Application of a vegetative cover on phosphogypsum stacks

• Published in: Minerals engineering 1999, Vol.12 (2), p.175-185
• Main Authors: Komnitsas, K., Lazar, I., Petrisor, I.G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Environmental; Exact sciences and technology; Metals. Metallurgy; pollution; Production of metals; reclamation; Scrap. Recycling. Recovery metals; tailings
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/S0892-6875(98)00130-7

The treatment of phosphates for the production of phosphoric acid and fertilisers at Navodari, Romania, has resulted in the production of over 3,000,000 m 3 of phosphogypsum, which have been disposed of in three stacks over an area of 40 ha. An environmental characterisation study followed by a risk assessment analysis performed on a source-pathway-target basis has shown that phosphogypsum is characterised by residual acidity, elevated concentrations of sulphates, heavy metals and radionuclides and due to the lack of a vegetative cover aerial transportation of fine particles as well as solubilisation and migration of heavy and radioactive elements occurs contaminating surrounding soils, surface and ground waters. Therefore the application of a remediation scheme is considered necessary in order to prevent further contamination of the ecosystem in the area. The establishment of a vegetative cover on phosphogypsum stacks is considered as a viable option for the prevention of future environmental impacts. In this paper, the experimental work conducted in order to study the establishment of a vegetative cover on phosphogypsum stacks is presented and discussed. The major part of this work is focused on the study of glasshouse pot experiments testing a number of herbaceous species and bushes which show tolerance and a potential for growth in such environments. Modification of substrates, in order to increase soil pH, add nutrients in the system and in general to provide the optimum growth characteristics for the species planted, was performed by mixing phosphogypsum tailings with several additives such as dolomite, kaolin, sewage sludge and clean soil in various modifications. Preliminary experimental data show that several perennial species and bushes tested show an excellent growth potential and can be used for the establishment of an in situ vegetative cover.