Researchers have developed a groundbreaking process to transform titanium white waste acid (TWWA) – a major byproduct from titanium dioxide production – into high-quality gypsum for construction applications. By utilizing TWWA and lime mud as raw materials, the team successfully synthesized short columnar α-calcium sulfate hemihydrate (α-HH) crystals in a single-step hydrothermal reaction. This innovative approach not only addresses the environmental concerns associated with TWWA disposal but also provides a cost-effective and sustainable solution for the building materials industry.
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Tackling Titanium Waste with Innovation
Titanium dioxide (TiO2) is a widely used pigment in a variety of industries, from paints and coatings to plastics and cosmetics. In China, more than 90% of TiO2 is produced using the sulfuric acid method, which generates a significant amount of titanium white waste acid (TWWA) as a byproduct. This acidic waste solution, with a high water content and viscosity, poses a major environmental challenge due to its potential for secondary pollution.
Transforming Waste into Valuable Building Material
In a groundbreaking study, a team of researchers from Hubei University in China has developed a novel approach to address this issue. They have successfully transformed TWWA and kiln’>lime production process) into high-quality α-calcium sulfate hemihydrate (α-HH) – a valuable material used in the construction industry.
The researchers utilized a one-step hydrothermal synthesis method, where TWWA and lime mud were combined in the presence of diffraction’>X-ray diffraction (XRD), electronmicroscopy’>scanning electron microscopy (SEM) confirmed the high purity and crystallinity of the α-HH products.
Exceptional Mechanical Properties
The researchers also evaluated the mechanical properties of the synthesized α-HH, which were found to be on par with commercially available high-strength gypsum. According to the Chinese standard for Click Here
![diffraction’>X-ray diffraction](https://en.wikipedia.org/wiki/Sodium<em>citrate’>sodium citrate</a> as a crystal modifier. This process resulted in the formation of short columnar α-HH crystals with a uniform size and excellent mechanical properties.</p>
<p><h3>Optimizing Crystal Morphology and Properties</h3>
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<p>The key to the success of this approach lies in the precise control of the α-HH crystal morphology. By adjusting the concentration of sodium citrate, the researchers were able to tune the length and diameter of the α-HH crystals, ultimately producing short columnar structures with an average aspect ratio of 2.4.</p>
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<p>Comprehensive analysis using techniques like <a href=){kind=link}
, the compressive strength of the α-HH samples after 7 days of curing was about 6.35 MPa, meeting the requirements for the first level of calcined gypsum.</p>
<p><figure class="wp-block-image size-large"><img decoding="async" src="https://famefreq.s3.us-east-2.amazonaws.com/1729685030_41598_2024_75949_Fig3_HTML.png" alt="figure 3" class="wp-image-3" /><figcaption class="wp-element-caption">Figure 3</figcaption></figure>
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<p>This remarkable performance can be attributed to the unique short columnar morphology of the α-HH crystals, which provides enhanced mechanical interlocking and improved overall strength compared to the more commonly observed rod-like or flaky gypsum structures.</p>
<p><h3>Sustainable and Cost-effective Solution</h3>
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<p>The proposed approach not only addresses the environmental concerns associated with TWWA disposal but also offers a cost-effective solution for the production of high-quality building materials. The researchers estimate that the cost of producing α-HH from TWWA and lime mud is significantly lower than the cost of traditional gypsum production, making it a highly competitive option in the construction industry.</p>
<p><figure class="wp-block-image size-large"><img decoding="async" src="https://famefreq.s3.us-east-2.amazonaws.com/1729685033_41598_2024_75949_Fig4_HTML.png" alt="figure 4" class="wp-image-4" /><figcaption class="wp-element-caption">Figure 4</figcaption></figure>
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<p><h3>Broader Implications and Future Prospects</h3>
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<p>This innovative research demonstrates the potential for transforming industrial waste into valuable resources. The successful synthesis of α-HH from TWWA and lime mud not only provides a sustainable solution for the titanium dioxide industry but also has broader implications for the circular economy and the development of advanced construction materials.</p>
<p>As the world continues to grapple with the challenges of waste management and resource scarcity, the work of these researchers offers a promising path forward, showcasing the power of scientific innovation to create a more sustainable future.</p>
<p>Author credit: This article is based on research by Xiaoxue Hu, Xunzi Zhang, Yiwei Dong, Luwei Chen, Tingting Yang, ChangfengYi, Qing Gao.</p>
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