Complete Production Process of Fluorite Powder by Flotation Method
Complete Production Process of Fluorite Powder by Flotation Method
1. Process Principle
2. Complete Process Flow
(1) Crushing Section
Large lump fluorite raw ore is coarsely crushed by jaw crusher.
Secondary fine crushing is carried out via cone crusher or hammer crusher, followed by screening to control particle size and produce uniform ore grains of 10–25 mm.
Pre-screening removes massive clay crusts and waste rock host rock in advance to mitigate interference from argillization.
(2) Grinding and Liberation Section
Crushed ore is fed into a ball mill for wet grinding down to around 200 mesh.
Purpose: Fully liberate fluorite crystals from gangue such as quartz and calcite; only liberated monomer particles can be effectively separated.
Closed-circuit circulation with classifier: coarse particles are sent back for regrinding to maintain consistent and stable fineness.
(3) Pulp Conditioning and Reagent Addition (Key Step)
Regulators (soda ash, sulfuric acid): control pH value and depress the flotation of calcite and quartz.
Depressants: suppress barite and silicate impurities to prevent them from floating together with fluorite.
Collectors (oleic acid series, fatty acid reagents): coat fluorite particle surfaces to endow fluorite with hydrophobic property.
Frothers: generate fine and stable air bubbles to carry floating fluorite particles.
Sufficient agitation ensures full reaction between reagents and mineral surfaces.
(4) Rough Flotation
Conditioned pulp is pumped into flotation cells; aeration and stirring generate abundant bubbles.
Hydrophobic fluorite adheres to bubbles and floats up to form a froth layer on the surface.
Bottom pulp containing large amounts of quartz, clay and waste gangue is discharged directly as tailings.
Froth from rough flotation is medium-to-high grade rough fluorite concentrate.
(5) Multi-stage Cleaning and Purification (Mandatory for Glass-Grade Powder)
Rough concentrate froth flows into 2 to 4 stages of cleaning flotation cells.
Reagent dosage is fine-tuned step by step to deeply strip fine entrained impurities of quartz and calcite.
After multiple cleaning cycles, CaF₂ purity stably reaches 95%–97%, with harmful impurities (iron, silicon, sulfur) reduced to ultra-low levels, meeting quality standards for glass and ceramics.
Minor middlings from the bottom of cleaning cells are recycled back to previous processes for recovery to boost overall recovery rate.
(6) Dewatering and Filter Pressing
High-grade fluorite froth concentrate is collected and sent to thickener tanks for sedimentation to remove most free water.
High-pressure filter press squeezes and dewaters the slurry; moisture content of filter cake is controlled at 8%–12%.
(7) Drying, Ultrafine Milling, Screening and Packaging
Filter cake is fed into drying kiln to lower moisture further.
Ultrafine pulverizer breaks up and grinds dried cake into fine powder.
Vibrating screen classifies powder into standard fineness grades (325 mesh, 400 mesh, etc.).
Iron removal and impurity elimination are conducted before bagging and warehousing as finished glass-specific fluorite powder.
3. Advantages of Flotation Process
Strong purification capacity: High-purity powder with CaF₂ over 95% can be produced even from low-grade raw ore.
Precise impurity control: Extremely low content of iron, silicon dioxide and sulfur, complying with strict requirements of float glass and ultra-clear glass.
Large production capacity, suitable for continuous mass industrial production.
Adjustable fineness: Custom powder sizes ranging from 200 mesh to 1250 mesh are available on demand.
4. Applicable Product Grades
Glass-grade fluorite powder: CaF₂ ≥95%, low iron and low silicon content
Acid-grade fluorite powder: CaF₂ ≥97%, used for hydrofluoric acid and chemical industry
Metallurgical-grade fluorite powder: Lower purity requirement, producible via simplified flotation flowsheet