CO2 Sparged Flotation for Acid-Consuming Carbonate Minerals
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Solution Overview
Problem
Processing of precious metal refractory sulfide mineral materials containing acid-consuming carbonate poses challenges in flotation and oxidative treatment, as high carbonate concentrations consume sulfuric acid, interfere with reaction processes, and lead to precipitation issues that complicate flotation and filtration.
Innovation Solution
The method involves subjecting the mineral material to acidic flotation using a carbon dioxide-containing gas to adjust the pH without decomposing the carbonate, which reduces the interference of acid-consuming carbonates and minimizes acid consumption, allowing for effective flotation and post-flotation processing without pre-treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sulfuric acid is added to adjust pH for flotation, then flotation effectiveness is improved, but acid consumption increases significantly due to carbonate decomposition
Solution Approach 1:
Carbon dioxide is introduced as an intermediary substance to adjust pH instead of using sulfuric acid directly. The CO2 dissolves in water to form carbonic acid, which provides the necessary acidic conditions for flotation without causing extensive carbonate decomposition and acid consumption
Solution Approach 2:
The pH adjustment mechanism is changed from direct acid addition to carbonic acid formation through CO2 dissolution. This parameter change allows pH control while avoiding the harmful side effects of strong acid consumption and excessive carbonate decomposition
2Object-affected harmful factors
If sulfuric acid is used to decompose carbonates before flotation, then carbonate interference is reduced, but processing cost increases significantly
Solution Approach 1:
Instead of decomposing carbonates to remove them, the process allows carbonates to remain and uses CO2-sparged flotation to achieve flotation effectiveness. The carbonates that would normally be harmful are effectively managed through the CO2 atmosphere, converting a potentially harmful situation into a workable process
Solution Approach 2:
Rather than completely decomposing all carbonates through acid treatment, the process uses partial carbonation control through CO2 sparging during flotation, achieving sufficient pH control and flotation performance without the excessive acid consumption and cost of complete carbonate decomposition
3Ease of operation
If acidification is performed to prepare for flotation, then pH is adjusted to desired level, but fine precipitate formation occurs causing filtration problems
Solution Approach 1:
Carbon dioxide serves as an intermediary for pH adjustment that does not produce the fine precipitate problems associated with sulfuric acid addition. The CO2-based pH control avoids the formation of problematic calcium sulfate and other acid-soluble salt precipitates that complicate filtration
Solution Approach 2:
The process uses carbonic acid formed from CO2 as a temporary, easily manageable pH adjuster that does not leave behind persistent precipitate problems. The carbonic acid system is more easily handled and does not create long-term filtration issues compared to sulfuric acid-based systems
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 efficient flotation of sulfide concentrates with reduced acid consumption and minimized precipitation issues, facilitating the recovery of precious metals while maintaining the carbonate in the tailings, thus reducing processing costs and complications.
Implementation Method 1
Carbon dioxide in the gas may dissolve into the slurry liquid and form carbonic acid and reduce the pH of the slurry
Implementation Method 2
flotation processing including flotation of the mineral material in aqueous liquid medium at a pH less than pH 7 with flotation gas to prepare a flotation concentrate enriched in sulfide minerals
Implementation Method 3
oxygen gas reacts with sulfide sulfur resulting in decomposition of sulfide minerals and generation of sulfuric acid. The sulfide sulfur oxidation is exothermic
Implementation Method 4
Many carbonate minerals, for example calcite, magnesite, siderite and dolomite, will react with sulfuric acid resulting in decomposition of the carbonate, generation of carbon dioxide and formation of sulfate salts
Data Source
AI summary
Processing of mineral material containing precious metal with one or more sulfide minerals and non-sulfide gangue minerals including acid-consuming carbonate may include preparation of a sulfide concentrate by flotation with the flotation or conditioning prior to flotation using a gas comprising carbon dioxide. Flotation may be at an acidic pH without prior decomposition of the acid-consuming carbonate and may be without addition of acid for pH adjustment.