JPH01123035A - Flux for molten aluminum or aluminum alloy and method of slagging-off using same - Google Patents

Abstract

PURPOSE:To manufacture a flux for molten Al capable of carrying out efficient slagging-off by incorporating specific percentages of atomized Al powder, KNO3, and K2SO4 to KCl. CONSTITUTION:A flux 3 for molten Al or Al alloy which has a composition consisting of, by weight, 2-10% atomized Al powder, 5-10% KNO3, 8-20% K2SO4, and the balance essentially KCl and containing, if necessary, 4-8% K3AlF6 is prepared. This flux 3 is provided to slag 2 on a molten metal 1 and agitated by means of an agitator 4, by which the reaction of the molten metal 1 and the slag 2 is accelerated to carry out slagging-off. By this method, metal contents in the slag 2 can be recovered into a furnace with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a flux for molten aluminum or aluminum alloy and a slag removal method using the flux.

[Prior Art] Conventionally, molten aluminum and aluminum alloys are refined by injecting flux containing halogen gas or halogen compounds for the purpose of quality assurance such as cleaning of the molten metal prior to casting.

At this time, inclusions that are mixed in the molten metal and floated up during scouring are usually called slag. The composition of this slag is a mixture of molten metal and oxide or nitride.

The above-mentioned slag is taken out of the furnace in a slag removal process, and in this case, the metal content in the ring is recovered for the purpose of reducing raw material costs.

The following two methods are generally used to recover the metal in the ring.

In other words, ■After the slag to be removed is pulled out of the furnace, it is cooled in a cooling kiln, and only the large metal chunks are taken out, reheated and melted, and solidified into a mold that is easy to insert into the furnace again. and use it as raw material for reuse.

Alternatively, (1) a slag squeezer that reheats, melts, and stirs the slag squeezes out the metal content, solidifies it into a mold that can be easily inserted into a furnace, and uses it as a raw material for reuse.

Or, the above-mentioned items (1) and (2) are used in combination.

As mentioned above, when using the metal content in the ring, the metal content in the ring taken out from the furnace is 80 to 90%, and the amount processed by kiln treatment, remelting treatment, and slag squeezing is quantitatively Quite a lot.

Therefore, in order to separate the metal components from the cooled slag using conventional methods and reuse it, it is necessary to heat and cool the cooled slag one or more times, which requires a large amount of energy for heating. In addition, there are problems such as oxidation loss occurring during reheating and melting when recovering the metal content, and the large amount of metal in the ring requiring a large amount of slag to be processed.

[Problems to be Solved by the Invention] As explained above, the present invention solves the problem that conventional fluxes have poor separation of slag from molten metal, and as a result, a high proportion of metal remains in the ring. The purpose of the present invention is to provide a flux that solves these problems, and also to provide a method for efficiently removing slag using this flux.

[Means for solving the problems] The present invention includes: Ai7 to v-i's powder: 2 to 10 wt%, KNO3: 5
There is a first gist in a flux for aluminum or aluminum alloy molten metal, which is characterized in that it contains ~10 wt%, SO4: 113 ~ 20 wt%, and the balance is substantially KClL, AfL atomized powder: 2 ~10wt%, KNO3:5~
10 wt%, 2S04: 8-20 wt%.

A second feature exists in a flux for molten aluminum or aluminum alloy, which contains 4 to 8 wt% of K3AJ2F6, with the remainder being substantially KCJl.

Furthermore, AJZ atomized powder: 2 to 10 wt%.

KNO3: 5-10wt%, Ni2 SO4: 8-20w
t%, with the balance being KCl, is sprinkled on the surface of the molten aluminum or aluminum alloy, and the slag existing on the surface of the molten metal and the flux are stirred using a stirring means, and the molten metal and the slag are mixed. promote the reaction of
There is a third gist in a method for removing slag from aluminum or molten aluminum alloy, which is characterized by removing sludge.

