Beginner's Guide to Quartz Ore Processing

silica sand washing plant in site

The core component of quartz ore is silicon dioxide (SiO₂), an indispensable basic raw material for modern industry. This article systematically introduces the complete beneficiation process from common quartzite to high-purity quartz sand. Through a combination of physical and chemical methods—including crushing, scrubbing, magnetic separation, flotation, and acid leaching—impurities such as iron and aluminum are efficiently removed. The final products meet varying purity requirements for industries such as glass, electronics, and photovoltaics. In the future, this technology is advancing towards greener fluorine-free processes, intelligent control, and comprehensive resource utilization.

1. Chemical Composition

• Silicon dioxide (SiO₂) is the fundamental component, with a crystal structure of silicon-oxygen tetrahedra and stable chemical properties.

• It often contains minor impurities (e.g., aluminum, iron, calcium, sodium, etc.), which can affect the color and application of quartz.

2. Physical Properties

• High hardness, wear-resistant, and corrosion-resistant.

• High melting point and good insulating properties.

• Typically colorless or white; can appear purple, pink, yellow, etc., when containing impurities.

3. Main Types

(1) Natural Quartz Ore

• Includes crystal, agate, flint, quartzite, etc.

(2) Quartz for Industrial Use

• Usually refers to high-purity quartz sand or quartzite, used in glass, ceramics, metallurgy, and other industries.

1. Gravity Separation

（1）Purpose

• To separate heavy mineral impurities (e.g., zircon, garnet, hematite, ilmenite) and light mineral impurities (e.g., weathered feldspar, flaky mica) that have significant density differences from quartz.

2. Magnetic Separation

(1) Purpose

• To remove iron-bearing magnetic minerals (magnetite, hematite, ilmenite, etc.) and weakly magnetic iron minerals, as well as minerals contaminated with iron.

(2) Processes

• Strong Magnetic Separation

• High-Gradient Magnetic Separation

3. Flotation

(1)Purpose

• To separate non-magnetic impurities with similar surface physicochemical properties to quartz, particularly feldspar and mica.

(2) Key Processes

• HF Method

• Fluorine-Free Flotation Method

• Acidic Fluorine-Free Method

• Alkaline Fluorine-Free Method

• Mica Flotation

4. Acid Leaching

(1) Purpose

• To remove non-structural impurities such as iron and aluminum encapsulated on the surface or within micro-cracks of quartz particles. It is the final deep purification step for obtaining high-purity/ultra-high-purity quartz (SiO₂ > 99.99%).

(2) Process

• Quartz sand is immersed in a hot mixed-acid solution for several hours to dissolve insoluble impurities, followed by repeated washing with high-purity water until neutral.

1. Crushing and Grinding Equipment

(1) Jaw Crusher

(2) Cone Crusher

(3) Rod Mill / Ball Mill

2. Classification and Desliming Equipment

(1) Hydrocyclone

(2) Spiral Classifier

3. Scrubbing and Pretreatment Equipment

(1) Trough Scrubber

(2) Drum Scrubber

4. Gravity Separation Equipment

(1) Spiral Chute

(2) Shaking Table

5. Magnetic Separation Equipment

(1) Permanent Magnetic Drum Separator

(2) Permanent Magnetic Roller High-Intensity Magnetic Separator

(3) High-Gradient Magnetic Separator

6. Flotation Equipment

(1) Mechanical Agitation Flotation Machine

(2) Flotation Column

7. Dewatering and Drying Equipment

(1) Dewatering Screen / High-Frequency Fine Screen

(2) Disc Vacuum Filter / Filter Press

(3) Rotary Dryer / Fluidized Bed Dryer

Quartz ore beneficiation is a physical-chemical combined process centered on "impurity removal and purification." Through established processes—including crushing, grinding, scrubbing, magnetic separation, flotation, and acid leaching—impurities such as iron and aluminum are systematically removed to ultimately obtain quartz products of various purity grades. In the future, this field will focus on the preparation of ultra-high-purity quartz for photovoltaics and semiconductors, advancing towards greener fluorine-free processes, intelligent control, and comprehensive resource utilization. This evolution will drive the industry toward a more efficient, clean, high-value, and sustainable development model.