Zinc-copper-nickel alloy smelting deslagging agent and preparation method and use method thereof

Abstract

The invention provides a zinc-copper-nickel-copper smelting deslagging agent and a preparation method and a use method thereof. The zinc-copper-nickel-copper smelting deslagging agent comprises the following raw materials in percentage by mass: 5-15% of calcium fluoride, 20-30% of sodium carbonate, 5-15% of sodium fluoride, 10-20% of sodium hexafluoroaluminate and the balance of borax. Compared with the prior art, the zinc-copper-nickel-copper slag remover prepared by mixing the raw materials can effectively reduce impurities to be less than 0.14% of Fe, less than 0.005% of Pb and less than 0.003% of Si in the smelting process, the impurity components are obviously reduced, the number of times of component adjustment and unqualified sampling is reduced, impurities mixed in a casting blank are reduced, and finally the metal purity and the casting quality are improved. Meanwhile, loss of zinc and nickel is reduced to the maximum extent; and adverse effects on the zinc-copper-nickel alloy are avoided.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal smelting, and relates to zinc-copper alloy smelting and casting processes. Specifically, it relates to a slag remover for zinc-copper alloy smelting, its preparation method, and its application method. Background Technology

[0002] Zinc-copper alloy, with copper-nickel-zinc alloy as its core, is a high-performance copper alloy. It has wide applications in industrial production; however, during the smelting process, the poor fluidity of molten copper makes it difficult for impurities, including oxides and other impurities, to float and be removed. When using raw materials with high impurity content in the smelting furnace, if these impurities are not removed in time, they will be carried from the smelting furnace to the holding furnace after the converter. As casting progresses, these impurities will eventually remain in the strip. During subsequent rolling to thin strips, the remaining impurities will peel off, severely affecting product quality. When impurities accumulate on the furnace wall, some molten copper will remain there, reducing the effective volume of the smelting or holding furnace and requiring regular cleaning. Furthermore, impurities adhering to the molten copper increase the amount of slag on the surface, increasing the workload of slag removal.

[0003] Furthermore, the high reactivity of zinc, the sensitivity of nickel, and the complexity of inclusions in zinc-copper alloys increase the difficulty of slag removal. Patent CN 114134352 A, published on March 4, 2022, discloses a slag remover for scrap smelting of brass and a method for brass smelting. The slag remover has the following mass percentage composition: sodium fluorosilicate 50%–80%, quartz sand 10%–15%, calcium oxide 5%–10%, aluminum oxide 5%–10%, potassium ferrite 5%–10%, soda ash 5%–10%, and manganese dioxide 5%–10%. This patent purifies the brass melt by controlling the added substances and their content, removing slag from the melt through physical adsorption and chemical reaction, thus purifying the melt and ensuring its composition meets requirements. However, this slag remover is designed for brass and is not suitable for slag removal in zinc-copper alloys. Summary of the Invention

[0004] The purpose of this invention is to provide a slag remover for zinc-copper smelting and its preparation method. Calcium fluoride, sodium carbonate, sodium fluoride, sodium hexafluoroaluminate, and borax are designed as raw materials for the slag remover, taking into account the characteristics of zinc-copper smelting. This not only uses simple and low-cost raw materials but also provides excellent slag removal effect.

[0005] The present invention also provides a method for using a zinc-white copper smelting slag remover. Utilizing the above-mentioned zinc-white copper smelting slag remover and the characteristics of zinc-white copper smelting, it can effectively reduce impurities to Fe < 0.14%, Pb < 0.005%, and Si < 0.003% during the smelting process. The impurity content is significantly reduced, reducing the number of composition adjustments and unqualified sampling, and reducing impurities in the cast billet.

[0006] The specific technical solution of this invention is as follows:

[0007] A slag remover for zinc-copper smelting comprises the following raw materials by weight percentage:

[0008] Calcium fluoride 5%-15%, sodium carbonate 20%-30%, sodium fluoride 5%-15%, sodium hexafluoroaluminate 10%-20%, balance borax.

[0009] All raw materials for the zinc-copper smelting slag remover must be dried before use, and the moisture content of each raw material must be less than 7%.

[0010] The particle size of each raw material in the zinc-copper smelting slag remover is ≤0.05mm;

[0011] All of the above raw materials can be directly purchased as finished products according to specifications.

[0012] The present invention provides a method for preparing a slag remover for zinc-copper smelting, specifically comprising:

[0013] Mix the ingredients in the specified amounts until they are thoroughly combined.

