Leaching studies for tin recovery from waste e-scrap
Manis Kumar Jha1, Pankaj Kumar Choubey, Amrita Kumari Jha
1Metal Extraction and Forming Division, National Metallurgical Laboratory (NML), Jamshedpur 831 007, India. maniskrjha@gmail.com
Waste Management (New York, N.Y.)
|June 1, 2012
Summary
Recycling printed circuit boards (PCBs) recovers valuable tin and lead. An Indo-Korean technique efficiently leaches tin from solder and epoxy resin, enabling safe disposal of metal-free resin.
Area of Science:
- Materials Science
- Environmental Engineering
- Chemical Engineering
Background:
- Printed circuit boards (PCBs) contain valuable and toxic metals, necessitating efficient recycling methods.
- Current recycling processes require optimization for metal recovery and safe disposal of residual materials.
Purpose of the Study:
- To develop and optimize an Indo-Korean recycling technique for waste PCBs.
- To investigate the recovery of tin and lead from PCBs using an organic swelling pre-treatment.
- To evaluate the safe disposal or reuse of metal-free epoxy resin.
Main Methods:
- Bench scale studies were conducted to optimize tin leaching from fresh solder and liberated epoxy resin.
- Parameters varied included acid concentration, temperature, mixing time, and pulp density.
- Kinetics of tin leaching were studied, and lead was removed from leach residue using nitric acid.
Main Results:
- Optimized conditions achieved 95.79% tin leaching from fresh solder using 5.5M HCl at 90°C for 165 min.
- 97.79% tin leaching from liberated epoxy resin was achieved using 4.5M HCl at 90°C for 60 min.
- Sodium stannate was precipitated from leach liquor, and lead was effectively removed from residue.
Conclusions:
- The developed Indo-Korean recycling technique is effective for recovering tin from waste PCBs.
- The process allows for the safe disposal or utilization of metal-free epoxy resin.
- This method contributes to sustainable electronic waste management and resource recovery.
More Related Videos
Related Concept Videos
01:27Microbial Leaching
Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific microorganisms. This biotechnological approach is particularly valuable for mining operations targeting copper, gold, and uranium, where traditional extraction methods may be economically or environmentally impractical.Copper Leaching and Microbial CatalysisIn copper bioleaching, crushed ore is arranged into heaps and irrigated with a dilute sulfuric...
00:56Extraction: Advanced Methods
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is formed in...
01:08Electrodeposition
Electrodeposition is a technique used to separate an analyte from interferents by electrochemical processes. Here, the analyte is a metal ion that can be deposited on an electrode immersed in the sample solution. The electrochemical setup consists of an anode and a cathode. When an electric current is applied to the setup, oxidation occurs at the anode. At the cathode, which consists of a large metal surface, metal ions undergo reduction and deposit onto the surface.
Electrodeposition can...
Electrodeposition can...
01:13Voltammetry: Stripping Methods
Anodic Stripping Voltammetry (ASV), Cathodic Stripping Voltammetry (CSV), and Adsorptive Stripping Voltammetry (AdSV) are electrochemical techniques used to determine trace amounts of analytes in solution. These methods involve applying a potential to an electrode and measuring the resulting current.
Anodic Stripping Voltammetry (ASV)
ASV is used to determine metals and metalloids at trace levels. It involves two steps: deposition and stripping. First, a negative potential is applied to the...
Anodic Stripping Voltammetry (ASV)
ASV is used to determine metals and metalloids at trace levels. It involves two steps: deposition and stripping. First, a negative potential is applied to the...
01:17Precipitation and Co-precipitation
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
01:08Sample Preparation for Analysis: Advanced Techniques
Accurate analysis of complex samples often requires advanced preparation techniques to achieve reliable and reproducible results. Samples containing inorganic or organic materials can be challenging to dissolve or decompose effectively. Standard sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion.
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...