Efficient refining method for impure red copper

Abstract

The invention discloses an efficient refining method for red impure copper. The efficient refining method comprises the following steps: (1) preparing calcium-cerium composite oxide powder; (2) preparing boron-phosphorus doped powder; (3) preparing a refining auxiliary agent; (4) red impure copper is put into a crucible, a medium-frequency induction furnace is adopted for heating and melting the red impure copper into a melt, the melt is covered with charcoal after being completely melted, the temperature of the melt is kept at 1110-1120 DEG C, then the refining auxiliary is added, and the mass ratio of the refining auxiliary to the melt is (3-4) kg: 1 t; and after charging, stirring the melt at a constant temperature of 1110-1120 DEG C for 10 minutes, then standing for 15 minutes, deslagging, casting and molding to obtain the refined impure red copper. After refining through the method, the tensile strength and the electric conductivity of the impure red copper can be remarkably improved, and the use performance of the impure red copper is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of copper alloy manufacturing, and particularly relates to a refining method for high-efficiency purple scrap copper. Background Art

[0002] With the rapid development of high-performance copper alloys for electronics in China, the supply and demand situation of copper raw materials is tense. Reasonably and efficiently utilizing various scrap copper resources is an important way to solve this problem. Therefore, the recycling of waste scrap copper has become an important development trend. Currently, the refining method is mainly used to recycle purple scrap copper. Purple scrap copper often contains a small amount of impurity elements such as sulfur, hydrogen, lead, bismuth, tin, and iron. These impurity elements will seriously deteriorate the performance and service life of copper materials. Among them, the solubility of lead in copper is not large, but it is easy to form a eutectic of (Cu + Pb) with low melting point and distributed in a network along the grain boundary. Its eutectic temperature is only 326 °C, which is easy to cause cracking during hot rolling and produce "hot brittleness". In particular, lead elements pose a potential hazard to human health and are not easy to remove from scrap copper. In addition, the presence of iron will increase the work hardening value and the difficulty of secondary processing of copper, causing a sharp drop in the plasticity, electrical conductivity, and thermal conductivity of copper, and resulting in a "burr" phenomenon on the surface of copper processed profiles. The existence of these two impurity elements greatly limits the application of scrap copper. Therefore, in order to improve the processing performance and service life of copper materials, it is necessary to reduce the content of impurity elements. Summary of the Invention

[0003] For this reason, the present invention provides a refining method for high-efficiency purple scrap copper, and its steps include:

[0004] (1) Prepare a composite aqueous solution of calcium nitrate and cerium nitrate, and prepare a composite aqueous solution of sodium hydroxide and sodium carbonate; heat the composite aqueous solution of calcium nitrate and cerium nitrate in a water bath to 40 ± 5 °C for insulation, and then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring. After the feeding is completed, continue to stir the solution at 40 ± 5 °C for more than 20 h, perform solid-liquid separation, wash the solid phase with deionized water for more than 3 times, then dry it, and calcine it at 800 - 900 °C for more than 4 h to obtain a composite powder;

[0005] (2) Add sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the composite powder to a mixed solution of water and ethanol in a reaction kettle, stir for more than 30 min under an ultrasonic environment, close the reaction kettle after stirring, heat it to 110 ± 3 °C for insulation for more than 2 h, naturally cool to room temperature after the insulation is completed, perform solid-liquid separation, wash the solid phase with deionized water for more than 3 times, and dry it to obtain a boron and phosphorus doped powder;

[0006] (3) Add the boron and phosphorus doped powder into the hydrogen peroxide solution, heat it in a water bath to 50 ± 5 °C, keep it warm and stir for more than 1 h, then separate the solid from the liquid. Wash the solid phase with deionized water for more than 3 times, dry it, then add it into the aqueous solution of ethanol, and stir and disperse it ultrasonically for more than 30 min to obtain a dispersion. Then, add tetraethyl orthosilicate to the dispersion under stirring. After the feeding is completed, continue to stir for more than 20 h, separate the solid from the liquid, wash the solid phase with deionized water, and dry it to obtain a refining aid;

[0007] (4) Put the purple miscellaneous copper into a crucible, heat it to melt into a melt by using an intermediate frequency induction furnace. After complete melting, cover it with charcoal, then add the refining aid. After feeding, stir the melt for 10 - 12 min, then let it stand, remove the slag, and cast it into a mold to obtain the refined purple miscellaneous copper.

[0008] Further, in the step (1), in the composite aqueous solution of calcium nitrate and cerium nitrate, the concentration of calcium nitrate is 40 - 50 g / L, the concentration of cerium nitrate is 30 - 35 g / L, and the solvent is water; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, the mass percentage of sodium carbonate is 4% - 6%, and the solvent is water; the volume ratio of the composite aqueous solution of calcium nitrate and cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate added is composite aqueous solution of calcium nitrate and cerium nitrate: composite aqueous solution of sodium hydroxide and sodium carbonate = 10:4 - 5.

