Norit RO 3515 Alternative Activated Carbon: Specs Compared

Norit RO 3515 has been the default gold recovery carbon in CIL/CIP circuits for decades. If you've worked in gold mining in South Africa, West Africa, or Australia, chances are RO 3515 was the first carbon your plant loaded — and possibly the only one your metallurgist ever approved.

That market position was earned. NORIT built RO 3515's reputation through long-standing use in gold recovery applications and a global supply network. But an established brand is not automatically the best fit for every circuit. Today, mines may also evaluate alternative carbons based on gold adsorption performance, attrition resistance, supply availability, and total operating cost.

This article compares RO 3515 against HMGOLD™7500 from Huamei Carbon — spec by spec, using Norit's published product data and Huamei's SGS test results (Report No. MSRCZ2500346-01A). Where the numbers speak, we let them. Where they don't, we say what's missing.

Spec Sheet: Head-to-Head

Parameter	Norit RO 3515	Huamei HMGOLD™7500	Notes
Raw material	Coconut shell	Coconut shell	Same
Activation	Steam	Steam	Same
Iodine number	≥1050 mg/g	1150 mg/g (spec) / 1208 mg/g (SGS actual)	✅ HMGOLD higher
Ash content	≤5%	2.52% (SGS)	✅ HMGOLD significantly lower
Moisture	≤5%	≤5%	Match
Ball-pan hardness	≥97% (ASTM D3802)	98.2% (GB/T method, SGS)	⚠️ Different test methods
K value (gold loading)	Not typically published	28 kg/t	HMGOLD published
R value (adsorption kinetics)	Not typically published	58%	HMGOLD published
Bulk density	0.46–0.50 g/cm³	0.48–0.52 g/cm³	Comparable range
Mesh size	6×12	6×12, 8×16	HMGOLD offers more options
pH	Alkaline	10.0 (SGS)	Both alkaline

One thing jumps out immediately: The first thing to note is that RO 3515 and HMGOLD™7500 are not identical product forms. RO 3515 is an extruded activated carbon, while HMGOLD™7500 is a coconut-shell granular carbon. HMGOLD shows strong iodine, ash, and hardness results in Huamei's SGS testing, but these values alone do not prove superior gold-recovery performance. Gold-specific adsorption and attrition tests under comparable conditions are more meaningful when evaluating an alternative.Iodine is 100+ mg/g higher. Ash is half. The real question is whether those spec-sheet advantages translate to performance advantages in your specific circuit — and that requires testing, not assumptions.

Why RO 3515 Became the Default

Understanding why mines use RO 3515 helps you evaluate whether switching makes sense:

Track record: RO 3515 has a long history of use in gold recovery and is widely recognized in CIL/CIP applications. Its established operating history is an important advantage for mines that prefer proven products with existing plant experience and internal approval records.

Consistency: Norit's manufacturing process delivered batch-to-batch consistency that mines relied on. When you ordered RO 3515, you got RO 3515 — the carbon performed within predictable bounds every time.

Distribution reach: From Johannesburg to Perth to Accra, Norit distributors could deliver. In regions where logistics are the bottleneck, having a reliable supply chain matters as much as the spec sheet.

Inertia: This is the honest one. Many mines run RO 3515 because they've always run RO 3515. The metallurgist who approved it may have retired. The procurement team reorders on autopilot. Nobody has run a comparative trial in years — because why would you change something that works?

That last point is the opening for HMGOLD. "Works" and "optimal" are different things. If you're paying a premium for a carbon that meets your minimum performance requirements, a lower-cost carbon that matches or exceeds those same requirements is worth evaluating.

Where HMGOLD™7500 Has the Edge

Iodine Number

Norit RO 3515: ≥1050 mg/g
HMGOLD™7500: 1150 mg/g (spec) / 1208 mg/g (SGS actual)

Iodine number isn't the primary metric for gold recovery carbon — K value matters more. But a higher iodine number indicates greater total micropore volume, which correlates with overall adsorption capacity. At 1208 mg/g (SGS verified), HMGOLD™7500 has roughly 15% more adsorptive capacity than RO 3515's minimum specification.

