The processing of feldspars and quartzites from rocks involves several steps that include mineral separation, crushing, grinding, and sometimes additional refining processes to obtain the desired purity and quality. Here are the common methods:
Feldspars
-
Mining:
- Open-pit mining: Feldspars are usually mined from large open pits.
- Drilling and blasting: The rocks are typically drilled and blasted to break them into manageable pieces.
-
Crushing and Grinding:
- Primary Crushing: Large chunks of feldspar ore are crushed into smaller pieces using jaw crushers.
- Secondary Crushing and Grinding: Further reduction in size using cone crushers and ball mills.
-
Separation:
- Magnetic Separation: Removes magnetic impurities like iron.
- Flotation: Typically used to separate feldspar from quartz and other minerals. Reagents and frothing agents are added to the crushed ore, causing feldspar to attach to bubbles and float to the surface for collection.
-
Dewatering:
- Thickening and Filtering: Removed water from the flotation concentrates using thickeners and filters.
-
Drying:
- Rotary or Fluid Bed Dryers: Remove any remaining moisture from the dried feldspar concentrate.
-
Final Processing:
- Screening and Classification: The material is screened and classified based on particle size.
- High-Intensity Magnetic Separation: Sometimes used to further purify feldspar by removing remaining iron or other impurities.
Quartzites
-
Mining:
- Open-pit mining: Quartzites are typically mined from surface quarries.
- Excavation: Methods include the use of heavy machinery to excavate and transport the rock.
-
Crushing and Grinding:
- Primary Crushing: Large blocks are broken down using jaw crushers.
- Secondary Crushing and Grinding: Further size reduction using cone crushers, rod mills, or ball mills.
-
Separation:
- Magnetic Separation: Removes iron-bearing minerals.
- Washing and Desliming: Removes fine particles and clay impurities.
- Gravity Separation: Sometimes used to separate quartz from associated heavy minerals.
-
Purification:
- Leaching with Acids: Removes impurities such as iron oxide.
- Thermal Treatment: Heating to high temperatures to further purify the quartz.
-
Dewatering:
- Thickening and Filtering: Removes excess water from the concentrated quartz.
-
Drying:
- Rotary Dryers or Fluid Bed Dryers: Dry the quartz concentrate.
-
Final Processing:
- Screening and Classification: The material is screened and classified for specific applications.
- High-purity Processing: Additional refining steps such as ultra-pure acid leaching or silicon dioxide production for high-tech applications like semiconductors.
Each step in the processing of feldspars and quartzites can vary depending on the specific characteristics of the ore and the desired final product. The techniques and technologies employed are designed to maximize recovery and improve the quality of the minerals for their intended industrial uses.