[0014] Once the mixture is thoroughly stirred, it is placed in a low-speed mixer and stirred at a speed of 500-800 rpm for 30-60 minutes.

[0015] After mixing thoroughly, store in a dry storage container and seal when not in use to prevent moisture absorption.

[0016] The method of using the zinc-white copper smelting slag remover provided by the present invention is as follows: during the zinc-white copper smelting process, after the raw materials in the melting furnace are dissolved, the zinc-white copper smelting slag remover is added to the melting furnace and stirred. After standing, the slag floats to the surface of the copper liquid, and the slag is removed using a slag removal tool.

[0017] The amount of slag remover used in the zinc-copper smelting process is 0.1-0.17% of the total weight of the furnace charge.

[0018] The settling time is 5-10 minutes.

[0019] The zinc-copper alloy obtained by smelting according to the above method comprises the following mass percentage composition: Cu 53.5%-56.5%, Ni 16.5%-19.5%, with the balance being Zn and unavoidable impurities.

[0020] The unavoidable impurities are Fe < 0.14%, Pb < 0.005%, and Si < 0.003%.

[0021] The design concept of this invention is as follows: In this zinc-white copper slag remover, both calcium fluoride and sodium fluoride can play a refining role. The free fluoride ions in calcium fluoride and sodium fluoride can react with impurities in the zinc-white copper melt, such as ferrous oxide, to generate oxide slag with a higher melting point and lower density, which is then separated from the copper liquid. Due to its compositional characteristics, zinc-white copper mainly contains oxide inclusions and foreign inclusions. This formula achieves the removal of various inclusions through the synergistic reaction of multiple components, including calcium fluoride, sodium fluoride, and sodium hexafluoroaluminate. Borax decomposes upon heating in molten copper, and the generated boron oxide is a strong deoxidizer that can effectively reduce the oxygen content in molten copper and reduce the probability of defects such as porosity in the billet. Furthermore, borax melts at high temperatures to form a glassy melt, which can encapsulate fine fluoride complexes and unreacted inclusions. Through adhesion, it promotes particle collision and aggregation, increasing the size (from micrometers to tens of micrometers), accelerating the floating to the surface of the melt, and further improving the removal of complex inclusions in zinc-white copper. The glassy melt formed by borax at high temperatures can isolate air, reduce the oxidation and burning loss of zinc in zinc-copper alloys, reduce zinc evaporation loss, and also has a certain heat-insulating effect. Adding sodium carbonate decomposes at high temperatures to generate sodium oxide and carbon dioxide gas bubbles, which can carry away some of the hydrogen gas produced during the high-temperature decomposition of oily raw materials, reducing the impact of hydrogen gas on the brittleness of the metal and the probability of peeling; the resulting... The gas forms an inert atmosphere, further reducing zinc oxidation; the sodium oxide generated by decomposition not only reacts with acidic oxides to remove slag, but also combines with borax and fluorides to form a molten covering layer, covering the surface of the melt and hindering the escape of zinc vapor. Adding sodium hexafluoroaluminate to the slag remover can remove some impurities in the copper molten metal, such as iron and lead; sodium hexafluoroaluminate reacts with these to form corresponding fluoride slag, which has a lower density than the copper molten metal, thus floating on the surface and facilitating slag removal; adding sodium hexafluoroaluminate to the melt can reduce the viscosity of the zinc-copper alloy melt, improve the fluidity of the copper molten metal, and reduce the probability of cracking and surface pitting during horizontal continuous casting. In the formula, the composite system of sodium hexafluoroaluminate, borax, and sodium fluoride can lower the melting temperature of the slag remover, allowing the slag removal process to be completed at a lower temperature, avoiding excessive zinc volatilization due to high temperatures; this invention improves the fluidity of the slag, facilitating flotation and removal. Zinc-copper alloy raw materials may contain impurities such as iron, silicon, aluminum, lead, and tin. The alkalinity in the formula (… The fluoride and borax system can effectively treat these diverse oxide impurities (FeO, fluoride, borax system). PbO, etc., are incorporated into the slag for effective removal. Addressing the nickel sensitivity of zinc-copper alloys, the fluorides added in this invention decompose NiO, preventing nickel oxidation loss (NiO is reduced to Ni and enters the melt), thus ensuring stable nickel content. Although borax is added in this invention, the addition of a certain amount of sodium hexafluoroaluminate and fluorides inhibits excessive boron dissolution, reduces the content of free boron (B) in the melt, and balances the fluxing effect of borax with the risk of boron contamination. Furthermore, the combination of calcium fluoride and cryolite reduces the corrosion of acidic refractory materials by fluorides.