[0009] Further, in the step (2), the amount ratio of sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the composite powder added into the mixed solution of water and ethanol is sodium tetraborate decahydrate: copper nitrate trihydrate: sodium dihydrogen phosphate dodecahydrate: composite powder: mixed solution of water and ethanol = 0.6 - 0.8 g: 0.9 - 1 g: 0.2 - 0.3 g: 1 - 2 g: 50 mL.

[0010] Further, the volume percentage of ethanol in the mixed solution of water and ethanol is 30% - 40%.

[0011] Further, in the step (3), the amount ratio of the boron and phosphorus doped powder added into the hydrogen peroxide solution is boron and phosphorus doped powder: hydrogen peroxide solution = 1 - 2 g: 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 5% - 10%.

[0012] Further, in the step (3), the amount ratio of the dried solid phase added into the aqueous solution of ethanol is solid phase: aqueous solution of ethanol = 1 g: 80 mL; where the volume percentage of ethanol in the aqueous solution of ethanol is 10%; the volume ratio of the added tetraethyl orthosilicate to the mass of the solid phase used to prepare the dispersion is tetraethyl orthosilicate: solid phase = 5 - 6 mL: 1 g.

[0013] Further, in the step (4), the mass ratio of the added refining aid to the mass of the melt is refining aid:melt = 3 - 4 kg:1 t.

[0014] Further, the heating and melting temperature is 1110 - 1120 °C.

[0015] The beneficial effects of the present invention are as follows: After refining by the method of the present invention, the tensile strength and electrical conductivity of purple miscellaneous copper can be significantly improved, and the service performance of purple miscellaneous copper can be enhanced. The calcium-cerium composite oxide matrix powder prepared by the present invention, after boron-phosphorus doping treatment and surface silicon modification, finally obtains a refining aid. After adding it to the purple miscellaneous copper for refining, the mechanical strength and electrical conductivity of purple miscellaneous copper can be significantly improved. This may be mainly because: Calcium in the calcium-cerium composite oxide can form stable Ca-Bi and Ca-Sn intermediate compounds with impurity elements such as Bi and Sn in purple miscellaneous copper, thereby significantly reducing the content of impurity elements in purple miscellaneous copper. As is well known, the influence of impurity elements such as Bi and Sn on the electrical conductivity of copper alloys is mainly due to the fact that Bi and Sn atoms exist in the form of solid solution in the copper matrix, causing the lattice structure of the copper matrix to distort, hindering the directional flow of free electrons under the electric field, and the electrons tend to be in a scattered state, thus significantly reducing the electrical conductivity. The added calcium-cerium composite oxide can reduce the content of impurity elements, and thus can reduce the influence of impurity elements on the electrical conductivity and improve the electrical conductivity of the copper alloy itself. And the solubility of cerium in the calcium-cerium composite oxide in copper is extremely small, and rare earth cerium is very easy to form high-melting-point compounds with Pb, Fe, etc. and disperse in the melt. On the one hand, it can reduce the solid solubility rate of impurity elements such as Pb and Fe and improve the electrical conductivity of the material; on the other hand, the high-melting-point dispersed phase serves as non-uniform nucleation sites, which can significantly increase the nucleation rate of purple miscellaneous copper castings, refine the grains, and the dispersed particles distributed at the grain boundaries can also hinder the growth of grains, achieving the purpose of improving the mechanical strength of the material. Subsequently, a boron-phosphorus doped layer was synthesized on the surface of the matrix powder by the hydrothermal method. Utilizing the characteristic that boron can form borides with Ni, Mn, and Cr, impurities in the copper alloy are further removed. Phosphorus can adsorb and dissolve oxides in the melt, react with impurity oxides in the melt to form compounds insoluble in the melt, and boron generally does not combine with copper and has little influence on the copper alloy itself. Finally, the hydroxyl content on the particle surface is increased by hydrogen peroxide, and then a silicon-containing layer is adsorbed. After the silicon-containing layer is added to the melt, it mainly exists in the form of [SiO4] tetrahedrons, which is conducive to the enrichment of oxygen in the melt. The oxygen valence at the apex of the tetrahedron is in an unsaturated state and connects with cerium ions dissolved in the melt to form a network structure, improving the strength of the material. Specific Embodiments

[0016] The following further illustrates the present invention with reference to embodiments.

[0017] Example 1

[0018] An efficient refining method for purple brass scrap, the steps of which include:

[0019] (1) Prepare a composite aqueous solution of calcium nitrate and cerium nitrate. In the composite aqueous solution of calcium nitrate and cerium nitrate, the concentration of calcium nitrate is 40 g / L, the concentration of cerium nitrate is 30 g / L, and the solvent is water; prepare a composite aqueous solution of sodium hydroxide and sodium carbonate; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, the mass percentage of sodium carbonate is 4%, and the solvent is water; heat the composite aqueous solution of calcium nitrate and cerium nitrate in a water bath to 40 °C and keep it warm, then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring. The volume ratio of the composite aqueous solution of calcium nitrate and cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate added to the composite aqueous solution of calcium nitrate and cerium nitrate is composite aqueous solution of calcium nitrate and cerium nitrate: composite aqueous solution of sodium hydroxide and sodium carbonate = 10:4; after the feeding is completed, continue to stir the solution at a constant temperature of 40 °C for 20 h, perform solid-liquid separation, wash the solid phase with deionized water 3 times, then dry it at 80 °C for 30 min, and calcine it at 800 °C for 4 h to obtain a composite powder;

