Flux Chemicals for Calcareous Refractory Sample Prep
Calcareous refractories are high-temperature materials mostly composed of calcium carbonate (CaCO3). Owing to the complex reaction mechanics of carbonation, calcareous aggregates make exceptional mortars as they have a positive long-term chemical effect on mortar behaviour. Additionally, calcites exhibit exceptional thermal properties such as melting points in the region of 1330°C (2430°F). These combined thermochemical qualities make calcareous minerals ideal aggregates for refractory concrete.
All industrial materials are subject to some form of quality assurance and control (QA/QC). In this article, we will explore the beneficial properties of calcareous refractories before discussing appropriate flux chemicals for sample preparation and analysis.
Why Use Flux Chemicals for Calcareous Refractories?
Castable refractories are important in a range of critical heat containment processes. They are a key form of insulation in ceramics manufacturing, steelmaking, and more, providing the necessary combination of moldability and high-temperature service to protect components throughout extreme operating temperatures—and in the presence of harsh chemistries. Flux chemicals are used in QC workflows to ensure materials are appropriate for harsh downstream applications.
Conventional castables exhibit typical cement contents in the region of 20% by weight. Their high-temperature performance is governed by cement chemistry with different aggregates affecting compressive strengths, flexural strengths, splitting tensile strengths, and moduli of elasticity. Generally speaking, calcareous refractories yield favourable mechanical performance at high temperatures compared to siliceous aggregates like granite.
Determining the cement content of distinct aggregates may be carried out via elemental analysis, particularly where their intended application is for conventional castables like refractory linings. Flux chemicals are used to prepare mineral samples like calcareous refractories for trace level elemental analysis, typically via X-ray fluorescence (XRF) or inductively-coupled plasma (ICP) spectroscopy.
The aim of borate fusion is to dissolve oxidized samples and free them from their mineral structures. One of the chief considerations here is achieving a neutral pH, which is achieved by altering the levels of borate salts, typically a ratio of lithium metaborate and lithium tetraborate, according to the melt chemistry. Ideal flux chemicals for calcareous refractories are relatively alkaline, so a ratio of 66:34 tetraborate to metaborate is often proposed for calcareous aggregate fusion.
Flux Chemicals from XRF Scientific
At XRF Scientific, we supply pre-mixed fusion flux chemicals suitable for calcareous refractories and alumino-silicate minerals. If you are looked for a standard batch mix, why not contact a member of the XRF Scientific team today? Additionally, we supply custom chemicals on-demand.
