WO2018218325A1 - Process for synthesizing carbon nanomaterials on blast-furnace slag, products and use - Google Patents

Process for synthesizing carbon nanomaterials on blast-furnace slag, products and use Download PDF

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WO2018218325A1
WO2018218325A1 PCT/BR2018/050175 BR2018050175W WO2018218325A1 WO 2018218325 A1 WO2018218325 A1 WO 2018218325A1 BR 2018050175 W BR2018050175 W BR 2018050175W WO 2018218325 A1 WO2018218325 A1 WO 2018218325A1
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Prior art keywords
carbon
furnace slag
blast furnace
synthesis
slag
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PCT/BR2018/050175
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French (fr)
Portuguese (pt)
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Luiz Orlando Ladeira
Ana Elisa Da Silva DIAS
Sergio De Oliveira
José Márcio Fonseca CALIXTO
Tarcizo Da Cruz Costa De SOUZA
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Intercement Brasil S.A.
Universidade Federal De Minas Gerais
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Publication of WO2018218325A1 publication Critical patent/WO2018218325A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/16—Preparation
    • 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
    • C04B5/00—Treatment of  metallurgical  slag ; Artificial stone from molten  metallurgical  slag 
    • C04B5/06—Ingredients, other than water, added to the molten slag or to the granulating medium or before remelting; Treatment with gases or gas generating compounds, e.g. to obtain porous slag
    • 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
    • C04B7/14—Cements containing slag
    • C04B7/147—Metallurgical slag
    • 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
    • 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

Definitions

  • the present invention is a chemical vapor phase deposition process for the synthesis of carbon nanotubes (NTC) and / or carbon nanofiber (NFC) directly on the blast furnace slag.
  • NTC carbon nanotubes
  • NFC carbon nanofiber
  • Carbon nanotubes and nanofibers are currently recognized as one of the most important materials in nanoscience and nanotechnology and are widely used in various segments of materials engineering, biomaterials, chemistry and petrochemicals, the pharmaceutical industry and medicine.
  • the incorporation of NTC into materials is today a source of generation of new composites with mechanical properties far superior to conventional materials (Ladeira, L. O et al., Processes for the continuous, large-scale synthesis of carbon nanotubes on cement clinker. , and nanostructured products (WO2009132407, November 5, 2009. PCT / BR2009 / 000119).
  • Carbon nanotubes are carbon fiber nanostructures in the form of tubes with a diameter ranging from 0.7 to 50 nm and a length ranging from 0.5 to 1000 nm.
  • the carbon atoms in the NTC are linked together by a strong covalent bond forming a flat hexagonal network typical of the graphene phase of carbon.
  • Carbon nanotubes have the shape of these coiled carbon sheets, which can be of a single rolled sheet or of multiple concentric rolled sheets, called NTCPS single wall or NTCPM, respectively.
  • This strong bond between the atoms of Carbon gives this nanomaterial exceptional physical and chemical properties such as: high mechanical strength, chemical inertia and large specific surface area (Ladeira, LO et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products WO2009132407, November 5, 2009. PCT / BR2009 / 000119).
  • the modulus of elasticity of carbon nanotubes is in the range of 1 to 1.8 TPa, which is much higher than 800 GPa, typical of commercial carbon fibers. Its tensile strength is up to 50 times higher than steel.
  • Such mechanical properties of NTCs give the materials containing them in their composition an improvement in their mechanical and structural characteristics (Treacy, M.J.; Ebbesen, T.W .; Gibson, J.M. Exceptionally high Young's modulus observed for individual carbon nanotubes.
  • NTC Chemical Vapor Deposition
  • CVD Chemical Vapor Deposition
  • This process works primarily through the decomposition or pyrolysis of light hydrocarbons (methane, ethylene, acetylene, etc.) as carbon precursor agents.
  • This decomposition is done under controlled atmosphere using mainly inert gases as a control agent of the synthesis environment and as a drag of reaction byproducts.
  • This synthesis system consists basically of a tubular reactor with temperature and gas flow controllers involved in the process (Ladeira, L. O; et al. Process for the continuous, large-scale synthesis of carbon nanotubes. on cement clinker, and nanostructured products. WO2009132407, November 5, 2009. PCT / BR2009 / 000119).
  • the classic transition metal nanoparticle anchoring supports used for the high efficiency synthesis of carbon nanotubes via chemical vapor deposition (CVD) are mesoporous structures involving highly thermally stable oxides at high temperatures, namely: AI 2 0 3 , Si0 2 , MgO and M0 3 or a mixture thereof, (Ladeira, L. O, et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, November 5, 2009 PCT / BR2009 / 000119).
  • Portland-type cement is a hygroscopic binder resulting from the mixture of fine-particulate calcium silicate, aluminate and ferroaluminate called cement clinker to which gypsum (CaSO, ⁇ ) is added.
  • cement clinker to which gypsum (CaSO, ⁇ ) is added.
  • Blast furnace slag is commonly used to replace part of this clinker, bringing significant advantages to the product (Silva, MG Portland cement with mineral additions.
  • ISAIA Geraldo Cechella (Org.) Building materials and principles of materials science and engineering. lv. Sao Paulo: IBRACON. Cap. 23, pp. 761-793,2007).
  • Blast furnace slag is a by-product of the manufacture of pig iron.
  • the materials are loaded in the blast furnace by the upper end.
  • the coke combustion gases preheat the materials until the ore reduction reactions are carried out. These gases are upstream and come in contact with downstream materials, reducing and melting the ore. This gives rise to pig iron and blast furnace slag at the bottom of the furnace.
  • the blast furnace slag is lighter and lies on the pig iron.
  • these materials are easily separated due to the difference in density (Mour ⁇ o, MB Brazilian Association of Metallurgy and Materials. Introduction to Steelmaking. S ⁇ o Paulo: Brazilian Association of Metallurgy and Materials, 2007. 428 P.; Rizzo, EMS Introduction to Processes S ⁇ o Paulo: Brazilian Association of Metallurgy and Materials (ABM), 2005. 150p.).
  • Blast furnace slag typically comprises approximately 45% calcium oxide (CaO), 35% silicon dioxide (SiO 2 ), 12% aluminum oxide (A1 2 0 3 ), 5% oxide of Magnesium (MgO) and 3% of other compounds.
  • the basic blast furnace slag has a hydraulic indicator of 1.2, determined by the CaO / S1O 2 > 1 ratio (Jacomino, VM et al. Environmental control of the pig iron production industries in Belo Horizonte: SEGRAC, 2002. 301p.), which is an ideal value to be added to cement without the need for any kind of activator.
  • nanostructured Portland cement becomes a high-tech material when compared to its current status as a conventional building material (Balaguru.P.N, et al. Nano-concrete: possibilities and challenges ", The State University of New Jersey, USA, RILEM Proceedings (2005), 2nd International Symposium on Nanotechnology in Construction (NICOM2), 233-243, 2005).