[0020] (2) Add sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the composite powder into a mixed solution of water and ethanol in a reaction kettle. The dosage ratio of sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, the composite powder to the mixed solution of water and ethanol is sodium tetraborate decahydrate: copper nitrate trihydrate: sodium dihydrogen phosphate dodecahydrate: composite powder: mixed solution of water and ethanol = 0.6 g: 0.9 g: 0.2 g: 1 g: 50 mL; the volume percentage of ethanol in the mixed solution of water and ethanol is 30%; stir for 30 min under an ultrasonic environment, close the reaction kettle after the stirring is completed, heat it to 110 °C and keep it warm for 2 h, naturally cool to room temperature after the heat preservation is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 80 °C for 30 min to obtain a boron and phosphorus doped powder;

[0021] (3) Add the boron and phosphorus doped powder into the hydrogen peroxide solution. The dosage ratio of the boron and phosphorus doped powder to the hydrogen peroxide solution is boron and phosphorus doped powder: hydrogen peroxide solution = 1 g: 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 5%; heat it in a water bath to 50 °C, keep stirring for 1 h, then separate the solid from the liquid. Wash the solid phase with deionized water three times, dry it at 80 °C for 30 min. Add the dried solid phase into the aqueous solution of ethanol. The dosage ratio of the dried solid phase to the aqueous solution of ethanol is solid phase: aqueous solution of ethanol = 1 g: 80 mL; where the volume percentage of ethanol in the aqueous solution of ethanol is 10%; stir and disperse it ultrasonically for 30 min to obtain a dispersion liquid. Then, add tetraethyl orthosilicate to the dispersion liquid under stirring. The volume ratio of the added tetraethyl orthosilicate to the mass of the solid phase used to prepare the dispersion liquid is tetraethyl orthosilicate: solid phase = 5 mL: 1 g; continue stirring for 20 h after the feeding is completed, separate the solid from the liquid, wash the solid phase with deionized water three times, and dry it at 80 °C for 30 min to obtain a refining aid;

[0022] (4) Put the purple miscellaneous copper into a crucible, heat it to melt into a melt using an intermediate frequency induction furnace. After complete melting, cover it with charcoal, keep the temperature of the melt at 1110 °C, and then add the refining aid. The mass ratio of the added refining aid to the mass of the melt is refining aid: melt = 3 kg: 1 t; stir the melt at a constant temperature of 1110 °C for 10 min after feeding, then let it stand for 15 min, remove the slag, and cast it into a mold to obtain the refined purple miscellaneous copper.

[0023] Example 2

[0024] A refining method for high-efficiency purple miscellaneous copper, the steps of which include:

[0025] (1) Prepare a composite aqueous solution of calcium nitrate and cerium nitrate. In the composite aqueous solution of calcium nitrate and cerium nitrate, the concentration of calcium nitrate is 45 g / L, and the concentration of cerium nitrate is 30 g / L, and the solvent is water; prepare a composite aqueous solution of sodium hydroxide and sodium carbonate; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, and the mass percentage of sodium carbonate is 5%, and the solvent is water; heat the composite aqueous solution of calcium nitrate and cerium nitrate in a water bath to 40 °C for heat preservation, and then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring. The volume ratio of the composite aqueous solution of calcium nitrate and cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate is composite aqueous solution of calcium nitrate and cerium nitrate: composite aqueous solution of sodium hydroxide and sodium carbonate = 10:4; continue to stir the solution at a constant temperature of 40 °C for 20 h after the feeding is completed, separate the solid from the liquid, wash the solid phase with deionized water three times, then dry it at 80 °C for 30 min, and calcine it at 850 °C for 4 h to obtain a composite powder;

[0026] (2) In a reaction kettle, sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the said composite powder are added into a mixed solution of water and ethanol. The mass ratio of sodium tetraborate decahydrate : copper nitrate trihydrate : sodium dihydrogen phosphate dodecahydrate : the composite powder : the mixed solution of water and ethanol is 0.7 g : 0.9 g : 0.2 g : 1 g : 50 mL; the volume percentage of ethanol in the mixed solution of water and ethanol is 30%; stir for 30 min under an ultrasonic environment, then seal the reaction kettle after stirring, heat it to 110 °C and keep it warm for 2 h, naturally cool it to room temperature after the heat preservation, separate the solid and liquid, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min to obtain the boron and phosphorus doped powder;

[0027] (3) Add the boron and phosphorus doped powder into a hydrogen peroxide solution. The mass ratio of the boron and phosphorus doped powder : the hydrogen peroxide solution is 1 g : 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 5%; heat it in a water bath to 50 °C, keep it warm and stir for 1 h, then separate the solid and liquid, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min. Add the dried solid phase into an aqueous solution of ethanol. The mass ratio of the dried solid phase : the aqueous solution of ethanol is 1 g : 80 mL; the volume percentage of ethanol in the aqueous solution of ethanol is 10%; stir and disperse it ultrasonically for 30 min to obtain a dispersion liquid. Then, add tetraethyl orthosilicate to the dispersion liquid under stirring. The volume ratio of tetraethyl orthosilicate added : the mass of the solid phase used to prepare the dispersion liquid is tetraethyl orthosilicate : the solid phase = 5 mL : 1 g; continue to stir for 20 h after adding the materials, separate the solid and liquid, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min to obtain the refining aid;

