A complex brass refining agent and a refining method for waste complex brass

Abstract

The present invention provides a complex brass refining agent and a refining method for waste complex brass. The complex brass refining agent of the present invention includes a Cu-Zr master alloy, silicon brass, a Cu-B master alloy, a Cu-Ca master alloy, and a covering agent. Specifically for complex brass containing impurities such as iron and aluminum that are difficult to remove, it has strong iron removal, aluminum removal, and lead removal capabilities, strong dehydrogenation ability, the refining products are easy to remove, will not contaminate the brass liquid, greatly improves the metallurgical quality of the copper liquid, and at the same time the remaining alloying elements can be used as beneficial elements, which can effectively refine the as-cast structure and improve the hot and cold working properties and mechanical properties of the alloy. The complex brass refining agent of the present invention can not only effectively remove target impurities such as iron and aluminum, but also the remaining metal elements in the refining agent can be used as beneficial alloying elements, promoting the direct recycling of complex brass. The present invention also provides a refining method for waste complex brass.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal recycling, and particularly relates to a complex brass refining agent and a refining method for waste complex brass. Background Art

[0002] At present, there are many methods for recycling waste copper, which can be mainly divided into two categories: The first category is the direct utilization method: The recycled copper is directly smelted into copper alloy ingots of similar grades, and then processed into strips, rods, wires, tubes, etc., which is called direct utilization; The second category is the indirect utilization method: The recycled copper is smelted into anode plates and then refined into electrolytic copper by electrolysis for users, which is called indirect utilization. Compared with smelting from ore → electrolytic purification → processing, directly using recycled copper to process products will save more than 80% of energy, and is about 50% more energy-efficient than electrolytic purification → processing products, and the carbon emissions during the electrolysis process are extremely large.

[0003] Manufacturing brass products directly from waste brass will save a large amount of electricity and reduce environmental pollution, but the technical difficulty lies in the control of impurity content.

[0004] In related technologies, the main reasons for the low direct utilization ratio of recycled copper are: The direct utilization production and preparation technology of recycled copper is backward, and the product quality and performance do not meet high-end requirements, resulting in a narrow application range. Taking the new energy vehicle industry as an example, its typical high-quality copper-using components include: in-vehicle camera gaskets, air compressor multi-way pipe connectors, wire harness terminal connectors, drive motor rotor winding wires, etc. The copper materials used for these components mostly use primary copper production. The reasons for not using recycled copper products include: The turning accuracy requirements for in-vehicle camera gaskets are extremely high, and the thickness tolerance requirements are ±1μm. Due to the excessive Fe and Al in recycled lead brass rods, the tool and workpiece heat severely during high-speed turning, resulting in a decrease in tolerance accuracy; Through electrolytic purification, a large amount of energy is inevitably consumed, and the electrolysis process causes serious environmental pollution. How to improve the utilization rate and utilization level of purple waste copper with the least investment, reduce metal loss, and reduce environmental pollution is of great significance.

[0005] In summary, there is still a need to develop a new complex brass refining agent and a refining method for waste complex brass. Summary of the Invention

[0006] The present invention aims to at least solve one of the above technical problems existing in the prior art. For this reason, the present invention provides a complex brass refining agent, which has strong iron removal, aluminum removal, and lead removal capabilities, strong dehydrogenation ability, and the refined product is easy to remove, will not pollute the brass liquid, greatly improves the metallurgical quality of the copper liquid, and at the same time, the remaining alloying elements can effectively refine the as-cast structure, improve the hot and cold processing performance and mechanical properties of the alloy.

[0007] The present invention also provides a refining method for waste complex brass.

[0008] The first aspect of the present invention provides a complex brass refining agent, which includes a Cu-Zr master alloy, silicon brass, a Cu-B master alloy, a Cu-Ca master alloy, and a covering agent.

[0009] One technical solution in the technical solution of the present invention regarding the complex brass refining agent has at least the following beneficial effects:

[0010] The complex brass refining agent of the present invention is especially aimed at complex brass containing impurities such as iron and aluminum that are difficult to remove. It has strong iron removal, aluminum removal, and lead removal capabilities, strong dehydrogenation ability, and the refining products are easy to remove, without polluting the brass liquid, greatly improving the metallurgical quality of the copper liquid. At the same time, the remaining alloying elements can be used as beneficial elements, which can effectively refine the as-cast structure, improve the hot and cold working properties and mechanical properties of the alloy. The complex brass refining agent of the present invention can not only effectively remove target impurities such as iron and aluminum, but also the remaining metal elements in the refining agent can be used as beneficial alloying elements, promoting the direct recycling of complex brass.