[0022] In use, the amount of slag remover used in zinc-copper smelting is controlled to be 0.1-0.17% of the total weight of the furnace charge. Under low usage conditions, a good impurity removal effect can be achieved after a short settling time (5-10 minutes).

[0023] Compared with existing technologies, the zinc-white copper slag remover formulated by mixing the above raw materials in this invention can effectively reduce impurities to Fe < 0.14%, Pb < 0.005%, and Si < 0.003% during the smelting process. Before using the slag remover of this invention, the total impurities were Fe < 0.25%, Pb < 0.008%, and Si < 0.008%, with a total impurity content of < 1.3%. Using the slag remover of this invention significantly reduces the impurity content, decreases the need for composition adjustments and non-conforming sampling, reduces impurity inclusions in the cast billet, and ultimately improves metal purity and casting quality. Simultaneously, it minimizes zinc and nickel losses, avoiding adverse effects on the zinc-white copper. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Comparative Example 1

[0026] A zinc-copper alloy comprising the following mass percentages: Cu 54.5%, Ni 17.5%, with the balance being Zn and unavoidable impurities.

[0027] During the smelting process, the raw materials in the melting furnace are stirred after melting, and after standing for 10 minutes, the slag is removed without using a slag remover.

[0028] During the aforementioned horizontal continuous casting process of zinc-copper alloy, macroscopic and microscopic observation of the cross-sectional grain structure of the billet revealed numerous obvious porosity and shrinkage cavities, as well as a significant amount of impurities between the grains. Spectroscopic analysis of the copper molten metal during smelting showed the following average impurities: Fe 0.20%, Pb 0.007%, and Si 0.006%. These defects have a high probability of causing surface peeling after the billet is rolled into a thin strip. Preliminary compositional analysis of samples exhibiting peeling revealed that the main impurity elements were Fe, Pb, and Si. Furthermore, the defects were primarily distributed laterally in the converter area.

[0029] Example 1

[0030] A zinc-copper smelting slag remover comprises the following raw materials by mass percentage: 10% sodium fluoride, 10% calcium fluoride, 20% sodium carbonate, 20% sodium hexafluoroaluminate, and the balance being borax.

[0031] All the above raw materials have a particle size of less than 0.05 mm; each of them needs to be dried and the moisture content is less than 7%.

[0032] The preparation method of the zinc-copper smelting slag remover described in Example 1 is as follows: the raw materials of the formula amount are put into a low-speed mixer and stirred at a speed of 600 rpm for 40 minutes. After being mixed evenly, they are stored in a dry storage container and sealed when not in use to prevent moisture.

[0033] The zinc-white copper smelting slag remover prepared in Example 1 was used in the production of zinc-white copper alloy. Specifically, the same process as Comparative Example 1 was followed to produce zinc-white copper with the same main chemical composition as Comparative Example 1. The difference was that during the smelting process, after the raw materials in the melting furnace were dissolved, the zinc-white copper smelting slag remover from Example 1 was added to the melting furnace and stirred using a tool. The amount of slag remover used was 0.10% of the total weight of the furnace charge. The current furnace charge was 1500 kg. After the raw materials were melted, 1.5 kg of zinc-white copper slag remover was added. After standing for 8 minutes, the slag was removed.

[0034] Microscopic examination of the cross-section of the billet revealed that shrinkage cavities and intergranular impurities in the billet were significantly reduced compared to Comparative Example 1. Spectroscopic analysis of copper samples taken during the smelting process showed that the main impurities were reduced to 0.13% Fe, 0.004% Pb, and 0.002% Si.

[0035] Compared with Comparative Example 1, the probability of transverse peeling at the converter position in Example 1 was significantly reduced. Under the same continuous casting process and the same raw material ratio, the peeling weight of 30 coils of zinc-white copper products produced, including those without the zinc-white copper slag remover (Comparative Example 1) and 30 coils with the zinc-white copper slag remover (Example 1), was compared. The average peeling weight of Example 1 was reduced by about 12 kg / ton.

[0036] Example 2

[0037] A zinc-copper smelting slag remover comprises the following raw materials by mass percentage: sodium fluoride 14%, calcium fluoride 13%, sodium carbonate 25%, sodium hexafluoroaluminate 16%, and the balance being borax.