[0028] (4) Put the purple miscellaneous copper into a crucible, heat it to melt into a melt using an intermediate frequency induction furnace. After complete melting, cover it with charcoal, keep the temperature of the melt at 1110 °C, and then add the refining aid. The mass ratio of the refining aid : the melt is 3 kg : 1 t; after adding the materials, keep the melt at a constant temperature of 1110 °C and stir for 10 min, then let it stand for 15 min, remove the slag, and cast it into a mold to obtain the refined purple miscellaneous copper.

[0029] Example 3

[0030] A refining method for high - efficiency purple miscellaneous copper, the steps of which include:

[0031] (1) Prepare a composite aqueous solution of calcium nitrate and cerium nitrate. In the composite aqueous solution of calcium nitrate and cerium nitrate, the concentration of calcium nitrate is 45 g / L, the concentration of cerium nitrate is 35 g / L, and the solvent is water; prepare a composite aqueous solution of sodium hydroxide and sodium carbonate; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, the mass percentage of sodium carbonate is 5%, and the solvent is water; heat the composite aqueous solution of calcium nitrate and cerium nitrate in a water bath to 40 °C and keep it warm, then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring. The volume ratio of the composite aqueous solution of calcium nitrate and cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate added is composite aqueous solution of calcium nitrate and cerium nitrate: composite aqueous solution of sodium hydroxide and sodium carbonate = 10:5; after the addition is completed, continue to stir the solution at 40 °C for 20 h, perform solid-liquid separation, wash the solid phase with deionized water 3 times, then dry it at 80 °C for 30 min, and calcine it at 850 °C for 4 h to obtain a composite powder;

[0032] (2) Add sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the composite powder into a mixed solution of water and ethanol in a reaction kettle. The dosage ratio of sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, the composite powder to the mixed solution of water and ethanol is sodium tetraborate decahydrate: copper nitrate trihydrate: sodium dihydrogen phosphate dodecahydrate: composite powder: mixed solution of water and ethanol = 0.7 g: 1 g: 0.3 g: 2 g: 50 mL; the volume percentage of ethanol in the mixed solution of water and ethanol is 30%; stir for 30 min under an ultrasonic environment, seal the reaction kettle after stirring is completed, heat it to 110 °C and keep it warm for 2 h, naturally cool to room temperature after the heat preservation is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 80 °C for 30 min to obtain a boron and phosphorus doped powder;

[0033] (3) Add the boron and phosphorus doped powder into a hydrogen peroxide solution. The dosage ratio of the boron and phosphorus doped powder to the hydrogen peroxide solution is boron and phosphorus doped powder: hydrogen peroxide solution = 2 g: 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 10%; heat it in a water bath to 50 °C, keep stirring for 1 h, then perform solid-liquid separation, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min, add the dried solid phase into an aqueous solution of ethanol. The dosage ratio of the dried solid phase to the aqueous solution of ethanol is solid phase: aqueous solution of ethanol = 1 g: 80 mL; where the volume percentage of ethanol in the aqueous solution of ethanol is 10%; stir and disperse it ultrasonically for 30 min to obtain a dispersion liquid, and then add tetraethyl orthosilicate to the dispersion liquid under stirring. The volume ratio of tetraethyl orthosilicate added to the mass of the solid phase used to prepare the dispersion liquid is tetraethyl orthosilicate: solid phase = 6 mL: 1 g; continue to stir for 20 h after the addition is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 80 °C for 30 min to obtain a refining aid;

[0034] (4) Put the purple scrap copper into a crucible, heat it to melt into a melt using an intermediate frequency induction furnace, cover it with charcoal after complete melting, keep the temperature of the melt at 1120 °C, then add the refining aid, and the mass ratio of the added refining aid to the mass of the melt is refining aid:melt = 4 kg:1 t; after feeding, keep the melt at a constant temperature of 1120 °C and stir for 10 min, then let it stand for 15 min, remove the slag, and cast it into shape to obtain the refined purple scrap copper.

[0035] Example 4

[0036] A refining method for high-efficiency purple scrap copper, the steps of which include:

[0037] (1) Prepare a composite aqueous solution of calcium nitrate and cerium nitrate. In the composite aqueous solution of calcium nitrate and cerium nitrate, the concentration of calcium nitrate is 50 g / L, the concentration of cerium nitrate is 35 g / L, and the solvent is water; prepare a composite aqueous solution of sodium hydroxide and sodium carbonate; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, the mass percentage of sodium carbonate is 6%, and the solvent is water; heat the composite aqueous solution of calcium nitrate and cerium nitrate in a water bath to 40 °C and keep it warm, then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring, and the volume ratio of the composite aqueous solution of calcium nitrate and cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate is composite aqueous solution of calcium nitrate and cerium nitrate:composite aqueous solution of sodium hydroxide and sodium carbonate = 10:5; after feeding, continue to stir the solution at a constant temperature of 40 °C for 20 h, perform solid-liquid separation, wash the solid phase with deionized water 3 times, then dry it at 80 °C for 30 min, and calcine it at 900 °C for 4 h to obtain a composite powder;

