CWK (Chemiewerk Bad Köstritz) silica gels, colloidal silica sols, molecular sieves and sulfur chemicals

Supply industrial adsorbents and specialty chemicals manufactured by Chemiewerk Bad Köstritz GmbH (CWK, Germany): Köstropur and Köstrosorb micronised silica gels, Köstrosol colloidal silica dispersions, Köstrolith zeolitic molecular sieves and sulfur chemicals.

Micronised Synthetic Silica Gels CWK Köstropur®

CWK Köstropur synthetic amorphous micronised silica gels (Silica Division) feature a precisely controlled average particle size (d50) from 2 to 25 µm and pore volume of 0.4–2.0 cm³/g, engineered as matting agents for industrial coatings, anti-blocking additives for polyolefin films and receptive

coatings for inkjet papers.

Particle size d50 of 2–25 µm, pore volume 0.4–2.0 cm³/g and BET specific surface area 300–420 m²/g
Standard grades: Köstropur 020308, 020408, 020508, 020612, 020812, 021012, 050612, 050618
Specialty grades: Köstropur 050818, 051818, 100612, 100808 and wax-treated W050618, W050818
Applications: wood and coil coatings matting, PP/PE/PET film anti-blocking, pharma & feed carriers

Beer & Beverage Stabilization Silica Gels CWK Köstrosorb®

CWK Köstrosorb specialized food-grade silica gels (xerogels and hydrogels with residual moisture from 2% to 60%) selectively adsorb haze-forming proteins in beer and beverages, preventing chill haze without altering foam stability, flavor profile or natural color.

Available as xerogels and hydrogels with tailored loss on ignition / moisture content (2–60%)
Commercial product grades: Köstrosorb 1008, 1008F, 1015, 1020, 3015 and 6015
Completely removed together with bound protein complexes during standard beer filtration
High chemical purity verified under CWK DIN EN ISO 9001:2015 quality management

Aqueous Colloidal Silica Dispersions CWK Köstrosol®

CWK Köstrosol silica sols are stable aqueous dispersions of discrete amorphous SiO2 nanoparticles ranging from 3 to 100 nm with silica concentrations from 7% to 50%, serving as high-temperature binders for lost-wax foundry molds and refractories, beverage fining agents and CMP polishing slurries.

Particle size 3–100 nm, SiO2 concentration 7–50% and Sears specific surface area 40–800 m²/g
Anionic grades: Köstrosol 0515, 0730, 0830, 1030, 1040, 1430 F, 1530, 1540, 2030, 2040, 3040, 3550, 4550, 9550
Specialty grades: ammonium-stabilized AS, cationic K 1530, and alumina-modified AD (AD 0820, AD 1530, AD 2035)
Applications: precision lost-wax ceramic shells, refractory fibers, wine/juice clarification, semiconductor CMP

Type A Zeolitic Molecular Sieves (3A, 4A, 5A) CWK Köstrolith®

CWK Köstrolith Type A synthetic hydrophilic zeolitic molecular sieves (Business Unit Molecular Sieves) are manufactured as 1–5 mm spherical beads, extruded pellets and micronised powders for deep dehydration of industrial gases, solvents, refrigerants, insulating glass and polyurethanes.

Köstrolith 3AK & 3ABFK (~3 Å pores): selective drying of ethylene, propylene, ethanol, methanol and IGU frames
Köstrolith 4AK & 4ABFK (~4 Å pores): universal dehydration of natural gas, compressed air, LPG and solvents
Köstrolith 5AK & 5ABFK (~5 Å pores): normal/iso-paraffin separation and hydrogen PSA purification
Active zeolite content from 80% (standard clay-bound K beads) up to 100% (binder-free BFK beads)

Large-Pore Zeolites 13X, NaMSX, NaY, SX6 & Thermal Regeneration CWK Köstrolith®

CWK Köstrolith Type X and Type Y molecular sieves (~9–10 Å pore aperture) and lithium-exchanged grades are engineered for cryogenic air separation pre-purification, hydrocarbon sweetening and PSA/VPSA oxygen generation, backed by factory thermal regeneration services.

