Grantee Research Project Results
Final Report: Industrial Process Pollution Reduction by Development of Amorphous Biogenic Silica to Replace Fumed Silica
EPA Contract Number: EPD15024Title: Industrial Process Pollution Reduction by Development of Amorphous Biogenic Silica to Replace Fumed Silica
Investigators: Chen, Haoran
Small Business: SioTeX Corporation
EPA Contact: Richards, April
Phase: I
Project Period: September 1, 2015 through February 29, 2016
Project Amount: $99,756
RFA: Small Business Innovation Research (SBIR) - Phase I (2015) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Air and Climate
Description:
Fumed silica is an important additive in many products including paints, plastics, and tires, and is a $1.5 billion market with a 6% growth rate. However, fumed silica producers rely on an energy-intensive, costly, and hazardous process. The air pollution resulting from the energy utilized to produce fumed silica is a combination of carbon emissions from the production of raw materials, energy generation, and overseas transportation as well as corrosive hydrogen chloride gas from the process. SioTeX, a specialty chemical and performance materials manufacturer, has developed a drop-in replacement for fumed silica. The patent pending technology uses rice hulls, an abundant biowaste, as the raw material. Biogenic silica is recovered from the rice hull and structured to meet the performance specifications of fumed silica. The process is simpler than the conventional method, consumes substantially less energy, and involves fewer toxic reactants. Every year, millions of tons of rice hulls are discarded to deteriorate in landfills, resulting in high levels of methane emissions. Field burning of biowaste rice hulls contributes to poor air quality by releasing fine particulates and carbon dioxide into the atmosphere.
Preliminary research shows that biogenic silica harvested from rice hulls is comparable to fumed silica in terms of surface area, particle size, and physical appearance. These properties are the three most important criteria regarding fumed silica applications. Our biogenic silica derived from rice hulls also provides improved material handling because of its higher bulk density. This feature reduces packaging, shipping, and storage costs without sacrificing performance.
This research project was directed at proving, fundamentally, the use of amorphous biogenic silica as a replacement for conventional synthetic fumed silica. It encompassed proving the process and scale-up, discovering the physical characteristics of biogenic silica from rice hulls, proving the performance characteristics in paints and coatings as compared to conventional fumed silica, proving the performance in epoxy resin, unsaturated polyester resin, and the performance in a thermoplastic elastomer. Additionally, focus was directed at ways in which the process can be made more economical and environmentally friendly such as water recovery and waste heat utilization.
Summary of Findings:
The process for producing amorphous biogenic silica developed by SioTeX is much more economical and environmentally friendly the conventional method for producing synthetic fumed silica. Figure 1 shows our proprietary process flow to make Eco-friendly, Eco-Sil.
Figure 1. Basic Process for Obtaining Eco-Sil, biogenic silica
The experiments conducted in this SBIR research project validate that the manufacture of high purity, amorphous, biogenic silica is not only reproducible but that it is economically scalable. The physical characteristic investigation reveals that the product is completely amorphous (free of hazardous crystallinity), very high purity of greater than 99.8%, none acidic, and was found to have a greater surface area than many grades of synthetic silica leading to excellent rheological performance. Our product has similar whiteness to that of fumed silica making it a great alternative in applications where color is of importance.
Conclusions:
How does Eco-Sil compare to other silica products? Eco-Sil is a biogenic, naturally sourced silica. Synthetic silica is the term used for any silica that is created chemically from quartz sand, silicon metal or other mineral sources. Synthetic silica comes in a variety of types that are used in a broad range of applications. The two most notable types are fumed silica and precipitated silica. Both are produced by very toxic and environmentally unfriendly chemical processes that involve hazardous chemical starting products and intermediates. The byproducts from the manufacturing of both types are also hazardous and difficult to manage leading to high production cost. Precipitated silica has a lower surface area, is not considered a true performance additive and has a low price point in most applications Fumed silica by contrast, has a high surface area that makes it a good performer as an additive. Problematically it has a low bulk density that makes it difficult to handle in manufacturing settings.
Our product Eco-Sil is a direct replacement for conventionally produced fumed silica. Eco-Sil has been tested and verified by third parties that it is a direct replacement for fumed silica. Additionally Eco-Sil has a unique very high surface area that gives it the performance characteristics of fumed silica but it also has the higher bulk density like precipitated silica that makes it more broadly useful and easier to integrate into commercial production. The two other key factors when comparing Eco-Sil to synthetic silica is that it is much less difficult to produce and can be made at a fraction of the cost. It doesn’t involve hazardous materials in the process or the waste stream. The raw material (rice hulls) is an abundant agricultural waste product. It is very inexpensive and in some cases cheaper than the sand used to make synthetic silica. The second factor is that we can make this material domestically saving on transportation costs and providing American jobs and an American made product.
Publications:
There have been no publications related to the work performed under this contract.
Commercialization:
SioTeX is currently prospecting and sampling Eco-Sil in the fumed silica market. Initially, SioTeX is prospecting and sampling customers in paint and coatings, unsaturated polyester resins, epoxy, inks, and silicones. Buyers are willing to adopt the technology if it is commercialized, because the amorphous biogenic silica is produced using rice hulls, an abundant, low cost, and renewable raw material. Annual production of millions of tons of rice hulls provides a solid and inexpensive raw material source. SioTeX has contacted approximately 175 potential customers in these industries and Eco-Sil is being tested by over 30 companies. Companies testing Eco-Sil are providing results and feedback to SioTeX. A technical director at a prominent architectural coatings company stated that Eco-Sil is a drop in replacement for fumed silica and is advantageous due to the eco-friendly composition of our product. SioTeX recently completed our first sale in the unsaturated polyester resin market to a manufacturer of kayaks, paddleboards, and recreational boats. SioTeX is also developing relationships with two reputable specialty chemical distribution companies. Specialty chemical distributors are already interested in exploring opportunities with SioTeX despite the fact that the company is still in pilot stages. Conventional fumed silica manufacturers tend to sell their products direct to the customer, cutting out the distribution channel. Fumed silica is a missing piece of many distributor’s product offerings.
SBIR Phase II:
Industrial Process Pollution Reduction by Development of Amorphous Biogenic Silica to Replace Fumed Silica | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.