JP2009209405A - Method for smelting copper-containing dross - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a smelting method for efficiently recovering valuable metals such as copper and lead from a copper-containing dross that is produced in a smelting process of smelting zinc and/or lead. <P>SOLUTION: The method for smelting the copper-containing dross includes: charging the copper-containing dross that contains copper and lead into a melt including a matte and copper alloy of a molten state, which are produced when fuming slag that is produced from a smelting furnace for smelting zinc and/or lead, under the coexistence of copper; and blowing an oxygen-containing gas into the melt. Then, the temperature of the melt is preferably 1,200 to 1,500°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a copper-containing dross smelting method, and more particularly, efficiently recovers valuable metals such as copper and lead from copper-containing dross produced by a zinc and / or lead smelting method. It relates to the smelting method.

  Conventionally, in zinc and / or lead smelting, a blast furnace method called smelting process of zinc and lead at the same time, which is referred to as Imperial Melting Process, has been widely used. The processing method of slag generated from the blast furnace by the blast furnace method is as follows. The slag is guided to the front floor of the smelting furnace to roughly separate the copper-containing crude lead and the furnace iron, and then water granulated, etc. The product slag has been. However, since the slag has a high zinc content and contains lead and arsenic, antimony and other metals which are components of spices, the slag is generally charged in a fume furnace and treated with a slag fuming treatment (for example, Patent Document 1). ), And then granulated and commercialized.

  The slag fuming treatment is to volatilize metals such as zinc, lead, arsenic, and antimony contained in the slag by heating and reducing the molten slag. As a result, zinc and lead can be recovered from the slag and the impurity metal can be removed, thereby obtaining a purified slag. Here, the slag fuming process is performed using a lance for gas blowing or a heating furnace provided with tuyere at the lower part of the furnace. The treated slag is extracted from the bottom of the furnace, and the volatilized metal is oxidized by adding air during the movement to the top of the furnace and recovered as slag fuming dust containing zinc and lead.

  Further, lead is recovered from the copper-containing crude lead, but for that purpose, first, separation of copper is indispensable. As a method for separating and recovering copper from copper-containing crude lead, copper-containing crude lead is usually introduced into a furnace called a stripping furnace to form a solid dross (hereinafter sometimes referred to as copper-containing dross). Copper is floated on a lead bath and then mechanically separated by scraping or the like. This method is based on a so-called melting method in which copper is precipitated and separated by gradually cooling a copper-containing crude lead melt by utilizing the low solubility of copper in lead near the melting point of lead. The main components of the copper-containing dross obtained here are partially oxidized solid copper and a large amount of crude lead adhering thereto, and the crude lead contains zinc and the like in addition to lead.

  However, in the slag treatment method described above, the behavior of group 15 elements such as arsenic and antimony in the slag fuming treatment, elution of lead and the like from the treated slag, and valuable metals such as copper and lead from the copper-containing dross There were problems such as efficient separation and recovery.

  As a method for smelting copper-containing dross, generally, sulfur is added to copper-containing dross to obtain sulfur or mat or white river, and this is put into a converter process of dry copper smelting to recover copper. Has been done. In other words, when copper-containing dross is directly put into the converter process, the copper-containing dross has a high lead content, so the amount of low melting point dust increases due to volatilization of lead in the converter, making it difficult to treat the generated dust. There was a problem of letting Moreover, since the oxidized copper in the copper-containing dross is distributed to the slag, there is a problem in that the recovery rate is reduced. Therefore, copper-containing dross is usually heat-treated by adding a sulfur source such as pyrite and a flux such as sodium carbonate using a kiln or the like, and lead is separated and recovered, and copper is matted. Processing is performed to avoid points. However, in the step of sulfiding copper-containing dross, there is a problem that the cost of fuel and labor costs increases because the time required for sulfiding is long.