[Function] The present invention has a method for treating the slag on the surface of the molten metal with the following:
Chloride-fluoride-oxidizing agent-Au powder of the invention, or
Chloride-oxidizing agent-AJ for high temperature molten metal, that is, the first invention
By spraying a flux consisting of two powders and sufficiently stirring the slag and flux, the ability to separate the metal content in the ring from inclusions is improved and the ability to remove sludge is promoted.

That is, due to the exothermic reaction between Al and oxygen, fluoride,
A chloride melt is formed. This melt has good wettability with the slag, but poor wettability with the metal, which improves the separation between the metal and the slag.

Conventional fluxes are used for cleaning purposes such as degassing and removal of inclusions by injecting flux into the molten metal, and for producing CJ:! as a by-product. , 2 to improve the separation between metal and slag.

However, in the present invention, the flux is a separating agent for metal and slag, which is produced with the main purpose of improving the separation between metal and slag.

In addition, conventional molten metal cleaning fluxes are blown into the molten metal together with a carrier gas, and the only stirring method used is bubbling of the carrier gas, and no method of actively reacting the flux with the slag has been used.

In contrast to the above-mentioned conventional example, the present invention separately performs a molten metal cleaning treatment, then sprinkles flux on the surface of the slag and mechanically stirs it to actively react with the slag.

The reasons for limiting the flux components of the present invention will be described below.

The amount of AJZ atomized powder is 2 to 10 wt%.

As the metal powder serving as the ignition source, aluminum was used from the viewpoint of cost and safety, and the particle size was atomized powder of 100 to 200 mesh, which poses no risk of explosion.

In addition, in terms of reactivity with slag, if it is less than 2wt%, the reactivity is poor, and if it exceeds 10%, there is a risk of explosion, so
It was set to 10 wt%. For safety reasons, it is more preferable to set the content to 2 to 6 wt%.

KNO3 is 5-1.　Ow　t　%.

It is an essential component as an oxygen supply source, and is not effective as an oxidizing agent at less than 5 wt%. Further, if the content exceeds 10 wt%, it is dangerous because KNO3 is a raw material for explosives. Therefore, the content should be 5 to 10 wt%. Note that the content is more preferably 5 wt%.

K2SO4 is set at 8 to 20 wt%.

K2SO4 supplies the amount of oxygen that is insufficient in KNO3, and a content of less than 8% is insufficient. Also,
If the content exceeds 20%, there will be an excessive supply of oxygen and the exothermic reaction will become intense, so the content of K2SO4 should be 8 to 20%.
It was set as wt%.

Leave the remainder of KCl.

As a chloride, KCl2 is a fluoride (K 2 A Il,
F a) lowers the melting point of the flux, improves the reactivity of the flux, and improves the reactivity of the flux with AIl atomized particles and 02
It has the function of slowing down the reaction and preventing an explosive reaction. In addition, KCβ and the slag have wettability, and the adsorption effect of the slag increases, improving the separation between the metal and the slag.

Furthermore, compared to other chlorides, the cost is low;
Since it is a non-Na-based material, it does not become a source of hot cracking for the AjZ-Mg-based material.

KCl was used as the remainder because KC1 itself has low hygroscopicity and can prevent H2 gas from being absorbed by the flux.

K3AflF6 should be 4 to 8 wt%.

It is an essential component for the second invention of the present invention.

When the molten metal temperature is low, the slag temperature is also as low as 700° C. or less, so the first invention flux may lack heat generation.

Possible means to solve the above problems include increasing the oxygen supply source, lowering the reaction starting temperature, and increasing the Aj2 powder distribution amount, but for safety reasons, lowering the reaction starting temperature is optimal, so this method was used.

In order to lower the decomposition temperature of the above-mentioned flux, 3 A j2 Fa was used as the fluoride in view of the fact that it does not harm the molten metal, is inexpensive, and takes safety issues into consideration. That is, by mixing 3AuF6 with KCl2, a eutectic was formed and the melting point was lowered.

When the content of K3 AuF6 is less than 4 wt%, the reactivity with the slag is poor, and when it exceeds 8 wt%, the reactivity is too intense, so the content was set to 4 to 8 wt%.

