The second is chemical sand fixation, which is to spray chemical bonding materials on the flowing sand, so that it forms a protective shell with certain strength on the surface of the sand, so that the sand dust can not be blown up. For example, Las Vegas, the gambling city of the United States, is surrounded by salt and alkali land except for deserts. With severe water shortage, it is difficult to plant trees. By means of science and technology, a hair gel like material was developed and sprayed on the sand dust to form a sand shell. The materials are generally divided into three categories: one is to mix plant fibers and old newspaper pulp with viscous substances and spray them on the surface of dust. When spraying, these materials can also be added with green dye, which looks like a layer of grass. This kind of fiber cement is not deep on the surface of sand dust, and it forms a block in a shallow way. Because it is relatively thin, people can't walk on it. Another kind of sticky gum material is sprayed on the desert. It needs to penetrate deeper into the desert. The plate layer is thick and hard, so people can walk, but cars and other motor vehicles can't. The third type of sticky gum material is called "sand dust locking". This kind of material is sprayed on the desert. It penetrates the desert for half an inch. The surface layer is thick and hard. It can be used by pedestrians and various vehicles. It is not afraid of pressure and ash. It is the strongest one. If there is no man-made damage or rainwater loss, the dust can be locked for one to two years after each spraying. The cost of these three types of viscous substances is generally between $500 and $2000 per acre, which is much lower than the cost of planting trees, flowers and plants.
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