CN1026709C - Deslagging agent for aluminum or aluminum alloy refining - Google Patents

Abstract

The slag remover for refining aluminum and aluminum alloy consists of various chlorides and fluorides, and the chemical composition of the slag remover comprises 15-30% of Na, 10-20% of K, 1-5% of Ca, 1-5% of Mg, 20-50% of Cl, 1-10% of Si, 5-20% of F, trace-5% of Al and 0-5% of C. The slag remover has obvious slag removing effect, and also has degassing and covering effects, wherein the slag remover contains H₂The rate reaches 81.5%, and the content of metal in the formed slag is reduced to below 2%.

Description

The invention relates to a slag remover for aluminum or aluminum alloy refining, which belongs to a refining flux for purifying aluminum or aluminum alloy melt. It is composed of various chlorides and fluorides. In addition to the effective slag removal, it also has the functions of degassing and covering.

Deslagging and degassing are the two central links and ultimate goals of the purification treatment of aluminum or aluminum alloy melts, and have been the subject of research by many researchers. For this reason, a variety of degassing methods, slag removal methods and online degassing and slag removal combined treatment methods have emerged, and the equipment and devices used are becoming more and more advanced, while their cost, maintenance costs and technical requirements are becoming more and more advanced. high. The flux used in the purification process is currently generally 1# flux, and its source of information is quoted from Table 5-1-8, page 15 of the second volume of "Light Metal Material Processing Handbook" (Metallurgical Industry Press, 1980). 1# Flux is in block shape, its chemical composition is: 47%KCl+30%NaCl+23%Na ₃ AlF ₆ , when used, it needs to be put into the refining basket and sent to the melt in the furnace for slag removal and refining. In addition to the disadvantage of inconvenient operation, this traditional flux has poor slagging effect in practical application, so the oxide slag inclusions in the aluminum melt cannot be completely removed, and the formed slag is not easy to separate from the aluminum melt. It is difficult to improve the purity of the aluminum liquid, and because the formed slag contains a considerable amount of aluminum liquid, generally reaching 3-10%, resulting in a waste of metal.

In view of the shortcomings of the existing fluxes, the purpose of the present invention is to provide a flux for refining aluminum or aluminum alloy with good spreadability, separation and refining properties, and the flux is easy to use.

In order to achieve the above object, the aluminum or aluminum alloy refining slag remover provided by the present invention is composed of the following components. The slag remover is composed of chlorides and fluorides, and its chemical composition is quantitatively containing 10% to 30% NaCl, 10~20KCl, 1~15%NaF, 5~20% _MgCl2 , 3~20% _CaCl2 , 10~30% _{Na2SiF6 ,} 7~15% _{Na3AlF6 .}

The deslagging agent provided by the present invention according to the above description is in powder form and is formed by mixing various chlorides and fluorides. When applied to aluminum or aluminum alloy melt for purification treatment, NaCl, CaCl ₂ , MgCl ₂ , NaF in it act as covering agent, Na ₂ SiF ₆ acts as refining agent, and Na ₃ AlF ₆ acts as Supplement the role of refining agent. The combination of NaCl, KCl, CaCl ₂ and MgCl ₂ has a good covering effect on the aluminum melt, because these compounds have small surface tension and low viscosity, and have good spreading, covering and separating properties. The melt is non-polluting. MgCl ₂ exists in a liquid state at 720°C and has the function of dissolving hydrogen. It can also surround the suspended particles in the melt and separate it from the aluminum melt, thereby degassing and removing slag. Adding a certain amount of NaF can reduce the melting point of KCl and NaCl mixed salt and improve the covering effect, and NaF can also erode the metal melt on the Al ₂ O ₃ -Al interface, mechanically detach the oxide film, and dissolve in the flux. Its reaction equation is as follows:

Na ₂ SiF ₆ in the slag remover plays an obvious refining role in the aluminum melt, and the following reaction occurs in the aluminum melt at high temperature:

The generated SiF ₄ and AlF ₃ are both volatile, and both can bring out a large amount of hydrogen during the flotation process, and both SiF ₄ and AlF ₃ are non-toxic, and have no toxic effect on personnel and equipment. As a supplementary refining agent, Na ₃ AlF ₆ and Na ₃ AlF ₆ formed by the reaction of Na ₂ SiF ₆ and Al ₂ O ₃ have a strong adsorption effect on Al ₂ O ₃ in the melt, and can also form slag with SiO ₂ Block, and melted on the surface of the melt, so it is very easy to remove slag.

