JPS6233728A - Method for removing copper from lead by dry process - Google Patents

Abstract

PURPOSE:To lower the Cu content in Pb to <=0.5ppm by a dry process by adding an Al-Mg-Zn alloy to molten Pb contg. Cu, allowing them to stand after agitation and adding alkali to formed scum to convert the scum into dross. CONSTITUTION:A Al-Mn-Zn alloy consisting of 40-60wt% Al, 10-50wt% Mg and 5-40wt% Zn is added to molten Pb contg. >=0.5ppm Cu and they are agitated and allowed to stand. NaOH or KOH is added to formed scum consisting of the Cu in the molten Pb and the constituents of the alloy or air is further blown into the scum to convert the scum into dross. Thus, the Cu in the molten Pb is separated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field) The present invention relates to a dry decoppering method for PB for obtaining PB with low content of impurities, fr K Cu, which is used for applications such as litharge for electronic materials and optical glasses. .

(Prior Art and its Problems) A conventionally frequently used method for removing impurities from metals is to add a third metal or alloy to remove impurities as an intermetallic compound. For example, iron powder addition method for As in ships, or ASVc in tin.
For this purpose, there is a method of adding Mn powder.

As an example of removing Cu in a ship, ffj fused P b VCA l-Z n alloy (A, 6
Add 4U of Zn6 (3% by weight) and stir and mix at a temperature of 530°C or higher to convert Cu into an intermetallic compound euA2!
There is an alloy addition method that reduces Cu to 2 to 10 ppm in PB obtained after separation from the PB bath and cooling. However, this method has the following problems.

Since the single point of the A-&-Zn alloy is high, the addition amount is high, and O +21 P'b is not practical as a large-capacity Pb decoppering method because it requires a large amount of energy. In order to reduce the Cu content in the steel to IP, a large amount of additive alloy is required, but it is difficult to reduce the Cu content to lppm or less by simply increasing the amount of additive alloy.

+3) In order to lower the solubility of Cu in Pb to the limit in the Pb bath, it is necessary to cool the temperature of the Pb bath to about 1 point. However, cooling the PB bath temperature to near the melting point of PB requires that the temperature of molten PB be at least 370°C in order to transport the molten Pb by a pump.
Since the above is necessary, work efficiency such as extracting and transporting PB will be significantly deteriorated.

(Object of the Invention) The object of the present invention is to improve the above-mentioned alloy addition method and to provide a method for dry producing Cu-containing lead from Cu-containing lead.

(Structure of the Invention) That is, according to the present invention, a molten PbVcAA-M, 1il-Zn alloy containing 0.5 ppml of Cu was added, the residue was stirred, and after standing still for 1f, it became a scum and floated. A dry deconditioning method for lead is obtained in which the slag is added with alkali or alkali and air is blown into the slag, followed by a dross treatment to separate Cu from the PB.

Added by an uninvented method 3 A -e -M g -Z
The composition of n alloy is A! 40-60 weight ratio, λIL melting ~5
0 weight percentage, Zn5 weight 0 weight percentage, melted pb bath V
C is added to the alloy to form a scum-like intermetallic compound consisting of Cu in Pb and the constituent elements of the alloy, and to this, N is added.
AOH or KOH is added to 6 to form a dross, and the drossed copper is separated from the PB bath. Therefore, the additive alloy and its constituent elements must satisfy the following conditions.

(Form a strong metal 1111 compound with Lieu; If it remains in the Vc bath in f21Pb, it can be easily removed in a subsequent process; (3) The melting point of the alloy is low.

Furthermore, when adding the additive alloy, it is necessary to disturb the temperature of the PB bath to near the melting point of the additive alloy. Therefore, if the melting point of the additive alloy is high, the temperature of the Pb bath will be high, but in this case, the solubility of the generated metal compound in the Pb bath will increase, and the impurities in the Pb will increase. , it is necessary that the melting point of the additive alloy be as low as possible.In the method of the present invention, the composition of the additive alloy is A4-
4t)~60fffffi%, M915~50g
This problem was solved by using a low melting point alloy with a melting point of 380 to 470° C., as shown in FIG. 1, by adjusting the amount of Zn to 5 to 401%.

