Hydrofluoric Acid Production from Recovered Fluorite and Closed-Loop Fluorine Resource Recovery Technology (RF-HF^™)

Independently developed by Water Healer, the RF-HF^™ (Hydrofluoric Acid Production from Recovered Fluorite) technology uses synthetic fluorite powder produced from the resource recovery of fluoride-containing wastewater as feedstock. By overcoming the limitations of conventional fluorite powder acidification, it enables the production of high-purity Hydrofluoric Acid (HF) and the recovery of fluorine resources across the entire process chain. The technology effectively resolves the bottlenecks of conventional HF production, including feedstock shortages, clogging caused by ultrafine powder and unstable acidification reactions, delivering a low-carbon, high-efficiency and resource-oriented fluorochemical solution for the photovoltaic, semiconductor and chemical industries.

Technology Background and Challenges

Conventional hydrofluoric acid production relies mainly on acid-grade fluorite ore powder as feedstock (purity of approximately 97%, D50 = 200–300 mesh), with mature processes and standardized units. However, synthetic fluorite powder obtained from the resource recovery of fluoride-containing wastewater has a purity of only 88%–93% and a much finer particle size (D50 = 300–800 mesh). During acidification, it is prone to the following problems:

• Highly vigorous reactions that cause material entrainment, agglomeration and wall adhesion.
• Frequent blockage of production units and mechanical failures, resulting in a high downtime rate.
• Impacts on HF yield and on the ratio between 98% acid and 105% acid grades, limiting the application of synthetic fluorite powder in HF production.

Through systematic research and development, Water Healer has overcome the acidification challenges of ultrafine synthetic fluorite powder, achieving resource utilization together with high-purity HF output.

RF-HF^™ Core Process

Process Innovation

• Staged temperature control and gradient mixing, combined with enhanced spiral flow guidance and fluidization circulation. A turbulence-enhanced mass transfer mechanism inside the pre-reactor, together with a spiral guide structure optimized through simulation, raises the gas–liquid mass transfer coefficient, allowing 40%–45% of the acidolysis reaction to be completed in the pre-reaction zone and ensuring a controllable acidification rate.
• A multi-layer thermal field with high- and low-temperature zones is established inside the acidolysis furnace. Gradient temperature control regulates the reaction rate precisely; meanwhile, the study of material motion trajectories and pyrolysis reaction kinetics keeps the reaction process stable and efficient, avoiding wall adhesion and local overheating.
• Together, these measures make the acidification reaction controllable and uniform, resolving the violent reaction and wall adhesion problems associated with ultrafine powder.

Low Carbon and Energy Saving

• A gas–solid two-phase fluidization circulation system fluidizes and recycles fluorogypsum from the low-temperature zone to dilute high-temperature material, lowering the wall adhesion rate while supplying heat to the high-temperature reaction section, thereby saving energy and recovering thermal energy.
• A strict incoming material inspection system and an intelligent sulfuric acid dosing system precisely control the acid-to-material ratio and reaction conditions, ensuring that synthetic fluorite powder can replace ore powder as feedstock and delivering a stable HF yield.
• Gas–liquid mass transfer optimization, thermal energy recycling and efficient acid-to-material proportioning reduce energy consumption, raw material waste and production carbon emissions.

High-Efficiency Resource Recovery

• The technology achieves full-process-chain recovery of fluorine resources, converting calcium fluoride sludge directly into high-purity HF, with a comprehensive recovery rate above 92% and HF purity of up to 99.99%, significantly enhancing the industrial value of fluoride-containing waste.

Strong Applicability and Industrial Feasibility

• Compatible with synthetic fluorite powder of different particle sizes and purities; the modular unit design facilitates large-scale application, reduces the risk of production equipment downtime and ensures continuous operation.

Ecological and Environmental Value

• By recovering fluorine resources from fluoride-containing wastewater, the technology prevents fluorine from being discharged into the environment and enhances the sustainability of the photovoltaic and semiconductor industry chains.

Industry Applications and Demonstration Effect

RF-HF^™ technology can directly use the synthetic fluorite powder generated from fluoride-containing wastewater in the photovoltaic, semiconductor and chemical industries to produce high-purity HF and recover fluorine resources, linking the full industrial chain from wastewater treatment to resource recovery and high-value-added products. The technology not only addresses the structural shortage of fluorite resources in China, but also provides an economical, efficient and green industrial solution for fluoride-containing wastewater treatment.

Through RF-HF^™ technology, Water Healer has established an integrated closed loop of fluoride removal, resource recovery and high-purity HF preparation in the field of photovoltaic and semiconductor manufacturing wastewater treatment. Complementing its earlier ACFP^® and WH-CADF^® fluoride removal technologies, it further completes the industrial fluorine resource utilization system and creates significant technological barriers and competitive commercial advantages.