[0011] In the complex brass refining agent of the present invention, Zr and B are used as the refining agent. Zr and iron can form a series of high-temperature intermetallic compounds. For example, the melting point of Fe2Zr is 1675°C, and it forms a series of high-melting-point intermetallic compounds with aluminum, such as the melting point of Al3Zr is 1560°C, and the melting point of AlZr3 is 1250°C. B forms F2B (melting point 1407°C), FeB (melting point 1650°C) with Fe, and also forms a series of high-melting-point intermetallic compounds such as Zr3Pb (melting point 1400°C) and Ca2Pb (melting point 1205°C). These high-melting-point intermetallic compounds form complexes with the salt refining agent and float to be removed; the remaining Zr and B serve as effective alloying elements, which can significantly refine the as-cast structure of the alloy and improve the hot and cold working properties and mechanical properties.

[0012] In the complex brass refining agent of the present invention, Si in the silicon brass forms high-melting-point intermetallic compounds such as FeSi (1410°C) with Fe, realizing the combined removal of Si and Fe.

[0013] Complex brass refers to an alloy mainly added with elements such as iron, aluminum, and lead to improve the properties of simple brass.

[0014] According to some embodiments of the present invention, the zirconium content of the Cu-Zr master alloy is 10% to 15%.

[0015] According to some embodiments of the present invention, the silicon content of the silicon brass is 3% to 6%.

[0016] According to some embodiments of the present invention, the silicon brass is waste silicon brass. On the one hand, the goal of iron removal is achieved, and on the other hand, the effective utilization of waste silicon brass is realized.

[0017] According to some embodiments of the present invention, the boron content of the Cu-B master alloy is 2% to 6%.

[0018] According to some embodiments of the present invention, the calcium content of the Cu-Ca master alloy is 8% to 12%.

[0019] According to some embodiments of the present invention, the covering agent includes lime, sodium carbonate, borax, barium sulfate, fluorite, barium carbonate, and cryolite.

[0020] According to some embodiments of the present invention, the covering agent includes:

[0021] Lime: 10 parts to 15 parts;

[0022] Sodium carbonate: 10 parts to 25 parts;

[0023] Borax: 15 parts to 30 parts;

[0024] Barium sulfate: 10 parts to 35 parts;

[0025] Fluorite: 2 parts to 5 parts;

[0026] Barium carbonate: 5 parts to 10 parts;

[0027] Cryolite: 2 parts to 5 parts.

[0028] According to some embodiments of the present invention, the borax is borax.

[0029] In the covering agent:

[0030] The function of lime is to form slag.

[0031] The function of sodium carbonate is to form slag.

[0032] The function of borax is to deoxidize.

[0033] The function of barium sulfate is to form slag.

[0034] The function of fluorite is to form slag.

[0035] The function of barium carbonate is to form slag.

[0036] The function of cryolite is to form slag.

[0037] According to some embodiments of the present invention, the complex brass refining agent includes the following components by weight:

[0038] Cu-Zr master alloy: 1.0 part to 5.0 parts,

[0039] Silicon brass: 1.0 part to 3.0 parts,

[0040] Cu-B master alloy: 0.5 parts to 5.0 parts,

[0041] Cu-Ca master alloy: 0.1 parts to 0.5 parts,

[0042] Covering agent: 50 parts to 125 parts.

[0043] The second aspect of the present invention provides a refining method for waste complex brass. The refining method is as follows: After melting the waste complex brass, add the components of the complex brass refining agent except the covering agent. After melting, add the covering agent, keep warm and blow in nitrogen.

[0044] One technical solution in the refining method of waste complex brass according to the present invention has at least the following beneficial effects:

[0045] The refining method of waste complex brass of the present invention can effectively remove impurities such as iron and aluminum, realize the effective utilization of waste complex brass, and the residual metal elements in the refining agent can also be used as beneficial alloying elements to improve the comprehensive performance of complex brass.

[0046] In the refining method of waste complex brass of the present invention, the removal rate of iron is more than 60%, the removal rate of aluminum is more than 55%, and the removal rate of lead is more than 65%.

[0047] According to some embodiments of the present invention, the temperature for heat preservation is 1180°C to 1230°C.

[0048] According to some embodiments of the present invention, the time for heat preservation is 15 min to 30 min.

