Antimony Ore Specifications and Penalty Elements Buyers Ask For (Arsenic, Lead, Sulphur)
Most antimony ore contracts turn on two things: the antimony grade and the arsenic. Everything else — lead, sulphur, bismuth, moisture — either adjusts the price or sits inside an agreed limit. If you're sourcing crushed antimony ore and you want to compare offers properly, you need to know which elements the buyer penalises and how those deductions actually get calculated.
Here's the short version. You pay for contained antimony. You get penalised for arsenic above a threshold, sometimes for lead and sulphur, and you argue about moisture at loading. The rest of this post breaks that down.
What goes into an antimony ore specification
An antimony ore specification is just the set of numbers a buyer and seller agree to measure the lot against. For stibnite-based ore (the common antimony mineral, Sb2S3), the headline figure is Sb percentage by weight.
The spec usually lists:
- Sb content — the main grade, quoted as a minimum or as a typical figure with a price scale
- Arsenic (As) — the element smelters care about most after Sb itself
- Lead (Pb) — penalised by some buyers, ignored by others
- Sulphur (S) — relevant because stibnite is a sulphide
- Moisture — measured so you pay for ore, not water
- Bismuth, mercury, selenium — sometimes capped, depending on the end use
- Size range — the crush size, because downstream processing needs a consistent feed
A clean spec also says how each number is determined. On our lots that means an SGS Pakistan certificate of analysis, and the buyer can test their own sample too. More on inspection further down.
One thing to settle early: whether figures are on a dry basis or as-received. Arsenic and Sb reported on a dry basis will read differently from the same ore reported wet. Always ask.
Antimony ore arsenic limit — why it dominates the negotiation
Arsenic is the penalty element that moves antimony pricing more than any other. Stibnite and arsenic minerals often occur together, so antimony ore naturally carries some arsenic, and smelters have to deal with it during roasting and refining.
High arsenic means more cost and more environmental handling at the smelter. That's why buyers set an arsenic threshold and deduct value above it.
Honestly, this is the number I'd check first on any offer — before you even look at Sb. A good grade with ugly arsenic can be worth less than a modest grade that's clean.
The threshold and the penalty rate vary by buyer and by end use. An antimony trioxide producer making flame-retardant grade cares a lot about arsenic. A buyer feeding a metal smelter with good gas-cleaning may tolerate more. There's no single published global number, so treat any "standard arsenic limit" claim with suspicion and confirm the actual figure in the contract.
What to pin down:
- The arsenic threshold (the As percentage below which there's no penalty)
- The penalty rate above it (often stepped — a rate per unit of As, sometimes steeper past a second level)
- Whether there's a rejection limit (a maximum As above which the buyer can refuse the lot)
- The basis — dry or as-received
How lead and sulphur penalties work
Lead gets penalised by buyers whose process can't absorb it cleanly. Some smelters set a Pb cap; others are relaxed. If your ore carries lead, ask whether the buyer treats it as a penalty element or just notes it.
Sulphur is a bit different. Stibnite is a sulphide, so sulphur is expected. A high sulphur figure can affect roasting and gas handling, and some contracts carry a sulphur clause. But for many antimony buyers sulphur is monitored rather than heavily penalised. Confirm per buyer.
A rough way to think about the hierarchy:
| Element | Typical treatment | What to confirm |
|---|---|---|
| Antimony (Sb) | Payable — this is what you buy | Price scale vs grade, dry basis |
| Arsenic (As) | Penalty, sometimes rejection | Threshold, step rate, reject limit |
| Lead (Pb) | Penalty for some buyers | Cap and rate, or whether it's ignored |
| Sulphur (S) | Often monitored | Whether a clause applies |
| Mercury (Hg) | Can be capped tightly | Limit, especially for oxide producers |
| Moisture | Weight adjustment | Determined at load port |
One common mistake: comparing two offers on Sb grade alone. Offer A at a higher grade with high arsenic and a lead cap you'll breach can land below Offer B that's lower grade but clean. Build a small spreadsheet, apply each buyer's penalty math to the same assay, and compare the net.
Crushed ore vs concentrate — know what you're buying
Worth being clear here. We sell crushed antimony ore, not flotation concentrate. It's crushed to the buyer's size range, sampled and sold against the SGS certificate of analysis for that lot.
That matters for your spec. Concentrate and run-of-crush ore sit at different grade levels and different penalty expectations, and you should never compare a concentrate price to a crushed-ore price as if they're the same product. Decide which one your process actually needs, then ask for offers on that basis only.
You can read more on the product page for antimony ore, and if you buy across metals, the full minerals list is there too.
Inspection, HS code and documents
The assay is only as good as the sampling behind it. So agree the inspection chain before loading.
On our side each lot is sampled and analysed by SGS Pakistan, and you get that certificate. You can also test a sample in your own lab, and you can appoint SGS or your own inspector at loading. That covers both sides — you're not relying on a number you can't check.
Antimony ores and concentrates generally fall under HS heading 2617 (confirm the exact subheading and any national suffix with your customs broker, since classification is your import jurisdiction's call, not ours).
Paperwork you'll typically need for an antimony ore shipment:
- Certificate of analysis (SGS)
- Commercial invoice and packing list
- Bill of lading
- Certificate of origin
- Any dangerous-goods or sulphide declaration your carrier requires
We quote FOB Karachi, with CFR on request. So decide your Incoterm early — it changes who books freight and carries risk after the rail at Karachi. Availability and the shipment window are confirmed when you enquire, because material is supplied to order.
What to do next
Write down your must-haves before you ask for a quote: minimum Sb, your arsenic ceiling, any lead or sulphur cap, your crush size, and whether you want FOB or CFR. The tighter your spec, the faster and more accurate the offer.
When you're ready, request a quote on the antimony ore page, or message us on WhatsApp at +92 300 3644444 with your target spec and destination port.
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