Quartz Crucible Production Wastewater Treatment: Arc Fusion Wash, Acid Leaching and Silica Fines

Quartz crucibles are made by fusing high-purity quartz sand in an arc furnace, shaping the transparent silica, and leaching the surface to remove the impurities that would contaminate a silicon melt. The water that leaves is a high-purity materials effluent. Fusion and shaping wash water carries the ultra-fine silica fraction, which is the finest solid in the plant. Acid leaching adds the chemical stream that gives the crucible its purity. Surface treatment and cleaning adds the traces that the semiconductor grade demands. The effluent is acidic in places, loaded with a very fine solid, and chemically active, and the design that works neutralises early, removes the fines with coagulation and flotation, and returns the recovered water to the washing circuit.

Where the Water Comes From

Fusion and shaping wash water carries the ultra-fine silica fraction. It is the finest solid in the plant, and it settles slower than anything else in the stream.

Acid leaching adds the chemical stream that gives the crucible its purity, and it is the most acidic water in the plant. If your site also runs this kind of duty, Titanium Dioxide Pigment effluent covers the cost side of the decision in more depth.

Surface treatment and cleaning adds the traces that the semiconductor grade demands, small in volume and chemically active.

Floor and equipment washing adds volume rather than load, and its contribution is the hydraulic design of the whole plant.

Neutralisation First

pH correction comes before anything else. Lime dosing lifts the acidic water above the range where the downstream chemistry works, and the mixing has to be real.

Neutralisation also precipitates a share of the dissolved metals, which joins the solids in the thickener rather than travelling to the outfall. If your site also runs this kind of duty, Black Mass, Electrolyte and Metal Removal covers the cost side of the decision in more depth.

The neutralisation point is where the plant sees the truth about its own variability, and operators who sample there know their real peaks.

Very Fine Solids

The ultra-fine silica fraction is removed with coagulation. A polyelectrolyte sweep at controlled pH collapses the fines into a floc that settles or floats, and the step is specified with the blinding problem in mind.

What This Looks Like in Practice

For comparison, our 2021 project in Taishan, Guangdong ran at 5 m³/day with influent COD near 1,000 mg/L and treated water around 50 mg/L. That is 95% removal in practice, not on paper.

Figures are site-measured values from commissioned plants, not modelled estimates.

Dissolved-air flotation lifts the light fraction, and a settling or thickening step handles the dense fraction, and the two are sized on the actual particle distribution rather than on an assumed one.

The recovered solids are collected rather than washed back into the drain, and the filter cloth is a consumable in this industry. Where several streams need joint treatment, Ammonium, Fluoride and Radioactive Residue is the more detailed reference.

The clarified water is the plant's best candidate for reuse in the washing circuit, and the loop is easy to close because that duty accepts water of modest quality. Much of this mirrors the situation set out in Aluminium Anodizing effluent.

The discharge, where it still exists, is the final polishing step: clarified, pH-corrected and monitored, and its quality is a report card on the upstream recovery rather than a design target of its own.

Where the recovery target is high, a membrane step polishes the clarified water, and the concentrate from that step returns to the neutralisation circuit rather than becoming a new problem.

Operating Notes

Neutralise early. Acidic water into a thickener is a slow, expensive way to learn about pH. The same selection criteria reappear in Phosphoric Acid Plant Wastewater Treatment system, which is worth opening alongside this one.

Coagulate the fines before anything biological. Particles this fine blind membranes and smother biomass, and neither recovers quickly.

Watch the filter cloth. The fines in this industry are the hardest thing a filter press will ever see, and the cloth is a consumable.

Why Choose Baihuipu as Your Manufacturer

Two decades in this industry teaches you that most treatment problems are procurement problems in disguise. Someone bought the cheapest skid, nobody checked the equalisation volume, and eighteen months on the plant cannot hold its consent limit. We build differently.

In-House Fabrication

Our Guangdong works produces everything from standard modular units to fully bespoke lines. Building in-house keeps cost, schedule and quality under our own control rather than a subcontractor's goodwill.

Certification and Export Practice

CE marking is standard and we work to ISO 9001 procedures. Where a project calls for specific material grades, pressure vessel certification or ATEX-rated equipment, we build to that standard and ship the full documentation pack.

Experience Built the Hard Way

Since the early 2000s we have commissioned plants for food and beverage processors, chemical works, electroplaters, textile mills, mines and municipalities. The lessons that stick are scaling, fouling and sludge handling — those inform every design we issue.

We Engineer the Whole Train

Screening, equalisation, biological or chemical treatment, membranes, evaporation, brine handling — the complete line comes from one organisation. Process design, mechanical, electrical and PLC programming sit under the same roof, so there is no gap for finger-pointing at handover.

Twenty-Plus Export Markets

We have shipped to the United States, Canada, Russia, Indonesia, India, Nigeria and Vietnam among others. Crating, export documentation and certificates are handled in-house, which keeps customs surprises to a minimum.

Documentation You Can Actually Audit

Each system ships with as-built drawings, material certificates, welding records and a functional specification. If a client's own consultant wants to review the process calculation basis, we hand it over rather than treating it as proprietary.

Spare Parts and After-Sales Support

We carry membranes, pumps, blowers, diffusers and instruments for every system we supply. Remote support through the PLC is standard on most builds, and on-site service covers commissioning, training and urgent callouts.

Let's Look at Your Numbers

Share your water analysis and site constraints and we will give you a straight assessment of the process route and the realistic operating cost before you commit to anything. Contact our engineers at WhatsApp: +86 13631765076, or find us at hkbhp.com.

WhatsApp: +86 13631765076

Frequently Asked Questions

What spare parts should we hold on site?

Critical spares are pumps, dosing valves, instrumentation sensors and any specialty media. We ship a recommended spares kit with the plant and hold stock for everything we supply, so lead times on replacements stay short.

What treatment capacity do you normally design for quartz crucible production?

Skid-mounted units cover roughly 32 to 497 m³/day depending on the duty, and parallel trains extend that further. We size against your actual peak hour flow rather than the daily average, because equalisation rarely absorbs the whole spike.

Which discharge standard will the treated water meet?

We design against whatever consent applies at your boundary — GB 8978, local sewer limits, or a ZLD target with no liquid discharge at all. The design basis is agreed in writing before fabrication, so there is no argument later about what "compliant" meant.