Silica, Synthetic Silica and Fumed Silica – Definition and Relationship

Silica, also known as silicon dioxide, is divided into two categories: natural silica and synthetic silica.

Natural silica

Natural silica is usually quartz powder or silica fumed/micro silica. Synthetic silica is an amorphous synthetic silicon oxide powder material.

Synthetic silica

Synthetic silica is white flocculent powder with physical properties of high-temperature resistance, non-combustibility, non-toxicity, odorlessness, and good electrical insulation.

Therefore, it is widely used in the fields of rubber, plastics, coatings, adhesives, sealants, insulation materials, and others.

Synthetic silica is classified according to manufacturing methods, mainly into fumed silica and precipitated silica.

fumed silica VS precipitated silica

What is fumed silica? – Definition & Properties

Fumed silica, also known as colloidal silicon dioxide, is made by high-temperature hydrolysis in a hydrogen-oxygen flame of silicon halides, mainly methyl silicochloroform (CH3SiCl3) or tetrachlorosilane (SiCl4). It is an amorphous nanoscale white powder with surface hydroxyl groups. Fumed silica appears as a white fluffy powder. It is a non-toxic, odorless, tasteless, and non-polluting inorganic oxide.

Fumed silica itself is hydrophilic, but its surface can be modified with hydrophobic groups to obtain hydrophobic fumed silica.

Fumed silica has an amorphous structure, small particle size, large specific surface area, high chemical purity and good dispersibility. It exhibits excellent performance in reinforcement, thickening, thixotropy, anti-settling, anti-sagging, moisture-adsorption, and thermal insulation.

Difference comparison table

The main differences between fumed silica and precipitated silica are in below aspects:

  • Manufacturing methods & raw materials,
  • Main Physico-chemical Data,
  • Application Industries
  • Cost & Price.
Fumed SilicaPrecipitated Silica
Manufacturing methods & Raw materialssilicon halides, mainly methyl trichlorosilane and silicon tetrachloride, are used as raw materials. They undergo high-temperature combustion and hydrolysis with water in a gas-phase reactionTypically, sodium silicate, sulfuric acid, or hydrochloric acid is used for neutralization and precipitation reactions in a liquid phase to prepare the product
Main Physical and Chemical DataPurity ≥99.8%,
moisture content typically less than 2%,
free from crystalline water,
is anhydrous silica dioxide,
specific surface area ranges from 100-400 ㎡/g,
low drying loss, and surface contains highly active silicon hydroxyl groups.
The primary particle size of silica dioxide is between 7-40nm
moisture content 4-8%,
ignition loss≤7%,
specific surface area typically ranges from 100-200㎡/g,
higher drying loss compared to fumed silica products
Application IndustriesFumed silica is widely used in various industries such as the silicone industry, mainly silicone rubber, printing inks, coatings, synthetic resins, adhesives, chemical mechanical polishing, composite materials, thermal insulation materials, colloidal batteries, pharmaceuticals, personal care products, and food.Precipitated is used in industries such as rubber, tires, footwear manufacturing, toothpaste, animal feed, paints and coatings, and battery separators.
Cost and PricePurity ≥99.8%,
moisture content typically less than 2%,
free from crystalline water,
is anhydrous silica dioxide,
specific surface area ranges from 100-400 ㎡/g,
low drying loss, and the surface contains highly active silicon hydroxyl groups.
The primary particle size of silica dioxide is between 7-40nm
low raw material cost and
price compared to fumed

Further Reading:

Related Products

Hubei Huifu Nanomaterial Co., Ltd. manufactures more than 10 grades of fumed silica, both hydrophilic and hydrophobic. We get ISO, REACH, and participate in setting ISO18473-3-2018, ISO18473-1-2015, and ISO23157. We are strong in R&D product quality and factory capacity. Feel free to contact us by email:


Our main products are fumed silica SiO2, fumed titanium dioxide TiO2, and fumed alumina Al2O3. We get 20+ years of expertise and 20,000 tons of annual capacity. We supply total of 23 grades of hydrophilic & hydrophobic fumed silica. We get registration of REACH and pre-registration of K-REACH & KKDIK. We are the leading setting body of ISO18473-1:2015ISO18473-3:2018, and ISO 23157:2021. Learn More About Hifull

Frequently Asked Question

A Manufacturer. Hubei Huifu has been researching and manufacturing fumed silica for 20+ years. We are the largest manufacturer of fumed silica with a well-developed and stable manufacturing process in China.
We get registration of REACH and pre-registration of K-REACH & KKDIK. We get certificates of ISO 9001, ISO 14001. We are the leading setting body of ISO18473-1:2015, ISO18473-3:2018 and ISO 23157:2021.

