Borates in Glass Manufacturing: Unbreakable Benefits, Unbeatable Versatility

:: Wednesday, October 23, 2019 :: Posted By Maryam Moravej
Glass is one of the oldest engineered technologies on earth. It is also one of the most promising modern technologies, an essential material in thousands of products we use every day. With ongoing research, process adaptations, and industry partnerships, glass manufacturers are helping to ensure a sustainable future for this versatile material.

Borates are a part of it all. Borosilicate glass provides the strength, resilience, and resistance to thermal shock, chemicals, and scratches that are essential in modern applications. U.S. Borax provides the high-quality borates that are required for today’s glass manufacturing processes—and the technical expertise to partner with industry researchers.

Borates in glass: Making a great technology even better

The value of borosilicate glass has been recognized by both consumers and industry for nearly 140 years. In 1882, German glass chemist Otto Schott discovered that optimizing the amount of boron in the glass recipe resulted in a type of glass that could endure uneven temperature shifts without shattering.
Today, glass manufacturers add 5-20% boric oxide to the silica base to significantly lower melting temperature and viscosity, inhibit crystallization of the glass, control thermal expansion, and inhibit devitrification. The resulting products have inherent durability and chemical resistance and are tough enough to withstand considerable mechanical or thermal shock.

Modern glass makers use borates in their formulations to produce a wide variety of products:
  • Borosilicate glass used in applications from pharmaceutical production to cookware to lighting
  • Insulation fiberglass (IFG or glass wool) used for energy savings in buildings
  • Super-fine glass fiber (microfiber glass) used for filtration paper, battery separators, and equipment insulation panels
  • Textile fiberglass (E-glass) used in electronics and for reinforcement of composites
  • Display glass, including thin film transistor (TFT) and liquid crystal display (LCD)
  • Special glass including optical glass, laboratory and technical glass, and heat-resistant borosilicate tubes
For these modern, often technical, applications, manufacturers must ensure that their end products meet a range of requirements—from industry and government compliance to customer specifications.

Quality starts with inputs: Benefits of refined borates

To maintain quality and consistency, glass manufacturers perform quality control monitoring and inspection through the whole process, from preparation of raw materials to the melting process to forming, annealing, and finishing.
Quality control methods and standards may differ across glass types. For example, display glass must meet strict standards for its optical properties and visual appearance, whereas visual appearance is less important in insulating glass. However, regardless of the application, quality and traceability of raw materials, including borates, is essential in glass manufacturing.
High-quality, consistent borates are essential because changes in raw materials affect the glass chemical and physical properties. Glass makers need to know the materials they add to their formulations will deliver a consistent level of boron and perform the same way in every melt.
Traceability of raw materials is also critical. If a quality issue does arise, glass manufacturers must be able to verify the original source of their borate products and confirm how they have been refined, packaged, and handled. This level of traceability helps manufacturers stay in compliance with any regulatory requirements and helps them to correct quality issues before they affect end customers.

U.S. Borax has a wide range of range of refined products, including sodium-containing and non-sodium-containing options, hydrous or anhydrous, and various particle size distributions (PSD) to meet customer needs. Our experts are available to consult with glass manufacturers to help them select the right 20 Mule Team® Borax products for their needs:
  • Neobor® and Dehybor® are used in the production of insulation fiberglass
  • Optibor® is recommended for producing textile fiberglass because of its low level of impurities and good consistency, which helps achieve a stable melting process
  • Display glass (TFT/LCD) also relies on the consistency of Optibor and boric oxide
  • Other borosilicate glasses use Neobor and Optibor as the primary borate products, and many manufacturers use Dehybor to improve production and lower energy costs

Using resources wisely to boost process efficiency and sustainability

Beyond quality management and performance, glass manufacturers leverage U.S. Borax products and experts to support their efforts to make better use of resources and reduce waste and emissions.
For example, refined borates enable better use of recycled glass in glass manufacturing operations. For most types of glass, an average of 15% recycled glass waste (cullet) is crushed and added as raw material to the glass melt, benefiting the environment, saving energy, and reducing costs. Among boron-containing glasses, insulation fiberglass is the top consumer of cullet.
However, the amount of recycled glass is often limited by the availability of borosilicate cullet, glass formulation restrictions, and contamination. Adding refined borates to complement non-boron-containing cullet is a common and recommended practice that enables manufacturers to control the quality and consistency of the melt and optimize the raw materials mix. Furthermore, using Dehybor can benefit manufacturers by enabling reduced energy consumption, higher furnace throughput, and lower overall production costs.
Practical optimizations like this are a part of the continuous improvement efforts of glass manufacturers. However, many organizations aim to go further to create a solid future for the industry.

Ongoing collaboration for a sustainable future

The North American glass industry, aided by the research and collaboration efforts of the Glass Manufacturing Industry Council (GMIC), is continually working to improve sustainability and energy efficiency while reducing carbon emissions.
As a corporate member of the GMIC since its inception in 1998, U.S. Borax participates in collaborative projects focused on energy efficiency (thermal energy regeneration/recuperation in glass manufacturing furnaces) and emission control (measurement and control of volatile organic compounds in glass manufacturing process) with glass industry partners. We are also involved in research on the combustion of renewable gases for heating raw materials and glass melts to facilitate an industry transition toward CO2-neutral glass melting furnaces.
U.S. Borax’s strong technical expertise and support is a key benefit for our customers, and we encourage customers to actively engage with us to explore projects. Glass manufacturers can take advantage of our internal and external lab services for glassmaking process analysis and testing. Our on-staff professionals have deep knowledge about the glass industry, can collaborate with manufacturers in application development, and can assist with technical enquiries. If you have a project that our expertise can help with, contact us.



U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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