Cobalt sulfate heptahydrate (CoSO4·7H2O, CAS 10026-24-1) is the default industrial form, with the anhydrous salt (CoSO4, CAS 10124-43-3) reserved for niche catalyst and high-temperature work [S3][S4][S5].
For battery-grade procurement, three spec families dominate quotes in 2026: agricultural/fertilizer grade (Co content 20–21% min on heptahydrate basis, 25 kg bags, China-origin), feed-grade (Co 21% min, granule 10% or 21% variants, 25 kg bags), and electroplating/reagent grade (ACS, ≥99%, 1–25 kg packs, US/EU distribution) [S3][S4].
Form, CAS, and what each grade is actually for
Industrial cobalt sulfate is a soluble cobalt(II) salt, with the heptahydrate (CAS 10026-24-1) shipped as pink to red monoclinic prismatic crystals, density 1.948 g/cm³, melting point 96.8°C, freely soluble in water and methanol, and only slightly soluble in ethanol; it loses its water of crystallization above 420°C [S3][S4]. The anhydrous salt (CAS 10124-43-3) is preferred when water of crystallization would interfere with downstream reactions, particularly in catalyst preparation and certain ceramic pigment firings [S2][S4].
Use cases split cleanly by grade: fertilizer and ruminant feed (cattle, sheep) use granular 10% or 21% Co heptahydrate because cobalt is required for vitamin B12 synthesis; electroplating uses high-purity heptahydrate as a cobalt-ion source for bright and decorative coatings; battery cathode precursors (Ni-Co-Mn) consume technical-grade 21% material in large lots; and laboratory work pulls ACS/reagent crystals in 1–25 kg packs [S3][S4][S5].
Supplier types by region and how they behave on RFQ
The supplier universe breaks into four tiers. Tier 1: Chinese primary manufacturers (e.g. Fairsky) shipping CoSO4·7H2O 21% min in 25 kg net bags directly ex-works, with related cobalt carbonate, hydroxide, and oxide lines for one-stop cathode precursor sourcing [S3]. Tier 2: US and EU chemical distributors and catalog houses (Alfa Chemistry, Molekula, Noah Chemicals, Spectrum Chemical, VWR/Aladdin, Todini) holding ISO 9001:2015 certification, stocking both reagent crystals (1–25 kg) and bulk 25 kg packs, and publishing SDS on request [S4][S5][S6][S7].
Tier 3: regional specialists such as Forge Chemicals Limited in South Africa (CAS 10124-43-3, crystalline CoSO4, marketed as Cobalt Monosulfate) serve African mining and industrial accounts with consistent local supply [S2]. Tier 4: aggregated industrial directories (Thomasnet, American Chemical Suppliers) used to cross-check vendor count, certifications, and US-based inventory, with Thomasnet listing 16042608 as the cobalt sulfate category ID and American Chemical Suppliers pulling live entries for CAS 10026-24-1 [S1][S4]. For cobalt procurement paired with downstream battery cells, see the battery management system supply chain map for 2026 for the cathode-to-pack capacity picture.
Selection criteria: purity, Co content, packaging, and certification
Quote review should weight five concrete criteria before price. (1) Co assay: fertilizer/feed grades typically spec CoSO4·7H2O 21% min, with anhydrous grades 32–33% min, and reagent/heptahydrate 99% min [S3][S4]. (2) Crystal form: large-crystal heptahydrate resists caking; pink powder at 33% Co is offered as a non-caking alternative for humid warehouses [S3]. (3) CAS and documentation: heptahydrate CAS 10026-24-1 vs anhydrous CAS 10124-43-3, with EC 600-050-9 for the heptahydrate and 99% purity reported across multiple US distributors [S4].
(4) Certification: ISO 9001:2015 is the floor for US reagent suppliers such as Noah Chemicals, Alfa Chemistry, and US Biological Life Sciences, while Chinese primary makers typically publish SDS plus typical analysis rather than ISO 9001 certificates on the product page [S3][S4]. (5) Packaging: 25 kg net bags are standard for industrial bulk; 1–5–10–25 kg packs are standard for lab and pilot buyers; storage must keep bags dry and away from heat to slow the hygroscopic caking that hits fine crystals first [S3][S4][S5]. For broader cell-level specs in cobalt-bearing cathodes, the 2026 battery electrolyte shortage note is a useful adjacent read.
Safety, regulatory, and handling constraints
Cobalt(II) sulfate is classified as hazardous to the environment, harmful if swallowed, capable of causing skin sensitisation, and potentially carcinogenic by inhalation; it is very toxic to aquatic organisms and may cause long-term aquatic effects, which is why every distributor routes buyers to sections 4, 5, 6, 7, 8, 10, 13, 14, and 15 of the SDS [S5]. Storage guidance is consistent across vendors: keep original sealed packaging, store in a dry place, avoid heating and damp, and segregate from incompatible oxidizers [S3][S5].
Workplace handling should assume sensitizer potential: gloves, dust control at bag-opening stations, and eye protection. The heptahydrate is hygroscopic and will absorb atmospheric moisture, dissolve, and recrystallize into solid bridges that produce caking; humidity swings, small particle size, and stack pressure accelerate the problem, which is why large-crystal and sealed-pack options exist [S3]. Buyers shipping internationally should also check REACH registration status for the heptahydrate and confirm IUPAC name (cobalt(2+); sulfate; heptahydrate) and EC 600-050-9 on the Certificate of Analysis [S4].
When cobalt sulfate is the wrong chemical for the job
Cobalt sulfate is not the right pick when the application needs a water-free cobalt source for high-temperature calcination; use cobalt oxide or cobalt carbonate instead, which decompose cleanly without releasing sulfuric acid residues [S3]. It is also wrong for ammonia-complex plating baths, where ammonium cobalt(II) sulfate hexahydrate (CAS 13586-38-4, 99%+ purity) is the correct double-salt precursor [S4].
For trace-catalyst work in organic synthesis, anhydrous CoSO4 (CAS 10124-43-3) is preferred over the heptahydrate because the water of crystallization can hydrolyze sensitive substrates; for environmental remediation of cobalt-contaminated waste streams, the same aquatic toxicity that flags the SDS makes sulfate-form dumping the worst option and drives buyers toward recovery and recycling loops [S4][S5]. Buyers pairing cobalt feed with downstream cell assembly should also review the battery management system supplier tiering for 2026 to see where cobalt chemistry meets pack-level controls.
Verifiable next steps for an RFQ
Send the same template to three suppliers from different tiers: a Chinese primary maker for heptahydrate 21% min in 25 kg bags, a US ISO 9001:2015 distributor for reagent 99% in 1–25 kg packs, and a regional specialist for local blended lots, asking for current Co assay, lead time ex-works, HS code, REACH status for CAS 10026-24-1, and the SDS sections listed above [S3][S4][S5]. Trackable signals to watch through Q4 2026: cobalt sulfate spot Co-content quotes (target 21% min heptahydrate, 32–33% min anhydrous) and any change in large-crystal vs pink-powder pricing, since caking behavior is the single biggest in-transit loss driver [S3].
For component-level specifications, see construction machinery and equipment, lamps and light fittings, and lighting equipment and electric lamps.