Some aspects of water leaching of argillites

In the Maardu phosphorite deposit in North Estonia unused graptolitic argillites are distributed. Being accumulated in quarry dumps, they may be source of environmental pollution. Argillites are subject to self-ignition. In this paper the effect of temperature on the leaching of several heavy metals from the Maardu argillites has been investigated. The anionic composition of teachings solutions has been studied as well. Laboratory experiments have shown that with the temperature increasing up to 20—60 °C the leaching of components from argillite increases about twice, amounting to 1—7%. The leaching of metals from the argillite mineral part was negligible. On the other hand, the leaching of all components from the organic matter concentrate of argillite was very intensive. Thus, the leaching of metals from the argillite organic matter was by factor of 4—9 higher from argillite.