CWK Silica — Köstropur & Köstrosorb micronised silica gels and Köstrosol colloidal silica sols

Supply amorphous silica materials from CWK Business Unit Silicas (Chemiewerk Bad Köstritz GmbH, Germany): Köstropur and Köstrosorb micronised silica gels for coatings, films and beer stabilization, and Köstrosol colloidal silica sols for precision foundry molds, refractories and CMP polishing.

CWK Köstrosorb® Silica Gels for Beer & Beverage Stabilization

CWK Köstrosorb synthetic amorphous silica gels (supplied as xerogels and hydrogels with controlled residual moisture of 2–60%) selectively bind haze-forming proteins in beer and beverages to prevent chill haze and are completely removed during filtration.

Commercial grades: Köstrosorb 1008, 1008F, 1015, 1020, 3015 and hydrogel grade 6015
Controlled particle size d50 within 2–25 µm and BET specific surface area of 300–420 m²/g
Preserves natural foam stability, hop bitterness, color and sensory profile of the beer
Applications: inline dosing ahead of kieselguhr, candle, sheet or membrane beer filters

CWK Köstropur® Matting Silica Gels for Paints & Coatings

CWK Köstropur micronised silica gels feature a narrow particle size distribution (d50 2–25 µm) and high pore volume (0.4–2.0 cm³/g), providing reproducible gloss reduction in clear and pigmented wood coatings, coil coatings, leather finishes, plastic lacquers and UV-curable systems.

Fine untreated matting grades: Köstropur 020308, 020408, 020508, 020612, 020812, 021012
Medium and high-pore-volume grades: Köstropur 050612, 050618, 050818, 051818, 100612, 100808
Wax-treated grades Köstropur W050618 & W050818 preventing hard settling in low-viscosity clearcoats
High shear-dispersion efficiency without milling, maintaining optical clarity and scratch resistance

CWK Köstropur® Silica Gels for Film Anti-Blocking, Inkjet & Carriers

In polymer film extrusion and specialty paper converting, Köstropur micronised silica gels create micro-roughness on BOPP, PE and PET film surfaces to prevent roll blocking, rapidly absorb ink droplets on inkjet media and act as free-flowing carriers for liquid active ingredients.

High-clarity anti-blocking masterbatch additives for BOPP, CPP, LDPE, LLDPE and PET packaging films
Microporous ink-receptive coating pigment for high-resolution inkjet papers and specialty films
High-absorption carrier and free-flow aid for pharmaceuticals, cosmetics and feed additives
Tailored particle size d50 (2–25 µm) and pore volume (0.4–2.0 cm³/g) matched to film thickness

CWK Köstrosol® Silica Sols for Lost-Wax Foundry Shells & Refractories

CWK Köstrosol aqueous colloidal silica dispersions (up to 50% SiO2, 3–100 nm particle size) serve as high-purity inorganic binders for precision lost-wax foundry ceramic shells and vacuum-formed ceramic refractory fiber boards, shapes and monolithics.

Foundry & refractory grades: Köstrosol 0830, 1030, 1430 F, 1530, 1540, 2030, 2040, 3040, 3530 F, 3550, 4550
Fast-gelling and modified formulations: Köstrosol F, FS, P-FS and ammonia-stabilized AS grades
Superior green and fired ceramic shell strength with zero VOC emissions compared to ethyl silicate
Applications: aerospace turbine foundry molds, precision steel foundries, refractory fiber insulation and kiln furniture

CWK Köstrosol® Silica Sols for Wine, Juice & Beverage Fining

In winemaking, fruit juice processing and brewing, beverage-grade Köstrosol colloidal silica sols act as powerful anionic flocculants in combination with gelatin or plant proteins, rapidly agglomerating suspended haze particles into compact sediment for fast clarification.

Beverage fining grades: Köstrosol 1530, 1540, 2030, 2040 and tailored food-grade dispersions
15–40% SiO2 concentration with high negative surface charge density for rapid protein-tannin flocculation
Forms a dense lees layer, minimizing beverage volume loss and extending filter sheet service life
Chemically inert amorphous silica that leaves wine aroma, fruit acidity and color unchanged

CWK Köstrosol® Silica Sols for Coatings, Paper, Textiles & Catalysts

Köstrosol nanodispersions (including sodium-free AS grades, potassium KD grades, cationic K 1530 and alumina-modified AD grades) enhance hardness, anti-soiling and fire resistance in architectural coatings, improve retention and drainage in papermaking, and bind extruded catalysts.

Sodium-free ammonia-stabilized grades: Köstrosol 0830 AS, 1530 AS, 2040 AS, 3540 AS
Potassium-stabilized grades for silicate paints: Köstrosol 1030 KD, 1430 KD, 1530 KD, 1540 KD, 2040 KD
Cationic Köstrosol K 1530 and alumina-modified Köstrosol AD 0820, AD 1530, AD 2035
Applications: mineral facade coatings, wet-end papermaking retention, textile anti-slip finishes, catalyst carriers

CWK Köstrosol® Silica Sols for Semiconductor CMP Polishing & Gel Batteries

High-purity large-particle and bimodal Köstrosol grades (up to 100 nm particle size and 50% SiO2 concentration) are formulated into Chemical Mechanical Planarization (CMP) slurries for silicon wafers, sapphire and optics, and serve as electrolyte gelling agents in GEL VRLA batteries.