[0038] (2) Add sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the composite powder to a mixed solution of water and ethanol in a reaction kettle. The amount ratio of sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, the composite powder to the mixed solution of water and ethanol is sodium tetraborate decahydrate:copper nitrate trihydrate:sodium dihydrogen phosphate dodecahydrate:composite powder:mixed solution of water and ethanol = 0.8 g:1 g:0.3 g:2 g:50 mL; the volume percentage of ethanol in the mixed solution of water and ethanol is 30%; stir for 30 min under an ultrasonic environment, close the reaction kettle after stirring, heat it to 110 °C and keep it warm for 2 h, naturally cool it to room temperature after the heat preservation is over, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 80 °C for 30 min to obtain a boron and phosphorus doped powder;

[0039] (3) Add the boron and phosphorus doped powder into the hydrogen peroxide solution, and the mass ratio of the boron and phosphorus doped powder to the hydrogen peroxide solution is boron and phosphorus doped powder: hydrogen peroxide solution = 2 g: 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 10%; heat it in a water bath to 50 °C, keep stirring for 1 h, then separate the solid from the liquid, wash the solid phase with deionized water for 3 times, dry it at 80 °C for 30 min, add the dried solid phase into the aqueous solution of ethanol, and the mass ratio of the dried solid phase to the aqueous solution of ethanol is solid phase: aqueous solution of ethanol = 1 g: 80 mL; where the volume percentage of ethanol in the aqueous solution of ethanol is 10%; stir and disperse it ultrasonically for 30 min to obtain a dispersion liquid, and then add tetraethyl orthosilicate to the dispersion liquid under stirring. The volume ratio of the added tetraethyl orthosilicate to the mass of the solid phase used to prepare the dispersion liquid is tetraethyl orthosilicate: solid phase = 6 mL: 1 g; continue stirring for 20 h after the feeding is completed, separate the solid from the liquid, wash the solid phase with deionized water for 3 times, and dry it at 80 °C for 30 min to obtain the refining aid;

[0040] (4) Put the purple miscellaneous copper into a crucible, heat it to melt into a melt by using an intermediate frequency induction furnace, cover it with charcoal after complete melting, keep the temperature of the melt at 1120 °C, and then add the refining aid. The mass ratio of the added refining aid to the mass of the melt is refining aid: melt = 4 kg: 1 t; keep the temperature of the melt at 1120 °C and stir it for 10 min after feeding, then let it stand for 15 min, remove the slag, and cast it into a mold to obtain the refined purple miscellaneous copper.

[0041] Comparative Example 1

[0042] A method for refining purple miscellaneous copper as a comparison, and its steps include:

[0043] (1) Prepare an aqueous solution of calcium nitrate, in which the concentration of calcium nitrate is 45 g / L and the solvent is water; prepare a composite aqueous solution of sodium hydroxide and sodium carbonate; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, the mass percentage of sodium carbonate is 5%, and the solvent is water; heat the aqueous solution of calcium nitrate in a water bath to 40 °C and keep it warm, then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring. The volume ratio of the aqueous solution of calcium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate is aqueous solution of calcium nitrate: composite aqueous solution of sodium hydroxide and sodium carbonate = 10:5; continue to stir the solution at a constant temperature of 40 °C for 20 h after the feeding is completed, separate the solid from the liquid, wash the solid phase with deionized water for 3 times, then dry it at 80 °C for 30 min and calcine it at 850 °C for 4 h to obtain the calcium oxide powder;

[0044] (2) In a reaction kettle, sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the calcium oxide powder are added to a mixed solution of water and ethanol. The mass ratio of sodium tetraborate decahydrate : copper nitrate trihydrate : sodium dihydrogen phosphate dodecahydrate : calcium oxide powder : mixed solution of water and ethanol is 0.7 g : 1 g : 0.3 g : 2 g : 50 mL. The volume percentage of ethanol in the mixed solution of water and ethanol is 30%. Stir for 30 min under an ultrasonic environment. After stirring is completed, seal the reaction kettle, heat it to 110 °C and keep it warm for 2 h. After the heat preservation is over, naturally cool it to room temperature, separate the solid and liquid, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min to obtain the boron and phosphorus doped powder.

[0045] (3) Add the boron and phosphorus doped powder to the hydrogen peroxide solution. The mass ratio of the boron and phosphorus doped powder : hydrogen peroxide solution is 2 g : 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 10%. Heat it in a water bath to 50 °C, keep it warm and stir for 1 h, then separate the solid and liquid, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min. Add the dried solid phase to an aqueous solution of ethanol. The mass ratio of the dried solid phase : aqueous solution of ethanol is 1 g : 80 mL. The volume percentage of ethanol in the aqueous solution of ethanol is 10%. Stir and disperse it ultrasonically for 30 min to obtain a dispersion. Then, while stirring, add tetraethyl orthosilicate to the dispersion. The volume ratio of tetraethyl orthosilicate added : mass of the solid phase used to prepare the dispersion is 6 mL : 1 g. After adding the materials, continue to stir for 20 h, separate the solid and liquid, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min to obtain the refining aid.