[0049] According to some embodiments of the present invention, the preparation methods of Cu-Zr master alloy, Cu-B master alloy and Cu-Ca master alloy can be as follows:

[0050] S1: Place electrolytic copper with a purity of 99.99% to 99.999% in a vacuum melting furnace. After the electrolytic copper melts, control the melt temperature at 1150°C to 1200°C, and evacuate to above 10-1 Pa;

[0051] S2: Stop evacuating, and introduce high-purity inert gas with a purity of more than 99.99%, and control the pressure in the furnace to be 0.5 to 1 atmosphere;

[0052] After step S2:

[0053] Add Zr to the copper melt, and cast the melt into a grid-shaped mold to prepare Cu-Zr master alloy;

[0054] Add B to the copper melt, and cast the melt into a grid-shaped mold to prepare Cu-Zr master alloy;

[0055] Add Ca to the copper melt and cast the melt into a grid-shaped mold to prepare the Cu-Zr master alloy.

[0056] When the melt is cast into a grid-shaped mold, the obtained master alloy has grids and is easy to break, thus facilitating batching.

[0057] According to some embodiments of the present invention, the way of blowing nitrogen is bottom-side blowing. After bottom-side blowing nitrogen, through the polymerization of nitrogen bubbles with high melting point metal compounds and other inclusions in the melt, on the one hand, it speeds up their floating speed, saves refining time and electric energy, and finally improves the refining efficiency and saves energy; on the other hand, it improves the refining effect. At the same time, through the pressure difference inside and outside the nitrogen bubbles in the melt, the free hydrogen [H] (the hydrogen formed by the decomposition of water vapor in the high-temperature melt environment, which does not exist in the form of gas and generally exists in the form of free hydrogen) diffuses into the nitrogen bubbles and floats up and is removed, and finally, there is no residue. Description of the Drawings

[0058] Figure 1 It is a schematic diagram of bottom-side blowing nitrogen. Detailed Embodiments

[0059] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in combination with the embodiments, but the present invention is not limited to these embodiments.

[0060] In some embodiments of the present invention, the present invention provides a complex brass refining agent, which includes a Cu-Zr master alloy, silicon brass, a Cu-B master alloy, a Cu-Ca master alloy and a covering agent.

[0061] It can be understood that the complex brass refining agent of the present invention is especially for complex brass containing impurities such as iron and aluminum that are difficult to remove. It has strong abilities to remove iron, aluminum and lead, strong dehydrogenation ability, and the refining products are easy to be removed, and will not pollute the brass liquid, greatly improving the metallurgical quality of the copper liquid. At the same time, the remaining alloying elements can be used as beneficial elements, which can effectively refine the as-cast structure and improve the hot and cold working properties and mechanical properties of the alloy. The complex brass refining agent of the present invention can not only effectively remove target impurities such as iron and aluminum, but also the remaining metal elements in the refining agent can be used as beneficial alloying elements, promoting the direct recycling of complex brass.

[0062] It can also be understood that for the complex brass refining agent of the present invention, Zr and B are used as the refining agent. Zr and iron can form a series of high-temperature intermetallic compounds. For example, the melting point of Fe2Zr is 1675 °C, and with aluminum, it can form a series of high-melting-point intermetallic compounds, such as the melting point of Al3Zr is 1560 °C, and the melting point of AlZr3 is 1250 °C. B forms F2B (melting point 1407 °C), FeB (melting point 1650 °C) with Fe, and also forms a series of high-melting-point intermetallic compounds such as Zr3Pb (melting point 1400 °C), Ca2Pb (melting point 1205 °C). These high-melting-point intermetallic compounds form complexes with the salt refining agent and float to be removed; the remaining Zr and B act as effective alloying elements, which can significantly refine the as-cast structure of the alloy and improve the hot and cold working performance and mechanical properties of the alloy.

[0063] For the complex brass refining agent of the present invention, Si in silicon brass forms high-melting-point intermetallic compounds such as FeSi (1410 °C) with Fe, realizing the combined removal of Si and Fe.

[0064] Complex brass refers to an alloy mainly added with elements such as iron, aluminum, and lead to improve the performance of simple brass.

[0065] In some embodiments of the present invention, the zirconium content of the Cu-Zr master alloy is 10% - 15%.

[0066] In some embodiments of the present invention, the silicon content of the silicon brass is 3% - 6%.

