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A method for recycling lead-free solder through α-sn phase transition separation

A lead-free solder, separation and recycling technology, applied in chemical instruments and methods, solid waste removal, transportation and packaging, etc., can solve the problems of high energy consumption, low recycling rate, and large pollution, and achieve low energy consumption, recycling High rate, low pollution effect

Inactive Publication Date: 2018-08-10
HONGHE COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of method not only pollutes a lot, but also consumes a lot of energy. In addition, these methods have the disadvantage of low recycling rate when they are applied to the recovery of lead-free solder.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Separation and recovery of lead-free solder through α-Sn phase transition, the method steps are as follows:

[0018] (1) Cold rolling the solder alloy that needs secondary recovery to a thickness of 1-10mm; the solder alloy refers to a Sn alloy containing Ag, Cu, Zn, Al and other impurity elements, wherein the content of each impurity element does not exceed 5wt.%. ;

[0019] (2) Cool the metal plate cold-rolled in step (1) to below -13.2°C, and spray powdered α-Sn on the surface of the metal plate; the α-Sn can be obtained through phase transformation of pure Sn in low-temperature refrigeration, or Obtained through follow-up process (5) separation;

[0020] (3) further cooling the metal plate to -33°C to complete the α-Sn phase transition of the metal plate; during the α-Sn phase transition of the metal plate, the α-Sn phase transition can be accelerated by thermal cycling; the thermal cycle, It is to adjust the temperature between -15°C and -33°C during the freezing...

Embodiment 2

[0024] Separation and recovery composition is the lead-free solder of Sn-3Ag-0.5Cu by α-Sn phase change, and its method step is as follows:

[0025] (1) Cold rolling the lead-free solder whose composition needs secondary recovery is Sn-3Ag-0.5Cu to a thickness of 1 to 10 mm; said cold rolling refers to rolling the raw alloy ingot at room temperature using a rolling mill, according to Metal ingot size, can be rolled many times;

[0026] (2) Cool the metal plate cold-rolled in step (1) to below -13.2°C, spray powdery α-Sn on the surface of the metal plate, the particle size of powdery α-Sn is 5 μm, and the spraying amount is 2g / m 2 ; The α-Sn can be obtained through the phase transition of pure Sn in low-temperature refrigeration, and can also be separated and obtained through the subsequent process (5);

[0027] (3) Further lower the temperature of the metal plate to -33°C, and then adjust the temperature to cycle between -15°C and -33°C. One hour is a cycle. After 48 hours, t...

Embodiment 3

[0031] Separation and recovery composition is the lead-free solder of Sn-3Ag-0.5Cu by α-Sn phase change, and its method step is as follows:

[0032] (1) Cold-roll the lead-free solder whose composition needs to be recovered twice to be Sn-3Ag-0.5Cu to a thickness of 1-10mm;

[0033] (2) Cool the metal plate treated in step (1) to below -13.2°C, spray powdery α-Sn on its surface, the particle size of powdery α-Sn is 5 μm, and the spraying amount is 2g / m 2 ;

[0034] (3) Further lower the temperature of the metal plate to -33°C, and place the metal plate at a constant temperature for 60 hours to complete the α-Sn transformation;

[0035] (4) After the α-Sn phase transformation is completed, the metal plate will be broken; use a hammer mill to initially pulverize the broken material, and then go through a jet mill to further pulverize the powder to a particle size of less than 5 μm;

[0036] (5) Separate α-Sn from intermetallic compounds and impurities using a cyclone separator...

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Abstract

A method for separating and recovering lead-free solder through α-Sn phase transformation, firstly cold-rolling the solder alloy that needs secondary recovery to a thickness of 1-10 mm; the solder alloy refers to a Sn alloy containing impurity elements, wherein each impurity element The content does not exceed 5wt.%; then the cold-rolled metal plate is cooled to below -13.2°C, and powdered α-Sn is sprayed on the surface of the metal plate; then the metal plate is further cooled to -33°C, so that the ‑Sn is crushed during the phase change process; the crushed material is initially crushed by a pulverizer, and then further crushed to a powder size of 5 μm or less by a jet mill, and finally α-Sn is separated from intermetallic compounds and impurities by cyclone separation. α-Sn powder was obtained. Compared with the traditional oxidation method, chlorination method and alkali method, the invention has the characteristics of less pollution and high recovery rate of alloy components.

Description

technical field [0001] The invention relates to the technical field of nonferrous metal recovery, in particular to a method for recovering solder alloy through phase transformation decomposition. Background technique [0002] With the promotion of lead-free solder, the usage of lead-free solder is gradually increasing. According to statistics, the output of lead-free solder in my country was 42,000 tons in 2012, and it has grown at an annual rate of 20% in recent years. Because lead-free solder contains Ag components, its recycling value is much higher than that of traditional Sn-Pb solder, and with the gradual increase in the amount of lead-free solder, the secondary recycling of lead-free solder has become an urgent problem to be solved. The recovery methods of traditional Sn-Pb solder include oxidation method, chlorination method and alkali method. This type of method not only pollutes a lot, but also consumes a lot of energy. In addition, these methods have the disadva...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B09B3/00
CPCB09B3/00B09B3/80
Inventor 罗庭碧姜艳孔馨刘贵阳刘卫
Owner HONGHE COLLEGE
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