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CN-121992243-A - Process for preparing high-density phosphor copper balls from scrap copper for electronic connection

CN121992243ACN 121992243 ACN121992243 ACN 121992243ACN-121992243-A

Abstract

The invention relates to a process for preparing high-density phosphor copper balls from scrap copper for electronic connection, belonging to the field of nonferrous metal processing. The method comprises the steps of placing crushed and magnetically separated scrap copper into sulfuric acid solution for pickling, placing the crushed and magnetically separated scrap copper into an intermediate frequency induction furnace for smelting, adding a refining agent into the smelted copper solution for refining, adding a phosphorus copper master alloy, adjusting the phosphorus content, carrying out continuous casting through an upward continuous casting machine to obtain a phosphorus copper rod, sending the phosphorus copper rod into a cold heading machine for cold heading into a ball blank, placing the ball blank into an annealing furnace, uniformly covering the surface of the ball blank by using titanate-carboxylate composite densification agent and absolute ethyl alcohol through atomization spraying, and carrying out annealing treatment, polishing, cleaning and drying to obtain phosphorus copper balls, wherein the titanate-carboxylate composite densification agent is prepared from triethyl citrate, 1' -bis (diphenylphosphine) ferrocene, tetraisopropyl titanate, ethyl alcohol and p-toluenesulfonic acid.

Inventors

  • PENG BINGFENG
  • DONG YU
  • LIN GAOYONG
  • ZHANG ZUGUO

Assignees

  • 江西保太有色金属集团有限公司

Dates

Publication Date
20260508
Application Date
20260227

Claims (7)

  1. 1. A process for preparing high-density phosphor copper balls from scrap copper for electronic connection is characterized by comprising the following operation steps: S1, pretreating scrap copper, namely firstly sorting the scrap copper to remove bulk plastic and rubber impurities, crushing the scrap copper to a particle size of 5-10mm, removing ferromagnetic impurities through magnetic separation, pickling the crushed scrap copper in sulfuric acid solution for 10-30 minutes to remove surface oxides, washing the crushed scrap copper with clear water and drying the washed scrap copper; S2, smelting, namely putting the pretreated scrap copper into an intermediate frequency induction furnace, and heating and smelting, wherein in the smelting process, a charcoal layer with the thickness of 50-100mm is covered on the surface of the copper liquid, so that air is isolated, and the copper liquid is prevented from being oxidized; S3 refining, namely adding 0.1 to 0.5 part by mass of refining agent into 70 to 100 parts by mass of smelted copper liquid, stirring to ensure that the refining agent is fully contacted with the copper liquid, and then standing for 30 to 60 minutes to remove surface scum; s4, regulating the phosphorus content, namely adding a phosphorus-copper master alloy, and uniformly stirring to ensure that the mass fraction of phosphorus in the copper liquid is 0.03% -0.07%; S5, continuous casting, namely, continuously casting the copper liquid with the adjusted phosphorus content by an upward continuous casting machine, wherein the cooling speed is 5-10 ℃ per second, and preparing a phosphorus copper rod with the diameter of 8-12 mm; S6, cold heading, namely conveying the phosphor copper rod into a cold heading machine for cold heading into a ball blank; s7, annealing: placing the ball blank into an annealing furnace, heating to 200-300 ℃ and preserving heat for 20-30 minutes; Diluting the titanate-carboxylate composite densification agent and absolute ethyl alcohol according to the mass ratio of 1:5-10 to prepare a mixed solution, uniformly covering the surface of the ball blank by atomizing and spraying the mixed solution with the mass of 0.14% -0.3% of the ball blank, wherein the spraying speed is 5-10mL/min, and ensuring that the densification agent completely infiltrates the ball blank; continuously heating to 400-600 ℃, preserving heat for 1-3 hours, and cooling to room temperature along with a furnace; S8, surface treatment, namely polishing the annealed ball blank for 15-30 minutes, cleaning with clear water, and drying at 80-100 ℃ to obtain a finished product of phosphor-copper ball; the preparation method of the titanate-carboxylate composite densification agent comprises the following steps of: H1, adding 10-15 parts of triethyl citrate, 0.1-0.5 part of 1,1' -bis (diphenylphosphine) ferrocene and 6-10 parts of tetraisopropyl titanate into 35-45 parts of absolute ethyl alcohol, and mixing under the protection of nitrogen; H2, adding 0.5-1 part of p-toluenesulfonic acid, stirring and reacting for 4-6 hours at 70-80 ℃, and then performing rotary evaporation to obtain the composite densification agent.
  2. 2. The process for preparing high-density phosphor copper balls by using scrap copper for electronic connection according to claim 1, wherein the mass percentage of the S1 sulfuric acid solution is 10-20%.
  3. 3. The process for preparing high-density phosphor copper balls from scrap copper for electronic connection according to claim 1, wherein the smelting temperature of S2 is 1100-1300 ℃.
  4. 4. The process for preparing high-density phosphor copper balls from scrap copper for electronic connection according to claim 1, wherein the refining agent is prepared by mixing borax and sodium carbonate according to a mass ratio of 2:1.
  5. 5. The process for preparing high-density phosphor copper balls by using scrap copper according to claim 1, wherein the stirring speed of S3 is 200-300r/min, and the time is 10-15 minutes.
  6. 6. The process for preparing high-density phosphor copper balls for electronic connection by using scrap copper according to claim 1, wherein the mass percentage of phosphor contained in the phosphor copper master alloy of S4 is 10-15%.
  7. 7. The process for preparing high-density phosphor copper balls from scrap copper for electronic connection according to claim 1, wherein the pressure of the S6 cold header is 300-500MPa.

