Vietnam: DAP Joint Stock Company has found a solution to deal with gypsum created during production processes. The public has criticised the company for many years because of the 'acid leaking from its gypsum dumping ground.' However, the problem will be solved as DAP has found a way to recycle gypsum, turning it into artificial plaster to be used as a cement additive.
Since 2009 DAP has produced some 2Mt of gypsum, which is being kept at its temporary dumping ground. The ground is surrounded by clay and stone embankments with high-density polyethylene (HDPE) stratum to ensure that the water does not leak. There is a reservoir to collect acid from the waste and pump it back to the plant for use. When the pH content falls below the allowed level, the gypsum will be relocated to a major gypsum gathering ground, covering an area of 0.4km2, where it will be recycled into cement additives. A monitoring report from 30 September 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.
Dinh Vu Gypsum JSC was established in 2010 following initial success in gypsum recycling tests. The company has finished the construction of a gypsum recycling plant and has installed 25% of the processing lines, with a capacity of 150,000t/yr per line. The plant, now in its trial run, has provided 10,000t of artificial plaster to the But Son Cement Plant in Ha Nam Province.
DAP has also 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 the resulting cement additive.