  • Manufacturer: Leading fumed silica manufacturer in China with 20+ years of expertise, 12,000 tons annual capacity 
  • Registration & Certificate: REACH, K-REACH, KKDIK, ISO9001, HALAL, KOSHER
  • Manufacturer Direct Supply: 23 grades of hydrophilic; hydrophobic fumed silica supplied, good quality, competitive price
  • International Standard: Leading setting body of ISO18473-3-2018 Fumed silica for silicone rubber application; Member of the setting body of ISO18473-1-2015 Nanoscale calcium carbonate for sealant application
  • Technology Expertise: 50+ technology patents experienced R&D team from top universities of China Project 211 & Project 985 

Free Sample: All grades of fumed silica sample available, Contact to Us

Pyrohydrolysi & Trichloromethylsilane

Fumed silica is synthesized by the pyrohydrolysis of silicon tetrachloride or trichloromethylsilane in the flame of hydrogen and oxygen. Our main raw material is silicon tetrachloride, and the secondary is trichloromethylsilane.

Hydrophilic Fumed Silica SiO2:

HL-150 / HL-200 / HL-300 / HL-380 / HL-150W / HL-200W

Hydrophobic Fumed Silica SiO2:

DDS Treated — HB-151/ HB-152 ;
PDMS Treated — HB-139 ;
HMDS Treated — HB-132 / HB-135 / HB-612/ HB-615 / HB-620 / HB-630.

Fumed Titanium Dioxide TiO2: NT-50

Fumed Aluminium Oxide Al2O3: Aluna-80 & Aluna-100

Price is based on the actual grade.

When the price of raw material fluctuates, we may adjust the price accordingly, please enquire before placing orders. Our email: Cell : + 8618571019514

When fumed silica is used as filler or additives, it helps in thickening, reinforcement, transparency, free-flow, thixotropic performance, dielectric properties, anti-settling, heat insulation, and anti-sagging. For example, for powder products, HIFULL fumed silica is used as an anti-caking agent; for liquid products, HIFULL fumed silica is used as an anti-settling agent or suspending agent.

ApplicationsFunctionsRecommended Dosage
Paints & Coatingsrheology & thixotropic control,anti-sagging,anti-settling0.5-2%
UPR, Gel Coatrheology & thixotropic control,,anti-sagging,anti-settling0.5-2%
HTV Silicone Rubberreinforcement15-30%
RTV Silicone Rubberthickening & reinforcing10-20%
Adhesivesrheology & thixotropic control, anti-sagging,anti-settling2-10%
Cable Gelthickening5-10%
Gel Batterythickening0.5-6%
Industrial Powdersanti-caking0.5-1%

Quality Stabilization: we are the earliest fumed silica manufacturers with independent R&D in China, which guarantees our product stabilization.

Largest Manufacturer: Our annual output of fumed silica is about 12,000 tons.

Strong R&D Team: Besides our own R&D institute and application& technology department, we’ve to build a research center with Sichuan University and Wuhan University, both are top-tier universities in China.

Leading Authority: We have already been the influential enterprise in the silicon industry in China. Doctor Wang Yuelin, the actual controller of Hifull, is the leader of the Sino-Germany project ISO18473-3 << Fumed Silica for Silicon Rubber>> and he is granted the Outstanding Contribution Award by the committee.

Mainly T/T, L/C and D/P, actual payment terms please check with sales when placing orders.

We will arrange delivery immediately according to the manufacturing schedule and conditions. Due to shipping schedule or other factors, please check with sales when placing orders.

Still have questions?

If you cannot find an answer to your question in our FAQ, you can always contact us and we will be with you shortly.

Contact Support

Hello, Customers

My name is Van, I’m the business manager of HIFULL, I have been in Fumed Silica Industry for more than 10 years. Feel free to contact me. I’m happy to provide you the best service and products.
Business Manager