Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
  • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
  • B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
  • B22C1/24—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of oily or fatty substances; of distillation residues therefrom
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S106/00—Compositions: coating or plastic
  • Y10S106/04—Bentonite

Definitions

• the invention relates to binder systems and methods using the same for carbon dust-free freshness, for the formation of bentonite bonds and for the production of casting cores.
• the invention comprises a binder system containing 0.5-20% by mass of vegetable lecithin or vegetable oil or a mixture thereof in any ratio, 0.1-5.5% by weight of hardening agent, hardening agent derivative or carboxymethyl cellulose sodium or a mixture thereof in any ratio, 0.3-4 , 5% by mass sodium carbonate, 0.05-1.25% by mass boron compounds and additionally 100% bentonite.
• the invention further comprises a method using this binder system in foundries, in which carbon dust-free freshening of the molding sand containing bentonite, which is continuously recovered by circulation, furthermore the manual or mechanical processing of the production of casting cores from which SO2 gas is no longer formed, takes place, whereby the use of bentonite is significantly reduced compared to the traditional method, and whereby the occupational hygiene protection, environmental protection and protection against corrosion can be significantly improved.
• the material and energy consumption as well as the working time be reduced and the method of freshening can be carried out much easier, more precisely and more effectively.
• the addition of coal dust can be completely avoided and the amount of bentonite required for freshening can be significantly reduced by about 25-40%.
• Quartz sand, clay, bentonite, coal dust and water-containing mixtures of shapes are widely known.
• the mineral coal dust is used as an additive in the bentonite-containing mold mixtures as a glossy carbon carrier to improve the quality of the casting surface and to reduce the burning of the sand.
• the general technological practice is also known in a wide circle, according to which, after casting, the molds containing bentonite content containing coal dust and the cores to the sand mixtures which have been cleared and then continuously recirculated by circulation, new sand, bentonite, coal dust and water are used to replace the amount of coal dust burned out and the thermally degraded bentonite can be added via separate measuring and dosing processes in order to freshen the molding sand.
• the mineral coal dust cannot be homogenized appropriately by the added bentonite or by the recovered molding sand during the short mechanical mixing time in the freshing method.
• the uniform technological strengths corresponding to the expectations no impact of the mechanical concentration work used in the molding can not be achieved.
• the ashes of coal dust are not only due to theirs physical presence, but fundamentally disadvantageous because it concurrently concentrates strictly acidic compounds that dissolve well in the water of the bentonite-containing molding sand and dissociate well.
• the pH of the electrolyte is shifted in the direction of the very harmful, acidic pH range, in contrast to the alkaline activity required for the advantageous Na cation exchange, and the continuously increasing hydrogen ion concentration makes the bentonite one from the forming technology point of view causes rather disadvantageous cation exchange. This reduces its ability to swell and the work capacity is significantly or completely reduced.
• the absorption of the SO2 gas is very disadvantageous because it depends on the given circumstances through various oxidation reactions forms mineral sulfuric acid or sulfuric acid, which dissolve well in the water present, dissociate well and thereby cause the continuous formation of the acidic pH range on the molds and cores, that is to say increase the unfavorable hydrogen ion concentration and thereby also bindable bentonite cause an adverse cation exchange and the formation of hydrogen bentonite.
• the advantageous swellability and the working capacity of the bentonite which is essential from the point of view of shaping technology, and which ensure the required technological strength of the molds and cores, are significantly or completely reduced.
• the refreshing method can be made simpler, more precise and more effective, and a significant reduction in the amount of bentonite required to restore the corresponding strength of the molding sand continuously recovered by circulation can be achieved by 25-40% and thereby significantly reduces the material transport, storage and material movement, the expenditure of energy, working time, the molding waste is reduced, the effectiveness is improved, the castings are made sand-free more easily and the quality of the surface is improved. Furthermore, it is possible by removing SO2 gas formation To increase the level of occupational hygiene protection, environmental protection and protection against corrosion.
• the invention is based on the knowledge that the above-mentioned goals can be achieved and the known disadvantages can be eliminated if the mineral sulfur containing coal dust in large quantities is no longer used as a glossy carbon carrier for freshening and bentonite is no longer added separately, but instead that Binder system according to the invention is added, which can be homogenized faster and better with the molding sand.
• the binder system contains compounds that are sulfur-free and fully compatible with the bindable Na bentonite. Health and safety is ensured in that the combustion by-products do not cause harmful hydrogen bentonite bonds.
• the binder according to the invention ensures the alkaline pH range required for binding Na bentonite and the corresponding Na ion concentration.
• the components also enable an improved cast binder system in the form of a stable bentonite suspension for carbon dust-free freshening.
• the present invention comprises an improved binder system comprising 0.5-20% by mass of vegetable lecithin or vegetable oil or a mixture thereof in any ratio, 0.1-5.5% by weight of curing agent or curing agent derivative or carboxymethyl cellulose sodium or their mixture any ratio, 0.3-4.5 mass% Na carbonate, 0.05-1.25% boron compounds and 100% complementary bentonite contains.
• the invention further relates to a method using the binder system according to the invention, in which a coal dust-free freshness of the molded sands containing continuously recovered by circulation, and further their processing by known, manual or mechanical operations to improve molds with bentonite bonding and to cores from their organic carbon donor Pouring SO2 gas will no longer arise, is included, and compared to the traditional, coal dust additive using molding and core manufacturing processes, the level of occupational hygiene protection and environmental protection, protection against corrosion can be significantly improved.
• the improved binder system according to the invention is illustrated by the following examples.
• binder systems with the above composition are stored in the foundries after their homogenization in silos, containers, plastic or metal barrels or in bags until they are used.
• the coal dust-free refining was carried out as follows: 540 kg. recovered sand 60 kg. Sand K4 7 kg. Binder system of Example 3 suspended in 14 l. water 607 kg.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Mold Materials And Core Materials (AREA)
• Ceramic Products (AREA)
• Glass Compositions (AREA)
• Package Frames And Binding Bands (AREA)
• Reinforced Plastic Materials (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=10969649

Family Applications (1)

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• 1988
  • 1988-09-30 HU HU885093A patent/HU201485B/hu not_active IP Right Cessation
• 1989
  • 1989-06-09 US US07/364,206 patent/US5106418A/en not_active Expired - Fee Related
  • 1989-06-14 GR GR890100397A patent/GR890100397A/el unknown
  • 1989-06-16 JP JP1152483A patent/JPH02117738A/ja active Pending
  • 1989-06-20 BG BG088908A patent/BG88908A/bg unknown
  • 1989-06-21 ES ES8902168A patent/ES2020812A6/es not_active Expired - Lifetime
  • 1989-06-22 EP EP19890111374 patent/EP0363568A3/fr not_active Withdrawn

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