High Sulphur Solid Treatment via Molten Slag Combustion
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Solution Overview
Problem
High sulphur solids, particularly leach residues from zinc hydrometallurgy processes, are difficult to process due to their unique chemical composition, leading to storage in tailings dams rather than effective treatment.
Innovation Solution
A process involving feeding high sulphur solids to a furnace with a molten slag bath, where elemental sulphur burns to form sulphur dioxide and lead compounds are oxidized, reporting to the slag, with the gas stream treated to recover lead fume and sulphur dioxide, and the slag further processed for lead recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high sulphur solids are stored in tailings dams, then storage is simple and requires no complex processing, but the material occupies large space and provides no economic value
Solution Approach 1:
The patent converts the harmful high sulphur content, which previously made the material difficult to process and required storage, into a beneficial fuel source. The elemental sulphur combusts exothermically to provide heat for the smelting process, transforming a processing obstacle into an energy resource that enables valuable lead recovery while eliminating the need for storage.
2Loss of substance
If conventional smelting processes are used on high sulphur solids, then lead recovery may be achieved, but uncontrollable foaming occurs and fuel requirements increase
Solution Approach 1:
The patent utilizes the exothermic combustion of elemental sulphur to provide the heat required for smelting, eliminating the need for external fuel sources. This converts the previously problematic high sulphur content into a beneficial fuel source, reducing fuel requirements while maintaining process stability through controlled combustion in the molten slag bath.
Solution Approach 2:
The patent changes the physical state and chemical environment of the sulphur by combusting it within the molten slag bath rather than in the gas phase. This parameter change from gas-phase combustion to liquid-phase combustion prevents foaming while maintaining efficient heat transfer and lead recovery, stabilizing the smelting process.
3Loss of substance
If lead compounds are oxidized in the furnace, then lead reports to the slag for recovery, but the process requires precise control of oxidation conditions
Solution Approach 1:
The patent employs a self-regulating oxidation process where the combustion of elemental sulphur and the oxidation of lead compounds occur simultaneously in the molten slag bath. The exothermic heat from sulphur combustion provides the necessary conditions for lead oxidation without requiring external energy input or complex control systems, allowing the process to self-regulate based on the material composition.
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 process effectively treats high sulphur solids, reducing fuel requirements, minimizing uncontrollable foaming, and enabling the recovery of lead and sulphur dioxide, thus providing a viable treatment route for previously challenging residues.
Implementation Method 1
elemental sulphur burns in the furnace to form sulphur dioxide
Implementation Method 2
lead in the solid material is oxidised and reports to the slag
Data Source
AI summary
A process for treating a solid material containing lead and elemental, sulphur, the process comprising feeding the solid material to a furnace containing a bath of molten slag under conditions such that elemental sulphur burns in the furnace to form sulphur dioxide and lead in the solid material is oxidised and reports to the slag, removing a gas stream containing sulphur dioxide from the furnace, and removing a lead-containing slag from the furnace.