Köstrolith NaMSXK & binder-free 13XBFK: simultaneous H2O, CO2 and mercaptan removal in cryogenic ASU and LPG plants
Köstrolith NaYK & NaYBFK faujasite zeolites: VOC emission control, solvent recovery and specialty catalysis
Köstrolith SX6K high-capacity adsorbent: industrial and medical PSA / VPSA oxygen concentrators
Factory services: thermal regeneration of spent molecular sieves and custom contract granulation

Sodium (STS), Ammonium (ATS) & Potassium (KTS) Thiosulfates CWK Sulfur Chemicals

The CWK Sulfur Chemicals division manufactures high-purity sodium, ammonium and potassium thiosulfates as aqueous solutions, crystalline pentahydrate and anhydrous powder for water dechlorination, pulp bleaching, non-cyanide gold leaching, photographic fixing and liquid fertilizers.

Sodium thiosulfate (STS, Na2S2O3): 30% and 50% solutions, pentahydrate crystals and anhydrous 'Siccum' powder
Ammonium thiosulfate (ATS, (NH4)2S2O3): high-purity aqueous solution and crystalline solid grades
Potassium thiosulfate (KTS, K2S2O3): clear aqueous solution for chloride-free K-S foliar fertilizers and synthesis
Applications: water & textile dechlorination (antichlor), gold/silver leaching, X-ray & photo processing

Aqueous Ammonium & Potassium Sulfite and Bisulfite Solutions CWK

Chemiewerk Bad Köstritz produces high-purity aqueous solutions of ammonium sulfite, potassium sulfite, ammonium bisulfite and potassium bisulfite used as oxygen scavengers in boiler water treatment, reducing agents in chemical synthesis, and processing chemicals in leather and paper manufacturing.

Sulfite solutions: aqueous ammonium sulfite ((NH4)2SO3) and aqueous potassium sulfite (K2SO3)
Bisulfite solutions: aqueous ammonium bisulfite (NH4HSO3) and aqueous potassium bisulfite (KHSO3)
Industrial packaging options: bulk road tankers, 1000 L IBC totes, drums and 20 L canisters
Applications: boiler water oxygen scavenging, chemical reduction, leather tanning, pulp & food processing

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

Commissioned in February 2022 at the Bad Köstritz site, CWK's state-of-the-art liquid sulfur combustion plant produces 96% concentrated sulfuric acid (H2SO4) with ultra-low metal impurities, tailored for battery electrolyte manufacturing and high-purity chemical synthesis.

96% H2SO4 concentration produced via direct liquid sulfur combustion (plant commissioned Feb 2022)
Ultra-low trace metal specification suitable for lead-acid and specialty battery manufacturing
Secures captive feedstock for CWK silica/zeolite synthesis alongside commercial bulk supply
Certified under DIN EN ISO 9001:2015, DIN EN ISO 14001:2015 and DIN EN ISO 50001:2018

Corporate structure of Chemiewerk Bad Köstritz GmbH (CWK) and its three business units

Chemiewerk Bad Köstritz GmbH (brand CWK, headquartered at Heinrichshall 2, 07586 Bad Köstritz, Thuringia, Germany; Commercial Register HRB 200380 Amtsgericht Jena; Managing Director Dr.

Lars Böttcher) traces its industrial origins to the Saline Heinrichshall saltworks founded in 1831 and has operated continuously as a chemical manufacturing plant since 1848.

CWK organizes its specialized production across three dedicated divisions: Business Unit Silicas (headed by Dr. Thomas Pautzsch), Business Unit Molecular Sieves (headed by Dr. Kristin Gleichmann) and Business Unit Sulfur Chemicals (headed by Dr. Tilo Breyer).

When requesting a quotation, please specify the CWK product brand (Köstropur, Köstrosorb, Köstrosol, Köstrolith or sulfur chemical formula), grade number, target particle or pore size, and required industrial packaging.

Business Unit Silicas: Köstropur® and Köstrosorb® micronised silica gels

CWK manufactures synthetic amorphous micronised silica gels with precisely controlled median particle sizes (d50) from 2 to 25 µm, pore volumes from 0.4 to 2.0 cm³/g, BET specific surface areas of 300–420 m²/g and loss on ignition (moisture content) ranging between 2% and 60%.

Köstropur grades (020308, 020408, 020508, 020612, 020812, 021012, 050612, 050618, 050818, 051818, 100612, 100808, plus wax-coated W050618 and W050818) serve as high-efficiency matting agents in wood, coil and industrial coatings, anti-blocking additives for PP, PE and PET packaging films, and

functional fillers for inkjet media.

