In the 1920s, the most advanced alkali production method in the world was the Solvay alkali production method monopolized by Solvay. In 1921, in order to change the backwardness of China's alkali production industry, Chinese industrialist Fan Xudong specially invited Hou Debang, who graduated from the Massachusetts Institute of Technology in the United States, to serve as an engineer and establish the Wynn Soda Plant. It only took Hou 4 years to imitate Solvay's method and produce soda ash with a purity greater than 99%. Later, in order to improve the utilization rate of salt and reduce the cost of raw materials, Yongli Alkali Plant planned to purchase the German "Cha'an Method" patent. The other party's harsh conditions angered Hou, who loved the motherland. After several years of hard work, he finally succeeded in creating the "Hou's method of making alkali" in 1941.