The production of phosphate fertiliser in China is very high, which does create problems regarding proper storage. In 2018, it emerged that poor storage had created a major problem in the Yangtze River basin, with phosphorus responsible for 56% of all water quality standard violations. Phosphorus, which still remains in phosphorus gypsum, can lead to eutrophication of water bodies and thus algal blooms.

The use of phosphogypsum

The construction industry in China is one of the largest users of phosphogypsum. It is widely used as a concrete retarder and in plasterboard. It is also used as a chemical feedstock to produce sulphates and as a soil improver.

Realisation of large-scale gypsum landfill cell

Shengyi Technology, partner of Trisoplast Mineral Liners has completed the "SANNING" project in Yichang city, Hubei province, China; the construction of a large-scale phosphorus gypsum storage landfill.

Sanning Chemical Co., Ltd. is one of the larger private companies operating in the phosphorus, chemical and petrochemical industries. With a history of more than 40 years, Sanning is among the top 50 companies operating in this market. They produce 2.6 million tonnes of phosphor gypsum (dry weight) per year.

Sanning has decided to store their Gypsum in secure depots. Shengyi did the design for Sanning using Trisoplast. The first project was to build a new depot of about 1,437,000 m2. Here, Trisoplast was applied as a soil protection and impermeable layer. The construction was realised in 1.5 years despite the epidemic and that year's heavy rainfall. The total capacity of this depot is 42.25 million m3. A second project, a couple of years later, covering an area of 900,000 was again designed by Shengyi, incorporating a combination of Trisoplast and a leak detection system. A few more such major works are sure to arrive for the next few years.

National regulations important

This project had to be built in accordance with the latest national regulations on technical safety regarding phosphogypsum landfills The use of Trisoplast as state-of-the-art soil protection mineral liner is a good demonstration of the sustainable developments in China's phosphorus chemical industry.