Solubility mainly refers to the ability of the metal elements in the fibers to be largely decomposed by lung fluid. Secondly, when the used fibers are disposed of as waste and buried, the required degradation cycle is shorter than that of traditional fibers.

Soluble fibers are eco-friendly inorganic refractory fibers primarily composed of SiO?, CaO, and MgO. In addition to possessing the advantages of traditional aluminosilicate refractory ceramic fibers, the chemical composition of these fibers meets the requirement that “the weight percentage of alkali oxides and alkaline earth oxides in man-made vitreous fibers is greater than 18%.” Their dissolution rate of 50–250 ng/cm2·hr meets the EU KNB index and the German KI index, and they contain no carcinogenic substances.

The application fields of soluble fiber products are similar to those of traditional ceramic fibers. However, due to the lower refractoriness of their main elements, they cannot replace traditional ceramic fibers in some areas. Limited by current technological levels and process equipment, soluble fiber products are currently only suitable for thermal conditions with long-term use temperatures below 1050°C.