Post: RZOLV™ A New Era for Processing High-Arsenic Gold Concentrates

RZOLV - Staff writer - November 23, 2025

For more than a century, high-grade gold concentrates have followed a predictable path: they are bulk-shipped to smelters, where they are thermally oxidized, refined, and paid out on a contract basis. But the rise of arsenic-rich concentrates—particularly those dominated by arsenopyrite and pyrite—has strained this traditional route. Smelters now impose escalating arsenic penalties, enforce strict blending requirements, and increasingly reject feeds that fall outside narrow environmental thresholds.

In an industry searching for cleaner, more efficient, and more economical solutions, RZOLV™ presents a compelling alternative. A controlled-pH, controlled-ORP hydrometallurgical reagent system engineered to dissolve gold selectively, RZOLV allows miners to recover gold on-site, without the thermal, environmental, or contractual burdens of conventional smelting.

The Smelter Bottleneck: Penalties, Rejections, and Lost Value

Smelters are designed around predictable inputs—clean, low-impurity concentrates. Arsenic breaks that model.

1. Punitive Arsenic Penalties

Smelters typically apply surcharges starting at 0.5–1.0% arsenic, rising sharply at 3–5% As and becoming uneconomic above 5–8%. Many high-grade gold concentrates contain 5–20% As, especially from refractory or structurally complex deposits. For miners, this translates into:

• Severe treatment charge (TC) increases

• Deducted gold payability

• Contract restrictions that limit throughput

  
  

2. Rejection or Blending Requirements

High-arsenic concentrates often cannot be smelted on their own. They must be blended with cleaner third-party concentrates—an expensive practice that delays sales, increases working capital, and exposes producers to counterparty risk.

3. Lower Payability vs. Contained Gold

Smelters rarely pay 100% for the gold. Standard contracts pay 85–95%, minus treatment charges, minus refining charges, minus arsenic/sulfur penalties. The gap between contained metal and paid metal can exceed 15–20%—millions of dollars annually for mid-tier operations.

4. Environmental Liability

At smelter temperatures (>1,000°C), arsenic volatilizes as arsenic oxides, requiring:

• Complex filtration systems

• Stable vitrified disposal streams

• Compliance with tightening emissions standards

  
  

This footprint adds cost and regulatory burden—both of which smelters pass back to feed suppliers.

RZOLV™ Offers a Cleaner, Higher-Payability Solution

With RZOLV™, miners no longer need to ship arsenic-rich material halfway around the world or accept heavy discounts. Instead, they can dissolve the gold directly at site while keeping arsenic fully contained in the solid phase.

1. Full Payability: >95–99% Gold Recovery On-Site

Unlike smelters, RZOLV doesn't impose payability deductions. Gold is dissolved chemically and recovered at the operation, with:

• No treatment charges

• No refining charges

• No impurity penalties

• No third-party blending costs

• No contract deductions

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Producers capture near-total value of the gold.

For high-grade concentrates—often tens to hundreds of grams per tonne—this is transformative.

2. Arsenic Stays Solid — and Can Be Stabilized as Ferric Arsenate

Perhaps the most significant advantage of RZOLV is its arsenic behavior:

• Under RZOLV leaching conditions (low pH, controlled ORP), arsenic does not dissolve.

• Arsenopyrite and related minerals remain solid during gold dissolution.

• With added stabilizers and oxidant control, arsenic converts to stable ferric arsenate (FeAsO₄·2H₂O)—a globally recognized permanent disposal mineral. This eliminates:

  
  

  • Volatilized arsenic oxide

  • Hazardous off-gas streams

  • Arsenic trioxide disposal liabilities

  • Air emission compliance challenges

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Environmentally, this is a breakthrough.

3. No Thermal Oxidation: Lower Energy, Lower Carbon, Lower Cost

Smelters rely on extreme temperatures to oxidize sulfides and liberate metals. This requires:

• Energy-intensive furnaces

• Refractory linings

• Heavy fuel consumption

• Continuous emission monitoring

  
  

RZOLV operates:

• At ambient pressure

• At ambient temperature

• In standard agitated leach tanks

The result:

• Far lower greenhouse gas footprint

• Simplified permitting

• Reduced capital and operating cost

  
  

4. Fast Metallurgical Kinetics With No Passivation

High-sulfide concentrates challenge cyanide via:

• Slow kinetics

• Passivation by elemental sulfur films

• Oxygen/dissolved oxygen mass-transfer limitations

RZOLV avoids these issues because:

• It operates in a non-cyanide chemical environment

• Sulfur passivation is minimized

• Gold dissolution is rapid, often reaching completion in hours rather than days

• ORP and pH are precisely controlled with off-the-shelf instrumentation

This makes processing predictable and efficient, even at sulfide contents of 30–70%.

5. Eliminates Dangerous Logistics of Shipping Arsenic-Rich Concentrates

Transporting arsenic-rich concentrates introduces major liabilities:

• Dangerous goods classification

• Railroad/port restrictions

• Elevated insurance premiums

• Public and community opposition

  
  

RZOLV removes nearly all of these challenges by converting concentrate to:

• A small doré bar (gold recovered on-site)

• A solid, stable residue suitable for engineered storage

  
  

This dramatically reduces the risk profile of the operation.

6. Capex-Friendly and Scalable — Especially for Mid-Tier and Small Operations

Technologies like pressure oxidation and roasting require enormous capital expenditures—often $150–300M+, years of permitting, and high technical expertise. RZOLV systems can be installed:

• In standard tanks

• With modular plant layouts

• At costs appropriate for mid-tier and junior producers

• With startup times measured in months, not years

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This democratizes processing of complex concentrates.

Why Miners Are Rethinking the Smelter Model

With gold prices high and arsenic penalties rising, producers are looking for ways to maximize value and minimize ESG exposure. RZOLV delivers:

• Higher economic return

• Stronger ESG performance

• Lower technical and regulatory risk

• Faster cash-flow realization

• Significantly reduced logistic hazard

• Independence from smelter market dynamics

In many cases, RZOLV transforms concentrates that smelters penalize—or outright reject—into fully recoverable, high-margin assets.

Conclusion: RZOLV™ Unlocks the True Value of High-Arsenic Concentrates

Traditional smelting is no longer the optimal route for many arsenic-rich gold concentrates. The economics are shrinking, the risks are rising, and the environmental liabilities are intensifying.

RZOLV™ offers a modern, clean, and economically superior path:

• Higher payability

• Higher recovery

• Lower cost

• Environmentally stable arsenic management

• Transport and logistics risk elimination

• Scalable, low-capex deployment

  
  

For producers facing arsenic challenges, RZOLV isn’t just an alternative—it may be the new standard for responsible, efficient, high-value gold recovery.

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Disclosure and Cautionary Statement

This article has been published by RZOLV Technologies Inc. as part of its corporate communications and investor relations activities and reflects the views and opinions of management as of the date of publication. It is provided for general informational purposes only and does not constitute investment advice, an offer to sell, or a solicitation to buy securities. Certain statements in this article may constitute forward-looking information within the meaning of applicable Canadian securities laws and are subject to risks, uncertainties, and assumptions that could cause actual results to differ materially. Readers should not place undue reliance on such statements. The Company’s officers, directors, and insiders may hold securities of RZOLV and therefore have a financial interest in the Company’s performance. Readers are encouraged to review RZOLV’s public disclosure documents available on SEDAR+ for a discussion of material risks and assumptions. Neither the TSX Venture Exchange nor its Regulation Services Provider has reviewed or approved the contents of this article.