  Further, as technical problems related to the behavior of group 15 elements such as arsenic and antimony in the slag fuming treatment, arsenic and antimony having low boiling point and high vapor pressure are contained in zinc and lead dust recovered from the fuming furnace. When the group 15 element is concentrated and repeated in the sintering process of the blast furnace method, it volatilizes and increases the load on the exhaust gas treatment system, or when it is charged into the blast furnace together with the sintered ingot In some cases, the operation of the blast furnace becomes difficult due to the generation of spices, which are high melting point metal compounds. In addition, due to variations in the slag fuming treatment, when harmful elements such as lead or arsenic remain in the slag, in the elution test of the slag after the treatment, there is a problem that the soil environment standard cannot be satisfied, A method that stably satisfies the soil environmental standards has been desired.

  As a solution for this, slag containing arsenic or arsenic and antimony together with zinc and lead produced from a zinc and / or lead smelting furnace is heated and reduced in a fuming furnace to volatilely separate zinc and lead. In the fuming method, the Cu-Fe-Pb-As-based copper alloy homogeneous melt is prepared by reacting the slag melt with arsenic or arsenic and antimony contained in the slag while coexisting with the copper melt. There has been proposed a slag fuming method (see, for example, Patent Document 2). Here, when sulfur is present in the slag, a part of the copper alloy forms a Cu—Fe—Pb—As—S mat depending on the sulfur content. The formation of the mat is not desirable because it increases the amount of copper source required for slag fuming and requires a mat processing step.

  According to this slag fuming method in the presence of copper, a Cu-Fe-Pb-As-based copper alloy and a Cu-Fe-Pb-As-S-based mat are produced, while arsenic and antimony contents are produced. In addition to obtaining dust containing zinc and lead with a low content, it is possible to stably satisfy the soil environment standards (Pb and As elution amounts in an elution test according to Environment Agency Notification No. 46: 0.01 mg / L or less each). Slag is obtained. Therefore, the problems relating to the behavior of group 15 elements such as arsenic and antimony in the slag fuming process and the elution of lead and the like from the slag after the process are solved.

  As described above, in the above slag treatment method, there is still a problem of efficiently recovering valuable metals such as copper and lead from the copper-containing dross even when the method of slag fuming in the presence of copper is adopted. It had been.

JP-A-11-269567 (first page, second page) WO2005 / 068669 specification

  In view of the above-mentioned problems of the prior art, the object of the present invention is a process for efficiently recovering valuable metals such as copper and lead from copper-containing dross produced by the zinc and / or lead smelting method. It is to provide a smelting method.

  In order to achieve the above object, the present inventor has conducted extensive research on a copper-containing dross smelting method produced by a zinc and / or lead smelting method. Cu-Fe-Pb-As-S-based mat and Cu-Fe-Pb-As-based copper alloy produced when slag produced from a smelting furnace is treated with slag in the presence of copper Then, the copper-containing dross was thrown into the melt consisting of the mat and the copper alloy in the molten state, and then the oxygen-containing gas was blown, the mat and the copper-containing dross disappeared, copper as the copper alloy and lead as the dust, The inventors have found that valuable metals can be efficiently recovered, and have completed the present invention.

  That is, according to the first aspect of the present invention, the molten mat and copper produced when slag produced from a smelting furnace for zinc and / or lead smelting is subjected to slag fuming treatment in the presence of copper. A copper-containing dross smelting method is provided, wherein a copper-containing dross containing copper and lead is introduced into a melt made of an alloy, and then an oxygen-containing gas is blown into the melt.

  Moreover, according to 2nd invention of this invention, the temperature of the said melt is 1200-1500 degreeC in 1st invention, The refining method of the copper containing dross characterized by the above-mentioned is provided.

  According to a third invention of the present invention, in the first or second invention, the oxygen-containing gas is blown into the vicinity of the mat layer formed in the melt, and the copper-containing dross is smelted A method is provided.

  According to a fourth invention of the present invention, in any one of the first to third inventions, the melt is held in a ladle equipped with a gas blowing lance. A method is provided.

The method for smelting copper-containing dross according to the present invention includes a copper-containing dross produced by a smelting method for zinc and / or lead smelting slag produced from a smelting furnace for zinc and / or lead smelting. Using a Cu-Fe-Pb-As-S-based mat and a Cu-Fe-Pb-As-based copper alloy produced during slag fuming treatment in the presence of coexisting copper while copper is oxidized As an alloy, valuable metals can be efficiently recovered by using lead as dust, and mat processing can be performed simultaneously with copper-containing dross, which contributes to cost reduction. Therefore, its industrial value is extremely large.
In addition, since the copper-containing dross and the copper in the mat can be used as a copper source in the slag fuming treatment method in the presence of copper, the cost of the copper source for the slag fuming treatment can be reduced.