  • Jiang and colleagues describe the use of carbon nanotubes for cement reinforcement showing that better results in increasing mechanical properties are achieved by optimizing the dispersion and connection of nanotubes to the concrete matrix (Jiang, Xin et al. Carbon nanotubes as a new. reinforcement material for modern cement-based binders. "Institute of Materials Engineering, University of Siegen, Germany. RILEM Proceedings (2005), 2nd International Symposium on Nanotechnology in Construction (NICOM2) 209-213, 2005).
  • the present invention concerns the process of large scale production of carbon nanostructures on slag.
  • the blast furnace slag in the present invention is used as a ceramic matrix to support transition metal nanoparticles, whose function is to promote the in situ growth of these nanostructures directly thereon, thereby enabling the production of a type of Portland cement with nanostructures. of carbon.
  • the process described herein can be incorporated into the conventional cement production process in industry.
  • the invention also proposes, as part of the synthesis process of NTC and NFC on blast furnace slag, the enrichment of blast furnace slag with transition metals for the production of this nanostructured composite whether or not integrated with conventional industry. of cement.
  • the nanostructured material resulting from this process proposed in the present invention promotes mechanical reinforcement of the cementitious matrix making it more resistant from a mechanical and environmental point of view.
  • This process described in the present invention generates carbon nanostructures, such as carbon nanotubes and nanofibers, with low production cost.
  • the addition of slag in cement can then be increased as compared to slag cement due to the increased mechanical property induced by the presence of carbon nanostructures, which reduces the amount of clinker, thereby reducing CO 2 emission in cement production. This fact makes the proposed process is very advantageous in minimizing environmental damage.
  • Figure 1 represents the micrograph of the slag with NTC / NFC. In this, regions with large amount of nanostructured materials are observed after process using mixing with only one oxide.
  • Figure 2 represents the micrograph of the NTC / NFC slag. In this, regions with large amount of nanostructured materials are observed after process using mixing with one or more oxides.
  • the present invention is a chemical vapor phase deposition process for the synthesis of carbon nanotubes (NTC) and carbon nanofiber (NFC), in which blast furnace slag is used as a ceramic matrix to support metal nanoparticles. of transition (catalyst).
  • a light hydrocarbon gas passes through a reactor where it is decomposed at temperatures between 600 and 750 ° C.
  • This decomposition is catalyzed by the presence of metallic nanoparticles generating an increased local carbon concentration which induces the formation of NTC or NFC on the catalytic support and consequently when this material is synthesized and mixed with cement generates the nanostructured cement.
  • the method proposed in the present invention comprises the following steps:
  • step “a” solid phase enrichment may be accomplished by the physical mixing of metals or oxides or organometallic transition metal compounds to the phases resulting from the calcination of blast furnace slag precursors, preferably alkali metal oxide supports or alkaline earth metals, alkaline or alkaline earth metal aluminosilicates, alkaline or alkaline earth metal silicates, alkaline earth metal oxides, transition metals and semi-metals such as AI 2 O 3 , S1O 2 , CaO, MgO or phases due to mixtures of these compounds.
  • a mass concentration of between 0.1 and 10% of the transition metals relative to the blast furnace slag (support) may be used.
  • step "a" The solid phase incorporation of oxides or transition metal compounds or mixtures thereof in step "a" may occur after the production of the cement clinker preferably.
  • Liquid phase enrichment should include the addition of transition metal ions to slag by the following steps:
  • step "a” sulfates, nitrates, oxalates, citrates, phosphates, acetates or transition metal organometallic compounds.
  • the precursor carbon sources are light hydrocarbons methane, ethylene, propane, acetylene, carbon monoxide, natural gas, preferably natural gas being used.
  • Inert gases are nitrogen, argon, helium, preferably nitrogen.
  • step "b” preferably rotary inclined tubular (rotating central part) furnace may be used for a homogeneous growth of carbon nanotubes on slag powder may be used;
  • the residence time of the slag dust within the oven is controlled by varying the slope.
  • the possible temperature range should be between 600 and 1400 ° C, preferably 800 ° C and the total pressure close to and above atmospheric pressure.
  • the atmosphere must be controlled to prevent oxygen from entering the external environment.
  • the carbon nanomaterial synthesis process proposed in the present invention comprises a catalytic reaction of "in situ" synthesis of nanomaterials on blast furnace slag.
  • the process proposed in the present invention produces a nanostructured composite comprising carbon nanomaterials integrated with the blast furnace slag as a result of said process.
  • a composite may be used for the formulation of nanostructured products.
  • Nanostructured cement comprising the nanostructured composite obtained by the process described in the present invention, has improved physical and chemical properties by the presence of carbon nanostructures integrated into its structure.
  • the products obtained by the process described in the present invention may be used in various construction modalities.
  • the present invention may be better understood by the following non-limiting examples of the technology.
  • EXAMPLE 1 SYNTHESIS OF CARBON NANOTUBES SUPPORTED ON HIGH OVEN SLAG MIXED WITH AN OXIDE.

Abstract

The present invention relates to a chemical vapour deposition process for synthesizing carbon nanotubes (CNT) and/or carbon nanofibres (CNF) directly on blast-furnace slag. Said method produces nanomaterials which can be used in the formulation of nanostructured cement for civil construction.

Description

PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO SOBRE ESCÓRIA DE ALTO-FORNO , PRODUTOS E USO  PROCESS FOR SYNTHESIS OF CARBON NANOMATERIALS ON HIGH-OVEN SLAG, PRODUCTS AND USE
A presente invenção trata de um processo de deposição química da fase vapor para a síntese de nanotubos de carbono (NTC) e/ou nanofibra de carbono (NFC) diretamente sobre a escória de alto-forno. Tal método produz nanomateriais que podem ser utilizados na formulação de cimento nanoestruturado para a construção civil.  The present invention is a chemical vapor phase deposition process for the synthesis of carbon nanotubes (NTC) and / or carbon nanofiber (NFC) directly on the blast furnace slag. Such a method produces nanomaterials that can be used in the formulation of nanostructured cement for civil construction.
Os nanotubos e nanofibras de carbono atualmente são reconhecidos como um dos materiais mais importantes em nanociência e nanotecnologia e seu emprego é amplo em vários segmentos da engenharia de materiais, biomateriais , na química e petroquímica, na indústria farmacêutica e em medicina. Em particular, a incorporação de NTC a materiais é hoje uma fonte de geração de novos compósitos com propriedades mecânicas muito superiores aos materiais convencionais (Ladeira, L. O et al.Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, 05 de novembro de 2009. PCT/BR2009/000119) .  Carbon nanotubes and nanofibers are currently recognized as one of the most important materials in nanoscience and nanotechnology and are widely used in various segments of materials engineering, biomaterials, chemistry and petrochemicals, the pharmaceutical industry and medicine. In particular, the incorporation of NTC into materials is today a source of generation of new composites with mechanical properties far superior to conventional materials (Ladeira, L. O et al., Processes for the continuous, large-scale synthesis of carbon nanotubes on cement clinker. , and nanostructured products (WO2009132407, November 5, 2009. PCT / BR2009 / 000119).
