Ore Slurry Heating via Molten Salt Heat Transfer
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Solution Overview
Problem
The existing high-temperature leaching processes for ore processing are laborious and costly due to inefficient stepwise heat recovery and dilution of the ore suspension during steam injection, leading to increased evaporation requirements in downstream processes.
Innovation Solution
The use of molten salt, thermal oil, or water as heat transfer mediums in a system with pre-heating and final heating exchangers arranged in series, along with a circulation system for efficient thermal energy transfer, minimizes heat transfer surfaces and maintains high temperatures without diluting the ore slurry, allowing for controlled heating and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If stepwise decompression of hot suspension is used for heat recovery, then cooling of suspension is achieved, but the process becomes laborious and costly
Solution Approach 1:
A heat transfer medium is introduced as an intermediary substance to facilitate heat exchange between the hot ore suspension and the cooling system. The heat transfer medium absorbs heat from the suspension in a heat exchanger and transports it to generate steam, avoiding direct stepwise decompression while achieving efficient heat recovery and steam generation simultaneously
Solution Approach 2:
The mechanical stepwise decompression process is replaced by a thermal field-based heat exchange system using heat transfer medium and heat exchangers. This substitution eliminates the need for complex pressure control stages while maintaining effective heat recovery and cooling functions
2Temperature
If steam is directly injected into suspension for final heating, then heating is achieved, but the suspension is diluted requiring increased evaporation capacity
Solution Approach 1:
A heat transfer medium serves as an intermediary for heat transfer to the suspension, replacing direct steam injection. The heat transfer medium transfers thermal energy through a heat exchanger without mixing with the suspension, achieving effective heating while preserving suspension concentration and eliminating the need for additional evaporation capacity
Solution Approach 2:
The heating process is segmented into indirect heat transfer through heat exchanger surfaces rather than direct steam injection. This separation allows heat to be transferred to the suspension without introducing water vapor that would cause dilution, maintaining process efficiency and suspension integrity
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 approach enables rapid and efficient heating and cooling of ore suspensions, reducing investment and maintenance costs, and maintaining high extraction yields while avoiding dilution, thus improving the efficiency and reliability of ore processing.
Implementation Method 1
heating ore slurry comprising ore and solvent by thermal energy of a first heat transfer medium in a pre-heating heat exchanger
Implementation Method 2
The heat exchangers use a non-scaling common liquid heat transfer medium
Implementation Method 3
cooling the reacted ore slurry by thermal energy of a first heat transfer medium in a cooling heat exchanger
Implementation Method 4
The heat exchangers use a non-scaling common liquid heat transfer medium
Implementation Method 5
molten salt is used as the heat transfer medium for the second heat transfer medium. This provides the advantage that the heating and cooling of the ore suspension takes place rapidly and with minimized heat transfer surfaces since molten salts allow for the operation at high temperatures without doing harm to the heat transfer medium
Data Source
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AI summary
A method and a system for pressurised leaching of ore. The method comprises: heating ore slurry comprising ore and solvent, reacting and holding the heated ore slurry at working temperature for leaching valuable species into the heated solvent, and cooling the ore slurry. The pre-heating of the ore slurry in a pre-heating step is realized by thermal energy of a first heat transfer medium. Said ore slurry is further heated in a final-heating step to said working temperature by thermal energy of a second heat transfer medium separate from the first heat transfer medium. The reacted ore slurry is cooled in a cooling step by absorbing the thermal energy of the reacted ore slurry to the first heat transfer medium. Said first heat transfer medium is circulated between the cooling step and the pre-heating step.