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
  • C04B7/00—Hydraulic cements
  • C04B7/14—Cements containing slag
  • C04B7/147—Metallurgical slag
  • C04B7/153—Mixtures thereof with other inorganic cementitious materials or other activators
  • C04B7/21—Mixtures thereof with other inorganic cementitious materials or other activators with calcium sulfate containing activators
• • 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
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/42—Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells
  • C09K8/46—Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells containing inorganic binders, e.g. Portland cement
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding

Definitions

• the invention relates to a method for producing sulfate cement or sulfate cement additives.
• blast furnace slag was ground with 15% by weight calcium sulfate in the form of raw gypsum and about 2% by weight Portland cement was added.
• the presence of hydrated lime in the first hardening stage has turned out to be necessary, because otherwise a dense gel layer will form primarily before sulfatic hardening takes place.
• blast furnace slags are unsuitable for the production of sulphate metallurgical cement. This is all the more true as conventional blast furnace slags generally have a relatively low alumina content, so that the desired formation of sulfoaluminates is unsuccessful or insufficient, so that the risk of gypsum blowing remains. Finally, a high lime content is required, which is also generally not the case with blast furnace slag. For all of the reasons mentioned, sulphate metallurgical cements have gained no importance in construction practice.
• the invention now aims to provide a method of the type mentioned at the beginning with which it is possible to achieve cement or cement aggregates with excellent resistance to sulfate and sea water and which can be used, for example, as borehole cements, the risk of gypsum blowing being avoided with certainty.
• the process according to the invention essentially consists in mixing hydraulically active synthetic slags with a slag basicity CaO / SiO 2 between 1.35 and 1.6, such as waste incineration slags and / or blast furnace slags mixed with steel slags after reduction of metal oxides in the melt, and an Al2 ⁇ -3 content of 10 to 20% by weight and an iron oxide content of less than 2.5% by weight with 5 to 20% by weight, based on the total mixture of an alkaline earth metal sulfate, such as raw gypsum, exhaust gypsum , Flue gas desulfurization system gypsum, gypsum or anhydrite mixed in ground or crushed form.
• the AI2O3 content can be set to the specified values of 10 to 20% by weight, whereby by reducing the liquid slag not only the heavy metal content but also the Iron oxide content must be brought below 2.5% by weight in order not to subsequently observe any undesirable side effects. Because such a highly purified synthetic slag is now used, a number of materials which are difficult to dispose of, such as, for example, flue gas desulfurization system gypsum, raw gypsum, exhaust gypsum, but also gypsum and anhydrite can be used as alkaline earth metal sulfate carriers.
• the slags must be ground to a much lower fineness than was the case with known sulfate smelter cements, and it is particularly not necessary to grind the slags together with gypsum, as was the case in the past, in order to achieve a correspondingly good, homogeneous mixture guarantee.
• the usual blending of raw gypsum with the slag in the production of sulphate metallurgical cements presents a number of difficulties during grinding. In such mixtures, gypsum has a tendency to smear, so that the desired fineness cannot be easily achieved.
• the high degree of fineness required for a homogeneous distribution of the gypsum can therefore only be achieved with great difficulty.
• the synthetic slag according to the invention it is sufficient to grind this slag to a much lower fineness and to subsequently add gypsum in a correspondingly lower fineness, although the desired homogeneity of the mixture can nevertheless be achieved.
• the procedure is advantageously such that a grinding fineness of the synthetic slags between 2800 and 3500 cm ⁇ / g is selected, such grinding fineness being significantly less than the grinding fineness required for known sulphate metallurgical cements.
• the procedure is advantageously such that the Al 2 O 3 content is set between 12 and 18% by weight.
• CaS04 is advantageously used in amounts of between 8 and 15% by weight, with a corresponding rapid hardening being ensured by selecting the slag basicity to be greater than 1.45, preferably about 1.5.
• the AI2O3 content can be adjusted in a particularly simple manner by adding clays or alumina, this adjustment being able to take place in the liquid slag phase.
