Is cinder alkaline or neutral?

Everything must proceed from the objective reality, and the specific situation must be analyzed concretely. As we all know, the main component of pure coal is carbon. Coal is mixed with rocks or soil impurities. If the coal in some areas is mixed with substances containing phosphorus and potassium ore, there must be phosphorus and potassium in the cinder. Longyan in the author's area is a coal-producing area. The coal produced by Longyan is mainly mixed with iron, sulfur and calcium carbonate grind stone ore. Calcium carbonate grinder burns into lime, so there is lime in the cinder. Lime is an alkaline substance, coal cinder naturally shows alkaline reaction. China has a vast territory, and the composition of coal produced in different places is different, so the chemical composition and chemical properties of cinder are different. All things in the world have contradictions, which are universal as well as special. To analyze, study and resolve contradictions, we must adhere to the viewpoint of specific analysis of specific problems. Whether there are carcinogens in cinder, whether the composition of cinder produced in different places is the same, and whether there is clean cinder with aseptic and non-toxic, the study and analysis of these problems must be carried out according to different coal producing areas and different compositions. we can't use points instead of surfaces and generalize them. (Zhang Bingfu)