The methods for the beneficiation and processing of fluorite ore are primarily selected based on the type of ore, ore composition, and its grade. In China, the methods for fluorite ore beneficiation include manual selection, gravity separation (using jig machines), and flotation.
Manual selection is mainly used when there is a clear boundary between fluorite and gangue minerals, and it is easy to separate waste rock. It is a simple and cost-effective beneficiation method.
The manual selection process typically involves the following steps:
Raw ore
Washing
Screening
Hand sorting
After washing and screening, the raw ore is divided into large chunks, medium-sized pieces, and particles (with a particle size of 6-15mm), which are then manually sorted according to their grade. The particles are processed in a jig machine to separate the gangue, while the lumps go to the flotation plant for further processing into fluorite concentrate.
Gravity separation, mainly using jig machines, is applied when dealing with fluorite ore of higher grade and particle sizes ranging from 6 to 20mm. Gravity separation has the advantages of a simple structure, ease of operation, and high efficiency. It is widely used in mines with a large quantity of particle ore and higher ore grade.
Fluorite lumps obtained through manual selection and gravity separation are mainly used for metallurgical purposes, known as metallurgical-grade lumps.
Flotation, also known as floatation, is a widely adopted beneficiation method for fluorite ore in both domestic and international mining operations. It is used for obtaining high-quality fluorite (fluorspar) concentrates, regardless of whether the ore is pure fluorite or associated with other minerals. This includes both simple and complex fluorite ore structures.
The flotation process usually consists of three main stages: crushing, grinding, and dewatering.
The typical flotation process is a three-stage closed-loop system. Small-scale mines may use a three-stage or two-stage open-loop process. The number of grinding cycles depends on the particle size and mineral association. When minerals are finely disseminated and separation is challenging, a second grinding cycle may be employed. For other ores, a single grinding cycle is sufficient.
The choice of flotation process depends on the ore's characteristics, whether it is pure fluorite or associated fluorite ore.
For pure fluorite ore, the beneficiation process generally involves roughing and scavenging, followed by 5-6 stages of cleaning.
For associated fluorite ores, the flotation process may first separate the multi-metal minerals before concentrating on fluorite. The flotation process for associated fluorite ore is the same as that for pure fluorite ore.
Flotation processes use ore beneficiation reagents as collectors for valuable minerals, depressants to suppress impurities, and pH modifiers for adjusting pH levels. Commonly used flotation reagents for fluorite flotation include oleic acid, caustic soda, sodium silicate, aluminum sulfate, and zinc sulfate, among others.
The dewatering process for fluorite concentrates consists of three stages: concentration, filtration, and drying. Exported fluorite concentrates typically do not require a drying process and only need to be filtered to ensure a water content below 10%. However, for some domestic manufacturers producing hydrofluoric acid using acid-grade fluorspar concentrates, the concentrates need to be dried to achieve a water content of less than 0.5%.
The above information provides an overview of three common methods and processing flows for fluorite ore beneficiation. The specific method chosen should be determined through ore beneficiation testing, and often a combination of methods is required to obtain high-quality fluorite concentrates.