[Example] The present invention will be described in detail below with reference to Examples.

Low-temperature molten metals were prepared under the following conditions, and the slag generation rate (%) was investigated for those with added flux and those without added flux.

Type: JIS 6063 Melting conditions = 15T reverberatory furnace, heavy oil firing, melting temperature near 20℃ Slag temperature: 680℃ Wire assembly conditions: C, Q2 gas injection slag removal conditions , 1 wt % was added and stirred to remove the sludge. A stirrer as shown in FIG. 1 was used for the flux added.

In FIG. 1, 1 is molten metal and 2 is slag. A flux 3 is placed on the slag 2 and stirred by a stirrer 4.

Stirring using the above means requires stirring for 5 to 10 minutes on the surface of the molten metal at 25rn', for example.

As a result of implementing the above, as shown in Table 1, the slag generation rate was 1.5% in the example of the present invention in which flux was added, and the slag generation rate was 2.6% in the comparative example in which no flux was added. %Met.

Note that the slag generation rate is expressed by the following formula.

Slag generation rate=(Slag generation amount/Raw material charging amount)X100 From the above results, it can be seen that the Slag generation rate was reduced in the examples in which flux was added according to the present invention. That is, the metal (AIL) content of the swing width was 85 to 95% when no flux was added, but it decreased to 60 to 75% with the addition of flux.

This is metal obtained by conventional slag processing (AJZ
) can be recovered directly into the molten metal in the furnace without leaving it outside the furnace, reducing the energy cost required for slag treatment.

(Example 2) A high-temperature molten metal was prepared under the following conditions, and the slag generation rate (%) was investigated in the same manner as in Example 1.

Type: JIS 3003 Melting conditions: 15T reverberatory furnace, heavy oil firing, melting temperature near 50°C, slag temperature near 20°C, fine line condition 2012 gas blowing sludge removal conditions: High temperature of the first invention configuration? 9. Flux for hot water was added in an amount of 1 wt% O of the amount of molten metal and stirred to remove sludge.The same stirrer as in Example 1 was used to add flux.

As a result of implementing the above, the slag generation rate was 2.0% when flux was added, and the slag generation rate was 2.7% when no flux was added, which was the same result as in Example 1.

[Effects of the Invention] As explained above, according to the present invention, it is possible to recover the metal content of the swinging width generated after scouring of low-temperature molten metal and high-temperature molten metal of aluminum or aluminum alloy into the furnace using flux. Compared to conventional methods, energy costs, oxidation loss due to reheating, and processing costs are reduced, and slag removal workability is improved.

Table 1

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a stirring device. 1... Molten metal, 2... Slag, 3... Flux, 4...
...Agitator.

Claims (4)

[Claims] (1) Al atomized powder: 2-10wt%, KNO_3
A flux for molten aluminum or aluminum alloy, characterized in that it contains K_2SO_4: 5 to 10 wt%, K_2SO_4: 8 to 20 wt%, and the remainder is substantially KCl. (2) Al atomized powder: 2-10wt%, KNO_3
:5-10wt%, K_2SO_4:8-20wt%,
A flux for molten aluminum or aluminum alloy, characterized in that it contains 4 to 8 wt% of K_3AlF_6, with the remainder being substantially KCl. (3) Al atomized powder: 2-10wt%, KNO_3
A flux containing 5 to 10 wt% of K_2SO_4 and 8 to 20 wt% of K_2SO_4 with the balance being KCl is sprinkled on the surface of the molten aluminum or aluminum alloy, and the slag present on the surface of the molten metal and the flux are mixed using a stirring means. A method for removing slag from aluminum or aluminum alloy molten metal, characterized in that the sludge is removed by stirring the molten metal using a slag to promote the reaction between the molten metal and the slag. (4) As a flux component, Al atomized powder: 2~
10wt%, KNO_3:5-10wt%, K_2SO
_4: 8-20wt%, K_3AlF_6: 4-8wt
% and the remainder is KCl.