Nanotubos de carbono são nanoestruturas fibrilares de carbono em forma de tubos com diâmetro variando de 0,7 a 50 nm e comprimento variando de 0,5 a 1000 nm. Os átomos de carbono nos NTC são ligados entre si por uma ligação covalente forte formando uma rede hexagonal plana típica da fase grafeno do carbono. Os nanotubos de carbono possuem formato destas folhas de carbono, enroladas, podendo ser de uma simples folha enrolada ou de múltiplas folhas concêntricas enroladas, denominadas nanotubos de carbono de parede simples - NTCPS ou de paredes múltiplas - NTCPM, respectivamente. Esta forte ligação entre os átomos de carbono confere a esse nanomaterial propriedades físicas e químicas excepcionais tais como: grande resistência mecânica, inércia química e grande área superficial específica (Ladeira, L. O. et al . Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, 05 de novembro de 2009. PCT/BR2009/000119) . Carbon nanotubes are carbon fiber nanostructures in the form of tubes with a diameter ranging from 0.7 to 50 nm and a length ranging from 0.5 to 1000 nm. The carbon atoms in the NTC are linked together by a strong covalent bond forming a flat hexagonal network typical of the graphene phase of carbon. Carbon nanotubes have the shape of these coiled carbon sheets, which can be of a single rolled sheet or of multiple concentric rolled sheets, called NTCPS single wall or NTCPM, respectively. This strong bond between the atoms of Carbon gives this nanomaterial exceptional physical and chemical properties such as: high mechanical strength, chemical inertia and large specific surface area (Ladeira, LO et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products WO2009132407, November 5, 2009. PCT / BR2009 / 000119).
O módulo de elasticidade dos nanotubos de carbono está na faixa de 1 a 1,8 TPa, o que é muito mais elevado que 800 GPa, típico das fibras de carbono comerciais. Sua tensão de ruptura chega a ser 50 vezes maior que a do aço. Tais propriedades mecânicas dos NTC conferem aos materiais que os contém em sua composição uma melhoria de suas características mecânicas e estruturais (Treacy, M. M. J.; Ebbesen, T. W.; Gibson, J. M. Exceptionally high Young' s modulus observed for individual carbon nanotubes.  The modulus of elasticity of carbon nanotubes is in the range of 1 to 1.8 TPa, which is much higher than 800 GPa, typical of commercial carbon fibers. Its tensile strength is up to 50 times higher than steel. Such mechanical properties of NTCs give the materials containing them in their composition an improvement in their mechanical and structural characteristics (Treacy, M.J.; Ebbesen, T.W .; Gibson, J.M. Exceptionally high Young's modulus observed for individual carbon nanotubes.
Nature, 381, 678-680 ,1996) .  Nature, 381, 678-680, 1996).
Dentre os vários processos de síntese de NTC tem-se o método por deposição química da fase vapor {Chemical Vapour Deposition - CVD) , o qual possui maior capacidade para escalonamento. Esse processo funciona basicamente através de decomposição ou pirólise de hidrocarbonetos leves (metano, etileno, acetileno, etc.) como agentes precursores de carbono. Essa decomposição é feita sob atmosfera controlada utilizando principalmente gases inertes como agente de controle do ambiente de síntese e como arraste dos subprodutos de reação. Este sistema de síntese é constituído basicamente de um reator tubular com controladores de temperatura e de vazão dos gases envolvidos no processo (Ladeira, L. O; et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, 05 novembro de 2009. PCT/BR2009/000119) . Among the various synthesis processes of NTC is the Chemical Vapor Deposition (CVD) method, which has the highest scalability. This process works primarily through the decomposition or pyrolysis of light hydrocarbons (methane, ethylene, acetylene, etc.) as carbon precursor agents. This decomposition is done under controlled atmosphere using mainly inert gases as a control agent of the synthesis environment and as a drag of reaction byproducts. This synthesis system consists basically of a tubular reactor with temperature and gas flow controllers involved in the process (Ladeira, L. O; et al. Process for the continuous, large-scale synthesis of carbon nanotubes. on cement clinker, and nanostructured products. WO2009132407, November 5, 2009. PCT / BR2009 / 000119).
Em geral, os processos de síntese de NTC por deposição química da fase vapor ocorrem à pressão atmosférica e a reação de síntese é catalisada com a utilização de metais de transição em forma de nanopartícuias ancoradas em um suporte metal-óxido termicamente estável. A função do catalisador é promover uma seletividade na reação de pirólise de modo que ela ocorra preferencialmente na superfície dessas partículas (Ladeira, L. O. et al . Process for the continuous, large- scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, 05 de novembro de 2009. PCT/BR2009/000119) .  In general, chemical vapor deposition NTC synthesis processes take place at atmospheric pressure and the synthesis reaction is catalyzed by the use of nanoparticulate transition metals anchored in a thermally stable metal oxide support. The function of the catalyst is to promote selectivity in the pyrolysis reaction so that it occurs preferentially on the surface of these particles (Ladeira, LO et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407 , November 5, 2009. PCT / BR2009 / 000119).
Os suportes clássicos de ancoramento de nanopartícuias de metais de transição usados para a síntese de grande eficiência de nanotubos de carbono via deposição química da fase vapor (CVD) são estruturas mesoporosas envolvendo óxidos de grande estabilidade térmica em altas temperaturas, a saber: AI203, Si02, MgO e M03 ou mistura destes, (Ladeira, L. O, et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, 05 de novembro de 2009. PCT/BR2009/000119) . The classic transition metal nanoparticle anchoring supports used for the high efficiency synthesis of carbon nanotubes via chemical vapor deposition (CVD) are mesoporous structures involving highly thermally stable oxides at high temperatures, namely: AI 2 0 3 , Si0 2 , MgO and M0 3 or a mixture thereof, (Ladeira, L. O, et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, November 5, 2009 PCT / BR2009 / 000119).
O cimento do tipo Portland é um aglomerante higroscópico resultante da mistura de silicatos, aluminatos e ferro-aluminatos de cálcio em particulado fino denominado clínquer de cimento ao qual é adicionado gipsita (CaSO,}) . Durante a fabricação do cimento, parte desse clínquer pode ser substituído por adições minerais. A escória de alto- forno é comumente empregada para substituir parte deste clinquer, trazendo vantagens significativas para o produto (Silva, M.G. Cimentos Portland com adições minerais. In: ISAIA, Geraldo Cechella (Org.) Materiais de construção civil e princípios de ciência e engenharia de materiais. lv. São Paulo: IBRACON. Cap. 23, p. 761-793,2007) . Portland-type cement is a hygroscopic binder resulting from the mixture of fine-particulate calcium silicate, aluminate and ferroaluminate called cement clinker to which gypsum (CaSO,}) is added. During cement manufacture, part of this clinker can be replaced by mineral additions. Blast furnace slag is commonly used to replace part of this clinker, bringing significant advantages to the product (Silva, MG Portland cement with mineral additions. In: ISAIA, Geraldo Cechella (Org.) Building materials and principles of materials science and engineering. lv. Sao Paulo: IBRACON. Cap. 23, pp. 761-793,2007).
