Lead/Silver By-Product Pressure Leaching for Low-Carbon Smelting
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Solution Overview
Problem
Conventional methods for processing lead/silver-containing by-products from zinc hydrometallurgy result in high carbon emissions and low recovery rates of valuable metals, particularly when using a fumer, which is inefficient compared to smelting.
Innovation Solution
A method involving a pressure leaching process using an autoclave to reduce zinc and iron contents in the by-product to less than 1 wt%, followed by a separation process and smelting, which includes adjusting the concentration of iron in the leachate to 10-12 g/L and maintaining specific temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If volatilization using a fumer is used to process the lead/silver-containing by-product, then the zinc and iron contents can be handled, but carbon emissions increase five times or more compared to smelting
Solution Approach 1:
The patent applies preliminary action by conducting pressure leaching before smelting to remove zinc and iron from the by-product. This pre-treatment step reduces the zinc and iron contents to acceptable levels, enabling subsequent smelting without the operational instability that would occur with high zinc ferrite content. The pressure leaching process uses acid to dissolve zinc and iron, which are then removed in the leachate, leaving a residue suitable for smelting.
Solution Approach 2:
The patent uses an intermediary substance (acid leaching solution) to facilitate the removal of zinc and iron from the by-product. The acid acts as a mediator that selectively dissolves zinc and iron compounds, separating them from lead and silver. This intermediary chemical process enables the transition from a high-zinc/iron by-product to a smelting-ready material with reduced harmful content.
2Productivity
If volatilization using a fumer is used to process the by-product, then processing can proceed, but the recovery rate of valuable metals such as silver, gold, and copper is significantly lower compared to smelting
Solution Approach 1:
The pressure leaching process performs preliminary separation of zinc and iron from the by-product before smelting. This pre-concentration of valuable metals in the leachate and pre-cleaning of the residue for smelting maximizes the recovery efficiency in subsequent steps. The leachate containing dissolved metals can be further processed to recover zinc, while the cleaned residue is optimized for smelting to recover lead, silver, gold, and copper.
Solution Approach 2:
The patent segments the processing into distinct stages: pressure leaching to remove zinc and iron, followed by smelting to recover valuable metals. This segmentation allows each process to be optimized for its specific function - leaching for zinc/iron removal and smelting for valuable metal recovery - thereby achieving high overall recovery rates while maintaining operational stability.
3Object-generated harmful factors
If the lead/silver-containing by-product is directly smelted without pressure leaching, then carbon emissions are reduced, but operational instability occurs due to zinc ferrite not melting easily
Solution Approach 1:
The patent applies preliminary action by conducting pressure leaching before smelting to remove zinc and iron from the by-product. This pre-treatment step reduces the zinc and iron contents to acceptable levels, enabling subsequent smelting without the operational instability that would occur with high zinc ferrite content. The pressure leaching process uses acid to dissolve zinc and iron, which are then removed in the leachate, leaving a residue suitable for smelting.
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
Reduces the amount of by-product requiring further treatment, increases the recovery rate of valuable metals, and significantly decreases carbon emissions by enabling smelting in a conventional smelter.
Implementation Method 1
a pressure leaching process of pressure leaching a lead/silver-containing by-product, which is generated in a finishing leaching process of zinc hydrometallurgy, by using an autoclave so that contents of zinc and iron contained in a leaching residue are less than 1 wt%, respectively
Implementation Method 2
The lead/silver-containing by-product may be leached under pressure with a zinc spent leachate
Implementation Method 3
a separation process of separating a leachate and the leaching residue from the pressure leaching process into a liquid and a solid
Implementation Method 4
a smelting process of processing the leaching residue using a smelter
Data Source
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AI summary
A method for processing a by-product of zinc hydrometallurgy, according to one embodiment of the present disclosure, includes a pressure leaching process of pressure leaching a lead/silver-containing by-product, which is generated in a finishing leaching process of zinc hydrometallurgy, by using an autoclave so that contents of zinc and iron contained in a leaching residue are less than 1 wt%, respectively.