Hereinafter, the method for smelting copper-containing dross by the slag fuming furnace of the present invention will be described in detail.
The copper-containing dross smelting method according to the present invention includes a molten mat and a copper alloy produced when slag produced from a zinc and / or lead smelting furnace is subjected to slag fuming treatment in the presence of copper. A copper-containing dross containing copper and lead is introduced into the melt comprising, and then oxygen-containing gas is blown.

  In the present invention, it is important to smelt copper-containing dross using a mat and a copper alloy produced when slag fuming is performed in the presence of copper while oxidizing the mat. That is, as described above, the copper-containing dross is made of partially oxidized solid copper and coarse lead containing lead, zinc, etc. attached thereto, and the mat is made of a Cu—Fe—Pb—As—S system. However, the reaction heat generated by the oxidation of the sulfur content of the mat in the furnace is effectively utilized to facilitate the melting and reduction reaction at high temperatures. Is absorbed by the copper alloy, while the highly volatile lead and zinc are separated as dust, leaving the soot composed of some oxides, and the mat and copper-containing dross disappear.

The above method is performed as follows, for example.
The copper alloy and the mat obtained after the surafuming treatment in the presence of copper are separated from the slag by a tap operation or the like and held in a reaction container such as a ladle. When a copper-containing dross is introduced into this melt, most of the copper and lead in the copper-containing dross are metallic, and thus quickly dissolve in the copper alloy. In addition, some copper in the copper-containing dross is oxidized, but the copper oxide reacts with the sulfide in the mat, or is easily reduced by adding a reducing agent such as coke if necessary. Can be absorbed in copper alloy. Further, an oxygen-containing gas such as oxygen gas or air is blown into the mat in the ladle, thereby performing an oxidation reaction of the mat as shown in the following formulas (1) and (2).

Cu ₂ S + O ₂ = 2Cu + SO ₂ (1)
FeS + O ₂ = Fe + SO ₂ (2)

Here, sulfur in the mat is volatilized as sulfur dioxide, but this oxidation reaction is an exothermic reaction and raises the temperature of the melt.
Although it does not specifically limit as temperature of the said melt, 1200-1500 degreeC is preferable and 1350-1450 degreeC is more preferable. As a result, lead dissolved in the copper alloy can be volatilized. That is, the activity value of lead decreases when it melts in copper, and the vapor pressure decreases accordingly. Therefore, lead volatilization rate becomes slow by copper alloying. When the activity is 1, it becomes 10 ⁻² atm or more, which is a vapor pressure generally volatilized at about 1150 ° C., whereas it becomes a copper alloy, for example, when the activity is 0.1 Is most effective in a temperature range of about 100 ° C. centered at about 1400 ° C., for example, a temperature of 1350-1450 ° C. By the way, according to the method of the present invention, the lead activity value may be 0.3 to 0.5 or more when the lead content in the copper alloy is high. As the content in the copper alloy decreases, the activity value of lead gradually decreases, and when lead is sufficiently removed from the copper alloy, it becomes about 0.1 or less. Therefore, it is desired that the temperature be at least 1200 ° C. or higher. On the other hand, if the temperature exceeds 1500 ° C., the cost of repairing a refractory material such as a ladle increases. Note that the temperature rise of the melt due to the oxidation reaction depends on the mat amount and the sulfur content of the mat, and in the case of shortage, it contains oxygen and heavy oil, natural gas, pulverized coal, etc. from the electric heating or lance tip. It can be supplemented using gas blowing to blow out the gas.

  As the reaction vessel used in the above-mentioned method, a melting furnace equipped with a gas blowing lance can be used in addition to a ladle that can be equipped with a gas blowing lance. For example, in the melting furnace, a mat and a copper alloy produced when a slag produced from a zinc and / or lead smelting furnace is subjected to a slag fuming treatment in the presence of copper are introduced, and electric heating or Melting with heavy oil, natural gas, pulverized coal, etc. and oxygen-containing gas blowing from the tip of the lance, forming a mat layer and a copper alloy layer, and then introducing copper-containing dross into the furnace, Next, oxygen gas is blown into the vicinity of the mat layer by a gas blowing lance, and the temperature of the copper alloy and the copper-containing dross is increased by the reaction heat while oxidizing the molten mat, and the copper from the mat and the copper-containing dross is increased. Promote absorption and lead volatilization.