A substituição de escória de alto-forno à moagem do clínquer com gesso apenas é possível porque a escória contém em sua composição os mesmos óxidos do clínquer, mas em quantidades diferentes (Neville, A M. Propriedades do concreto. 2. ed. São Paulo: Pini, 828: 1997) .  Substitution of blast furnace slag to clinker grinding with plaster is only possible because slag contains in its composition the same oxides as clinker, but in different amounts (Neville, A M. Properties of concrete. 2. ed. São Paulo : Pini, 828: 1997).
A escória de alto-forno é um subproduto da fabricação do ferro gusa. Para a produção do ferro-gusa, os materiais são carregados no alto-forno pela extremidade superior. Os gases resultantes da combustão do coque pré- aquecem os materiais até realizarem as reações de redução do minério. Esses gases seguem em fluxo ascendente e entram em contato com os materiais que têm fluxo descendente, reduzindo e fundindo o minério. Assim, origina-se o ferro- gusa e a escória de alto-forno na parte inferior do forno. A escória de alto-forno é mais leve e fica sobre o ferro- gusa. Com isso, esses materiais são facilmente separados devido à diferença de densidade (Mourão, M.B Associação brasileira de metalurgia e materiais. Introdução à siderurgia. São Paulo: Associação Brasileira de Metalurgia e Materiais, 2007. 428 p . ; Rizzo, E.M.S. Introdução aos processos siderúrgicos. São Paulo: Associação Brasileira de Metalurgia e Materiais (ABM) , 2005. 150p.) .  Blast furnace slag is a by-product of the manufacture of pig iron. For the production of pig iron, the materials are loaded in the blast furnace by the upper end. The coke combustion gases preheat the materials until the ore reduction reactions are carried out. These gases are upstream and come in contact with downstream materials, reducing and melting the ore. This gives rise to pig iron and blast furnace slag at the bottom of the furnace. The blast furnace slag is lighter and lies on the pig iron. Thus, these materials are easily separated due to the difference in density (Mourão, MB Brazilian Association of Metallurgy and Materials. Introduction to Steelmaking. São Paulo: Brazilian Association of Metallurgy and Materials, 2007. 428 P.; Rizzo, EMS Introduction to Processes São Paulo: Brazilian Association of Metallurgy and Materials (ABM), 2005. 150p.).
A escória de alto-forno sai do alto-forno na forma de líquido viscoso com temperatura entre 1350 °C e 1500 °C, (John, V.M. et al . Tecnologias e Materiais Alternativos de Construção. São Paulo: Editora da UNICAMP. Cap. 6, p.145- 190p, 2003) . Blast furnace slag exits the blast furnace as a viscous liquid with a temperature between 1350 ° C and 1500 ° C (John, VM et al. Construction. São Paulo: Publisher of UNICAMP. Chapter 6, p.145-190p, 2003).
A escória produzida em alto-forno possui composição típica de aproximadamente 45 % de óxido de cálcio (CaO) , 35 % de dióxido de silício (SÍO2) , 12 % de óxido de alumínio (A1203) , 5 % de óxido de Magnésio (MgO) e 3 % de outros compostos. A escória de alto-forno de caráter básico possui indicador de hidraulicidade de 1,2, determinado pela relação CaO / S1O2 > 1, (Jacomino, V.M. et al. Controle ambiental das indústrias de produção de ferro-gusa em altos-fornos a carvão vegetal. Belo Horizonte: SEGRAC, 2002. 301p.), que é um valor ideal para ser acrescentado ao cimento sem necessidade de nenhum tipo de ativador. Blast furnace slag typically comprises approximately 45% calcium oxide (CaO), 35% silicon dioxide (SiO 2 ), 12% aluminum oxide (A1 2 0 3 ), 5% oxide of Magnesium (MgO) and 3% of other compounds. The basic blast furnace slag has a hydraulic indicator of 1.2, determined by the CaO / S1O 2 > 1 ratio (Jacomino, VM et al. Environmental control of the pig iron production industries in Belo Horizonte: SEGRAC, 2002. 301p.), which is an ideal value to be added to cement without the need for any kind of activator.
Na literatura relacionada à pesquisa e desenvolvimento tecnológico do cimento existem várias inovações com intuito de melhorar as qualidades do cimento. Em geral, as pesquisas e desenvolvimentos tecnológicos nesta área estão centrados principalmente na incorporação de aditivos nanoestruturados ou surfactantes de modo a aumentar a resistência mecânica, alterar a fluidez ou modificar a velocidade de cura do cimento. Foram encontrados no estado da técnica alguns documentos que descrevem tecnologias e trabalhos científicos correlacionados a cimentos nanoestruturados (Ladeira, L. O.; et al . Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, 05 de novembro de 2009. PCT/BR2009/000119) .  In the literature related to the research and technological development of cement there are several innovations in order to improve the qualities of cement. In general, research and technological developments in this area are mainly focused on incorporating nanostructured additives or surfactants in order to increase mechanical strength, change flowability or modify the curing speed of cement. Some documents describing technologies and scientific work related to nanostructured cements (Ladeira, LO; et al. Process for the continuous, large-scale synthesis of carbon nanotubes on cement clinker, and nanostructured products. WO2009132407, 05 de November 2009. PCT / BR2009 / 000119).
Balaguru e colaboradores mostram que o cimento com adição de objetos em escala nanométrica abre um enorme campo de oportunidades na área de compósitos de ultra-alta resistência. Assim, o cimento Portland nanoestruturado torna-se um material de alta tecnologia quando comparado com seu atual status de um material convencional de construção (Balaguru.P. N, et al . Nano-concrete : possibilities and challenges", The State University of New Jersey, USA. RILEM Proceedings (2005) , 2nd International Symposium on Nanotechnology in Construction (NICOM2), 233- 243, 2005) . Balaguru and colleagues show that nanoscale object-added cement opens up a huge field of opportunity in the ultra-high composites area resistance. Thus, nanostructured Portland cement becomes a high-tech material when compared to its current status as a conventional building material (Balaguru.P.N, et al. Nano-concrete: possibilities and challenges ", The State University of New Jersey, USA, RILEM Proceedings (2005), 2nd International Symposium on Nanotechnology in Construction (NICOM2), 233-243, 2005).
