CWK Sulfur Chemicals — sodium, ammonium & potassium thiosulfates, sulfites, bisulfites and 96% sulfuric acid

Supply high-purity sulfur chemicals from CWK Business Unit Sulfur Chemicals (Chemiewerk Bad Köstritz GmbH, Germany): sodium thiosulfate (30%/50% solutions, pentahydrate, anhydrous Siccum), ammonium and potassium thiosulfates, sulfite/bisulfite solutions and ultra-low-metal 96% sulfuric acid.

Sodium Thiosulfate 30% & 50% Aqueous Solutions (STS) CWK Sulfur Chemicals

CWK Sulfur Chemicals manufactures ready-to-dose aqueous sodium thiosulfate solutions (STS, Na2S2O3) in 30% and 50% concentrations for automated water dechlorination, hypochlorite neutralization, and pulp and textile antichlor treatment.

Standard solution concentrations: 30 wt% and 50 wt% Na2S2O3 for direct metering pump dosing
Rapid dechlorination of municipal drinking water, industrial effluents and cooling water streams
Antichlor neutralization following chlorine or hypochlorite bleaching in pulp, paper and textile mills
Available in bulk road tankers, 1000 L IBC totes, plastic drums and 20 L canisters

Crystalline Pentahydrate & Anhydrous Sodium Thiosulfate ('Siccum') CWK

For dry-blend formulations and long-distance export logistics, Chemiewerk Bad Köstritz supplies solid sodium thiosulfate both as crystalline pentahydrate (Na2S2O3·5H2O) and as high-assay anhydrous powder ('Siccum', Na2S2O3).

Two solid product forms: free-flowing pentahydrate crystals and anhydrous 'Siccum' powder
High active Na2S2O3 content in the anhydrous Siccum grade reduces freight weight and storage volume
Used in dry photographic fixers, fine chemical synthesis, chrome leather tanning and ore processing
Controlled crystal size distribution ensuring rapid dissolution and minimal insoluble residue

Ammonium Thiosulfate (ATS) Solution & Crystals CWK Sulfur Chemicals

CWK manufactures high-purity ammonium thiosulfate (ATS, (NH4)2S2O3) as both a concentrated aqueous solution and a crystalline solid for rapid X-ray and photographic fixing, non-cyanide gold and silver leaching, and liquid nitrogen-sulfur fertilizers.

Supplied as both clear concentrated ATS aqueous solution and high-purity crystalline (NH4)2S2O3
Eco-friendly complexing lixiviant for non-cyanide hydrometallurgical leaching of gold and silver ores
Primary active ingredient in rapid photographic, graphic arts and industrial X-ray fixer baths
High-efficiency nitrogen-sulfur liquid fertilizer component with urease/nitrification inhibition properties

Potassium Thiosulfate (KTS) Aqueous Solution CWK Sulfur Chemicals

CWK supplies potassium thiosulfate (KTS, K2S2O3) as a clear, chloride-free aqueous solution used as a selective reducing and complexing agent in specialty chemical synthesis and as a concentrated liquid potassium-sulfur fertilizer for fertigation.

Clear, stable aqueous solution of potassium thiosulfate (K2S2O3) with high chemical purity
Chloride-free and low-sodium profile tailored for sensitive chemical reactions and specialty crops
Selective reducing agent, dechlorinator and stabilizer in fine chemical and polymer processes
Liquid K-S nutrient source for drip irrigation (fertigation) and foliar application

Aqueous Ammonium Sulfite & Potassium Sulfite Solutions CWK

Chemiewerk Bad Köstritz manufactures high-purity aqueous solutions of ammonium sulfite ((NH4)2SO3) and potassium sulfite (K2SO3), serving as mild reducing agents, oxygen scavengers and buffering chemicals across industrial applications.

Aqueous ammonium sulfite solution ((NH4)2SO3) for chemical synthesis, metallurgy and photographic baths
Aqueous potassium sulfite solution (K2SO3) for antioxidant protection, pulp processing and specialty formulations
Efficient dissolved oxygen scavenging and prevention of oxidative degradation in process streams
Supplied in bulk road tankers, 1000 L IBC totes, plastic drums and 20 L canisters

Aqueous Ammonium Bisulfite & Potassium Bisulfite Solutions CWK

CWK's aqueous solutions of ammonium bisulfite (NH4HSO3) and potassium bisulfite (KHSO3) act as sodium-free oxygen scavengers in oilfield and boiler water systems, sulfonating reagents in organic synthesis, and antioxidants in industrial processing.

Aqueous ammonium bisulfite solution (NH4HSO3): sodium-free oxygen scavenger for boiler feed and oilfield injection water
Aqueous potassium bisulfite solution (KHSO3): reducing agent and stabilizer in beverage, leather and chemical industries
Reagent for bisulfite addition reactions with aldehydes and ketones in pharmaceutical and fine synthesis
Ready-to-use liquid format minimizing workplace SO2 dust and vapor exposure compared to metabisulfite powders

Concentrated Sulfuric Acid 96% with Ultra-Low Metal Content CWK

Commissioned in February 2022 at the Bad Köstritz site, CWK's new liquid sulfur combustion plant manufactures 96% concentrated sulfuric acid (H2SO4) featuring ultra-low trace metal levels for battery electrolyte production and high-purity chemical synthesis.