Köstrosorb xerogel and hydrogel grades (1008, 1008F, 1015, 1020, 3015, 6015) are engineered for colloidal stabilization of beer and beverages, selectively binding haze-active proteins without affecting foam stability or flavor and filtering out completely.

Köstrosol® aqueous colloidal silica dispersions (silica sols)

Produced in Bad Köstritz since 1996, Köstrosol colloidal silica sols are stable aqueous dispersions of discrete, non-porous amorphous SiO2 nanoparticles with diameters from 3 to 100 nm, silica concentrations of 7–50 wt% and Sears specific surface areas of 40–800 m²/g.

The portfolio covers sodium-stabilized anionic grades (0515, 0730, 0830, 1030, 1040, 1430 F, 1530, 1540, 2030, 2040, 3040, 3530 F, 3550, 4550, 9550), potassium-stabilized KD grades, ammonia-stabilized AS grades (0830 AS, 1530 AS, 2040 AS, 3540 AS), cationic K 1530 and alumina-modified AD grades (AD

0820, AD 1530, AD 2035).

Köstrosol dispersions function as high-temperature inorganic binders for precision lost-wax foundry ceramic shells and vacuum-formed refractory fibers, fining agents for wine and fruit juice clarification, battery electrolyte gelling agents, and semiconductor CMP polishing slurries.

Business Unit Molecular Sieves: Köstrolith® synthetic zeolites (Types A, X, Y)

CWK has developed and manufactured synthetic hydrophilic zeolitic molecular sieves under the Köstrolith brand since 1958. Available as 1–5 mm spherical beads, extruded pellets and powders, Köstrolith grades feature active zeolite contents between 80% and 100%.

Köstrolith 3AK and binder-free 3ABFK (~3 Å pores) dehydrate unsaturated hydrocarbons (ethylene, propylene, cracked gas), alcohols (ethanol, methanol), refrigerants and insulating glass units without co-adsorbing hydrocarbons; 4AK and 4ABFK (~4 Å) provide universal drying for natural gas, compressed

air and polyurethane systems; 5AK and 5ABFK (~5 Å) separate normal and iso-paraffins and purify hydrogen via PSA.

Large-pore zeolites Köstrolith NaMSXK, 13XBFK, NaYK and NaYBFK (~9–10 Å) remove H2O, CO2 and mercaptans in cryogenic air separation units (ASU) and LPG sweetening, while lithium-exchanged Köstrolith SX6K delivers high nitrogen selectivity in medical and industrial PSA/VPSA oxygen generators.

Business Unit Sulfur Chemicals: thiosulfates, sulfites, bisulfites and 96% sulfuric acid

The CWK Sulfur Chemicals division supplies sodium thiosulfate (STS: 30% and 50% solutions, pentahydrate crystals, anhydrous Siccum powder), ammonium thiosulfate (ATS: solution and crystals) and potassium thiosulfate (KTS: solution) for water dechlorination, pulp and textile bleaching, non-cyanide

gold leaching, photographic fixing and sulfur fertilizers.

In parallel, CWK produces aqueous solutions of ammonium sulfite ((NH4)2SO3), potassium sulfite (K2SO3), ammonium bisulfite (NH4HSO3) and potassium bisulfite (KHSO3) delivered in road tankers, 1000 L IBC totes, drums and 20 L canisters for boiler water oxygen scavenging, chemical synthesis and

leather tanning.

Since February 2022, CWK operates a new liquid sulfur combustion plant producing 96% concentrated sulfuric acid (H2SO4) with ultra-low metal impurities for battery manufacturing and fine chemical processes, all certified under DIN EN ISO 9001:2015, ISO 14001:2015 and ISO 50001:2018.

International B2B supply, packaging options and temperature-controlled logistics

We coordinate global export supply of CWK specialty silica products, zeolitic molecular sieves and sulfur chemicals in factory-sealed drums, big bags, IBC totes and bulk containers.

Frost-sensitive aqueous Köstrosol dispersions are shipped under temperature-controlled conditions, while hygroscopic Köstrolith molecular sieves are packed in moisture-tight steel drums or lined big bags to preserve full adsorption capacity.

Send us your target CWK grade, technical datasheet requirements and delivery destination to receive a tailored commercial offer.

Lead times, minimum order quantities and pricing for CWK materials are calculated individually upon commercial request; public price lists are not published by the manufacturer, and batch-specific CoA/SDS documentation is provided with shipment.

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