Description

Process for preparing high-density phosphor copper balls from scrap copper for electronic connection Technical Field The invention relates to the field of nonferrous metal processing, in particular to a process for preparing high-density phosphor copper balls from scrap copper for electronic connection. Background In the field of electronic connection, phosphor copper balls are used as important anode materials, and the quality of the phosphor copper balls plays a key role in electroplating effect and reliability of electronic connection. The traditional phosphor copper ball is prepared by taking electrolytic copper as a raw material, and has higher cost. With the rapid development of the electronic industry, the amount of scrap copper generated is increasing, and how to efficiently utilize the scrap copper to prepare high-quality phosphor copper balls becomes a research hot spot. Chinese patent CN101698271A discloses a high-efficiency high-density phosphor copper ball processing method, which adopts a continuous extruder to extrude raw material phosphor copper rods, so that the inside and the outside of the phosphor copper rods are in a fine crystal state. Chinese patent CN108890221B discloses a production method of phosphor copper balls, which comprises the following steps of placing phosphor copper bars crystallized by an up-casting method into a preheating heat preservation furnace for preheating, wherein the preheating temperature is 420-440 ℃, rolling balls, taking out phosphor copper bars from the preheating heat preservation furnace, then placing the phosphor copper bars on a spiral mold, rolling the phosphor copper bars into a plurality of phosphor copper balls, polishing, placing the phosphor copper balls, grinding agent and brightening agent into a roller polishing machine, adding water into the roller, polishing for 15-25 minutes, air-drying and washing, placing the polished phosphor copper balls into a water-washing air dryer for washing for 10-15 minutes, packaging and weighing, placing a packaging box onto an electronic scale, then gradually placing qualified phosphor copper balls into the packaging box until the electronic scale is 25+/-0.02 kg, sealing the packaging box, and bundling the packaging box by using a bundling belt. In the prior art, the problems of incomplete impurity removal, low density and the like exist in the preparation of the phosphor copper ball by utilizing scrap copper, so that the prepared phosphor copper ball is unevenly dissolved in the electroplating process, and the electronic connection quality is affected. Disclosure of Invention In order to solve the problems, the invention provides a process for preparing high-density phosphor copper balls from scrap copper for electronic connection, which comprises the following operation steps: S1, pretreating scrap copper, namely firstly sorting the scrap copper to remove bulk plastic and rubber impurities, crushing the scrap copper to a particle size of 5-10mm, removing ferromagnetic impurities through magnetic separation, pickling the crushed scrap copper in sulfuric acid solution for 10-30 minutes to remove surface oxides, washing the crushed scrap copper with clear water and drying the washed scrap copper; S2, smelting, namely putting the pretreated scrap copper into an intermediate frequency induction furnace, and heating and smelting, wherein in the smelting process, a charcoal layer with the thickness of 50-100mm is covered on the surface of the copper liquid, so that air is isolated, and the copper liquid is prevented from being oxidized; S3 refining, namely adding 0.1 to 0.5 part by mass of refining agent into 70 to 100 parts by mass of smelted copper liquid, stirring to ensure that the refining agent is fully contacted with the copper liquid, and then standing for 30 to 60 minutes to remove surface scum; s4, regulating the phosphorus content, namely adding a phosphorus-copper master alloy, and uniformly stirring to ensure that the mass fraction of phosphorus in the copper liquid is 0.03% -0.07%; S5, continuous casting, namely, continuously casting the copper liquid with the adjusted phosphorus content by an upward continuous casting machine, wherein the cooling speed is 5-10 ℃ per second, and preparing a phosphorus copper rod with the diameter of 8-12 mm; S6, cold heading, namely conveying the phosphor copper rod into a cold heading machine for cold heading into a ball blank; s7, annealing: placing the ball blank into an annealing furnace, heating to 200-300 ℃ and preserving heat for 20-30 minutes; Diluting the titanate-carboxylate composite densification agent and absolute ethyl alcohol according to the mass ratio of 1:5-10 to prepare a mixed solution, uniformly covering the surface of the ball blank by atomizing and spraying the mixed solution with the mass of 0.14% -0.3% of the ball blank, wherein the spraying speed is 5-10mL/min, and ensuring that the densification agent completely infiltrates the ball blank;