Hengnan Sheng Long Chemical Co.. Founded in 1999 on September 8 said. It is repose hengyan hunan province in China . Major barium carbonate production operations, thiourea, sodium bicarbonate and other chemicals joint-stock enterprises. Years Thang Long Company "integrity-based. Quality first. customers supremacy. optimal''prices for the purpose. committed to working with customers and common development. create brilliant achievements.