In the method of the present invention, the intermetallic compound produced by the addition of the above-mentioned alloy becomes a scum, but it cannot be removed as it is, so it is necessary to convert it into dross to remove it. The present inventors investigated the formation of dross from intermetallic compounds produced by the addition of additive metals, and found the following.

(1) The relationship between the amount of alloy added and the copper removal effect is shown in Figure 2. The larger the amount added, the better the copper removal effect. , alloy addition
It is necessary to use at least 600 times the amount of Cu contained in the old Pb bath. Figure 2 shows 10 kg of Pb (Cu 3.5 ppm combined) IC, AA6 (1 weight range, Mg-30 weight ratio, molten nlO weight ratio alloy) and a Pb bath temperature of 460°C.
It shows the relationship between the alloy addition amount and Cu in Pb in the case of .

(2) The relationship between the amount of NaOH added and the amount of air blown on the dross formation time is shown in Figure 3. Dross formation is possible with just the addition of NaOH, but air blown at the same time as NaOH. By doing so, the time required to form dross can be shortened. Figure 3 shows Pb(Cu3.5 p
pm ) 10 to 9 and the effect of NaOH addition on the dross formation time when the bath temperature is 460°C and the air blowing ft (
This shows the relationship between the conditions (stirring).

(As shown in Figure 4, the fourth coefficient of the cooling temperature of the 31Pb bath and the Cu content in the Pb is The Cu content also increases.On the other hand, A!-M,!i'-
In the Zn alloy, the Cu content in Pb can be reduced even when the cooling temperature of the Pb bath is high, that is, 380 to 470°C. Figure 4 shows Pb (Cu3.5ppm
) shows the relationship between cooling temperature and decopper removal effect when an An-Mg-Zn alloy is added to 10 kg. Furthermore, in the method of the present invention, the Cu content in pb is significantly reduced in AA-M,! This can be achieved by repeating the copper removal process consisting of addition and stirring of ii'-Zn alloy and separation of dross.

EXAMPLES Next, the present invention will be specifically explained with reference to Examples, but the following Examples do not limit the scope of the present invention.

Example 1 This example is shown in FIG. 650ppm of eu
A -13-M j! - Added 20 kg of Zn alloy, then added 8 kg of NaOH, stirred and mixed for 130 minutes, and left it to stand. After 1.400 kg of dross floated on the Pb bath surface.
A primary decopper treatment was carried out to separate 1 kg of Pb from the Pb bath.

Furthermore, the Pb bath temperature was maintained at 440°C and the process was repeated with M-M g
-Zn alloy 15 kg was added, followed by 9 kg of NaOH, stirred and mixed for 100 minutes, and left to stand. A secondary decopper treatment was performed to separate 900 kp of dross floating on the surface of the Pb bath from the Pb bath.

As a result, Cu in Pb after the primary decopper treatment was 5 ppm,
The Cu content in PB after the secondary copper removal treatment was around 0.35 yen.

Example 2 This example is shown in FIG. 160T of crude lead containing 6 ppm of Cu was dissolved, Pb bath ii was maintained at 450°C, A-g-M,! Add 300'Kg of 1l-Zn alloy, then add 100kg of NaOH and 50kg of air! The mixture was stirred and mixed for 40 minutes while blowing at 1/2 min, and after being allowed to stand still, a primary decopper treatment was performed to separate 4,200 dross floating on the surface of the PB bath from 9 from the PB bath.

Furthermore, the Pb bath temperature was maintained at 420°C and NaOH6 was added again.
To 0! After stirring and mixing for 40 minutes while blowing air at 502 g/min and leaving it to stand, a secondary decopper treatment was performed to separate 2.500 kg of dross from the surface of the Pb bath.

As a result, Cu in Pb after the primary decopper treatment was O4ppm.
, Cu content in Pb after the secondary copper removal treatment was 0.28 ppm.