Jiang e colaboradores descrevem o uso de nanotubos de carbono para reforço de cimento mostrando que melhores resultados em aumento de propriedades mecânicas são alcançados com a otimização da dispersão e conexão dos nanotubos à matriz de concreto (Jiang, Xin et al. Carbon nanotubes as a new reinforcement material for modern cement-based binders". Institute of Materials Engineering, University of Siegen, Germany. RILEM Proceedings (2005) , 2nd International Symposium on Nanotechnology in Construction (NICOM2) 209-213, 2005) .  Jiang and colleagues describe the use of carbon nanotubes for cement reinforcement showing that better results in increasing mechanical properties are achieved by optimizing the dispersion and connection of nanotubes to the concrete matrix (Jiang, Xin et al. Carbon nanotubes as a new. reinforcement material for modern cement-based binders. "Institute of Materials Engineering, University of Siegen, Germany. RILEM Proceedings (2005), 2nd International Symposium on Nanotechnology in Construction (NICOM2) 209-213, 2005).
A adição de nanoestruturas de carbono ao cimento produz melhorias nas matrizes cimenticias, promovendo mudanças na microestrutura de forma a melhorar o desempenho do compósito. Em particular, a adição de 0,05 a 1 % de nanotubos de carbono ao cimento induze um aumento de até 79 % em seu módulo de compressão. A adição de nanotubos de carbono em concentrações na faixa de 0,05 a 1 % ao cimento é um fator impeditivo devido ao custo e limitações em quantidade de fornecimento desse nanomaterial . Resultados referentes à melhoria de propriedades mecânicas são apresentados por Han et al . , 2015 (Han, B et al . Review of nanocarbon-engineered multifunctional cementitious composities. Composities: Part A, n.70, p. 69-81, 2015) . No estado da técnica não foi encontrada tecnologia similar utilizando-se do processo de produção de nanotubos de carbono sobre escória de alto-forno propostos no presente pedido. The addition of carbon nanostructures to cement produces improvements in cementitious matrices, promoting changes in the microstructure to improve composite performance. In particular, the addition of 0.05 to 1% carbon nanotubes to cement induces an increase of up to 79% in its compression modulus. The addition of carbon nanotubes in concentrations in the range of 0.05 to 1% to the cement is an impeding factor due to the cost and limitations in supply of this nanomaterial. Results regarding the improvement of mechanical properties are presented by Han et al. , 2015 (Han, B et al. Review of nanocarbon-engineered multifunctional cementitious composites. Composities: Part A, No. 70, pp. 69-81, 2015). In the state of the art no similar technology was found using the process of producing carbon nanotubes on blast furnace slag proposed in the present application.
A presente invenção trata do processo de produção em larga escala de nanoestruturas de carbono sobre a escória. A escória de alto-forno na presente invenção é usada como matriz cerâmica para suporte de nanoparticulas de metais de transição, cu a função é promover o crescimento em situ dessas nanoestruturas diretamente sobre ela, permitindo assim a produção de um tipo de cimento Portland com nanoestruturas de carbono. O processo aqui descrito pode ser incorporado no processo produtivo convencional de cimento na indústria. O invento propõe, também, como parte do processo de síntese de NTC e NFC sobre a escória de alto-forno, o enriquecimento da escória de alto-forno com metais de transição para a produção deste compósito nanoestruturado de forma integrada ou não à indústria convencional de cimento.  The present invention concerns the process of large scale production of carbon nanostructures on slag. The blast furnace slag in the present invention is used as a ceramic matrix to support transition metal nanoparticles, whose function is to promote the in situ growth of these nanostructures directly thereon, thereby enabling the production of a type of Portland cement with nanostructures. of carbon. The process described herein can be incorporated into the conventional cement production process in industry. The invention also proposes, as part of the synthesis process of NTC and NFC on blast furnace slag, the enrichment of blast furnace slag with transition metals for the production of this nanostructured composite whether or not integrated with conventional industry. of cement.
O material nanoestruturado resultante deste processo proposto na presente invenção promove o reforço mecânico da matriz cimentícia tornando-a mais resistente tanto do ponto de vista mecânico quanto ambiental. Este processo descrito na presente invenção gera nanoestruturas de carbono, tais como nanotubos e nanofibras de carbono, com baixo custo de produção. A adição de escória em cimento pode então ser aumentada quando comparada ao cimento com escória devido ao aumento da propriedade mecânica induzida pela presença de nanoestruturas de carbono, o que reduz a quantidade de clínquer, consequentemente reduzindo a emissão de CO2 na produção de cimento. Este fato torna o processo proposto muito vantajoso, por minimizar danos ambientais . The nanostructured material resulting from this process proposed in the present invention promotes mechanical reinforcement of the cementitious matrix making it more resistant from a mechanical and environmental point of view. This process described in the present invention generates carbon nanostructures, such as carbon nanotubes and nanofibers, with low production cost. The addition of slag in cement can then be increased as compared to slag cement due to the increased mechanical property induced by the presence of carbon nanostructures, which reduces the amount of clinker, thereby reducing CO 2 emission in cement production. This fact makes the proposed process is very advantageous in minimizing environmental damage.
BREVE DESCRIÇÃO DAS FIGURAS BRIEF DESCRIPTION OF THE FIGURES
A Figura 1 representa a micrografia da escória com NTC/NFC. Nesta, observa-se regiões com grande quantidade de materiais nanoestruturado após processo utilizando-se mistura com apenas um óxido. Figure 1 represents the micrograph of the slag with NTC / NFC. In this, regions with large amount of nanostructured materials are observed after process using mixing with only one oxide.
A Figura 2 representa a micrografia da escória com NTC/NFC. Nesta, observa-se regiões com grande quantidade de materiais nanoestruturado após processo utilizando-se mistura com um ou mais óxidos.  Figure 2 represents the micrograph of the NTC / NFC slag. In this, regions with large amount of nanostructured materials are observed after process using mixing with one or more oxides.
DESCRIÇÃO DETALHADA DA TECNOLOGIA DETAILED DESCRIPTION OF TECHNOLOGY
A presente invenção trata de um processo de deposição química da fase vapor para a síntese de nanotubos de carbono (NTC) e nanofibra de carbono (NFC) , no qual a escória de alto-forno é usada como matriz cerâmica para suporte de nanopartícuias de metais de transição (catalisador) .  The present invention is a chemical vapor phase deposition process for the synthesis of carbon nanotubes (NTC) and carbon nanofiber (NFC), in which blast furnace slag is used as a ceramic matrix to support metal nanoparticles. of transition (catalyst).
Trata-se de um processo de síntese direta de NTC/NFC suportados em escória de alto-forno, que posteriormente podem ser misturados ao cimento através da mistura física, gerando um compósito de nanotubos de carbono/escória de alto-forno/cimento .  It is a direct synthesis process of NTC / NFC supported on blast furnace slag, which can then be mixed with cement by physical mixing, generating a carbon nanotube / blast furnace / cement composite.
