my country's iron ore resources have large reserves and are widely distributed, but a large part of them are low-grade refractory iron ore. The ore types are complex, the useful minerals and gangue minerals are seriously encapsulated and disseminated, and various iron minerals are associated. Comprehensive utilization rate lower. These refractory iron ores include siderite, limonite, oolitic hematite, composite iron ores, and the like.
01 Siderite beneficiation process
Siderite is a carbonate mineral of iron, with an iron content of 43.47%~48.27%. Roasting-magnetic separation method is a commonly used siderite beneficiation process. After neutral roasting, the siderite will decompose carbon dioxide, and the ore grade and the magnetic properties of the ore will be improved. Iron ore is enriched.
The single sorting process of gravity separation and strong magnetic separation can be used to treat single siderite with coarse grains, but it is difficult to obtain qualified concentrate products when sorting fine grained siderites. These two methods All of them can be used as a pretreatment method for siderite, which can improve the separation index of siderite. In addition, flotation can also be used in the combined process of siderite separation. As the main separation method of siderite, the main purpose is to flotate mixed iron minerals containing siderite.
02 Limonite beneficiation process
The iron content of limonite is generally 35% to 40%, and some can reach 50%. Gangue minerals contain harmful impurities such as sulfur and phosphorus. Due to the weak magnetic properties of limonite, strong magnetic separation can be used for separation. The single strong magnetic separation method is a relatively simple and economical method for limonite beneficiation. The ore grade will be greatly affected. The single gravity separation method can also select qualified limonite concentrate products, but the processing capacity of this method is , and it is more suitable for use in small limonite concentrators.
Because the moisture content of limonite varies greatly, some limonites are often rich in crystal water, and the ore grade can be effectively improved after roasting. For this type of ore, the limonite beneficiation method that can be used is magnetization roasting. - Weak magnetic separation method, on this basis, the reverse flotation method can be used to improve the separation index of limonite according to the nature and characteristics of the limonite deposit.
03 Oolitic hematite beneficiation process
The iron content of oolitic hematite is generally about 30%, and the iron minerals are embedded in very fine particle sizes. They are often symbiotic or encapsulated with siderite, oolitic chlorite and phosphorus-containing minerals, which are easy to muddy during the crushing and grinding process. It is easy to affect the subsequent selection operation.
Intensive magnetic separation can be used to classify oolitic hematite well and obtain a good recovery rate, but because its embedded particle size is too fine, it often fails to meet the requirements in terms of concentrate grade. Using gravity separation to treat oolitic hematite can obtain better concentrate grade, but its selected particle size cannot be too fine, and the recovery rate is low. Therefore, the oolitic hematite can be separated by the combination of strong magnetic separation and gravity separation under the appropriate grinding fineness.
Flotation method is also an effective method to separate oolitic hematite. Single flotation has a good separation effect on oolitic hematite with simple properties. For oolitic hematite with complex composition, flotation is required. A method used in conjunction with other sorting methods.
04 composite iron ore
Most iron ore contains two or more iron minerals, and this type of ore is called composite iron ore. When siderite, hematite, goethite, limonite, mirror iron ore and other weak magnetic separation ores coexist in iron ore, their physical and chemical properties and embedded particle size are different, and the selectivity is poor. At the same time, the gangue minerals of the composite iron ore are more complex, and the silicon content is relatively high. Its beneficiation methods include strong magnetic-weak magnetic-reverse flotation, weak magnetic-strong magnetic-classification-gravity-reverse flotation, desliming-reverse flotation, enhanced roasting-weak magnetic-reverse flotation, etc. The beneficiation process is mainly determined by the specific ore properties.
The above is about the content of the beneficiation process of refractory iron ore. With the deepening of the development of ore resources, the rational use of resources is very important. The editor hereby reminds everyone that ore analysis and beneficiation tests are required before determining the beneficiation process. Understand the properties and characteristics of the ore, and formulate the separation process scientifically and reasonably to obtain the ideal beneficiation index
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