96 wt% H2SO4 produced via clean liquid sulfur combustion (new plant commissioned in February 2022)
Ultra-low iron and heavy metal impurity profile preventing self-discharge in battery electrolytes
Used in lead-acid and GEL battery manufacturing, high-purity chemical synthesis and internal CWK silica production
Integrated heat recovery operating under DIN EN ISO 50001:2018 energy and ISO 14001:2015 environmental standards

Industrial Packaging (1000 L IBC, Drums, 20 L Canisters, Bags) & Logistics

CWK Sulfur Chemicals delivers liquid solutions and crystalline salts in UN-approved chemical packaging accompanied by batch-specific Certificates of Analysis (CoA) and Safety Data Sheets (SDS) under DIN EN ISO 9001:2015.

Liquid packaging for thiosulfates, sulfites & bisulfites: bulk tankers, 1000 L IBC totes, drums and 20 L canisters
Solid packaging for STS pentahydrate, Siccum & ATS crystals: palletized PE-lined bags and FIBC big bags
In-house laboratory verification of assay, density, pH and trace metal purity for every production batch
Reliable international B2B supply chain with chemical-grade transport compliance

CWK Business Unit Sulfur Chemicals (Geschäftsbereich Schwefelverbindungen) overview

The Sulfur Chemicals Business Unit of Chemiewerk Bad Köstritz GmbH (CWK Sulfur Chemicals, located at Heinrichshall 2, 07586 Bad Köstritz, Thuringia, Germany; General Manager Dr. Tilo Breyer) is an established European producer of high-purity inorganic sulfur compounds and concentrated sulfuric acid.

The division’s product portfolio comprises three core chemical groups: sodium, ammonium and potassium thiosulfates (STS, ATS, KTS), aqueous solutions of ammonium and potassium sulfites and bisulfites, and 96% concentrated sulfuric acid (H2SO4) with ultra-low metal impurities.

When requesting a quotation, specify the compound name (STS, ATS, KTS, ammonium/potassium sulfite or bisulfite, or 96% sulfuric acid), physical form (30%/50% solution, pentahydrate crystals or anhydrous Siccum powder), batch quantity and preferred container type.

Thiosulfates (STS, ATS, KTS): solution concentrations, pentahydrate crystals and anhydrous Siccum

Sodium thiosulfate (STS, Na2S2O3) is manufactured by CWK in four commercial formats: ready-to-meter 30% and 50% aqueous solutions, free-flowing crystalline pentahydrate (Na2S2O3·5H2O) and high-assay anhydrous powder ("Siccum").

Ammonium thiosulfate (ATS, (NH4)2S2O3) is supplied both as a concentrated clear aqueous solution and as high-purity alkali-free crystals; potassium thiosulfate (KTS, K2S2O3) is produced as a clear chloride-free aqueous solution.

Industrial applications span municipal and industrial water dechlorination, pulp and textile antichlor bleaching, non-cyanide gold and silver ore leaching, rapid X-ray and photographic fixing baths, leather tanning and liquid sulfur fertilizers.

Aqueous sulfite and bisulfite solutions: oxygen scavenging and chemical synthesis

CWK produces stable aqueous solutions of ammonium sulfite ((NH4)2SO3), potassium sulfite (K2SO3), ammonium bisulfite (NH4HSO3) and potassium bisulfite (KHSO3).

Using ready-to-dose liquid sulfite and bisulfite solutions eliminates workplace dust and pungent sulfur dioxide (SO2) gas emissions associated with handling and dissolving solid metabisulfite powders.

These solutions are widely used as sodium-free dissolved oxygen scavengers in boiler feedwater and oilfield injection water, reducing agents and sulfonating intermediates in fine chemical synthesis, and antioxidants in pulp, leather and beverage processing.

Concentrated 96% sulfuric acid with ultra-low trace metals (new 2022 plant)

In February 2022, Chemiewerk Bad Köstritz commissioned a new state-of-the-art liquid sulfur combustion plant producing 96% concentrated sulfuric acid (H2SO4) with an ultra-low trace metal impurity profile.

Minimal iron and heavy metal content makes CWK 96% sulfuric acid suitable for formulating lead-acid and GEL battery electrolytes (minimizing self-discharge and gassing) as well as high-purity chemical synthesis and internal CWK silica/zeolite production.

Industrial packaging (IBC totes, drums, 20 L canisters, bags) and ISO-certified quality

All CWK Sulfur Chemicals processes operate under DIN EN ISO 9001:2015, DIN EN ISO 14001:2015 and DIN EN ISO 50001:2018 certified management systems, with batch-specific Certificates of Analysis (CoA) and Safety Data Sheets (SDS).

Liquid thiosulfates, sulfites and bisulfites are delivered in bulk road tankers, 1000 L IBC totes, plastic drums and 20 L canisters, while crystalline STS, Siccum and ATS grades are packed in moisture-resistant bags and FIBC big bags.

Pricing, minimum order quantities and delivery lead times for CWK Sulfur Chemicals are calculated individually upon commercial request; public price lists are not published by the manufacturer, and batch-specific CoA/SDS documents accompany each shipment.

We operate as an independent B2B supplier, not an authorized distributor of Chemiewerk Bad Köstritz GmbH.