For operations where carbon also handles organic fouling alongside gold adsorption — common in high-organic ore bodies — that extra capacity provides a useful buffer before performance degrades.

Ash Content

Norit RO 3515: ≤5%
HMGOLD™7500: 2.52% (SGS verified)

This is the biggest measurable gap. HMGOLD's ash is roughly half of RO 3515's maximum specification.

Why this matters in your circuit:

Elution efficiency: Inorganic ash residues trap gold within the carbon structure during Zadra or AARL stripping. Lower ash = cleaner stripping = less residual gold left on carbon after each elution cycle. Over hundreds of cycles, that gold retention compounds into real losses.

Reactivation longevity: Ash doesn't burn off during thermal reactivation. It accumulates cycle after cycle. Carbon starting at 2.52% ash builds up contamination slower than carbon starting at 5%, maintaining its gold loading capacity through more reactivation cycles before requiring replacement.

Doré purity: Lower-ash carbon contributes fewer inorganic impurities to your final gold precipitate. If your refinery penalizes you for impurities in doré bars, your carbon's ash content directly affects your refining charges.

K Value and R Value

Here's where things get interesting. Norit/Cabot does not typically publish K value and R value for RO 3515 in the same format that Jacobi publishes for PICAGOLD G210AS.

HMGOLD™7500 publishes both:

K value (gold loading): 28 kg/t
R value (adsorption kinetics): 58%

These are competitive numbers. For context, Jacobi G210AS — another premium gold carbon — publishes K=28 kg/t and R=60%. HMGOLD™7500's K value matches G210AS exactly; the R value is 2 percentage points lower, which is within normal batch variation for most CIL circuits.

The fact that HMGOLD publishes K and R values while Norit does not is itself significant. If you're currently running RO 3515, you probably don't know its K and R values — unless you've tested it yourself. That means you're paying premium pricing for a carbon whose gold-specific performance metrics you may have never quantified.

Mesh Size Options

Norit RO 3515: 6×12 only
HMGOLD™7500: 6×12, 8×16, 5×10

RO 3515 comes in one size. HMGOLD offers three — which matters because mesh size selection directly affects circuit performance:

6×12: Standard for CIL circuits with aggressive inter-stage screening
8×16: Better for CIP circuits — faster kinetics, higher gold loading per unit mass, fewer screen blinding issues
5×10: Coarser option for high-abrasion circuits where attrition drives carbon consumption

If you're running a CIP circuit on 6×12 carbon because that's all your supplier offers, you may be leaving performance on the table.

Where Norit RO 3515 Still Wins

Track Record

No amount of spec-sheet comparison replaces 40+ years of operational data. RO 3515 has been tested, approved, and documented in more CIL/CIP plant operating manuals than any other gold carbon. When your client requires a "proven carbon with established track record," RO 3515 checks that box without discussion.

HMGOLD™7500 is growing — Tanzania, Ghana, South Africa, Egypt, Azerbaijan — but it doesn't have decades of data yet.

Brand Approval

Some mining companies have approved vendor lists. RO 3515 is on most of them. Getting HMGOLD approved requires a formal evaluation process — lab testing, plant trial, metallurgical report, management sign-off. That process takes 3–6 months and costs money.

If your company's procurement policy mandates approved-vendor-only purchasing, you'll need to run that approval process before HMGOLD becomes an option — regardless of how good the specs look.

Local Support

Cabot's distributor network provides local technical support in major mining regions. If you have a carbon performance issue, your Cabot rep can visit your site. Huamei's support is primarily remote (WhatsApp, email, video calls) with periodic site visits for key accounts.

For operations in remote locations where on-site technical support matters, this is a real consideration — not a deal-breaker, but a factor.

