JPH1180851A - Flux for treating molten metal of aluminum and aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent environmental contamination concerning chlorine by forming this flux into a composition composed of one or more kinds of fluororesin and inorganic fluoride, metallic sulfate, one or more kinds of metallic carbonate and metallic nitrate and one or more kinds among oxide, Al and carbonaceous substance and contg. no chloride. SOLUTION: This flux contains at least one kind of 30 to 60 wt.% fluororesin and inorganic fluoride, 10 to 50 wt.% metallic sulfate, at least one kind of 0 to 30 wt.% metallic carbonate and metallic nitrate and at least one kind among 0 to 50 wt.% oxide, Al and carbonaceous substance. Fluororesin and inorganic fluoride are essential components, which are decomposed to gasify in molten metal, diffuse gaseous hydrogen into bubbles, and float and remove them and facilitate the separation of slag and the molten metal by exothermic reaction with the slag, and for example, polytetrafluoroethylene or the like is given. Metallic sulfate is also an essential component and is used as a combustion improver making the flux exothermic in the molten metal treatment, and Na2 SO4 or the like is exemplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing aluminum and an aluminum alloy,
The present invention relates to a flux for molten metal treatment for removing and cleaning nonmetallic inclusions, and to a non-chlorine flux for controlling environmental pollution related to chlorine.

[0002]

2. Description of the Related Art Aluminum and aluminum alloys have an extremely large difference in hydrogen solubility between melting and solidification compared to other metals, so that hydrogen absorbed in the molten metal during melting has a high degree of pore formation during solidification. Cause.

[0003] Oxides and other non-metallic inclusions floating on the surface or inside of the molten metal become internal defects of the product after solidification, and significantly reduce the quality of the product together with the pores described above.

[0004] Therefore, so-called degassing and slagging for removing these from the molten metal is an extremely important operation as a molten metal treatment for cleaning the molten aluminum and aluminum alloy and improving the quality of products. .

[0005] As a treating agent used for such a molten metal treatment, conventionally, as a representative one, chlorine gas, nitrogen gas, a mixed gas thereof, or an organic chloride, an inorganic chloride, an inorganic fluoride, or a metal. Many kinds of fluxes in which various salts and the like are blended as a composition have been used.

[0006]

[0005] In recent years, as a problem of toxic products related to chlorine has been raised as a part of measures for controlling industrial pollution and environmental pollution, fluxes for treating aluminum and molten aluminum alloys have been developed. The development of a new non-chlorine-based flux to replace the chlorine-based flux, which was the mainstream product, has been demanded to solve the above-mentioned problems.

[0007]

Means for Solving the Problems The present inventors have invented a novel non-chlorine flux as a result of intensive studies to solve the above-mentioned problems. It is as follows.

That is, the first aspect of the invention is “fluororesin,
3 to 60% by weight of at least one kind of inorganic fluoride, 10 to 50% by weight of metal sulfate, 0 to 30% by weight of at least one kind of metal carbonate and metal nitrate, oxide, aluminum,
At least one of the carbonaceous materials comprises from 0 to 50% by weight;
A flux for treating molten aluminum and aluminum alloy, characterized in that the composition does not contain chloride. ".

Next, a second aspect of the invention is that at least one of a fluorine resin and an inorganic fluoride is 3 to 60% by weight, a metal bromide is 2 to 30% by weight, a metal sulfate is 10 to 50% by weight, a metal carbonate is The composition is characterized in that at least one of the salt and the metal nitrate comprises 0 to 30% by weight and at least one of the oxide, aluminum and the carbonaceous substance comprises 0 to 50% by weight, and the composition does not contain chloride. For treating molten aluminum and aluminum alloys. "

Further, in the above first or second invention, it is preferable that the fluorine resin and the inorganic fluoride are polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkylvinyl ether copolymer, and tetrafluoroethylene / hexanefluoropropylene copolymer. Merging, tetrafluoroethylene / ethylene polymer, polyvinylidene fluoride, a group of polyvinyl fluoride, and LiF,
NaF, KF, MgF ₂ , CaF ₂ , BaF ₂ , AlF
₃ , NaAlF ₄ , KAlF ₄ , Na ₃ AlF ₆ , K ₃
AlF ₆ , Na ₂ SiF ₆ , K ₂ SiF ₆ , NaB
At least one metal bromide selected from the group consisting of F ₄ , KBF ₄ , and K ₂ TiF ₆ ;
Seed, metal sulfate is Na ₂ SO ₄ , K ₂ SO ₄ , MgSO
₄ , CaSO ₄ , BaSO ₄ , at least one metal carbonate, metal nitrate is Na ₂ CO ₃ , K ₂ C
At least one selected from the group consisting of O ₃ , MgCO ₃ , CaCO ₃ , and BaCO _{3 and} the group consisting of NaNO ₃ , KNO ₃ , and BaNO ₃ , and the oxide is at least one selected from the group consisting of MgO, SiO ₂ , and Al ₂ O _3. And at least one carbonaceous substance selected from the group consisting of charcoal, coke, coal, graphite, and burnt rice. ].

