Feldspar Benefication Process

Feldspar is a commonly occurring aluminosilicate mineral that contains calcium, sodium, and potassium. There are various types of feldspar, including orthoclase (potassium feldspar), albite, anorthite, micro plagioclase, sanidine, and more. To process feldspar for beneficiation, magnetic and flotation separation techniques are predominantly utilized.

Magnetic separation is employed to separate iron minerals, biotite, tourmaline, and other magnetic minerals from feldspar ore. This process effectively eliminates magnetic impurities.

Flotation separation, on the other hand, is utilized to remove iron and titanium minerals from potassium feldspar. It not only achieves this but also facilitates the separation of feldspar and quartz, improving the quality of the feldspar concentrate.

The common feldspar beneficiation process flow can be categorized into the following four types, depending on the type of ore deposit:

1. High-quality feldspar produced in pegmatite: Hand selection – Crushing – Wet grinding – Classifying.
2. Feldspar in weathered granite: Washing – Crushing – Grinding – Classification – Flotation (removal of iron and mica or separation of feldspar and quartz).
3. Feldspar in fine crystal rock: Crushing – Grinding – Screening – Magnetic separation.
4. Feldsparous placer: Washing mud – Screening or flotation to separate quartz.

Iron minerals are often present as impurities in feldspar ore and can significantly impact the quality of the feldspar concentrate, affecting its color and overall quality. Therefore, the removal of iron is an important step in feldspar beneficiation.

Feldspar Mining Process

1. Ore washing: This step aims to remove impurities like clay, fine mud, and mica from potassium feldspar. It helps reduce the content of ferric oxide and increase the levels of potassium and sodium. Ore washing is suitable for separating weathered granite or feldspar placer.
2. Crushing & screening: Coarse and fine crushing of feldspar is done using a crusher, followed by screening with a vibrating screen. This stage ensures that the ore particles are of the desired size for the subsequent processing.
3. Grinding & classifying: Feldspar ore is ground to the required particle size for further processing. Grinding can be performed either as dry grinding or wet grinding, depending on the technology requirements and feldspar properties.
4. Separation stage: The appropriate beneficiation process is selected based on the nature of the ore.

• Strong magnetic separation process is used for weak magnetic minerals like iron oxide, mica, and garnet present in potassium feldspar ore.
• When the iron-containing impurities in potassium feldspar are pyrite, mica, iron-containing alkali metal silicate minerals (such as garnet and tourmaline), or when potassium feldspar contains non-magnetic impurities, flotation is often employed.
• Potassium feldspar with fine-grained or iron-stained refractory impurities requires combined processes such as flotation-magnetic separation or scrubbing-magnetic separation-flotation.

Feldspar Processing Plant

1. Feldspar Flotation + Magnetic Separation Process

The raw feldspar ore contains impurities such as iron, calcium, and mica. To obtain high-grade feldspar, the ore dressing process involves magnetic separation, flotation, or gravity separation to remove these impurities. This ensures that the final product is of high quality and suitable for various applications.

1. Crushing section: Use coarse jaw crusher, fine jaw crusher, and vibrating screen to crush the raw ore down to a size of 20mm from the initial 200mm.
2. Grinding section: Utilize a ball mill and spiral classifier to create a closed grinding circuit, achieving a discharge size of more than 90% passing 200 mesh (0.074mm).
3. Magnetic separation: Low-intensity magnetic separators are used to remove magnetite (Fe3O4), while high-intensity magnetic separation removes hematite, limonite, and ilmenite (Fe2O3).
4. Flotation separation: The flotation process is employed to further remove impurities from the feldspar ore, obtaining a high-grade feldspar concentrate.
5. Dewatering of the concentrate: The concentrate is sent to a thickener using a slurry pump. The overflow from the thickener is directed to a clear water pond, while the underflow is dehydrated using a disc filter machine. The moisture concentration of the dehydrated concentrate is reduced to less than 10%.
6. Tailing dry disposal process: All tailings are pumped to a cone thickener to adjust the concentration. The overflow from the cone thickener is directed to a recycled clear water pond, and the underflow is dehydrated using a plate filter machine. Finally, the moisture content of the tailings is reduced to less than 10% through the dry stacking tailings process.

2. Feldspar Grinding + Magnetic Separation Plant

• Jaw crusher
• Ball mill
• Spiral classifier
• High-intensity magnetic separator
• Trommel scrubber

1. Crushing stage: Raw ore is crushed using a jaw crusher and then further crushed using a fine jaw crusher to ensure the particle size meets the requirements for the next stage.
2. Grinding stage: The crushed material is transferred to a powder silo and then sent to a ball mill and classifier for closed-circuit grinding. Coarse particles are sent back to the ball mill for further grinding.
3. Magnetic separation: The material is subjected to high-intensity magnetic separation to separate impurities. The soil is washed by a trommel scrubber to obtain qualified feldspar powder, which is then transported to the finished product warehouse via a belt conveyor.