The Cost Question

Factor	Norit RO 3515	Huamei HMGOLD™7500
Pricing model	Cabot distributor network	Factory-direct
Distribution layers	Manufacturer → Regional distributor → Local agent → Mine	Manufacturer → Mine
MOQ	Varies by distributor (typically 20+ tons)	10 tons
Lead time	2–6 weeks (dependent on distributor stock)	2–3 weeks production + shipping
Sample	Through distributor	Free 1–2 kg sample direct
COA	Yes	Yes (SGS reports available)

The structural price difference is distribution economics. RO 3515 passes through 2–3 intermediaries between Cabot's factory and your mine. Each adds margin. HMGOLD ships factory-direct from Fujian, China — one invoice, no intermediary markup.

On equivalent specifications, the price gap is significant. But "significant" varies by region, volume, and current market conditions. Get current quotes from both suppliers for your specific requirements before making assumptions based on list prices.

The Honest Scorecard

Category	Norit RO 3515	HMGOLD™7500	Edge
Iodine number	≥1050 mg/g	1150 mg/g (spec) / 1208 (SGS)	HMGOLD
Ash content	≤5%	2.52% (SGS)	HMGOLD
Hardness	≥97% (ball-pan, ASTM D3802)	98.2% (GB/T, SGS)	Not directly comparable
K value (gold loading)	Not published	28 kg/t	HMGOLD (data available)
R value (kinetics)	Not published	58%	HMGOLD (data available)
Mesh options	6×12 only	6×12, 8×16, 5×10	HMGOLD
Track record	40+ years, global	Growing, Africa/Asia focus	Norit
Brand approvals	Industry standard	Requires evaluation	Norit
Pricing	Distributor markup	Factory-direct	HMGOLD
MOQ	20+ tons	10 tons	HMGOLD

The bottom line: HMGOLD™7500 matches or exceeds Norit RO 3515 on every measurable specification — and publishes gold-specific metrics (K value, R value) that Norit doesn't. What HMGOLD lacks is the decades of operational track record and automatic brand-approval status that RO 3515 carries. If your procurement decision is based on specs and price, HMGOLD wins. If it's based on institutional history and approved-vendor lists, Norit wins. For most operations, the smart move is to run a parallel trial and let the data decide.

FAQ

What activated carbon is equivalent to Norit RO 3515?

HMGOLD™7500 from Huamei Carbon matches or exceeds RO 3515 on published specifications: higher iodine (1150 vs ≥1050 mg/g), lower ash (2.52% vs ≤5%), and comparable hardness. Both are coconut shell, steam-activated carbons designed for CIL/CIP gold recovery. A bottle-roll test and plant trial with your specific ore is recommended to confirm equivalent performance in your circuit.

Is Norit RO 3515 still manufactured?

Yes. Norit RO 3515 is now manufactured by Cabot Corporation, which acquired Norit in 2012. The product continues to be available through Cabot's global distributor network. Some industry professionals report longer lead times and availability fluctuations since the acquisition, but the product specification remains unchanged.

What is the iodine number of Norit RO 3515?

Norit RO 3515 specifies a minimum iodine number of ≥1050 mg/g. This measures total micropore volume using the ASTM D4607 method. While useful as a general quality indicator, iodine number is not the primary metric for evaluating gold recovery carbon performance — K value (gold loading capacity) and R value (adsorption kinetics) are more relevant for CIL/CIP applications.

Why are mines switching from Norit RO 3515?

Three main drivers: (1) pricing — RO 3515 routes through Cabot's multi-layer distributor network, adding margin at each step; (2) alternatives have improved — Chinese manufacturers like Huamei now offer SGS-verified carbons with equivalent or superior specifications; (3) data transparency — newer brands publish gold-specific metrics (K value, R value) that help metallurgists make informed comparisons, while Norit relies on legacy reputation.

How much cheaper is HMGOLD™7500 than Norit RO 3515?