[0067] In some embodiments of the present invention, the silicon brass is waste silicon brass. On the one hand, the goal of iron removal is achieved, and on the other hand, the effective utilization of waste silicon brass is also realized.

[0068] In some embodiments of the present invention, the boron content of the Cu-B master alloy is 2% - 6%.

[0069] In some embodiments of the present invention, the calcium content of the Cu-Ca master alloy is 8% - 12%.

[0070] In some embodiments of the present invention, the covering agent includes lime, sodium carbonate, borax, barium sulfate, fluorite, barium carbonate, and cryolite.

[0071] In some embodiments of the present invention, the covering agent includes:

[0072] Lime: 10 parts - 15 parts;

[0073] Sodium carbonate: 10 parts - 25 parts;

[0074] Borax: 15 parts - 30 parts;

[0075] Barium sulfate: 10 parts - 35 parts;

[0076] Fluorite: 2 parts to 5 parts;

[0077] Barium carbonate: 5 parts to 10 parts;

[0078] Cryolite: 2 parts to 5 parts.

[0079] In some embodiments of the present invention, borax is pyroborax.

[0080] In the covering agent:

[0081] The function of lime is to form slag.

[0082] The function of sodium carbonate is to form slag.

[0083] The function of borax is to deoxidize.

[0084] The function of barium sulfate is to form slag.

[0085] The function of fluorite is to form slag.

[0086] The function of barium carbonate is to form slag.

[0087] The function of cryolite is to form slag.

[0088] In some embodiments of the present invention, the complex brass refining agent comprises the following components by weight:

[0089] Cu-Zr master alloy: 1.0 part to 5.0 parts,

[0090] Silicon brass: 1.0 part to 3.0 parts,

[0091] Cu-B master alloy: 0.5 part to 5.0 parts,

[0092] Cu-Ca master alloy: 0.1 part to 0.5 part,

[0093] Covering agent: 50 parts to 125 parts.

[0094] In some other embodiments of the present invention, the present invention also provides a refining method for waste complex brass. The refining method is as follows: after melting the waste complex brass, add the components of the complex brass refining agent of the present invention except the covering agent. After melting, add the covering agent, keep warm and blow in nitrogen.

[0095] It can be understood that the refining method for waste complex brass of the present invention can effectively remove impurities such as iron and aluminum, realize the effective utilization of waste complex brass, and the residual metal elements in the refining agent can also be used as beneficial alloying elements to improve the comprehensive performance of complex brass.

[0096] For the refining method of waste complex brass of the present invention, the removal rate of iron is more than 60%, the removal rate of aluminum is more than 55%, and the removal rate of lead is more than 65%.

[0097] In some embodiments of the present invention, the heat preservation temperature is 1180 °C to 1230 °C.

[0098] In some embodiments of the present invention, the heat preservation time is 15 min to 30 min.

[0099] In some embodiments of the present invention, the preparation methods of the Cu-Zr master alloy, Cu-B master alloy, and Cu-Ca master alloy may be as follows:

[0100] S1: Place electrolytic copper with a purity of 99.99% to 99.999% in a vacuum melting furnace. After the electrolytic copper melts, control the melt temperature at 1150 °C to 1200 °C, and evacuate to above 10-1 Pa;

[0101] S2: Stop evacuating, and introduce high-purity inert gas with a purity of more than 99.99%, and control the pressure in the furnace to be 0.5 to 1 atmosphere;

[0102] After step S2:

[0103] Add Zr to the copper melt, and cast the melt into a grid-shaped mold to prepare the Cu-Zr master alloy;

[0104] Add B to the copper melt, and cast the melt into a grid-shaped mold to prepare the Cu-Zr master alloy;

[0105] Add Ca to the copper melt, and cast the melt into a grid-shaped mold to prepare the Cu-Zr master alloy.

[0106] Cast the melt into a grid-shaped mold. The obtained master alloy has grids and is easy to break, thus facilitating batching.

[0107] In some embodiments of the present invention, the way of blowing in nitrogen is bottom-side blowing, as Figure 1 shown. After bottom-side blowing in nitrogen, through the polymerization of nitrogen bubbles with high-melting-point metal intermetallic compounds and other inclusions in the melt, on the one hand, it speeds up their floating speed, saves refining time and electric energy, and ultimately improves the refining efficiency and saves energy; on the other hand, it improves the refining effect. At the same time, through the pressure difference inside and outside the nitrogen bubbles in the melt, the free hydrogen [H] diffuses into the nitrogen bubbles and floats up and is removed, and finally, there is no residue.