• Steel slags usually contain about 16% by weight SiO 2, 50% by weight CaO and 1% by weight Al 2 O 3. Such steel slags can thus be used as lime carriers to adjust the basicity of other slags, such as waste incineration slags, which are mostly to be addressed as acid slags.
• Blast furnace slags are usually also referred to as acidic slags and are rarely available with a slag basicity greater than 1.1 or 1.2.
• Blast furnace slag cements usually contain SiO 2 in amounts of approximately 37% by weight and CaO in amounts of approximately 32% by weight.
• AI2O3 is usually contained in an amount of about 13% by weight, so that mixtures of steel slags and blast furnace slags in liquid form after the basicity of the AI2O3 content has been appropriately adjusted and after the excessive chromium and iron content of steel slags has been reduced , for example using a metal bath, are suitable for a synthetic slag which subsequently converts to sulfate cement can be worked.
• Waste incineration slags are generally also referred to as acidic slags, such slags generally being characterized by an Al 2 O 3 content of the order of 10 to 25% by weight and a basicity of less than 0.5.
• Such slags thus contain significantly higher proportions of SiO 2 than CaO and are also not suitable for themselves as a starting material without appropriate adjustment of the basicity and corresponding reduction of the metal oxides.
• the appropriate slag mixture for the required hydraulically active synthetic slag must be set in the liquid phase to ensure the desired basicity values between 1.35 and 1.6, only this basicity can ensure that the sulfoaluminate reaction without a primary hydration below
• the use of hydrated lime or Portland cement is made possible, since otherwise the formation of a gel layer would hinder this reaction.
• a sulfate smelter cement was produced and compared with a cement produced according to the invention.
• This comparison showed that the compressive strength development in the cement according to the invention is characterized by a higher final strength with a slightly lower strength after 3 days.
• the compressive strength values for sulfate metallurgical cement after 3 days were 41 N / mm 2 compared to 38 N / mm 2 for the cement according to the invention. After 28 days, a compressive strength of 76 N / mm 2 could be achieved with sulphate metallurgical cement, whereas the cement according to the invention gave values of 82 N / mm 2 .
• the flexural strength of the cement according to the invention was about twice as high as that of known sulphate metallurgical cements.
• Sulphate metallurgical cement achieved a bending strength of 7 N / mm 2 , where against values of 14 N / mm 2 were achieved with the cement according to the invention.
• the cement according to the invention is characterized by a significantly lower tendency to shrink. While cracking was observed in metallurgical cements and conventional blast furnace slag mixed cements, cracking was largely excluded in the cement according to the invention due to the significantly lower tendency to shrink and was also not observed.
• the grinding fineness was determined in the course of the Blaine tests in accordance with ASTM standard C 204-55.
• the sulphate smelter cement used in the comparative experiments was ground up much more elaborately and was used with a fineness of 5000 cm / g, whereas the cement according to the invention used in the comparative experiments was ground only to 3000 cm 2 / g fineness.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Processing Of Solid Wastes (AREA)
• Soil Conditioners And Soil-Stabilizing Materials (AREA)
• Treating Waste Gases (AREA)

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• 1997
  • 1997-04-09 AT AT0061197A patent/AT404723B/de not_active IP Right Cessation
• 1998
  • 1998-03-12 US US09/202,063 patent/US6139621A/en not_active Expired - Fee Related
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  • 1998-03-12 BR BR9804812-0A patent/BR9804812A/pt active Search and Examination
  • 1998-03-12 WO PCT/AT1998/000066 patent/WO1998045218A2/de not_active Application Discontinuation
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  • 1998-03-12 CA CA002257643A patent/CA2257643A1/en not_active Abandoned
  • 1998-03-12 JP JP10542129A patent/JP2000505776A/ja active Pending
  • 1998-03-12 AU AU63846/98A patent/AU725892B2/en not_active Ceased
  • 1998-03-12 RU RU99100300/03A patent/RU2163574C2/ru active
  • 1998-03-12 CZ CZ984244A patent/CZ424498A3/cs unknown
  • 1998-03-12 CN CN98800449A patent/CN1229404A/zh active Pending
  • 1998-03-12 EP EP98909205A patent/EP0923506A3/de not_active Withdrawn
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  • 1998-03-16 HR HR980137A patent/HRP980137B1/xx not_active IP Right Cessation
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• 1999
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