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the flux for treating molten aluminum and aluminum alloy of the present invention, an essential composition common to the first and second inventions is a fluororesin, at least one kind of inorganic fluoride, and a metal sulfate. It is.

Decomposition and gasification of fluorine resin and inorganic fluoride in a molten metal, and hydrogen gas is diffused in bubbles to float and remove, or the exothermic reaction with the slag facilitates separation of the slag and the molten metal. .

[0013] Among the fluorocarbon resins, polychlorotrifluoroethylene and chlorotrifluoroethylene / ethylene copolymers other than the six kinds mentioned in claim 3,
Since both are chlorine-based, they were excluded in the present invention.

Although the above six kinds of fluororesins can be used for the purpose of the present invention, in terms of cost, used and recovered products such as gaskets and sheets are crushed and used. Is preferred.

Any of the inorganic fluorides described in claim 3 can be used in the present invention. In particular, those containing B and Ti can be used to reduce the grain size of Al-Cu, Al-Mg alloys and the like. Therefore, it is preferable to use it when it also serves the purpose.

If the composition ratio of the fluorine resin and the inorganic fluoride is less than 3% by weight, the effect of the molten metal treatment is insufficient, and if it exceeds 60% by weight, the reaction in the molten metal becomes excessive.

The metal sulfate is used in the present invention as an auxiliary agent for generating heat during the treatment of the molten metal, and in combination with the above-mentioned fluorine-containing composition, Na ₂ S
O ₄ , K ₂ SO ₄ , MgSO ₄ , CaSO ₄ , BaSO
_It has been found that it is preferable to select from the group of ₄ , and the same applies to the composition ratio.

Na which is an essential composition in the second invention
Conventionally, Br and KBr have been considered to have a low melt processing effect and have not been omitted because they are expensive. However, the present inventors have found that the combined use of a fluorine-based composition and a metal sulfate, It has been found that it can substitute for physical flux, and its composition ratio has been found as a practical range in terms of both effect and cost.

Next, the metal carbonates and metal nitrates, which are optional compositions in the present invention, are used as auxiliary heat-generating and combustion-promoting agents equivalent to metal sulfates, and are also used in conventional fluxes. From the thing, as metal carbonate N
a ₂ CO ₃ , K ₂ CO ₃ , MgCO ₃ , CaCO ₃ , B
The group of aCO ₃ was also changed to NaNO ₃ ,
The group of KNO ₃ and BaNO ₃ was preferred.

Further, excessive use of metal carbonates and metal nitrates results in an excessive amount of slag, so the upper limit is set to 30% by weight.

The oxide is arbitrarily used as an adjusting agent or an extender for appropriately controlling the reaction during the treatment of the molten metal with respect to the above-mentioned composition. It may be selected from the group of MgO, SiO ₂ , and Al ₂ O _3. Aluminum is a molding aid when used as a combustion aid or molding flux as described above, and a carbonaceous substance is also used as a combustion aid together with aluminum.
Each of them can be used arbitrarily to supplement the heat generation of the fluorine-based composition.

The upper limit of the total amount of the oxide, aluminum and carbonaceous material was set to 50% by weight in order to avoid influence on other effective compositions.

As described above, the combination of each composition is appropriately selected each time according to the type of the molten metal, the degree of degassing and the degree of deslagging.

When using the above-mentioned flux composition, it may be sprayed or pressed as a powder on the surface of the molten metal, may be blown into the molten metal with an inert gas such as nitrogen by a lance pipe, or may be formed as a molded solid in the molten metal. It is preferable to appropriately select the method of pushing the material into the furnace according to the type and capacity of the furnace.

In order to conform to the method of use, adjustment of the particle size of the powder is required.
It shall be pressure molded to the size.

[0026]

EXAMPLES In the description of Examples 1 to 6 as examples of the present invention, the composition of the flux used in each example is as shown in Table 1.