[0108] The technical solution of the present invention will be better understood by combining specific embodiments below.

[0109] Example 1

[0110] This example first provides a complex brass refining agent, including the following components and covering agent:

[0111] Cu-Zr master alloy: 5.0 wt%,

[0112] Waste silicon brass: 2.5 wt% (silicon content 6 wt%),

[0113] Cu-B master alloy: 5 wt%,

[0114] Cu-Ca master alloy: 0.5 wt%;

[0115] The covering agent contains:

[0116] Lime 15 wt%,

[0117] Sodium carbonate 24 wt%,

[0118] Pyroborax 23 wt%,

[0119] Barium sulfate 15 wt%,

[0120] Fluorite 2 wt%,

[0121] Barium carbonate 5 wt%,

[0122] Cryolite 3 wt%.

[0123] Then, using this complex brass refining agent, 100 kg of complex brass containing 0.9 wt% Fe and 0.6 wt% Al is refined. The refining method is as follows:

[0124] First, the complex brass is dried at 200 °C for 2 hours, then put into an intermediate frequency furnace to melt at a temperature of 1180 - 1190 °C. Cover the molten copper with calcined charcoal, add 2% of the refining agent based on the weight of the complex brass, blow N2 gas from the side for 10 minutes, remove the slag and then cast it into an iron mold to obtain an ingot. The compositions before and after refining are shown in Table 1.

[0125] Table 1

[0126] Before refining (wt%) After refining (wt%) Al 0.9 0.35 Fe 1.2 0.53 Pb 0.05 0.02

[0127] Example 2

[0128] This example first provides a complex brass refining agent, including the following components and covering agent:

[0129] Cu-Zr master alloy: 2.5 wt%,

[0130] Waste silicon brass: 2 wt% (silicon content 6 wt%),

[0131] Cu-B master alloy: 2 wt%,

[0132] Cu-Ca master alloy: 0.5 wt%;

[0133] The covering agent contains:

[0134] Lime: 20 wt%,

[0135] Sodium carbonate: 23 wt%,

[0136] Borax pyro: 20 wt%,

[0137] Barium sulfate: 15 wt%,

[0138] Fluorite: 5 wt%,

[0139] Barium carbonate: 5 wt%,

[0140] Cryolite: 5 wt%.

[0141] Then, using this complex brass refining agent, 100 kg of complex brass containing 0.9 wt% Fe and 0.6 wt% Al is refined. The refining method is as follows:

[0142] First, the complex brass is dried at 200 °C for 2 hours, then put into an intermediate frequency furnace to melt at a temperature of 1190 - 1210 °C. Cover the molten copper with calcined charcoal, add 2% of the refining agent based on the weight of the complex brass, blow N2 gas from the side for 10 minutes, remove the slag and then cast it into an iron mold to obtain an ingot. The composition before and after refining is shown in Table 2.

[0143] Table 2

[0144] Before refining (wt%) After refining (wt%) Al 0.6 0.23 Fe 0.9 0.40 Pb 0.06 0.022

[0145] Example 3

[0146] This example first provides a complex brass refining agent, including the following components and covering agent:

[0147] Cu-Zr master alloy: 5.0 wt%,

[0148] Waste silicon brass: 3 wt% (silicon content 6 wt%),

[0149] Cu-B master alloy: 3.5 wt%,

[0150] Cu-Ca master alloy: 0.5 wt%;

[0151] The covering agent contains:

[0152] Lime: 20 wt%,

[0153] Sodium carbonate: 20 wt%,

[0154] Borax pyro: 20 t%,

[0155] Barium sulfate: 13 wt%,

[0156] Fluorite: 5 wt%,

[0157] Barium carbonate: 5 wt%,

[0158] Cryolite: 5 wt%.

[0159] Then, using this complex brass refining agent, 100 kg of complex brass containing 2 wt% Fe and 0.8 wt% Al was refined. The refining method was as follows:

[0160] First, the complex brass was dried at 200 °C for 2 hours, then put into an intermediate frequency furnace to melt at a temperature of 1200 - 1210 °C. The molten copper was covered with calcined charcoal, 4% of the refining agent based on the weight of the complex brass was added, and N2 gas was blown from the side for 10 minutes. After slag removal, it was cast into an iron mold to obtain an ingot. The compositions before and after refining are shown in Table 3.