Example 3 This example is shown in FIG. 2. lppm
Melt 160T of crude lead, maintain the Pb bath temperature at 460℃, add 200T of A-e Mg-Zn alloy, then add 60T of NaOH and 50T of air. After stirring and mixing for 45 minutes while blowing 3.5 ml of dross per minute, 3.0 ml of dross was left on the surface of the Pb bath. A primary decopper treatment to separate IUOkg was performed.

Furthermore, the pb bath temperature was maintained at 420°C, and KOH70 was added again.
After stirring and mixing for 30 minutes while blowing air at 50 rpm, and leaving it to stand, a secondary decopper treatment was performed to separate 2,000 kg of dross from the surface of the PB bath.

As a result, the Cu content in PB after the primary decoppering treatment was 0.3pp.
m, Cu in Pb after secondary copper removal treatment is 0.25 ppm
Met.

(Effects of the Invention) By adopting the above configuration, the present invention exhibits the following effects.

(1) Conventionally, in order to obtain Pb with a low Cu content, an expensive re-electrolysis method was required, but in the present invention, the Cu content in Pb can be reduced to 0.5 ppm or less by a dry decoppering method. can be lowered.

(2) The q4 removal operation is performed after adding A, 8 Ml-Zn alloy,
This can be done by a relatively simple operation of just stirring and mixing.

(3) Since the additive alloy A-eM9-Zn alloy has a low melting point, the degree of purity of the Pb bath at the time of addition is set to 380 to 4.
The temperature can be lowered to 70° C., and this temperature range is a temperature range that reduces waste in terms of energy.

(If the 41Pb bath temperature is below 370℃, the melted pbσ
] Although pumping becomes impossible, Pb bath suspension 13su~4
It is possible to send molten PB in the range of 70℃,
From the viewpoint of handling the Pb bath, high-temperature treatment is possible because it is easy to handle.

This can be done relatively easily by treating the raw carbon scum with an intermetallic compound generated by the Cu in +51Pb and the additive alloy, by adding alkali, or by using a combination of alkali addition and air blowing.

[Brief explanation of the drawing]

Figure 131 shows the state of the A, e-M i -Z n alloy, and the notch part is the main part in the west figure) 8JP! A-g- used in light
Ml-Zn alloy equivalent diagram, Figure 2 shows Pb(Cu3.5pp
rn containing) 101.9 vs. A460iINKS, M
l 30. i-MF- consisting of ttl, Zn10 management staff
A graph showing the relationship between the alloy addition performance and the remaining amount of Cu in PB when Zr1 combination is added and Pb common is at 460 ° C.
Figure 3 shows the pb bath iM+ using 10% Pb (containing Cu 3.5ppxn). Effect of NaOH on dross formation time at 46u°C 1. ) A graph showing the relationship between Kei and lu of the air blowing site, 1g4 diagram is P b (Cu 3.5p
pm *) PbM with 10, 9KAA- and 1y-Zn alloy added at 47υ℃
! -Gutsume showing the relationship between the steel pipe and g) Figure 1, Figure 5 is a flow note diagram of Example 1, Figure 6 is the actual bml~...12
The 70-sheet diagram %'Fi' near diagram is the flow note diagram 1 of 113. Fig. 2 2%-Z Fig. 3 10 2Q 3Q 5 <6% 46/su2 Fig. 10 'mp pb Rakuhisa L (・9 Fig. 7 1fi ja /60 (Cw 2.IP?-)
Pure lead (-a, 2.?rF)

Claims (3)

[Claims] (1) Al-M in molten Pb containing 0.5 ppm or more of Cu
After g-Zn alloy is added, stirred and left to stand, the scum that floats in the form of a scum is added with alkali or alkali and air is blown into the slag, which is then treated to form dross to separate Cu from Pb. Dry copper removal method for lead. (2) The method according to claim 1, wherein the composition of the Al-Mg-Zn alloy is 40 to 60% by weight Al.
, Mg 15-50% by weight, and Zn 5-40% by weight. (3) The method according to claim 1, wherein the alkali added to the floating slag in the form of a scum is Na.
How to be OH or KOH.