Copper oxide ores are an important mineral resource, and due to the unique properties of oxide minerals, their flotation process is quite complex. Understanding the flotation methods of copper oxide ores and their mixed ores is essential for improving copper recovery rates and economic efficiency. This article will provide a detailed introduction to the conventional flotation methods for copper oxide ores and discuss the characteristics of non-ferrous metal oxide ores and their impact on the flotation process.
1. Complex Structure: Non-ferrous metal oxide ores have a complex structure and fine-grained dissemination, making them difficult to liberate during fine grinding, which often leads to the formation of slimes.
2. Diverse Composition: These ores often contain multiple types of oxide minerals within the same deposit, resulting in significant differences in floatability.
3. High Mud and Soluble Salts Content: These ores typically contain a large amount of mud and soluble salts.
4. Variable Properties: The properties of non-ferrous oxide ores vary greatly between different deposits, including differences in the degree of oxidation and ore characteristics.
Due to these characteristics, the flotation process of oxide ores is relatively difficult. Common types of copper oxide minerals include malachite, azurite, followed by chrysocolla and cuprite.
1. Sulphidization Flotation: This is a common and straightforward process. Any oxidized copper ore that can be sulphidized can be processed using this method. Sulphidized oxidized minerals can be floated with xanthate collectors. The amount of sodium sulfide used for sulphidization should be controlled based on the amount of raw ore. Sodium sulfide and other sulphidizing agents should be added to the slurry in batches without prior mixing, as the sulphide film formed is unstable and can detach under intense agitation. The sulphidization rate increases as the slurry pH decreases. When the slurry contains a lot of mud, a dispersant such as sodium silicate should be added. Collectors like butyl xanthate or a combination of black reagents can be used for collection. The slurry pH should be maintained around 9, and if it drops too low, lime should be added for adjustment.
2.Organic Acid Flotation: This method can be used for the flotation of malachite and azurite. When gangue minerals are not carbonate minerals, this method can be used to treat non-ferrous metal oxide ores. Otherwise, the flotation selectivity is lost. If the gangue minerals contain a lot of floatable iron and manganese minerals, the flotation selectivity is lost, affecting the flotation indices. When using organic acid collectors, gangue mineral depressants (such as sodium carbonate, sodium silicate, and phosphates) and pH regulators should be added. Some concentrators also use a combined flotation method of sulphidization and organic acid flotation, first floating sulphide copper and part of the oxidized copper, then using organic acid to float the remaining oxidized copper.
3. Leaching-Precipitation-Flotation: This method is used when sulphidization and organic acid flotation are ineffective. Oxidized copper minerals dissolve easily and can be leached with sulfuric acid. The dissolved copper can be precipitated with iron powder, and the precipitated copper can then be floated. This method requires the ore to be ground to liberation, depending on the mineral particle size. A dilute sulfuric acid solution is used for leaching, with the amount adjusted based on ore properties. For difficult-to-leach ores, heating may be used to improve leaching efficiency. The entire flotation process is conducted in an acidic medium, and cresylic acid or di-xanthate can be used as collectors for copper.
4. Ammonia Leaching-Sulphidization-Flotation: For ores with a high content of basic minerals, acid leaching increases reagent consumption and production costs. Therefore, concentrators generally use ammonia leaching. After fine grinding, sulfur powder is added for ammonia leaching. Ammonia and carbon dioxide react with copper ions in oxidized copper ores, forming new sulphide copper particles, which are then floated. The pH of the slurry is maintained at 6.5-7.5. Standard sulphide copper flotation reagents are used, and the ammonia generated during the process should be promptly recovered to prevent environmental pollution.
5. Separation-Flotation: The ore of suitable particle size is mixed with coal powder and salt, then subjected to chloridizing reduction roasting at 700-800°C. Chloridized copper evaporates and is reduced to metallic copper, adsorbed onto coal particles, which are then floated to obtain the concentrate. This method is mainly used for refractory copper oxide ores and ores with high malachite and cuprite content, and it is particularly effective for ores with a high mud content.
6. Mixed Copper Ore Flotation: The flotation process for these ores should be determined based on beneficiation tests. The flotation process can involve floating sulphide and oxidized minerals together, or first floating sulphide minerals, followed by floating oxidized minerals from the tailings. The conditions for floating oxidized and sulphide copper minerals are similar, but as the content of oxides decreases, the amounts of sodium sulfide and collectors should be reduced accordingly.
In summary, there are many flotation methods for copper oxide ores, each with its applicable ore types and process characteristics. Choosing and optimizing these methods based on the specific ore properties and flotation indices can effectively improve the recovery rate and concentrate grade of copper oxide ores, maximizing economic benefits.
Y&X Beijing Technology Co., Ltd. is a dedicated provider of beneficiation solutions for metal mines, specializing in efficient and environmentally friendly reagents. With extensive experience in copper, molybdenum, gold, silver, lead, zinc, nickel, magnesium, rare metals like cobalt and palladium, and non-metallic ores like bismuth, fluorite, and phosphate, we offer customized solutions tailored to the specific nature of your ore and production conditions. Our goal is to ensure maximum benefits for our customers through advanced beneficiation methods and high-efficiency reagents. Y&X is committed to providing one-stop beneficiation solutions and looks forward to a successful partnership with you.