[0046] (4) Put the purple miscellaneous copper into a crucible, heat it to melt into a melt using an intermediate frequency induction furnace. After complete melting, cover it with charcoal, keep the temperature of the melt at 1120 °C, and then add the refining aid. The mass ratio of the refining aid : melt is 4 kg : 1 t. After adding the materials, keep the melt at a constant temperature of 1120 °C and stir for 10 min, then let it stand for 15 min, remove the slag, and cast it into a mold to obtain the refined purple miscellaneous copper of this comparative example.

[0047] Comparative Example 2

[0048] A method for refining purple miscellaneous copper as a comparison, the steps of which include:

[0049] (1) Prepare an aqueous solution of cerium nitrate. In the aqueous solution of cerium nitrate, the concentration of cerium nitrate is 35 g / L and the solvent is water. Prepare a composite aqueous solution of sodium hydroxide and sodium carbonate. In the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10% and the mass percentage of sodium carbonate is 5%, and the solvent is water. Heat the aqueous solution of cerium nitrate in a water bath to 40 °C and keep it warm, then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring. The volume ratio of the aqueous solution of cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate added to the aqueous solution of cerium nitrate is aqueous solution of cerium nitrate: composite aqueous solution of sodium hydroxide and sodium carbonate = 10:5. After the addition is completed, continue to stir the solution at a constant temperature of 40 °C for 20 h, perform solid-liquid separation, wash the solid phase with deionized water 3 times, then dry it at 80 °C for 30 min, and calcine it at 850 °C for 4 h to obtain cerium oxide powder.

[0050] (2) Add sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the cerium oxide powder to a mixed solution of water and ethanol in a reaction kettle. The amount ratio of sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, cerium oxide powder added to the mixed solution of water and ethanol is sodium tetraborate decahydrate: copper nitrate trihydrate: sodium dihydrogen phosphate dodecahydrate: cerium oxide powder: mixed solution of water and ethanol = 0.7 g: 1 g: 0.3 g: 2 g: 50 mL. The volume percentage of ethanol in the mixed solution of water and ethanol is 30%. Stir for 30 min under an ultrasonic environment, then seal the reaction kettle after stirring is completed, heat it to 110 °C and keep it warm for 2 h. After the heat preservation is completed, cool it naturally to room temperature, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 80 °C for 30 min to obtain boron and phosphorus doped powder.

[0051] (3) Add the boron and phosphorus doped powder to a hydrogen peroxide solution. The amount ratio of the boron and phosphorus doped powder to the hydrogen peroxide solution is boron and phosphorus doped powder: hydrogen peroxide solution = 2 g: 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 10%. Heat it in a water bath to 50 °C, keep it warm and stir for 1 h, then perform solid-liquid separation, wash the solid phase with deionized water 3 times, dry it at 80 °C for 30 min. Add the dried solid phase to an aqueous solution of ethanol. The amount ratio of the dried solid phase to the aqueous solution of ethanol added is solid phase: aqueous solution of ethanol = 1 g: 80 mL. The volume percentage of ethanol in the aqueous solution of ethanol is 10%. Stir and disperse it ultrasonically for 30 min to obtain a dispersion liquid. Then, add tetraethyl orthosilicate to the dispersion liquid under stirring. The volume ratio of tetraethyl orthosilicate added to the mass of the solid phase used to prepare the dispersion liquid is tetraethyl orthosilicate: solid phase = 6 mL: 1 g. After the addition is completed, continue to stir for 20 h, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 80 °C for 30 min to obtain a refined additive.

[0052] (4) Put the purple brass scrap into a crucible, heat it to melt into a melt using an intermediate frequency induction furnace, cover it with charcoal after complete melting, keep the temperature of the melt at 1120 °C, then add the above-mentioned refining aid, and the mass ratio of the added mass of the refining aid to the mass of the melt is refining aid:melt = 4 kg:1 t; after feeding, keep the melt at a constant temperature of 1120 °C and stir for 10 min, then let it stand for 15 min, remove the slag, and cast it into shape to obtain the refined purple brass scrap of this comparative example.

[0053] Comparative Example 3

[0054] A method for refining purple brass scrap for comparison, the steps of which include:

[0055] (1) Prepare a composite aqueous solution of calcium nitrate and cerium nitrate. In the composite aqueous solution of calcium nitrate and cerium nitrate, the concentration of calcium nitrate is 45 g / L, the concentration of cerium nitrate is 35 g / L, and the solvent is water; prepare a composite aqueous solution of sodium hydroxide and sodium carbonate; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, the mass percentage of sodium carbonate is 5%, and the solvent is water; heat the composite aqueous solution of calcium nitrate and cerium nitrate in a water bath to 40 °C and keep it warm, then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring, and the volume ratio of the composite aqueous solution of calcium nitrate and cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate is composite aqueous solution of calcium nitrate and cerium nitrate:composite aqueous solution of sodium hydroxide and sodium carbonate = 10:5; after the feeding is completed, continue to stir the solution at a constant temperature of 40 °C for 20 h, perform solid-liquid separation, wash the solid phase with deionized water 3 times, then dry it at 80 °C for 30 min, and calcine it at 850 °C for 4 h to obtain a composite powder;

