This standard is an analytical method standard for the determination of the pH value of carbon black, with its core focus on specifying two methods: the boiling slurry method (Method A) and the ultrasonic slurry method (Method B). It is applicable to carbon black samples used in rubber, acetylene carbon black, pigment carbon black, and other types of carbon black. The test primarily involves analyzing the acidity or alkalinity of the aqueous phase after preparing a slurry of carbon black with deionized water to indicate the relative acidity or alkalinity on the surface of the carbon black. For evaluation, a laboratory pH meter calibrated with standard buffer solutions must be used, along with a magnetic stirrer to ensure sample uniformity. The pH value of carbon black is a key indicator affecting its vulcanization process in rubber compounds, making this determination method significant for the quality control of carbon black production and the formulation and processing of downstream rubber products.