  The copper-containing dross used in the above method contains copper and lead, and as described above, the dross (primary dross) consisting of partially oxidized copper and crude lead separated from the copper-containing crude lead by a slagging furnace or the like. In addition, a dross (also referred to as a secondary dross) generated from the crude lead by further cooling when casting the crude lead into the anode is used. Here, as shown in Table 1, the composition of primary and secondary dross has relatively high zinc quality in addition to copper and lead, and secondary dross has higher lead quality. . Table 1 shows a typical example of the composition of copper-containing dross (1, 2nd dross).

  In the above method, the ratio of the copper-containing dross to the mat produced in the slag fuming treatment in the presence of copper is not particularly limited, and it is produced by a zinc and / or lead smelting method. The copper-containing dross and the mat and the copper alloy produced when the produced slag is subjected to the slag fuming treatment in the presence of copper are efficiently processed. In particular, the melt temperature is set to 1200. It is important to adjust the temperature so that the temperature is maintained at 1 ° C. or higher, preferably 1350 to 1450 ° C. That is, depending on the ratio of copper-containing dross, a large amount of metallic lead is brought in, and the activity of lead dissolved in the copper alloy is reduced, and the vapor pressure of lead is reduced accordingly. In order to obtain a low lead copper alloy, the reaction time becomes long.

Matts and copper alloys used in the above method are those produced when slag fuming treatment is performed in the presence of copper by adding a copper source to slag produced from a zinc and / or lead smelting furnace. It is. Below, the slag fuming process in the coexistence of copper of the slag produced from the smelting furnace of zinc and / or lead smelting is demonstrated.
The slag used for the slag fuming treatment is not particularly limited, and is produced from a zinc and / or lead smelting furnace and contains arsenic or arsenic and antimony in addition to zinc and lead. Slag formed in a sex atmosphere is used. For example, slag produced in the zinc and / or lead smelting, the preparation of the raw material and the flux, for _example, the slag composition is _{FeO-SiO 2 -Al 2 O 3} -CaO-ZnO-PbO system relatively low melting point To be prepared. Therefore, the slag temperature is operated at 1200 to 1350 ° C.

  As a copper source used for the slag fuming treatment, at least one copper-containing raw material selected from smelting intermediates or scraps is used. Here, the said copper containing raw material can mix and use various copper containing raw materials. Moreover, it can use together with metallic copper as a copper source. The smelting intermediate is not particularly limited, and includes each step of smelting, particularly copper smelting, converter, etc., in addition to crude copper (copper grade 98 to 99% by weight) obtained from copper smelting. Used are copper-containing intermediates such as dust and soot. Also, copper-containing scraps such as metal and alloy-type processing scraps recycled from the fields of use of many copper materials are used.

  The amount of copper used in the copper source with respect to the slag used for the slag fuming treatment is not particularly limited, and reacts with spices contained in the slag to cause Cu-Fe- in a temperature range of 1100 to 1500 ° C. The conditions for forming a uniform melt of the Pb—As copper alloy are selected. For example, the content ratio (weight ratio) of Cu and Fe in the uniform melt in this temperature range is 1: 0.05 to 1: It is 0.5, and it is desirable that the amount used be equal to or greater than the amount of copper determined from the amount of iron dissolved in copper, depending on the temperature used and the amount of iron in the spices contained in the slag.

  The temperature of the melt in the fuming furnace used for the slag fuming treatment is preferably 1100 to 1500 ° C, more preferably 1350 to 1450 ° C. That is, when the temperature of the melt is less than 1100 ° C., the formation of zinc vapor is insufficient from the Zn—ZnO equilibrium, so that the volatilization efficiency of zinc from the slag deteriorates, or the stable slag containing FeO from the Fe—FeO equilibrium. Since the formation is insufficient, there arises a problem that the viscosity of the slag is too high. On the other hand, when the temperature of the melt exceeds 1500 ° C., the amount of damage to the refractory in the fuming furnace increases or the required thermal energy increases.

