Directed and Controlled Crystallisation of Slightly Soluble Minerals - a New Technology to Seal Water Inflows and to Immobilise Contaminants

摘要

The paper summarizes a novel technology for sealing of soil or rock formations by directed crystallisation processes. Supersaturated solutions are used as grout. They are prepared by mixing of solutions which are normally incompatible, for example CaCl_2 and Na_2SO_4 solutions or Ba(OH)_2 and diluted sulphuric acid. Spontaneous crystallisation is prevented by the addition of precipitation inhibitors. The Obtained solutions are temporary stable. When they are used as grout, crystallisation takes place in the treated flow paths. Both sealing and fixation of contaminants can be achieved. It is possible to synthesise solutions containing up to 600 mg/1 BaSO_4 or 100 g/1 CaSO_4. The paper summarises the fundamentals of the technology and gives an overview about properties and applications of mineral forming solutions.