Exact pricing varies by volume, destination, and current market conditions. The structural difference comes from distribution: RO 3515 passes through 2–3 intermediaries (Cabot → regional distributor → local agent), while HMGOLD ships factory-direct. Request current quotes from both suppliers for your specific requirements — pricing from even 6 months ago may not reflect today's market.

Jacobi PICAGOLD G210AS Alternative

Most activated carbon comparisons stop at the spec sheet — iodine number, hardness, ash content. Useful for procurement paperwork, but not for predicting what happens inside a CIL circuit where carbon spends months being pumped through abrasive ore slurry, screened at high velocity, stripped in acid, and thermally reactivated — over and over.

This article compares Jacobi PICAGOLD G210AS and Huamei HMGOLD™7500 based on verified data: Jacobi's official gold recovery brochure parameters for G210AS, and Huamei's SGS test report (No. MSRCZ2500346-01A) for HMGOLD™7500. Where data is available, we compare directly. Where it isn't, we say so.

Spec Sheet: Head-to-Head

Parameter	Jacobi PICAGOLD G210AS	Huamei HMGOLD™7500
Raw material	Coconut shell	Coconut shell
Activation	Steam	Steam
Iodine number	Not primary metric*	1150mg/g
Ash content	≤4%	2.52% (SGS)
Moisture	≤5%	≤5%
Hardness/Strength	≥99% (ball-pan)	98.2%
K value (gold loading)	28 kg/t	28 kg/t
R value (adsorption kinetics)	60%	58%
Mesh size	6×12 or 8×16	6×12, 8×16

*Jacobi's gold recovery brochure does not use iodine number as a primary specification for G210AS. This is standard practice — iodine measures total microporosity, not gold-specific adsorption capacity. K value and R value are the metrics Jacobi uses to define gold carbon performance.

Attrition: Where Gold Gets Lost

Carbon attrition is the single largest source of unrecoverable gold loss in CIL circuits. When carbon breaks into fines smaller than your screen aperture, those fines — loaded with adsorbed gold — pass through inter-stage screens and exit with tailings.

Hardness: The Test Method Problem

Jacobi G210AS: ≥99% ball-pan hardness
HMGOLD™7500: 98.2% strength (GB/T method, SGS Report No. MSRCZ2500346-01A)

These numbers come from different test methods using different equipment, sample preparation, and measurement criteria. A direct percentage-to-percentage comparison is not valid. Both values indicate high-strength carbons, but you cannot conclude that one is harder than the other based on these numbers alone.

What This Means for Your Circuit

Jacobi provides three attrition-relevant metrics (ball-pan hardness, rolling bottle attrition, platelet content) that together give a comprehensive picture of G210AS durability in CIL circuits.

Huamei provides one metric (GB/T strength) from a different test standard.

If attrition-related gold loss is a primary concern for your operation — and for most CIL plants, it should be — this data gap matters. Request rolling bottle attrition and platelet testing from Huamei before making a procurement decision based on durability.

Ash Content: HMGOLD's Clear Advantage

Jacobi G210AS: ≤4% (specification limit)
HMGOLD™7500: 2.52% (SGS verified)

This is one area where HMGOLD has a clear, verifiable edge. Lower ash = fewer inorganic mineral residues = cleaner carbon matrix.

Why this matters in CIL:

Elution efficiency: During Zadra or AARL stripping, inorganic residues can trap gold within the carbon structure, reducing strip recovery per cycle. Lower ash content means cleaner stripping and less residual gold left on carbon after elution.

Reactivation quality: During thermal reactivation, mineral ash doesn't burn off — it accumulates cycle over cycle. Carbon that starts with 2.52% ash accumulates less than carbon starting at 4%, meaning the low-ash carbon maintains its performance characteristics over more reactivation cycles.

Contamination risk: In operations producing doré bars or shipping gold precipitate for refining, lower-ash carbon contributes fewer impurities to the final product.

Elution: Getting Your Gold Back

Both G210AS and HMGOLD™7500 are coconut shell, steam-activated carbons. Both are coconut-shell, steam-activated carbons, but their actual elution performance should be verified under identical operating conditions.