[0056] (2) Put sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the above-mentioned composite powder into a mixed solution of water and ethanol in a reaction kettle. The amount ratio of sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, the composite powder to the mixed solution of water and ethanol is sodium tetraborate decahydrate:copper nitrate trihydrate:sodium dihydrogen phosphate dodecahydrate:composite powder:mixed solution of water and ethanol = 0.7 g:1 g:0.3 g:2 g:50 mL; the volume percentage of ethanol in the mixed solution of water and ethanol is 30%; stir for 30 min under an ultrasonic environment, seal the reaction kettle after the stirring is completed, heat it to 110 °C and keep it warm for 2 h, naturally cool it to room temperature after the heat preservation is completed, perform solid-liquid separation, wash the solid phase with deionized water 3 times, and dry it at 80 °C for 30 min to obtain a boron and phosphorus doped powder;

[0057] (3) Add the boron and phosphorus doped powder into the hydrogen peroxide solution, and the mass ratio of the boron and phosphorus doped powder to the hydrogen peroxide solution is boron and phosphorus doped powder: hydrogen peroxide solution = 2 g: 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 10%; heat in a water bath to 50 °C, keep stirring for 1 h, then separate the solid from the liquid, wash the solid with deionized water for 3 times, and dry it at 80 °C for 30 min to obtain the refining aid of this comparative example;

[0058] (4) Put the purple miscellaneous copper into a crucible, heat it to melt into a melt by using an intermediate frequency induction furnace, cover it with charcoal after complete melting, keep the temperature of the melt at 1120 °C, and then add the refining aid. The mass ratio of the added mass of the refining aid to the mass of the melt is refining aid: melt = 4 kg: 1 t; after feeding, keep the temperature of the melt at 1120 °C and stir for 10 min, then let it stand for 15 min, remove the slag, and cast it into shape to obtain the refined purple miscellaneous copper of this comparative example.

[0059] Example 5

[0060] Test the tensile strength and conductivity of the refined purple miscellaneous copper obtained by the methods of the above examples and comparative examples, and the results are shown in Table 1.

[0061] As can be seen from Table 1, the tensile strength and electrical conductivity of purple miscellaneous copper can be significantly improved after refining by the method of the present invention, and the service performance of purple miscellaneous copper is improved. By comparing Example 3 of the present invention with each comparative example, it can be seen that the prepared calcium-cerium composite oxide matrix powder, after boron-phosphorus doping treatment and surface silicon modification, finally obtains a refining aid, and after adding it to refine purple miscellaneous copper, the mechanical strength and electrical conductivity of purple miscellaneous copper can be significantly improved. This may be mainly due to the fact that calcium in the calcium-cerium composite oxide can form stable Ca-Bi and Ca-Sn intermediate compounds with impurity elements such as Bi and Sn in purple miscellaneous copper, thereby significantly reducing the content of impurity elements in purple miscellaneous copper. As is well known, the influence of impurity elements such as Bi and Sn on the electrical conductivity of copper alloys is mainly because Bi and Sn atoms exist in the form of solid solution in the copper matrix, causing distortion of the lattice structure of the copper matrix, hindering the directional flow of free electrons under the electric field, and the electrons tend to be in a scattered state, thus significantly reducing the electrical conductivity. The added calcium-cerium composite oxide can reduce the content of impurity elements, and thus can reduce the influence of impurity elements on the electrical conductivity and improve the electrical conductivity of the copper alloy itself. The solubility of cerium in the calcium-cerium composite oxide in copper is extremely small, and rare earth cerium is very easy to form high-melting-point compounds with Pb, Fe, etc. and disperse in the melt. On the one hand, it can reduce the solid solubility rate of impurity elements such as Pb and Fe and improve the electrical conductivity of the material; on the other hand, the high-melting-point dispersed phase serves as a heterogeneous nucleation site, which can significantly increase the nucleation rate of purple miscellaneous copper castings, refine the grains, and the dispersed particles distributed at the grain boundaries can also hinder the growth of grains, achieving the purpose of improving the mechanical strength of the material. Subsequently, a boron-phosphorus doped layer was synthesized on the surface of the matrix powder by the hydrothermal method. Utilizing the characteristic that boron can form borides with Ni, Mn, and Cr, impurity elements in the copper alloy are further removed. Phosphorus can adsorb and dissolve oxides in the melt, react with impurity oxides in the melt to form compounds insoluble in the melt, and boron generally does not combine with copper and has little influence on the copper alloy itself. Finally, the hydroxyl content on the particle surface is increased by hydrogen peroxide, and then a silicon-containing layer is adsorbed. After the silicon-containing layer is added to the melt, it mainly exists in the form of [SiO4] tetrahedrons, which is conducive to the enrichment of oxygen in the melt. The oxygen valence at the apex of the tetrahedron is in an unsaturated state and is connected to cerium ions dissolved in the melt to form a network structure, improving the strength of the material.

