In 1920, Mr. Hou Debeng returned to China. Mr. Hou devoted himself to the improvement of alkali production process and equipment, and finally Mr. Hou found out the production technology of Solvay method. 1924 August, Tanggu Alkali Factory was officially put into production, and in 1926, "Red Triangle" brand of soda ash produced in China won the gold medal at the Universal Exposition in Philadelphia, USA. The products not only sell well at home, but also exported to Japan and Southeast Asia.