN1171829C (en) * | 2002-03-07 | 2004-10-20 | 华南理工大学 | A method of firing clay ceramsite by utilizing biological sludge of sewage treatment plant |
| KR20030011757A (en) * | 2002-12-28 | 2003-02-11 | 이기강 | method for manufacturing composition for lightweight aggregate |
| KR100562169B1 (en) * | 2003-08-25 | 2006-03-20 | 전북대학교산학협력단 | Manufacturing method of lightweight aggregate using urban / industrial waste incineration |
| KR200423178Y1 (en) | 2006-05-16 | 2006-08-03 | 하용진 | Artificial aggregate manufacturing equipment of clay and waste mixture |
-
2009
- 2009-03-03 KR KR20090018020A patent/KR101165395B1/en not_active Expired - Fee Related
-
2010
- 2010-03-03 AU AU2010220974A patent/AU2010220974A1/en not_active Abandoned
- 2010-03-03 CN CN2010800186655A patent/CN102414141A/en active Pending
- 2010-03-03 WO PCT/KR2010/001329 patent/WO2010101412A2/en not_active Ceased
- 2010-03-03 CA CA 2761252 patent/CA2761252A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| KR101165395B1 (en) | 2012-07-12 |
| AU2010220974A1 (en) | 2011-11-17 |
| WO2010101412A2 (en) | 2010-09-10 |
| CN102414141A (en) | 2012-04-11 |
| KR20100099494A (en) | 2010-09-13 |
| WO2010101412A3 (en) | 2010-11-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Li et al. | Sulfate resistance of steam cured ferronickel slag blended cement mortar | |
| Gunning et al. | Production of lightweight aggregate from industrial waste and carbon dioxide | |
| Dai et al. | Evaluating physical-mechanical properties and long periods environmental risk of fired clay bricks incorporated with electroplating sludge | |
| El-Mahllawy | Characteristics of acid resisting bricks made from quarry residues and waste steel slag | |
| Qiao et al. | Production of lightweight concrete using incinerator bottom ash | |
| Gu et al. | Facile route for preparing refractory materials from ferronickel slag with addition of magnesia | |
| CN110218051A (en) | A kind of high strength lightweight aggregate concrete and its preparation process | |
| RU2705646C1 (en) | Cement-free binder and use thereof | |
| Najimi et al. | Properties of concrete containing copper slag waste | |
| CN101603346A (en) | A kind of sludge brick and preparation method thereof | |
| JP5800387B2 (en) | Soil improvement material | |
| Er et al. | Recycling of metallurgical wastes in ceramics: A sustainable approach | |
| CN106277881A (en) | A kind of compounded mineral admixture | |
| CA2844052A1 (en) | Method for manufacturing light-weight construction material using waste product and light-weight construction material manufactured thereby | |
| Gómez-Casero et al. | Comparative study of alkali activated cements based on metallurgical slags, in terms of technological properties developed | |
| CN108821692A (en) | A kind of sand base water-permeable brick and preparation method thereof of electric arc furnace steel slag preparation | |
| Lin et al. | Utilization of reduction slag and waste sludge for Portland cement clinker production | |
| EP3371125B1 (en) | Process for producing a building material obtained from an alkaline activation of sawing sludge of stone materials | |
| Auliya et al. | Compressive strength and sustainability indicators of concrete manufactured with recycled refractory brick furnace waste | |
| CA2761252A1 (en) | Method for manufacturing artificial lightweight aggregate using cold and hot rolling mill sludge | |
| WO2017175240A1 (en) | Autoclaved fly ash bricks and method of manufacturing the same | |
| Shukla et al. | Utilization of concentrate of membrane filtration of bleach plant effluent in brick production | |
| Ojha et al. | Bauxite Waste as cement Substitute after Normalisation: Sustaining environment | |
| JP2003171153A (en) | Method for producing lightweight mixed sintering product from waste material | |
| JP6151008B2 (en) | Fired product |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |
Effective date: 20140304 |