Large-particle and high-solids grades: Köstrosol 3550, 4550, 9550, 2018 DD, A 1530, WA 1530
Monodisperse or controlled spherical SiO2 particles (3–100 nm) for scratch-free wafer planarization
Thixotropic sulfuric acid electrolyte immobilization in deep-cycle GEL lead-acid batteries
Tightly controlled trace metal purity and batch-to-batch particle size reproducibility

Custom Silica Tailoring, Industrial Packaging & Temperature-Controlled Logistics

CWK's R&D laboratories and flexible production lines in Bad Köstritz customize particle size distribution, pore volume, pH, stabilizing counter-ions and surface treatments of Köstropur, Köstrosorb and Köstrosol grades to match specific customer formulations.

Certified manufacturing under DIN EN ISO 9001:2015, DIN EN ISO 14001:2015 and DIN EN ISO 50001:2018
Köstropur & Köstrosorb packaging: palletized multi-wall paper/PE valve bags and FIBC big bags
Köstrosol packaging: canisters, plastic drums, 1000 L IBC totes and insulated bulk road tankers
Frost-protected transport (+5°C to +35°C) for aqueous colloidal silica dispersions with batch CoA

CWK Business Unit Silicas (Geschäftsbereich Kieselsäuren) overview

The Silicas Business Unit of Chemiewerk Bad Köstritz GmbH (CWK Silica, located at Heinrichshall 2, 07586 Bad Köstritz, Thuringia, Germany; General Manager Dr. Thomas Pautzsch) specializes in the synthesis and surface engineering of high-purity amorphous silicon dioxide materials.

Production is structured around two core product families: micronised synthetic silica gels marketed under the Köstropur® and Köstrosorb® brands, and aqueous colloidal silica dispersions (silica sols) marketed under the Köstrosol® brand.

To request a technical quote, specify the exact grade code (such as Köstropur 050618, Köstrosorb 1015 or Köstrosol 2040 AS), target particle size or SiO2 concentration, batch volume and preferred packaging.

Köstropur® and Köstrosorb® micronised silica gels: grade coding and pore structure

CWK synthetic amorphous silica gels are engineered with 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 tailored loss on ignition (residual moisture) between 2% and 60%.

The Köstropur series covers untreated fine grades (020308, 020408, 020508, 020612, 020812, 021012), medium and high-porosity grades (050612, 050618, 050818, 051818, 100612, 100808) and wax-modified anti-settling grades (W050618, W050818) for matting coatings, anti-blocking polyolefin films, inkjet

media and active ingredient carriers.

The Köstrosorb series (xerogels and hydrogels 1008, 1008F, 1015, 1020, 3015 and 6015) is specifically designed for beer and beverage stabilization, selectively adsorbing haze-active polypeptides while leaving foam-positive proteins untouched.

Köstrosol® colloidal silica sols: particle sizes (3–100 nm) and stabilization chemistries

Manufactured at the Bad Köstritz plant since 1996, Köstrosol silica sols are stable aqueous dispersions of discrete, non-porous spherical SiO2 nanoparticles with diameters from 3 to 100 nm, silica contents from 7% to 50% and Sears specific surface areas of 40–800 m²/g.

Standard anionic sodium-stabilized grades include Köstrosol 0515, 0730, 0830, 1030, 1040, 1430 F, 1530, 1540, 2018 DD, 2030, 2030 D, 2030 F, 2040, 2040 F, 2040 FS, 3040, 3530 F, 3550, 3550 F, 3550 P-FS, 4550 and 9550, where the numeric code indicates nominal particle size (nm) and SiO2 concentration

(%).

Modified grades include sodium-free ammonia-stabilized AS grades (0830 AS, 1530 AS, 2040 AS, 3540 AS), potassium-stabilized KD grades (1030 KD, 1430 KD, 1530 KD, 1540 KD, 2040 KD), alumina-modified AD grades stable across broader pH ranges (AD 0820, AD 1530, AD 2035) and cationic Köstrosol K 1530.

Lost-wax foundry ceramic shells, refractories and industrial applications

In precision lost-wax foundries, Köstrosol 1430 F, 1530, 2030, 2040, 3040 and fast-drying F/FS/P-FS grades act as VOC-free inorganic binders for primary and backup ceramic shell coats, delivering high green strength and dimensional accuracy during alloy pouring.

In refractory manufacturing, Köstrosol binds vacuum-formed ceramic fiber boards, burner blocks and monolithic linings; in winemaking and juice processing, beverage grades clarify suspended solids in combination with gelatin.

In electronics and energy storage, high-purity large-particle Köstrosol grades (3550, 4550, 9550) provide scratch-free Chemical Mechanical Planarization (CMP) of silicon and sapphire wafers and immobilize sulfuric acid electrolytes in GEL VRLA batteries.

Quality assurance (ISO 9001 / 14001 / 50001), packaging and frost-free logistics

All CWK Silica products are manufactured in Germany under DIN EN ISO 9001:2015, DIN EN ISO 14001:2015 and DIN EN ISO 50001:2018 certified management systems and supplied with batch-specific Certificates of Analysis (CoA).

Dry Köstropur and Köstrosorb silica gels are shipped in moisture-resistant palletized bags and FIBC big bags, while liquid Köstrosol silica sols are delivered in canisters, drums, 1000 L IBC totes and insulated tankers under frost-free conditions (+5°C to +35°C).

Pricing, minimum order quantities and lead times for CWK Silica products 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.