The TAPPI T 244 standard specifies a method for the determination of acid-insoluble ash content in wood, pulp, paper and Cardboard. After the sample is dried and ashing, the residue is treated with muriatic acid to filtrate, wash, ignite and weigh the insoluble residue. This method is suitable for cellulose samples and provides rapid measurement of all acid-insoluble substances, but with lower accuracy than wet ashing methods (e.g. TAPT PI 245). Acid-insoluble ash is mainly composed of silica or silicate. If the content is too high, it may cause the paper to cause abrasion on metal parts during printing or processing. This standard provides scientific testing methods for the paper industry to help control the mass of raw materials and products and ensure that paper performance meets requirements.