Do you know how tin deposits are formed? The content of tin in the crust is relatively low, with an average of only 6%. Therefore, tin is a relatively rare and valuable metal. In nature, there is rarely pure metallic tin. The most important tin ore is cassiterite, with a chemical composition of tin dioxide. Smelting tin is easier than smelting copper, iron, or aluminum.
After many years of research, it has been proven that the formation of tin deposits is closely related to magmatic activity deep within the Earth's crust. About 70 million to 100 million years ago, there were intense magmatic activities on Earth. As magma rose from deep underground, changes in temperature and pressure caused some easily solidifiable minerals to crystallize first. Some of the residual magma intruded into rock fissures, where tin compounds underwent hydrolysis to form tin-bearing cassiterite. Another part continued upward, especially magma containing large amounts of volatile substances, which had particularly strong mobility. They acted like high-pressure steam in a boiler, finding every crack to penetrate. Tin elements have a "quirk" - they prefer to "befriend" volatile substances such as fluorine and chlorine, forming volatile compounds. When these gaseous and liquid substances intruded into surrounding rocks along fractures, under high temperature and pressure, displacement reactions caused some tin elements to crystallize out and form tin deposits. At this point, the remaining last part of the gas-liquid containing volatile substances continued forward, reaching the top of the solidified granite or even beyond the granite mass, gradually turning into hot water solutions. Due to environmental changes, tin fluoride and chloride underwent hydrolysis, also forming tin deposits. Of course, what is mentioned above is not the entire cause of tin deposits. Sometimes, near the surface, due to long-term exposure to oxygen and carbon dioxide in groundwater, sulfide minerals coexisting with tin can turn into oxide minerals, thus forming cassiterite oxide deposits.
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