DAP Joint Stock Company has found a solution after many efforts to deal with gypsum created during production processes. The public has criticized the company for many years because of the acid leaking from its gypsum dumping ground.
However, the problem will be settled at the root as DAP has announced it has found a way to recycle gypsum, turning it into artificial plaster to be used as cement additive.
Is gypsum hazardous?
Scientists say all kinds of waste from industrial production are harmful to varying degrees to both people and the environment. As for gypsum, it harms the environment when acid residue leaks into the environment and cannot be treated.
Gypsum, or CaSO4.2H2O, is a solid waste created during the production of acid phosphoric from apatite ore to collect P2O5 in the ore for fertiliser production.
DAP, since 2009, has created 2 million tons of gypsum, which is being kept at its temporary dumping ground.
The ground is surrounded by clay and stone embankments and HDPE stratum to ensure that the water cannot leak out. There is a reservoir to collect acid from the waste and pump it back to the factory for use.
When the pH content goes to below the allowed level, the gypsum will be relocated to a major gypsum gathering ground, covering an area of 40 hectares, where it will be recycled into cement additive.
The monitoring report of September 30, 2014 showed that the waste water was within the safety limits in accordance with the Ministry of Natural Resources and the Environment (MONRE) QCVN 09:2008/BTNMT standard on underground water quality.
The Dinh Vu Gypsum JSC was established in 2010 following initial success in gypsum recycling. The company has finished construction of a gypsum recycling factory, and has installed one-quarter of the processing lines, with a capacity of 150,000 tonnes per production line per year.
The factory, now in its trial run, has provided 10,000 tonnes of artificial plaster to the But Son Cement Plant in Ha Nam Province. The partner said the product was very good.
DAP has joined forces with the Vietnam Cement Corporation (Vicem) to develop a project on processing gypsum.
The two sides have signed a cooperation agreement, under which Vicem would be responsible for the consumption of cement additive.
Nguyen Van Sinh, general director of DAP, said it would be better if Vicem and Dinh Vu could agree to make artificial plaster at the company’s site. If so, they could avoid complicated procedures required to get land and licenses.