The oxygen partial pressure of the melt in the fuming furnace used for the slag fuming treatment is not particularly limited, and an oxygen partial pressure capable of reducing zinc, lead, arsenic, and antimony to a metal state is used. In particular, −8> logPo ₂ > −11.5 (where Po ₂ represents the partial pressure of oxygen in the slag in units of atm and is converted to a temperature reference of 1400 ° C.). It is preferable to control the oxygen partial pressure within the range shown.

That is, when Po ₂ exceeds 10 ⁻⁸ atm, the reducibility is weakened, so that volatilization of metallic zinc is difficult to occur. Further, by Fe ₃ O ₄ which is a refractory by Po ₂ dependent FeO-Fe ₃ O ₄ equilibrium deteriorates the fluidity of the slag was increased in the slag, a stable slag fuming operation becomes difficult . On the other hand, if Po ₂ is less than 10 ^−11.5 atm, iron becomes stable in the metal state due to Po ₂ dependence of the Fe—FeO equilibrium, which is not preferable because generation of furnace iron occurs and inhibits operation.

  The amount of copper used for the slag used in the slag fuming treatment is not particularly limited, and reacts with spices contained in the slag to react with Cu-Fe-Pb-As-based copper in a temperature range of 1100 to 1500 ° C. The conditions for forming a uniform melt of the alloy are selected. For example, in this temperature range, the amount of iron dissolved in the uniform melt is 5 to 50% by mass with respect to copper, and is included in the temperature and slag used. Depending on the amount of iron in the spices, it is desirable to use more than the amount of copper determined from the amount of iron dissolved in copper.

Specifically, by changing the amount of copper according to the amount of iron in the spices contained in the slag, or by changing the amount of slag to be processed with a constant amount of copper, Cu-Fe-Pb-As-based copper A uniform melt of the alloy can be stably formed.
Further, in the formation of a Cu-Fe-Pb-As-based homogeneous melt, there is a concern about the formation of a copper spice phase, but under the condition of adding an excess amount of copper selected based on the dissolved amount of iron, the copper spice phase Therefore, it is practically prepared based on the dissolved amount of iron. Moreover, if lead is about 10 mass% or less, since a spice phase will not produce | generate to the composition which arsenic contains about 20 mass%, it turns out that spice does not produce | generate in the copper metal vicinity.

The molten copper alloy and mat produced in the fuming furnace in the slag fuming process are separated from the slag by the specific gravity difference and can be easily recovered by tilting or tapping the furnace. In the slag fuming treatment, the produced copper alloy can be repeatedly used as a copper source until iron, lead, arsenic, antimony, etc. are saturated and the absorption capacity is reduced. The copper alloy used in the smelting method can be used by appropriately tapping with the mat. Accordingly, the composition of the copper alloy is not particularly limited. For example, the copper quality is 50 to 90% by mass, the iron quality is 3 to 10% by mass, the lead quality is 5 to 40% by mass, and the arsenic quality is 0. 0.02 to 4.5% by mass.
On the other hand, as said mat, a part of said copper alloy forms a Cu-Fe-Pb-As-S type | system | group mat | matte by content of the sulfur in slag, Although the production | generation ratio with respect to a copper alloy fluctuates. The sulfur grade is 15 to 25% by mass.
Thus, the mat and the copper alloy produced when the slag fuming process is performed in the presence of copper are used for an efficient smelting process of copper-containing dross.

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples of the present invention, but the present invention is not limited to these examples. The metal used in the examples and comparative examples was analyzed by ICP emission analysis.
Moreover, the slag produced from the blast furnace was used for the raw material slag of the slag fuming treatment used in the examples and comparative examples. Table 2 shows the chemical composition.

