Hexavalent Chromium Extraction via Reducing Agents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for removing hexavalent chrome from chrome plating or chromate films are either ineffective for solid workpieces, require expensive and complex equipment, or are inefficient in mass production, leading to environmental pollution and health risks.
Innovation Solution
A method involving contacting a workpiece with a liquid or fine particle reducing agent or electrolyte, potentially combined with ultrasonic waves, to extract hexavalent chrome without altering the workpiece's shape, allowing for efficient and cost-effective extraction both during production and disposal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If existing chrome removing methods using reaction vessels and precipitation vessels are employed, then hexavalent chrome can be removed from effluent, but the equipment cost becomes expensive and the space requirement increases
Solution Approach 1:
The invention extracts the harmful hexavalent chrome from the effluent by adding reducing agents that convert Cr(VI) to Cr(III), which then precipitates. This removes the need for complex reaction vessels and precipitation vessels, achieving chrome removal through simple chemical treatment that can be performed in existing wastewater treatment systems
Solution Approach 2:
The invention changes the chemical parameter of chromium from hexavalent (Cr(VI)) to trivalent (Cr(III)) state by adding reducing agents such as ferrous sulfate, sodium metabisulfite, or hydrogen peroxide. This parameter change enables the chromium to be removed through simple precipitation rather than requiring complex separation equipment
2Object-affected harmful factors
If existing chrome removing methods with measuring means and controlled adding systems are used, then hexavalent chrome removal efficiency improves, but the equipment cost and operational complexity increase
Solution Approach 1:
The invention employs self-service mechanisms where the reducing agent automatically reacts with hexavalent chrome in the effluent, and the chromium precipitates naturally through chemical reactions. This eliminates the need for complex measuring means and controlled adding systems, as the process self-regulates through chemical equilibrium and precipitation
3Object-affected harmful factors
If chrome precipitates are generated in large amounts, then hexavalent chrome removal efficiency increases, but pipeline blocking occurs
Solution Approach 1:
The invention applies partial action by carefully controlling the amount of reducing agent added to achieve sufficient chromium removal without generating excessive precipitates. The process uses stoichiometric calculations to add just enough reducing agent to convert Cr(VI) to Cr(III), preventing pipeline blocking while maintaining effective removal efficiency
Solution Approach 2:
The invention ensures continuous useful action by maintaining continuous flow of effluent through the treatment system with continuous addition of reducing agent. This prevents precipitate accumulation that could block pipelines, as the continuous flow keeps the system dynamic and prevents sedimentation in pipelines
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
Enables rapid, precise, and inexpensive extraction of hexavalent chrome, preventing environmental pollution and ensuring safe disposal, while meeting regulatory standards like WEEE and RoHS, without the need for specialized equipment.
Implementation Method 1
contacting a workpiece having a film where hexavalent chrome remains with a liquid or fine particle reducing agent and extracting the hexavalent chrome from the film
Implementation Method 2
the workpiece having a film where the hexavalent chrome remains is contacted with the reducing agent while maintaining a strictly or approximately strictly original shape of the workpiece
Data Source
AI summary
Hexavalent chrome is extracted from a film on a workpiece which film contains hexavalent chrome and reduced by contacting the contacting workpiece with a liquid or fine particle reducing agent.