[0038] All the above raw materials have a particle size of less than 0.05 mm; each of them needs to be dried and the moisture content is less than 7%.

[0039] The preparation method of the zinc-copper smelting slag remover described in Example 2 is as follows: put the raw materials of the formula into a low-speed mixer and stir and mix at a speed of 700 rpm for 45 minutes. After mixing evenly, store in a dry storage container and seal when not in use to prevent moisture absorption.

[0040] The zinc-copper alloy slag remover prepared in Example 2 was used in the production of zinc-copper alloys. Specifically, during the smelting process, after the raw materials in the melting furnace were dissolved, the zinc-copper alloy slag remover from Example 2 was added to the furnace and stirred. The amount of slag remover used was 0.12% of the total weight of the furnace charge. After standing for 8 minutes, the slag was removed. The composition was: Cu 55.3%, Ni 19.1%, balance Zn, impurities Fe 0.12%, Pb 0.004%, Si 0.002%.

[0041] Example 3

[0042] A zinc-copper smelting slag remover comprises the following raw materials by mass percentage: sodium fluoride 7%, calcium fluoride 13%, sodium carbonate 25%, sodium hexafluoroaluminate 16%, and the balance being borax.

[0043] All the above raw materials have a particle size of less than 0.05 mm; each of them needs to be dried and the moisture content is less than 7%.

[0044] The preparation method of the zinc-copper smelting slag remover described in Example 3 is as follows: put the raw materials of the formula into a low-speed mixer and stir and mix at a speed of 800 rpm for 35 minutes. After mixing evenly, store in a dry storage container and seal when not in use to prevent moisture absorption.

[0045] The zinc-copper alloy slag remover prepared in Example 3 was used in the production of zinc-copper alloys. Specifically, during the smelting process, after the raw materials in the melting furnace were dissolved, the zinc-copper alloy slag remover from Example 3 was added to the furnace and stirred. The amount of slag remover used was 0.15% of the total weight of the furnace charge. After standing for 8 minutes, the slag was removed. The composition was: Cu 56.2%, Ni 16.8%, balance Zn, impurities Fe 0.13%, Pb 0.003%, Si 0.001%.

[0046] The above description of the embodiments is intended to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A zinc white copper smelting de- slagging agent, characterized in that, The zinc white copper smelting slag removing agent comprises the following raw materials in mass percentage: calcium fluoride 5%-15%, sodium carbonate 20%-30%, sodium fluoride 5%-15%, sodium hexafluoroaluminate 10%-20%, and the balance being borax.

2. The zinc white copper smelting flux according to claim 1, characterized in that, The water content of each raw material of the zinc white copper smelting slag removing agent is less than 7%.

3. Zinc white copper smelting slag remover according to claim 1 or 2, characterized in that The particle size of each raw material of the zinc white copper smelting slag removing agent is less than or equal to 0.05 mm.

4. A process for the production of a zinc white copper smelting flux according to any one of claims 1 to 3, characterized in that, The preparation method specifically comprises the following steps: stirring and uniformly mixing the raw materials in the formula amount, and obtaining the zinc white copper smelting slag removing agent.

5. The preparation method according to claim 4, characterized in that, The stirring and uniformly mixing is performed at a speed of 500-800 revolutions per minute for 30-60 minutes.

6. A method of using the zinc white copper smelting de- slagging agent according to any one of claims 1 to 3, characterized in that, The use method specifically comprises the following steps: during the zinc white copper smelting process, after the raw materials of a melting furnace are dissolved, the zinc white copper smelting slag removing agent is added into the melting furnace for stirring, and after standing, the slag is floated to the surface of the copper liquid, and the slag is fished out by using a slag removing tool.

7. The method of use of claim 6, wherein, The use amount of the zinc white copper smelting slag removing agent is 0.1-0.17% of the total weight of the furnace charge.

8. The method of use of claim 6, wherein, The standing time is 5-10 minutes.

9. The method of use according to any one of claims 6-8, wherein, The zinc white copper obtained by smelting comprises the following components in mass percentage: Cu 53.5%-56.5%, Ni 16.5%-19.5%, and the balance being Zn and unavoidable impurities.

10. The method of use of claim 9, wherein, The unavoidable impurities are as follows: impurity Fe <0.14%, impurity Pb <0.005%, and impurity Si <0.003%.