[0161] Table 3

[0162] Before refining (wt%) After refining (wt%) Al 2.0 0.69 Fe 0.8 0.34 Pb 0.04 0.0016

[0163] Example 4

[0164] In this example, a complex brass refining agent was first provided, including the following components and covering agent:

[0165] Cu-Zr master alloy: 5.0 wt%,

[0166] Waste silicon brass: 3 wt% (silicon content 6 wt%),

[0167] Cu-B master alloy: 2.5 wt%,

[0168] Cu-Ca master alloy: 0.5 wt%;

[0169] The covering agent contains:

[0170] Lime: 20 wt%,

[0171] Sodium carbonate: 20 wt%,

[0172] Pyroborax: 20 t%,

[0173] Barium sulfate: 15 wt%,

[0174] Fluorite: 4 wt%,

[0175] Barium carbonate: 5 wt%,

[0176] Cryolite: 5 wt%.

[0177] Then, using this complex brass refining agent, 100 kg of complex brass containing 2.6 wt% Fe and 0.5 wt% Al was refined. The refining method was as follows:

[0178] First, the complex brass is dried at 200 °C for 2 hours, and then put into an intermediate frequency furnace for melting at a temperature of 1200 - 1210 °C. The molten copper is covered with calcined charcoal, a refining agent accounting for 3% of the weight of the complex brass is added, and N2 gas is blown from the side for 10 minutes. After slag removal, it is cast into an iron mold to obtain an ingot. There are no hydrogen pores in the ingot, indicating strong dehydrogenation ability. Alloying elements Zr and B are common alloying elements for refining the as-cast structure of alloys. When they remain in the melt, they can refine the ingot structure, and theoretically, the refinement of the ingot structure improves the hot and cold working properties and mechanical properties of the ingot.

[0179] The compositions before and after refining are shown in Table 4.

[0180] Table 4

[0181] Before refining (wt%) After refining (wt%) Al 2.6 0.87 Fe 0.8 0.32 Pb 0.03 0.011

[0182] The complex brass refining agent of the present invention is especially aimed at complex brass containing impurities such as iron and aluminum which are difficult to remove. It has strong iron-removing, aluminum-removing, and lead-removing abilities, strong dehydrogenation ability, and the refining products are easy to remove, and will not pollute the brass liquid. It greatly improves the metallurgical quality of the copper liquid. At the same time, the remaining alloying elements can be used as beneficial elements, which can effectively refine the as-cast structure and improve the hot and cold working properties and mechanical properties of the alloy. The complex brass refining agent of the present invention can not only effectively remove target impurities such as iron and aluminum, but also the remaining metal elements in the refining agent can be used as beneficial alloying elements, which promotes the direct recycling of complex brass.

[0183] In summary, the complex brass refining agent and the waste complex brass refining method of the present invention can effectively remove impurities such as iron and aluminum, realize the effective utilization of waste silicon brass, and improve the refining efficiency and save energy by blowing nitrogen from the bottom. The remaining metal elements in the refining agent can also be used as beneficial alloying elements to improve the comprehensive performance of complex brass.

[0184] The above has described the present invention in detail in combination with the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present invention.

Claims

1. A complex brass refining agent, characterized in that, Comprising the following components by parts by weight: Cu-Zr master alloy: 1.0 part to 5.0 parts, Silicon brass: 1.0 part to 3.0 parts, Cu-B master alloy: 0.5 part to 5.0 parts, Cu-Ca master alloy: 0.1 part to 0.5 part, Covering agent: 50 parts to 125 parts; The covering agent comprises lime, sodium carbonate, borax, barium sulfate, fluorite, barium carbonate and cryolite; The silicon content of the silicon brass is 3% to 6%.

2. The complex brass refining agent according to claim 1, characterized in that The zirconium content of the Cu-Zr master alloy is 10% to 15%.

3. The complex brass refining agent according to claim 1, characterized in that, The boron content of the Cu-B master alloy is 2% to 6%.

4. The complex brass refining agent according to claim 1, characterized in that, The calcium content of the Cu-Ca master alloy is 8% to 12%.

5. A refining method for waste complex brass, characterized in that, The refining method is: after melting the complex brass, adding the components other than the covering agent in the complex brass refining agent according to any one of claims 1 to 4, after melting, adding the covering agent, keeping warm and blowing nitrogen; The way of blowing nitrogen is bottom side blowing.

6. The refining method according to claim 5, characterized in that, The temperature for keeping warm is 1180°C to 1230°C.

7. The refining method according to claim 5, characterized in that, The time for keeping warm is 15 min to 30 min.

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