Modeling calcium dissolution from oil shale ash. Part 1, Ca dissolution during ash washing in a batch reactorVelts, Olga; Hautaniemi, Marjaana; Kallas, Juha; Kuusik, Rein, keemikFuel processing technology2010 / 5, p. 486-490 : illhttps://www.sciencedirect.com/science/article/abs/pii/S0378382009003567