The deslagging agent provided by the present invention according to the above description, the chloride and fluoride of composition are further realized by the components described in table 1 in weight percent:

Table 1

Ingredient content%

NaCl 10～30

KCl 10～20

NaF 1～15

MgCl ₂ 5～20

CaCl ₂ 3～20

Na ₂ SiF ₆ 10～30

Na ₃ AlF ₆ 7～15

Since C ₂ Cl ₆ chloride and CaF ₂ fluoride can play a refining role in combination with the slag remover composed of the above components in aluminum or aluminum alloy melts, they can be used as supplementary additives for refining agents and supplementary refining agents. When containing C ₂ Cl ₆ and CaF ₂ additives, the deslagging agent provided by the invention is realized by the components described in table 2:

Table 2

Ingredient content%

NaCl 10～30

KCl 10～20

NaF 1～15

MgCl ₂ 5～20

CaCl ₂ 3～20

Na ₂ SiF ₆ 10～30

C ₂ Cl ₆ 0～10

Na ₃ AlF ₆ 7～15

CaF ₂ 0～10

The slag remover for aluminum or aluminum alloy refining provided by the present invention is formulated according to the above-mentioned components when the product is made, and produced through the process of smelting-ingot-crushing-milling-packaging; the ingredients can also be dried -Process production such as mixing-screening-packaging. The slag removal agent provided by the invention is suitable for the slag removal treatment of all types of aluminum and aluminum alloys except aluminum-magnesium alloys with high magnesium content and hypereutectic aluminum-silicon alloys, and can also be widely used in furnace walls and The slag removal at the bottom of the furnace can be performed by manual throwing and stirring, or by inert gas injection. When the manual throwing and stirring method is adopted, the slag remover is directly and evenly thrown to the surface of the molten aluminum, and stirred, and when the scum is formed and clearly separated from the molten aluminum, the scum is removed with a scum removal tool, and the amount of addition is 0.3-0.6% of the amount of aluminum processed. When using the inert gas injection method, use a special injection device to spray the slag remover evenly into the melt, and stir while injecting. The injection gas is Ar or N ₂ . This injection method not only enhances the slag removal effect, but also enhances the degassing effect, and at the same time greatly reduces the operating intensity of workers, so it is suitable for melt treatment in furnaces, ladles, crucibles and transfer transition containers.

The slag remover provided by the present invention has good spreadability, separability and refining properties, and has the characteristics of wide application range and convenient use. Compared with the existing 1# flux, it not only has outstanding slag removal effect, It also has the functions of removing _H2 and covering. For example, on a casting and rolling production line, the slag remover provided by the present invention and 1# flux are respectively added according to 0.3% of the amount of aluminum melt to be processed, and the casting and rolling slab samples are cut to measure the oxidation slag inclusion. Its measurement result shows: under the same condition, the average number of oxidized slag inclusion particles in the sample treated with the slag removal agent provided by the present invention is 21.2, which is 42.3 less than the 63.5 treated with 1# flux, and the slag removal effect is significantly better than 1 # flux. And the degassing effect comparative test of the present invention and 1# flux shows that under the same conditions, the _degassing effect of the present invention improves 40% than 1# flux, and the deslagging agent provided by the present invention adopts _N When spraying, Its H ₂ removal effect is 50.6% higher than that of 1# flux, and the H ₂ removal rate reaches 81.5%. When the slag removal agent provided by the invention is used to purify aluminum or aluminum alloy melts, in addition to the characteristics of thorough slag removal and clean separation, the metal content in the formed slag is greatly reduced to below 2%.