Nesse processo, um gás hidrocarboneto leve passa por um reator onde é decomposto a temperaturas entre 600 a 750 °C. Essa decomposição é catalisada pela presença de nanopartícuias metálicas gerando uma concentração local aumentada de carbono o que induz a formação de NTC ou NFC sobre o suporte catalítico e consequentemente quando esse material é sintetizado e misturado ao cimento gera o cimento nanoestruturado. O método proposto na presente invenção compreende as seguintes etapas: In this process, a light hydrocarbon gas passes through a reactor where it is decomposed at temperatures between 600 and 750 ° C. This decomposition is catalyzed by the presence of metallic nanoparticles generating an increased local carbon concentration which induces the formation of NTC or NFC on the catalytic support and consequently when this material is synthesized and mixed with cement generates the nanostructured cement. The method proposed in the present invention comprises the following steps:
a) Enriquecer a escória de alto-forno em fase sólida e/ou fase líquida com metais ou óxidos ou compostos organometálicos de metais de transição ou sais, compreendendo cátions de metais de transição tais como Ti, Cr, Mn, Cu, Mo, W, Al, Ta, Rh, Pt, Pd, Au, Ir, Ru, Nb, Zr, sendo preferencialmente Fe, Co e Ni; b) Introduzir a escória de alto-forno enriquecida em um reator, de atmosfera controlada e redutora, com a injeção de fontes precursoras de carbono, preferencialmente hidrocarbonetos leves, e um gás inerte como agente carreador e aplicação de altas temperaturas nesse ambiente para a ocorrência da reação de pirólise e consequente síntese de NTC e/ou NFC. c) Submeter o material produzido em "b" a um resfriamento natural.  (a) Enriching solid phase and / or liquid phase blast furnace slag with metals or oxides or organometallic compounds of transition metals or salts, comprising transition metal cations such as Ti, Cr, Mn, Cu, Mo, W Al, Ta, Rh, Pt, Pd, Au, Ir, Ru, Nb, Zr, preferably Fe, Co and Ni; b) Introduce the enriched blast furnace slag into a controlled atmosphere and reducing reactor with the injection of carbon precursor sources, preferably light hydrocarbons, and an inert gas as carrier and application of high temperatures in this environment to occur. pyrolysis reaction and consequent synthesis of NTC and / or NFC. c) Subject the material produced in "b" to natural cooling.
Na etapa "a", o enriquecimento em fase sólida pode ser realizado pela mistura física de metais ou óxidos ou compostos organometálicos de metais de transição às fases resultantes da calcinação dos precursores da escória de alto-forno, preferencialmente os suportes óxidos de metais alcalinos ou metais alcalinos terrosos, aluminosilicatos de metais alcalinos ou alcalinos terrosos, silicatos de metais alcalinos ou alcalinos terrosos, óxidos de metais alcalinos terrosos, metais de transição e semi-metais tais como AI2O3, S1O2, CaO, MgO ou fases decorrentes de misturas destes compostos. Na etapa "a", para o enriquecimento em fase sólida pode-se utilizar uma concentração, em massa, entre 0,1 e 10% dos metais de transição em relação à escória de alto- forno (suporte) . In step "a", solid phase enrichment may be accomplished by the physical mixing of metals or oxides or organometallic transition metal compounds to the phases resulting from the calcination of blast furnace slag precursors, preferably alkali metal oxide supports or alkaline earth metals, alkaline or alkaline earth metal aluminosilicates, alkaline or alkaline earth metal silicates, alkaline earth metal oxides, transition metals and semi-metals such as AI 2 O 3 , S1O 2 , CaO, MgO or phases due to mixtures of these compounds. In step "a", for solid phase enrichment, a mass concentration of between 0.1 and 10% of the transition metals relative to the blast furnace slag (support) may be used.
A incorporação, em fase sólida, de óxidos ou compostos de metais de transição ou mistura deles na etapa "a" pode ocorrer após a produção do clinquer de cimento preferencialmente .  The solid phase incorporation of oxides or transition metal compounds or mixtures thereof in step "a" may occur after the production of the cement clinker preferably.
O enriquecimento em fase liquida deve compreender a adição de ions de metais de transição à escória pelas seguintes etapas:  Liquid phase enrichment should include the addition of transition metal ions to slag by the following steps:
i. Dissolução de compostos de metais de transição como soluto, preferencialmente em líquidos orgânicos polares anidros e voláteis como solventes;  i. Dissolution of transition metal compounds as solute, preferably in anhydrous and volatile polar organic liquids as solvents;
ii. Mistura da solução obtida em (i) à escória de alto-forno, até se alcançar uma mistura homogénea;  ii. Mixing the solution obtained in (i) with the blast furnace slag until a homogeneous mixture is achieved;
iii. Secagem da mistura obtida em (ii) por evaporação do solvente;  iii. Drying the mixture obtained in (ii) by evaporation of the solvent;
iv. Calcinação da mistura obtida em (iii) em temperaturas de 200°C a 800°C.  iv. Calcination of the mixture obtained in (iii) at temperatures from 200 ° C to 800 ° C.
Os seguintes ânions podem ser utilizados na etapa "a": sulfatos, nitratos, oxalatos, citratos, fosfatos, acetatos ou compostos organometálicos de metais de transição .  The following anions may be used in step "a": sulfates, nitrates, oxalates, citrates, phosphates, acetates or transition metal organometallic compounds.
Na etapa "b", as fontes precursoras de carbono são os hidrocarbonetos leves metano, etileno, propano, acetileno, monóxido de carbono, gás natural, sendo preferencialmente utilizado gás natural. Os gases inertes utilizados como agentes carreadores são nitrogénio, argônio, hélio, sendo preferencialmente o nitrogénio. In step "b", the precursor carbon sources are light hydrocarbons methane, ethylene, propane, acetylene, carbon monoxide, natural gas, preferably natural gas being used. Inert gases The carrier agents used are nitrogen, argon, helium, preferably nitrogen.
Na etapa "b", pode-se utilizar forno, preferencialmente tubular inclinado rotativo (parte central giratória) para um crescimento de modo homogéneo dos nanotubos de carbono sobre o pó da escória pode ser utilizado; além do tempo de residência do pó da escória dentro do forno ser controlado pela variação da inclinação do mesmo.  In step "b", preferably rotary inclined tubular (rotating central part) furnace may be used for a homogeneous growth of carbon nanotubes on slag powder may be used; In addition, the residence time of the slag dust within the oven is controlled by varying the slope.
A faixa de temperatura possível deve ser entre 600 a 1400°C, sendo preferencialmente 800°C e a pressão total próxima e superior à pressão atmosférica. A atmosfera deve ser controlada para evitar a entrada de oxigénio do ambiente externo.  The possible temperature range should be between 600 and 1400 ° C, preferably 800 ° C and the total pressure close to and above atmospheric pressure. The atmosphere must be controlled to prevent oxygen from entering the external environment.
O processo de síntese de nanomateriais de carbono proposto na presente invenção compreende uma reação catalítica de síntese "in si tu" de nanomateriais sobre a escória de alto-forno.  The carbon nanomaterial synthesis process proposed in the present invention comprises a catalytic reaction of "in situ" synthesis of nanomaterials on blast furnace slag.
