High Purity Copper Sulfate Production from Spent PCB Etching Waste
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Solution Overview
Problem
Current methods for treating acidic copper chloride etching waste liquids in the PCB industry are inefficient, leading to high production costs, low product value, secondary pollution, and poor quality of copper sulfate due to impurities and inadequate impurity removal.
Innovation Solution
A method involving the use of liquid ammonia to react with acidic copper chloride etching solutions, followed by filtration and crystallization steps to produce high purity copper oxychloride, which is then converted to copper sulfate in a sulfuric acid solution, allowing for impurity removal and high concentration hydrochloric acid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional treatment methods are used for acidic copper chloride etching waste liquid, then the treatment process can be completed, but the production cost is high and product added value is low
Solution Approach 1:
The patent changes the chemical parameters of the waste liquid by adjusting pH to specific ranges (pH 2-4 for copper chloride solution, pH 8-10 for ammonia reaction) to optimize the reaction conditions. This enables efficient conversion of waste components into high-value products like copper sulfate and ammonium chloride, thereby reducing treatment cost and increasing product added value
Solution Approach 2:
The patent converts the harmful waste liquid into beneficial products by utilizing the copper chloride and ammonia components. The waste liquid, which was previously harmful to the environment, is transformed into high-purity copper sulfate and ammonium chloride through controlled chemical reactions, turning a harmful substance into valuable products
2Productivity
If sodium chloride is added for distillation and crystallization, then hydrochloric acid and sodium chloride can be obtained, but the sodium chloride product contains multiple impurities such as heavy metal and ammonium
Solution Approach 1:
The patent extracts and removes impurities from the sodium chloride product through multiple filtration and purification steps. By separating the copper chloride solution into specific pH ranges and using selective precipitation, the method removes heavy metals and ammonium impurities, obtaining high-purity sodium chloride and hydrochloric acid
Solution Approach 2:
The patent performs preliminary treatment by adjusting the pH of the copper chloride solution to specific ranges before adding sodium chloride. This preliminary action prevents impurities from forming in the first place and enables subsequent easy separation, resulting in high-purity products without requiring complex post-purification steps
3Productivity
If electrolysis is used to obtain elemental copper, then copper can be recovered, but the quality of elemental copper is low due to lack of impurity removal
Solution Approach 1:
The patent performs preliminary purification by removing impurities from the copper chloride solution before electrolysis. Through pH adjustment and filtration steps, the solution is pre-treated to eliminate heavy metals and other contaminants, ensuring that the subsequent electrolysis produces high-quality elemental copper
Solution Approach 2:
The patent extracts and removes impurities from the electrolysis solution through filtration and pH control. By separating impurities before and during electrolysis, the method obtains high-purity elemental copper while recovering valuable byproducts, thereby improving both copper quality and overall process efficiency
4Productivity
If alkaline etching waste liquid is mixed with acidic etching waste liquid, then copper oxychloride can be produced, but the treatment cost of wastewater is high and NH4+ residues remain in the mother liquor
Solution Approach 1:
The patent segments the treatment process into separate stages: first treating the acidic copper chloride solution to a specific pH range, then adding ammonia solution to a controlled pH range. This segmentation allows for efficient copper oxychloride formation and subsequent purification, reducing treatment cost and avoiding high NH4+ residues in the mother liquor
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves high purity copper sulfate with reduced impurities and lower costs, utilizing energy efficiently and producing high-value byproducts, thereby addressing the limitations of existing technologies.
Implementation Method 1
introducing liquid ammonia into the first acidic copper chloride etching solution for reaction and filtration to obtain a copper-containing refined liquid
Implementation Method 2
performing a reaction with the copper-containing refined liquid and the acidity-adjusted second acidic copper chloride etching solution as raw materials, controlling a crystallization process to obtain copper oxychloride
Implementation Method 3
adding the washed copper oxychloride to a sulfuric acid solution for reaction to obtain a copper sulfate slurry and hydrochloric acid
Implementation Method 4
adding water to the copper sulfate slurry, and performing cooling crystallization and solid-liquid separation to obtain Semi-finished copper sulfate
Implementation Method 5
adding a first solution to Semi-finished copper sulfate, performing heating dissolution and temperature-controlled filtration to obtain a first filtrate
Implementation Method 6
performing cooling crystallization and centrifugation on the first filtrate to obtain high purity copper sulfate
Data Source
AI summary
The present disclosure relates to the fields of chemical engineering and environmental protection, and in particular to a method of preparing high purity copper sulfate by using an acidic copper chloride etching waste liquid, which includes: introducing liquid ammonia into a first acidic copper chloride etching solution and a second acidic copper chloride etching solution, mixing the obtained solutions and allowing the mixture to be subjected to crystallization and filtration to produce an intermediate copper oxychloride; washing and separating copper oxychloride and adding it into a sulfuric acid solution to obtain a copper sulfate slurry, and then adding water to the copper sulfate slurry and performing cooling, crystallization and separation to obtain Semi-finished copper sulfate; adding a first solution to Semi-finished copper sulfate and then performing heating, and temperature-controlled filtration, and performing cooling, crystallization and centrifugation on an obtained first filtrate so as to obtain a high purity copper sulfate.