Researchers have conducted significant studies focused on the properties of low cement high alumina gunning refractories, highlighting how different plasticizers can dramatically influence their effectiveness. By examining the impact of superplasticizers, this research pushes the boundaries of how these advanced materials are utilized, particularly within the steel and metal industries.
Refractories are integral to industrial operations, serving as protective linings for high-temperature applications. This research primarily investigates how rheological properties—essential for the adhesion of gunning mixtures—can be optimized by adjusting the composition of plasticizers such as carboxymethyl cellulose (CMC) and commercial binders like H19.
Fired at temperatures of 1100 °C and 1550 °C, the study identifies the gunning mixture with 1 wt% of ball clay as offering the best performance. This mixture showcased the highest strength, highest density, and lowest apparent porosity compared to other formulations. The research demonstrates the importance of tailoring gunning refractory mixtures to achieve optimal mechanical properties, which is particularly relevant for industries requiring durable materials under extreme conditions.
The researchers also explored the influence of water consumption on the mixtures. Differences in properties were attributed to the particle size and nature of the plasticizers. Samples containing H19 showed results aligning strongly with the desired characteristics but were less favorable when combined with CMC. Evaluations indicated mixtures containing higher amounts of commercial binders provided desirable properties, particularly at elevated firing temperatures.
According to the team, the role of silica proved significant during testing, particularly citing how excess silica can lead to unwanted low melting point phases, thereby affecting overall strength and structural integrity. Although these phases can contribute positively at certain firing temperatures, they can compromise the performance of the refractories under higher operational temperatures.
Analyzing various combinations results not only confirmed the influence of silica on mechanical properties but also underscored the need for comprehensive testing protocols to assess rheological performance. The study presents data from X-ray diffraction analyses and scanning electron microscopy, allowing for accurate visualizations of the material's behavior at different temperatures.
The findings revealed how these variants of low cement high alumina refractories cater to specific applications, emphasizing their potential for use within high-heat environments such as metal melting furnaces and kilns. Notably, Mix 4 illustrated ideal properties at 1550 °C, showcasing exceptional strength but also highlighting concerns over the presence of low melting point phases.
Lastly, the researchers strongly recommend using these optimized mixtures with care, particularly those containing high silica levels, due to potential performance reductions at higher temperatures. Further studies could refine these findings and explore the nuances of gunning mixtures, facilitating even greater advancements within the refractory materials sector.