河沙是天然矿石在山洪急流中互相碰撞、摩擦脱落下来的沙粒。多少年来,沉积在河床沙滩之上。因矿石的种类和结构不同,河沙又分粗沙和细沙两种。河沙的沙粒小,颗粒均匀,质地坚硬,无毒耐氧化,且相互间具有吸热传热的性能,传热速度快、无粘性、不溶于水,完全干燥时,呈半流 River sand is the natural ore in flash floods collide with each other, friction off the sand down. For years, it has been deposited on beach beds. Because of the different types of ore and structure, river sand is divided into two kinds of coarse sand and fine sand. The sand has small sand grains, uniform grains, hard texture, non-toxic and anti-oxidation, and has the characteristics of endothermic heat transfer between each other, heat transfer speed, non-sticky, insoluble in water, completely dry,