Stepwise Sulfidation Control for High-Arsenic Copper Smelter Waste Acid
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Solution Overview
Problem
Existing methods struggle to accurately determine the amount of hydrogen sulfide needed for sulfidation based on the valence state and concentration of arsenic species in waste acid from copper smelters, leading to high arsenic concentrations in raw waste acid, excessive hydrogen sulfide use, high emissions of toxic gases, and excessive hazardous waste generation.
Innovation Solution
An intelligent decision-making and control system for microchemical reactions in stepwise sulfidation, utilizing a stepwise sulfidation module with gradient stages, real-time monitoring, and intelligent decision-making to adjust sulfidation reactions based on arsenic valence state and concentration, and a terminal execution module to control hydrogen sulfide addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sulfide precipitation technology is used to treat waste acid from copper smelter, then the treatment process can be implemented, but excessive arsenic remains in filtrates and large amounts of toxic gases are emitted
Solution Approach 1:
The patent divides the sulfidation process into multiple reaction stages with different hydrogen sulfide addition rates. The first stage uses a higher addition rate to rapidly precipitate most arsenic, while subsequent stages use progressively lower rates to complete the reaction and prevent excessive gas emission. This segmented approach resolves the contradiction by improving removal efficiency while controlling harmful emissions.
Solution Approach 2:
The patent dynamically adjusts the hydrogen sulfide addition rate based on real-time monitoring of arsenic concentration and reaction progress. The addition rate changes from high to low across different stages, optimizing the balance between arsenic removal efficiency and toxic gas emission control.
2Reliability
If a large amount of hydrogen sulfide is added to ensure complete sulfidation, then arsenic removal is improved, but toxic gas emissions and hazardous waste generation increase
Solution Approach 1:
The patent implements periodic action by dividing the sulfidation into distinct stages with different hydrogen sulfide addition rates. The first stage uses high addition rate for rapid precipitation, followed by stages with progressively lower rates. This periodic approach ensures complete sulfidation while minimizing excessive hydrogen sulfide consumption and associated harmful emissions.
Solution Approach 2:
The patent uses real-time monitoring of arsenic concentration and reaction parameters to provide feedback for adjusting hydrogen sulfide addition rates. This feedback mechanism ensures that sufficient hydrogen sulfide is added for complete sulfidation while avoiding excessive addition that would increase toxic gas emissions and hazardous waste.
3Ease of operation
If existing analytical methods are used to determine total arsenic content, then measurement is simple, but the actual valence states and forms of arsenic species cannot be analyzed
Solution Approach 1:
The patent introduces an intermediary substance (specific reagent) that selectively reacts with different valence states of arsenic to produce distinguishable signals. This intermediary enables the differentiation of arsenic species while maintaining operational simplicity, resolving the contradiction between ease of measurement and measurement precision.
4Productivity
If stepwise sulfidation with precise control is implemented, then production efficiency and cost-effectiveness are improved, but the system complexity increases
Solution Approach 1:
The patent segments the sulfidation process into multiple reaction stages, each with defined hydrogen sulfide addition rates and duration. This segmentation enables precise control and optimization of each stage for maximum efficiency, while the modular structure makes the overall system manageable despite increased complexity.
Solution Approach 2:
The patent systematically changes key parameters (hydrogen sulfide addition rate, reaction time, pH) across different stages to optimize production efficiency. Each parameter is adjusted according to the specific requirements of each stage, enabling precise control while the structured parameter changes make the complexity manageable and predictable.
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 system enables precise control of sulfidation reactions, reducing arsenic concentrations in filtrates to below 20 mg/L, minimizing hazardous waste, and optimizing production efficiency and cost-effectiveness.
Implementation Method 1
the plurality of containers are divided into a plurality of gradient stages... implement a sulfidation reaction... controlling addition of a corresponding amount of a hydrogen sulfide gas to a container
Implementation Method 2
electromagnetic valves are installed on the main pipes and the bypass pipes to open or close a corresponding pipe
Data Source
AI summary
Provided are an intelligent decision-making and control method and system for a microchemical reaction in stepwise sulfidation of a high arsenic-contained waste acid from copper smelter. Microchemical information from the real-time monitoring module is acquired by the intelligent decision-making module. A stage combination for a sulfidation reaction is determined based on a concentration of arsenic in raw waste acid. A total amount of arsenic and an amount of hydrogen sulfide to be added at a first stage are calculated based on a valence state and concentration of arsenic in and a flow rate of inflow at the first stage, and a total amount of arsenic and an amount of hydrogen sulfide to be added at a second stage are calculated based on a valence state and concentration of arsenic in and a flow rate of inflow at the second stage.