One of the embodiments provided by the invention:

The deslagging agent provided by the invention, its chloride and fluoride are made up of the components shown in table 3:

table 3

Ingredient content %

NaCl 20～25

KCl 12～18

NaF 8～12

MgCl ₂ 8～15

CaCl ₂ 5～12

Na ₂ SiF ₆ 15～25

Na ₃ AlF ₆ 8～15

Two of the embodiments provided by the present invention:

The deslagging agent provided by the invention, its chloride and fluoride are made up of the components shown in table 4:

Table 4

Ingredient content%

NaCl 10～20

KCl 10～15

NaF 8～12

MgCl ₂ 8～10

CaCl ₂ 5～15

Na ₂ SiF ₆ 20～30

Na ₃ AlF ₆ 8～10

C ₂ Cl ₆ 0～10

CaF ₂ 0～10

Embodiment three provided by the present invention:

The deslagging agent provided by the invention, its chloride and fluoride are made up of the components shown in table 5:

table 5

Ingredient content%

NaCl 15～30

KCl 10～20

NaF 12～15

MgCl ₂ 10～20

CaCl ₂ 10～20

Na ₂ SiF ₆ 10～20

Na ₃ AlF ₆ 10～15

C ₂ Cl ₆ 0～5

CaF ₂ 0～5

Four of the embodiments provided by the present invention:

The chlorides and fluorides that make up the slag remover are composed of one of the 1 to 13 components shown in Table 6:

Table 6

Contains

NaCl KCl CaCl ₂ MgCl ₂ Na ₂ SiF ₆ C ₂ Cl ₆ NaF Na ₃ AlF ₆ CaF ₂

Order %

Number

1 24 16 7 10 21 - 11 11 -

2 17 15 7 7 27 7 10 10 -

3 10 23 7 10 20 5 15 10 -

4 30 10 9 11 15 10 8 7 -

5 18 15 20 5 30 - 5 7 -

6 20 20 10 20 10 - 7 13 -

7 22 14 15 11 15 - 1 15 -

8 25 12 10 15 15 5 8 10 -

9 22 20 5 15 18 - 5 10 5

10 27 18 3 12 16 - 7 7 10

11 25 17 8 10 14 - 11 12 3

12 16 23 7 10 21 - 11 11 1

13 15 15 7 7 27 7 10 10 2

Claims (5)

1, a kind of aluminum or aluminum alloy slag remover for refining is made up of muriate and fluorochemical, is characterized in containing 10～30%NaCl, 10～20KCl, 1～15%NaF, 5～20%MgCl ₂, 3～20%CaCl ₂, 10～30%Na ₂SiF ₆, 7～15%Na ₃AlF ₆

2, according to the described deslagging agent of claim 1, the component that is characterized in muriate and fluorochemical is 10～30%NaCl, 10～20KCl, 1～15%NaF, 5～20%MgCl ₂, 3～20%CaCl ₂, 10～30%Na ₂SiF ₆, 0～10%C ₂Cl ₆, 7～15%Na ₃AlF ₆, 0～10%CaF ₂

3, according to the described deslagging agent of claim 1, be characterized in 20～25%NaCl, 12～18%KCl, 8～12%NaF, 8～15%MgCl ₂, 5～12%CaCl ₂, 15～25%Na ₂SiF ₆, 8～15%Na ₃AlF ₆

4, according to the described deslagging agent of claim 2, be characterized in 10～20%NaCl, 10～15%KCl, 8～12%NaF, 8～10%MgCl ₂, 5～15%CaCl ₂, 20～30%Na ₂SiF ₆, 8～10%Na ₃AlF ₆, 0～10%C ₂Cl ₆, 0～10%CaF ₂

5, according to claim 1,2 described deslagging agents, be characterized in 15～30%NaCl, 10～20%KCl, 12～15NaF, 10～20%MgCl ₂, 10～20%CaCl ₂, 10～20%Na ₂SiF ₆, 10～15%Na ₃AlF ₆, 0～5%C ₂Cl ₆, 0～5%CaF ₂

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