[0062] Table 1

[0063]

[0064]

[0065] The above has introduced the technical solution provided by the present invention in detail. For those of ordinary skill in the art, based on the idea of the embodiments of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A refining method for high-efficiency miscellaneous purple copper, characterized in that the steps Including: (1) Prepare a composite aqueous solution of calcium nitrate and cerium nitrate, and a composite aqueous solution of sodium hydroxide and sodium carbonate; heat the composite aqueous solution of calcium nitrate and cerium nitrate in a water bath to 40 ± 5 °C and keep it warm, then add the composite aqueous solution of sodium hydroxide and sodium carbonate to the solution under stirring. After the addition is completed, continue to stir the solution at 40 ± 5 °C for more than 20 h. Separate the solid and liquid, wash the solid with deionized water for more than 3 times, then dry it, and calcine it at 800 - 900 °C for more than 4 h to obtain a composite powder; (2) Add sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the composite powder into a mixed solution of water and ethanol in a reaction kettle, stir for more than 30 min under an ultrasonic environment. After stirring is completed, seal the reaction kettle, heat it to 110 ± 3 °C and keep it warm for more than 2 h. After the heat preservation is completed, naturally cool it to room temperature. Separate the solid and liquid, wash the solid with deionized water for more than 3 times, and dry it to obtain a boron and phosphorus doped powder; (3) Add the boron and phosphorus doped powder into a hydrogen peroxide solution, heat it in a water bath to 50 ± 5 °C, keep it warm and stir for more than 1 h, then separate the solid and liquid, wash the solid with deionized water for more than 3 times, dry it, then add it into an aqueous solution of ethanol, stir and disperse it ultrasonically for more than 30 min to obtain a dispersion liquid. Then, add tetraethyl orthosilicate to the dispersion liquid under stirring. After the addition is completed, continue to stir for more than 20 h. Separate the solid and liquid, wash the solid with deionized water, and dry it to obtain a refining aid; (4) Put purple miscellaneous copper into a crucible, heat it to melt into a melt using an intermediate frequency induction furnace. After complete melting, cover it with charcoal, then add the refining aid. After adding, stir the melt for 10 - 12 min, then let it stand, remove the slag, and cast it into shape to obtain refined purple miscellaneous copper.

2. The refining method of high-efficiency purple brass scrap according to claim 1, characterized in that, In the step (1), in the composite aqueous solution of calcium nitrate and cerium nitrate, the concentration of calcium nitrate is 40 - 50 g / L, the concentration of cerium nitrate is 30 - 35 g / L, and the solvent is water; in the composite aqueous solution of sodium hydroxide and sodium carbonate, the mass percentage of sodium hydroxide is 10%, the mass percentage of sodium carbonate is 4% - 6%, and the solvent is water; the volume ratio of the composite aqueous solution of calcium nitrate and cerium nitrate to the composite aqueous solution of sodium hydroxide and sodium carbonate added is the composite aqueous solution of calcium nitrate and cerium nitrate: the composite aqueous solution of sodium hydroxide and sodium carbonate = 10:4 - 5.

3. The refining method of high-efficiency purple brass scrap according to claim 1, characterized in that, In the step (2), the amount ratio of sodium tetraborate decahydrate, copper nitrate trihydrate, sodium dihydrogen phosphate dodecahydrate, and the composite powder added into the mixed solution of water and ethanol is sodium tetraborate decahydrate: copper nitrate trihydrate: sodium dihydrogen phosphate dodecahydrate: composite powder: mixed solution of water and ethanol = 0.6 - 0.8 g: 0.9 - 1 g: 0.2 - 0.3 g: 1 - 2 g: 50 mL.

4. The refining method of high-efficiency purple brass scrap according to claim 1, characterized in that The volume percentage of ethanol in the mixed solution of water and ethanol is 30% - 40%.

5. The refining method of high-efficiency purple brass scrap according to claim 1, characterized in that In the step (3), the amount ratio of the boron and phosphorus doped powder added into the hydrogen peroxide solution is the boron and phosphorus doped powder: hydrogen peroxide solution = 1 - 2 g: 50 mL, where the mass percentage of the solute in the hydrogen peroxide is 5% - 10%.

6. The refining method of high-efficiency purple brass scrap according to claim 1, characterized in that In the step (3), the mass ratio of the solid phase after drying to the aqueous ethanol solution added is solid phase: aqueous ethanol solution = 1 g: 80 mL; wherein the volume percentage of ethanol in the aqueous ethanol solution is 10%; the volume ratio of tetraethyl orthosilicate added to the mass of the solid phase added to prepare the dispersion is tetraethyl orthosilicate: solid phase = 5 - 6 mL: 1 g.

7. An efficient refining method for purple brass scrap according to claim 1, characterized in that, In the step (4), the mass ratio of the refining aid added to the mass of the melt is refining aid: melt = 3 - 4 kg: 1 t.

8. An efficient refining method for purple copper scraps according to claim 1, characterized in that, The heating and melting temperature is 1110 - 1120 °C.

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