O processo proposto na presente invenção produz um compósito nanoestruturado caracterizado por ser constituído de nanomateriais de carbono integrados à escória de alto- forno, resultado do referido processo. Tal compósito pode ser utilizado para a formulação de produtos nanoestruturados .  The process proposed in the present invention produces a nanostructured composite comprising carbon nanomaterials integrated with the blast furnace slag as a result of said process. Such a composite may be used for the formulation of nanostructured products.
O cimento nanoestruturado, compreendendo o compósito nanoestruturado obtido pelo processo descrito na presente invenção, apresenta melhoria nas propriedades físicas e químicas pela presença de nanoestruturas de carbono integradas à sua estrutura. Os produtos obtidos através do processo descrito na presente invenção podem ser utilizados em diversas modalidades de obas na construção civil. Nanostructured cement, comprising the nanostructured composite obtained by the process described in the present invention, has improved physical and chemical properties by the presence of carbon nanostructures integrated into its structure. The products obtained by the process described in the present invention may be used in various construction modalities.
A presente invenção pode ser mais bem compreendida através dos exemplos que se seguem, não limitantes da tecnologia .  The present invention may be better understood by the following non-limiting examples of the technology.
EXEMPLO 1. SÍNTESE DE NANOTUBOS DE CARBONO SUPORTADOS SOBRE ESCÓRIA DE ALTO-FORNO COM MISTURA DE UM ÓXIDO.  EXAMPLE 1. SYNTHESIS OF CARBON NANOTUBES SUPPORTED ON HIGH OVEN SLAG MIXED WITH AN OXIDE.
Dez gramas de escória de alto-forno moída foram misturadas a 1,44 g de Fe203, o que gera uma mistura com composição 10% em peso de Fe em relação à massa da escória de alto-forno. A mistura do material foi levada a um reator tipo CVD, durante 30 minutos sobre uma placa de carbeto de silício (SiC) . O material foi submetido a uma atmosfera inerte de argônio em um fluxo de 100 sccm e um fluxo de etileno a 40 sccm. Em seguida, o fluxo de etileno é interrompido e a amostra é resfriada até a temperatura ambiente sob fluxo de argônio a 100 sccm. Após o resfriamento, a amostra é retirada do reator. Este processo de síntese foi caracterizado por microscopia eletrônica de varredura para verificar a eficiência do processo, como demonstrado na Figura 1. Nesta figura observa-se a formação de NTC e NFC com diferentes morfologias. Ten grams of ground blast furnace slag were mixed with 1.44 g of Fe 2 03, which creates a mixture having the composition 10% Fe by weight relative to the mass of blast furnace slag. The material was mixed in a CVD reactor for 30 minutes on a silicon carbide (SiC) plate. The material was subjected to an inert argon atmosphere at a flow rate of 100 sccm and an ethylene flow at 40 sccm. Then the ethylene flow is stopped and the sample is cooled to room temperature under argon flow at 100 sccm. After cooling, the sample is taken from the reactor. This synthesis process was characterized by scanning electron microscopy to verify the efficiency of the process, as shown in Figure 1. This figure shows the formation of NTC and NFC with different morphologies.
EXEMPLO 2. SÍNTESE DE NANOTUBOS DE CARBONO SUPORTADOS SOBRE ESCÓRIA DE ALTO-FORNO COM MISTURA DE DOIS OU MAIS ÓXIDOS.  EXAMPLE 2. SUMMARY OF CARBON NANOTUBES SUPPORTED ON HIGH OVEN SLAG MIXED OF TWO OR MORE OXIDES.
Dez gramas escória de alto-forno moída foi misturado a 1,44 g de Fe203, o que gera uma mistura com composição 10% em peso de Fe em relação à massa da escória de alto-forno. Alternativamente, adicionou-se 0,2 g de AI2O3 que representa uma composição com 0,2% em peso de Al em relação à massa da escória de alto-forno. A seguir, a mistura foi espalhada sobre uma placa de carbeto de silício (SiC) e levada sob atmosfera inerte a 750°C num fluxo de argônio e etileno, respectivamente, de 100 sccm e 40 sccm durante 30 minutos. Em seguida, o fluxo de etileno é interrompido e a amostra é resfriada até a temperatura ambiente sob fluxo de argônio a 100 sccm. Após o resfriamento, a amostra é retirada do reator. Esta amostra foi caracterizada por microscopia eletrônica de varredura e os resultados são mostrados na Figura 2. Ten grams of ground slag furnace was mixed with 1.44 g of Fe 2 03, which creates a mixture having the composition 10% Fe by weight relative to the mass of blast furnace slag. Alternatively, 0.2 g Al 2 O 3 representing a composition with 0.2 wt.% Al by weight of the blast furnace slag was added. Next, the The mixture was spread over a silicon carbide (SiC) plate and brought under an inert atmosphere at 750 ° C in an argon and ethylene flow of 100 sccm and 40 sccm respectively for 30 minutes. Then the ethylene flow is stopped and the sample is cooled to room temperature under argon flow at 100 sccm. After cooling, the sample is taken from the reactor. This sample was characterized by scanning electron microscopy and the results are shown in Figure 2.

Claims

REIVINDICAÇÕES
1. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, caracterizado por utilizar a escória de alto-forno como suporte catalítico para o crescimento "in si tu" de nanotubos de carbono (NTC) e/ou nanofibra de carbono (NFC) compreendendo as seguintes etapas:  1. CARBON NANOMATERIAL SYNTHESIS PROCESS, characterized by using blast furnace slag as a catalytic support for the in situ growth of carbon nanotubes (NTC) and / or carbon nanofiber (NFC) comprising the following steps: :
a) Enriquecer a escória de alto-forno em fase sólida ou em fase líquida com metais ou óxidos ou compostos organometálicos de metais de transição ou sais, compreendendo cátions de metais de transição tais como Ti, Cr, Mn, Cu, Mo, W, Al, Ta, Rh, Pt, Pd, Au, Ir, Ru, Nb, Zr, sendo preferencialmente Fe, Co e Ni; (a) enriching solid or liquid blast furnace slag with metals or oxides or organometallic compounds of transition metals or salts, comprising transition metal cations such as Ti, Cr, Mn, Cu, Mo, W, Al, Ta, Rh, Pt, Pd, Au, Ir, Ru, Nb, Zr, preferably Fe, Co and Ni;
b) Introduzir a escória de alto-forno enriquecida em um reator, de atmosfera controlada e redutora, com a injeção de hidrocarbonetos leves e um gás inerte como agente carreador e aplicação de altas temperaturas nesse ambiente para a ocorrência da reação de pirólise e consequente síntese de NTC e/ou NFC; b) Introduce the enriched blast furnace slag into a controlled atmosphere and reducing reactor with the injection of light hydrocarbons and an inert gas as carrier and application of high temperatures in this environment for the occurrence of the pyrolysis reaction and consequent synthesis. NTC and / or NFC;
c) Submeter o material produzido em "b" a um resfriamento natural . c) Subject the material produced in "b" to natural cooling.
2. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, de acordo com a reivindicação 1, etapa "a", caracterizado pelo enriquecimento em fase sólida ser realizado pela mistura física de metais ou óxidos ou compostos organometálicos de metais de transição às fases resultantes da calcinação dos precursores da escória de alto-forno, preferencialmente os suportes óxidos de metais alcalinos ou metais alcalinos terrosos, aluminosilicatos de metais alcalinos ou alcalinos terrosos, silicatos de metais alcalinos ou alcalinos terrosos, óxidos de metais alcalinos terrosos, metais de transição e semi-metais, tais como AI2O3, S1O2, CaO, MgO ou fases decorrentes de misturas destes compostos. CARBON NANOMATERIAL SYNTHESIS PROCESS according to claim 1, step "a", characterized in that the solid phase enrichment is carried out by the physical mixing of metals or oxides or organometallic compounds of transition metals to the phases resulting from the calcination of the compounds. blast furnace slag precursors, preferably alkali metal or alkaline earth metal oxide supports, alkaline or alkaline earth metal aluminosilicates, alkaline or alkaline earth metal silicates, alkaline earth metal oxides, transition metals and semi-metals, such as AI 2 O 3 , S1O 2 , CaO, MgO or phases resulting from mixtures of these compounds.
3. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, de acordo com a reivindicação 2, caracterizado por utilizar uma concentração, em massa, entre 0,1 e 10% dos metais de transição em relação à escória de alto-forno (suporte) .  CARBON NANOMATERIAL SYNTHESIS PROCESS according to claim 2, characterized in that it uses a mass concentration of between 0.1 and 10% of the transition metals in relation to the blast furnace slag (support).
4. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, de acordo com a reivindicação 1, etapa "a", caracterizado pelo enriquecimento em fase liquida compreender a adição de ions de metais de transição à escória e compreender as seguintes etapas:  CARBON NANOMATERIAL SYNTHESIS PROCESS according to claim 1, step "a", characterized in that the liquid phase enrichment comprises the addition of transition metal ions to the slag and comprises the following steps:
i. Dissolução de compostos de metais de transição como soluto, preferencialmente em líquidos orgânicos polares anidros e voláteis como solventes; i. Dissolution of transition metal compounds as solute, preferably in anhydrous and volatile polar organic liquids as solvents;
ii. Mistura da solução obtida em (i) à escória de alto- forno, até se alcançar uma mistura homogénea; ii. Mixing the solution obtained in (i) with the blast furnace slag until a homogeneous mixture is achieved;
iii. Secagem da mistura obtida em (ii) por evaporação do solvente ; iii. Drying the mixture obtained in (ii) by evaporation of the solvent;
iv. Calcinação da mistura obtida em (iii) em temperaturas de 200°C a 800°C. iv. Calcination of the mixture obtained in (iii) at temperatures from 200 ° C to 800 ° C.
5. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, de acordo com a reivindicação 1, etapa "a", caracterizado por compreender os seguintes ânions : sulfatos, nitratos, oxalatos, citratos, fosfatos, acetatos ou compostos organometálicos de metais de transição.  A process for the synthesis of carbon dioxide according to claim 1, step "a", comprising the following anions: sulfates, nitrates, oxalates, citrates, phosphates, acetates or transition metal organometallic compounds.
6. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, de acordo com a reivindicação 1, etapa "b" , caracterizado pelas fontes precursoras de carbono serem os hidrocarbonetos leves metano, etileno, propano, acetileno, monóxido de carbono, gás natural, sendo preferencialmente o gás natural . CARBON NANOMATERIAL SYNTHESIS PROCESS according to claim 1, step "b", characterized in that the precursor carbon sources are methane, ethylene, propane, acetylene, light hydrocarbons. carbon monoxide, natural gas, preferably natural gas.
7. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, de acordo com a reivindicação 1, etapa "b" , caracterizado pelos gases inertes como agentes carreadores serem nitrogénio, argônio, hélio, sendo preferencialmente o nitrogénio .  Process for the synthesis of carbon dioxide according to claim 1, step "b", characterized in that the inert gases as carrier agents are nitrogen, argon, helium, preferably nitrogen.
8. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, reivindicação 1, etapa "b", caracterizado por ser realizada em forno, preferencialmente tubular inclinado rotativo (parte central giratória) para um crescimento de modo homogéneo dos nanotubos de carbono sobre o pó da escória; e pelo tempo de residência do pó da escória dentro do forno ser controlado pela variação da inclinação do mesmo.  CARBON NANOMATERIAL SYNTHESIS PROCESS, claim 1, step "b", characterized in that it is carried out in an oven, preferably rotating inclined tubular (rotating central part) for a homogeneous growth of carbon nanotubes on the slag powder; and the residence time of the slag dust within the furnace is controlled by varying the slope thereof.
9. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE CARBONO, de acordo com a reivindicação 1, etapa "b", caracterizado por compreender uma temperatura na faixa de 600 a 1400°C, sendo preferencialmente a 800°C.  A process for the synthesis of carbon dioxide according to claim 1, step "b", characterized in that it comprises a temperature in the range of 600 to 1400 ° C, preferably at 800 ° C.
10. PROCESSO PARA SÍNTESE DE NANOMATERIAIS DE 10. PROCESS FOR SYNTHESIS OF NANOMATERIALS OF
CARBONO, de acordo com a reivindicação 1, etapa "b", caracterizado por compreender uma pressão total próxima e superior à pressão atmosférica. CARBON according to claim 1, step "b", characterized in that it comprises a total pressure close to and above atmospheric pressure.
11. COMPÓSITO NANOESTRUTURADO caracterizado por ser constituído por nanomateriais de carbono integrados à escória de alto-forno, resultado do processo descrito nas reivindicações 1 a 10.  Nanostructured composite consisting of carbon nanomaterials integrated with the blast furnace slag as a result of the process described in claims 1 to 10.
12. PRODUTOS NANOESTRUTURADOS caracterizados por conterem o compósito nanoestruturado descrito na reivindicação 11. Nanostructured products characterized in that they contain the nanostructured composite described in claim 11.
13. CIMENTO NANOESTRUTURADO, caracterizado por compreender o compósito nanoestruturado descrito na reivindicação 11. Nanostructured cement comprising the nanostructured composite described in claim 11.
14. USO dos produtos definidos pelas reivindicações 11 a 13, caracterizado por ser para a construção civil.  Use of the products as defined in claims 11 to 13, characterized in that they are for construction.
PCT/BR2018/050175 2017-05-30 2018-05-28 Process for synthesizing carbon nanomaterials on blast-furnace slag, products and use WO2018218325A1 (en)

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