Example 1
(1) Preparation of copper alloy and mat by slag fuming treatment First, 2000 g of slag and metallic copper (copper grade 99) were placed in an alumina crucible installed in a slag fuming device heated by an externally heated electric furnace. .99 mass%) 800 g was added and slag fuming treatment was performed. Here, fuming was performed by blowing gas into the melt with a gas blowing tube. After the completion of fuming, the produced copper alloy and mat were recovered from the cooled crucible. Further, 2000 g of the slag, the recovered copper alloy and the mat were placed in an alumina crucible, and the fume operation was performed. The same operation was performed 5 times in total, and the copper alloy and the mat were recovered. Table 3 shows the compositions of the prepared copper alloy and mat.

(2) Smelting of copper-containing dross Next, 450 g of the prepared copper alloy and 300 g of the mat were placed in an alumina crucible heated by an externally heated electric furnace, and the furnace temperature was maintained at 1300 ° C. in a nitrogen atmosphere. did. Then, after confirming melting of the mat and the copper alloy, 100 g of the copper-containing dross (primary dross) was put into the crucible. Subsequently, after maintaining the furnace temperature at 1300 ° C. for 30 minutes, the furnace was turned off, and oxygen gas was blown in the vicinity of the mat layer formed in the crucible at a flow rate of 2 L / min for 30 minutes. At the end of blowing, the temperature of the melt was 1440 ° C.
Thereafter, the crucible made of alumina was cooled, and the soot that was slightly present in the surface layer and about 580 g of the copper alloy were separated, recovered and analyzed. The presence of mat and copper-containing dross phase was not observed. Table 4 shows the composition of the obtained copper alloy.

(Example 2)
In the smelting of the copper-containing dross, the same operation as in Example 1 was performed except that the furnace temperature was 1200 ° C. At this time, the temperature of the melt at the end of blowing was 1290 ° C.
As a result, no copper-containing dross phase remained.

(Example 3)
In the smelting of the copper-containing dross, the same operation as in Example 1 was performed except that the secondary dross was used as the copper-containing dross. At this time, the temperature of the melt at the end of the blowing was 1420 ° C.
As a result, no copper-containing dross phase remained.

Example 4
In the smelting of the copper-containing dross, the same operation as in Example 1 was performed except that the furnace temperature was 1200 ° C. and the secondary dross was used as the copper-containing dross. At this time, the temperature of the melt at the end of blowing was 1260 ° C.
As a result, no copper-containing dross phase remained.

(Example 5)
In the smelting of the copper-containing dross, the same operation as in Example 1 was performed except that a mixture of 50 g of primary dross and 50 g of secondary dross was used as the copper-containing dross. At this time, the temperature of the melt at the end of blowing was 1430 ° C.
As a result, no copper-containing dross phase remained.

  As described above, by using the mat and copper alloy obtained by the slag fuming treatment, co-existing these and the copper-containing dross, blowing oxygen-containing gas and oxidizing the mat, the copper-containing dross and the mat It can be seen that a copper alloy that can be reused for slag fuming treatment is obtained by eliminating copper and absorbing copper and volatilizing lead.

  As is clear from the above, the copper-containing dross smelting method of the present invention is a slag produced from a smelting furnace in zinc and / or lead smelting, for example, a slag produced from a blast furnace by a blast furnace method. By using a mat and a copper alloy produced in a slag fuming process that volatilizes and recovers zinc and lead by fuming and performing a reaction to oxidize the mat by blowing an oxygen-containing gas. Since copper dross is extinguished and copper is made into a copper alloy and lead is made into dust, valuable metals can be efficiently recovered, so in combination with slag fuming treatment in zinc and / or lead smelting, This is useful as a contribution to reducing costs.

Claims (4)

  Copper and lead are contained in a molten material made of a mat and a copper alloy in a molten state produced when slag produced from a zinc and / or lead smelting furnace is subjected to slag fuming treatment in the presence of copper. A method for smelting copper-containing dross, comprising introducing copper-containing dross and then blowing oxygen-containing gas.   The temperature of the said melt is 1200-1500 degreeC, The smelting method of the copper containing dross of Claim 1 characterized by the above-mentioned.   The said oxygen containing gas blows in the mat | matte layer vicinity formed in a melt, The smelting method of the copper containing dross of Claim 1 or 2 characterized by the above-mentioned.   The method for refining copper-containing dross according to any one of claims 1 to 3, wherein the melt is held in a ladle equipped with a lance for gas blowing.