The green transformation of quartz sand production: Membrane analysis technology drives resource recycling and cost reduction and efficiency improvement

Against the backdrop of the continuous growth in global demand for high-purity quartz sand in the semiconductor and photovoltaic industries, the problems of waste acid and wastewater treatment generated in the traditional quartz sand production process have become increasingly prominent. Membrane chromatography technology, with its low energy consumption and high selectivity in separation, has achieved the dual goals of resource recycling and environmental protection and cost reduction in the acid washing and purification process of quartz sand. This article, in light of the latest industry advancements, systematically expounds the core application scenarios and economic benefits of membrane analysis technology in quartz sand production.

I. Technical Principles and Their Applicability in Quartz Sand Production

Membrane chromatography technology is based on a membrane separation mechanism driven by concentration gradients. It utilizes the selective permeability of anion and cation exchange membranes to achieve directional separation of acids, bases, and metal ions. In the treatment of quartz sand acid washing waste liquid, this technology has the following advantages:

Precise separation capability: Anion exchange membranes can effectively retain metal ions such as Fe²⁺ and Al³⁺, while allowing H⁺ and SO₄²⁻ to pass through, achieving effective separation of acid solutions from metal impurities. For instance, a certain enterprise adopted membrane chromatography technology to treat pickling waste liquid containing 12% sulfuric acid, achieving a purity of 18% for the recovered acid and a metal ion retention rate exceeding 92%.

Low energy consumption operation: This technology does not require an external electric field or high-temperature and high-pressure conditions. It only relies on concentration differences to drive substance migration. The equipment investment is 40% lower than that of electrodialysis, and the operating cost is only one-third of that of the chemical precipitation method.

Good process compatibility: Membrane chromatography technology can be seamlessly integrated with processes such as acid leaching and flotation of quartz sand. For instance, the ratchet membrane structure developed by Henan GCL Company has increased the dialysis efficiency by 30% and reduced the acid washing cost per ton of quartz sand by 28 yuan by increasing the contact area between waste acid and the membrane.

Ii. Core Application Scenarios and Economic Value

Resource utilization of pickling waste liquid

Typical case: A certain photovoltaic quartz sand production enterprise processes 150,000 tons of waste acid annually. After adopting membrane chromatography technology:

The acid recovery rate has reached 85%, and the concentration of recovered acid has increased from 12% to 18%, which can be directly reused in the acid leaching process.

After crystallization treatment of the retained FeSO₄ residual liquid, 12,000 tons of FeSO₄·7H₂O products were sold annually, increasing revenue by 4.8 million yuan.

The environmental benefits are remarkable. The cost of hazardous waste disposal has dropped from 800 yuan per ton to 120 yuan per ton, and the annual reduction of CO₂ is 12,000 tons.

In terms of technological breakthroughs, through the optimized design of membrane modules, the dialysis time has been shortened from 4 hours to 2.5 hours, and the processing capacity has been increased to 20m³/h, meeting the demands of large-scale continuous production.

Construction of a fluorine resource recycling system

Membrane separation technology can achieve efficient recovery of fluorine resources for the treatment of fluorine-containing waste liquid in the production of high-purity quartz sand.

After membrane separation treatment, the waste liquid generates a mixed acid containing HF, HCl and HNO₃.

Sodium fluoride is added and heated to 55 ° C. After cooling, Na₂SiF₆ crystals are formed.

The crystal is pyrolyzed at 155℃ to generate HF gas. After condensation, hydrofluoric acid with a purity of ≥99.5% is obtained, which can be directly used in the acid leaching process of quartz sand.

Economic analysis shows that a certain enterprise recovers 1,200 tons of fluorine resources annually, saving 7.2 million yuan in the procurement cost of hydrofluoric acid and reducing the disposal cost of fluorine-containing hazardous waste by 3.6 million yuan at the same time.

Multi-metal collaborative recycling system

In the production of quartz sand containing rare earth elements, membrane separation technology can achieve the synchronous separation of acid solution and rare earth metals:

It adopts a dual-membrane system design, with the anion membrane recovering acid solution and the cation membrane retaining rare earth ions such as La³⁺ and Ce⁴⁺.

By optimizing the process parameters (dialysis temperature of 35℃ and flow rate of 0.8m/s), the rare earth recovery rate reached 95% and the acid recovery rate was 88%.

The annual output value of the recovered rare earth oxides exceeds 20 million yuan, forming a closed-loop economic model of "quartz sand - acid washing - rare earth recovery".

Iii. Future Trends: Integration of Intelligence and Circular Economy

Internet of Things integration: By embedding RFID chips in membrane modules, data can be tracked and processed in real time and financial reports can be automatically generated, shortening the capital recovery cycle by 30%.

Blockchain application: Building an acid trading platform, enterprises can directly sell recycled acid, reducing the cost of intermediate links by 15%.

Zero-emission factory: By integrating membrane separation and membrane distillation technologies, it achieves full recovery of water, acid and metal, reducing the production cost per ton of quartz sand by 120 yuan.

It is predicted that by 2028, the coverage rate of membrane analysis technology in China's quartz sand industry will reach 70%, saving more than 5 billion yuan in acid procurement costs annually. Enterprises should transform from traditional "pollutant processors" to "resource managers", and build a three-dimensional collaborative circular economy model of "acid - metal - capital" through membrane analysis technology to seize the initiative in the green transformation.