Ash content (advantage: HMGOLD): As discussed above, HMGOLD's lower ash (2.52% vs ≤4%) theoretically supports cleaner stripping with less gold retention per cycle.

Pore size distribution: Two carbons with different iodine numbers may have different mesopore-to-micropore ratios. Gold cyanide complexes (~0.6nm) load preferentially in mesopores. Carbons with more micropores may trap gold more tightly, making it harder to strip. Without comparative mercury porosimetry data for both products, this remains a theoretical consideration.

What to test during your trial: Track gold-on-carbon before and after each elution cycle for both carbons. If one consistently retains more gold after stripping, that's a quantifiable cost — both in gold recovery and in progressive performance degradation.

Price and sample

Factor	Jacobi PICAGOLD G210AS	Huamei HMGOLD™7500
Pricing model	Distributor/agent network	Factory-direct
Sample availability	Through distributor	Free 1–2 kg sample direct
COA with shipment	Yes	Yes (SGS reports available)

The structural price difference comes from distribution model: Jacobi sells through a global agent network (each adding margin), while Huamei ships factory-direct. On equivalent specifications, factory-direct pricing is typically significantly lower per ton.

For exact pricing: request quotes from both suppliers for your specific volume, destination, and delivery schedule. Published price ranges become outdated quickly — get current numbers.

The Honest Scorecard

Category	Jacobi G210AS	HMGOLD™7500
Gold loading data (K value)	28 kg/t (published)	28 kg/t
Adsorption kinetics (R value)	60% (published)	58%
Attrition data	<1.0% rolling bottle, <4% platelets	＜2%
Hardness	≥99%	98.2% (GB/T, SGS)
Ash content	≤4%	2.52% (SGS verified)
Iodine number	Not primary metric	1150 mg/g
Pricing	Distributor markup	Factory-direct
MOQ flexibility	20 tons	10 tons
Track record in CIL	Decades, global	Growing, primarily Africa/Asia

The bottom line: Jacobi wins on data transparency — they publish the gold-specific metrics (K, R, attrition, platelets) that matter most for CIL procurement decisions. HMGOLD wins on ash content and pricing structure, but has significant data gaps on the metrics that CIL metallurgists need to see before approving a carbon switch.

Is Jacobi PICAGOLD G210AS better than HMGOLD™7500 for CIL?

G210AS has more comprehensive published performance data — K value (28 kg/t), R value (60%), rolling bottle attrition (<1.0%), and platelet content (<4%). HMGOLD™7500 has verified advantages in ash content (2.52% vs ≤4%) and offers factory-direct pricing with lower MOQ.

What is the K value of Jacobi PICAGOLD G210AS?

According to Jacobi's official gold recovery brochure, the typical K value (gold loading) for G210AS is 28 kg/tonne, measured by the Mintek method. K value indicates how much gold the carbon loads from cyanide solution under standardized conditions. This is a competitive value for premium gold recovery carbon.

What activated carbon is equivalent to Jacobi PICAGOLD G210AS?

HMGOLD7500 can be evaluated as an alternative, but equivalence should be confirmed through K/R, attrition and plant-trial data.

Why is HMGOLD™7500 cheaper than Jacobi PICAGOLD?

Distribution structure. Jacobi sells through a global network of agents and distributors who each add margin. HMGOLD ships factory-direct from Huamei Carbon in China with no intermediary markup. Both use coconut shell raw material and steam activation. The price difference reflects distribution economics, not necessarily a difference in manufacturing quality.

Can I replace G210AS with HMGOLD™7500 without losing gold recovery?

Possibly — but you must verify through testing, not assumptions. HMGOLD's published specifications (iodine 1150 mg/g, ash 2.52%, 6×12 mesh) indicate a high-quality coconut shell carbon suitable for CIL. Run a parallel plant trial in one CIL train for 8–12 weeks, tracking gold recovery, attrition, and elution performance against your current G210AS results before committing to a full switch.