In Table 1, Examples 1 to 3 are NaB
r and KBr are not equivalent to the first invention,
Embodiments 4 to 6 correspond to the second invention containing at least one of NaBr and KBr.

The fluororesin used in Examples 2, 3, 4 and 6 was PTFE (polytetrafluoroethylene-trade name: Teflon), and the used recovered gaskets were crushed and re-used. Used for use.

The composition of Example 2 was pressed into a cylindrical shape of φ90 × 21 mm at 1 ton / cm ² in order to be pressed into the molten metal by an insertion tool. In the case of Examples 3 and 5, which were used for blowing into a molten metal with nitrogen gas,
The lance for blowing was prevented from clogging by adjusting the particle size of 05 μm to 50% by weight or less.

Next, Table 2 shows the molten metal treatment conditions and the effects when the fluxes having the compositions shown in Table 1 were used in actual operation.

In Table 2, regarding the method of treating the molten metal, Examples 1, 4 and 5 disperse the powder flux on the surface of the molten metal, and then agitate the molten metal by pushing it into the molten metal with a stirrer. The flux of the molded solid is settled and held in the molten metal by a plunger-type insert, and the mixture is stirred after being decomposed.
The molten metal surface was sufficiently stirred.

As the effects of the molten metal treatment, the degassing effect is indicated by the amount of hydrogen gas in the sample, and the deslagging effect relating to separation / removal of nonmetallic inclusions is indicated by the cleanness. Is determined by the initial bubble method, and cleanliness is determined according to JIS G 0555 (ASTM E45-95a).
Method.

The obtained results show that, in the molten metal treatment using the flux according to the composition of the present invention, both of the degassing and slagging effects satisfy the requirements of the industry,
It has been shown that the product of the present invention can replace conventional chloride-based flux.

[0034]

[0035]

[0036]

According to the present invention, since the composition of the flux does not contain chloride, harmful chlorine or chloride is not generated in the treatment of molten aluminum and aluminum alloy, and environmental pollution related to chlorine is prevented beforehand. It can be controlled.

Further, it has been clarified that the non-chlorine flux of the present invention can provide a sufficient degassing and de-slagging effect in actual operation, contributing to environmental conservation measures as an alternative to conventional chlorine flux. Is what you do.

Claims (3)

[Claims] (1) at least one of a fluorine resin and an inorganic fluoride;
3 to 60% by weight of seed, 10 to 50% by weight of metal sulfate,
At least one of metal carbonates and metal nitrates is 0 to 30% by weight, and at least one of oxides, aluminum and carbonaceous materials is 0 to 50% by weight, and the composition does not contain chloride. Flux for treating molten aluminum and aluminum alloys. 2. At least one of a fluorine resin and an inorganic fluoride.
3 to 60% by weight of seed, 2 to 30% by weight of metal bromide, 10 to 50% by weight of metal sulfate, 0 to 30% by weight of at least one of metal carbonate and metal nitrate, oxide, aluminum, A flux for treating molten aluminum and aluminum alloys, characterized in that at least one of the carbonaceous substances comprises 0 to 50% by weight and does not contain chloride as a composition. 3. The fluororesin and the inorganic fluoride are polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / ethylene polymer, A group of vinylidene fluoride, polyvinyl fluoride, and L
iF, NaF, KF, MgF ₂ , CaF ₂ , BaF ₂ ,
AlF ₃ , NaAlF ₄ , KAlF ₄ , Na ₃ Al
F ₆ , K ₃ AlF ₆ , Na ₂ SiF ₆ , K ₂ SiF ₆ ,
At least one selected from the group consisting of NaBF ₄ , KBF ₄ , and K ₂ TiF ₆ , the metal bromide is at least one of NaBr and KBr, and the metal sulfate is Na ₂ SO ₄ , K ₂ SO ₄ , Mg
At least one metal carbonate, metal nitrate selected from the group consisting of SO ₄ , CaSO ₄ , and BaSO ₄ is Na ₂ CO ₃ , K
₂ CO ₃ , MgCO ₃ , CaCO ₃ , BaCO ₃ group,
And at least one oxide selected from the group consisting of NaNO ₃ , KNO ₃ and BaNO ₃ , wherein the oxide is MgO, SiO ₂ , Al ₂
At least from the group of O ₃ one, aluminum and aluminum alloy melt according carbonaceous material charcoal, coke, coal, graphite, to claim 1 or 2 is at least one selected from the group consisting of baked fir Processing flux.