Mining Reagents: Flotation Collectors, Depressants and Gold-Plant Chemicals

Mineral processing uses a suite of reagents, each with a specific job in the circuit. This page is the overview of the mining reagents we supply – flotation collectors, depressants, frothers and modifiers, plus the chemicals used in gold leaching and cyanide destruction and in tailings dewatering. Use it to see how the reagents fit together, then follow the links for the detail.

1. The reagent suite in a flotation circuit

Reagent class	Job in the circuit	Products we supply
Collectors	Make target minerals hydrophobic so they attach to bubbles	Xanthates – SIBX, SIPX (and PAX/SEX discussed in the comparisons)
Frothers	Stabilise the froth so the mineralised bubbles can be recovered	Speciality frothers (quoted per circuit)
Depressants / modifiers	Suppress unwanted minerals and control pulp chemistry	Sodium metabisulfite (sphalerite/pyrite depression), pH modifiers
Flocculants	Thicken tailings and dewater concentrate	Polyacrylamide (PAM)

2. Collectors: the xanthates

Xanthates are the workhorse sulphide collectors. The choice of alkyl chain sets the balance between selectivity and collecting power.

SIBX – sodium isobutyl xanthate (CAS 25306-75-6): a strong, widely used collector for sulphide flotation, especially for copper, lead, zinc and gold-bearing sulphides.
SIPX – sodium isopropyl xanthate (CAS 140-93-2): more selective than the longer-chain xanthates, used in copper and lead-zinc circuits (dosage and circuit practice).

Choosing a collector? See SIBX vs SIPX vs PAX and SEX vs SIPX.

Xanthate handling is critical: xanthates are moisture- and heat-sensitive and can decompose, so storage and handling matter. See Xanthate safety, handling, storage and decomposition and SIBX safety and storage.

3. Depressants and pulp modifiers

Sodium metabisulfite (CAS 7681-57-4) acts as a reducing reagent and depressant: it helps depress sphalerite and pyrite in selective circuits and lowers pulp potential where oxidised surfaces hurt selectivity. It is also the standard reagent for cyanide destruction in gold plants (see below).

pH modifiers (lime, and in some circuits sodium hydroxide or soda ash) and activators complete the picture; tell us the circuit and we will quote the reagents that go with it.

4. Gold processing: leaching and cyanide destruction

Cyanide leaching is the standard route for gold; glycine leaching is an alternative for cyanide-free circuits and some refractory ores.
Cyanide destruction in tailings uses the SO₂/air process, with sodium metabisulfite as the SO₂ source (typically with air, a copper catalyst and lime for pH control).

5. Tailings thickening and slurry dewatering

Polyacrylamide (PAM) flocculates the fine solids so tailings thicken and concentrate dewaters efficiently – a key reagent for water recovery and for tailings-dam management. Grade selection (charge type and molecular weight) is set by the slurry; see the PAM overview for the chemistry.

6. Supplying mining reagents to Africa

Africa is a major market for all of these reagents, and we supply them from China with the packaging and paperwork mining buyers require:

Reagent	Typical packaging
Xanthates (SIBX, SIPX)	Drums / bags / bulk, per supplier specification
Sodium metabisulfite	25 kg bags, 1000 kg jumbo bags, full container loads
Polyacrylamide (PAM)	25 kg bags, 750 kg / 1000 kg jumbo bags

We quote FOB or CIF to African ports including Durban, Mombasa, Dar es Salaam, Tema/Takoradi, Lagos/Apapa, Beira and Walvis Bay, with per-batch COA and SDS and third-party inspection on request. For a worked example of the supply package, see export to Africa: packaging, ports and documents.

7. How to select and buy mining reagents

Step	What to confirm
Fix the circuit	Ore type, target minerals, flowsheet stage (rougher, cleaner, scavenger)
Specify the reagent	Collector type and strength; depressant grade; PAM charge and molecular weight
Confirm the form	Solid vs solution, packaging and dosing method
Get the paperwork	COA and SDS per batch; transport classification on the SDS
Agree supply	Volume, port, FOB or CIF, lead time and safety stock

Frequently Asked Questions

Which xanthate should I use, SIBX or SIPX?

SIBX is a stronger collector for copper, lead, zinc and gold sulphides; SIPX is more selective and is common in copper and lead-zinc circuits. The right choice depends on the ore – screen it in the lab. See SIBX vs SIPX vs PAX.

What is sodium metabisulfite used for in mining?

As a flotation depressant/modifier (sphalerite, pyrite, pulp potential) and as the standard reagent for cyanide destruction in gold tailings (SO₂/air process).

What flocculant is used for tailings?

Polyacrylamide (PAM), selected by charge type and molecular weight for the slurry. Anionic grades are common for tailings thickening.

Do you supply mining reagents to African mines?

Yes – xanthates, sodium metabisulfite, PAM and related reagents, FOB or CIF to Durban, Mombasa, Dar es Salaam, Tema/Takoradi, Lagos/Apapa, Beira and Walvis Bay, with COA/SDS per batch.