Abstract: The invention relates to a method and to an arrangement for removing gaseous elementary mercury from a stream of gas and to an arrangement for carrying out the method. The arrangement comprises a first washing tower (2) for receiving a stream of gas, a second washing tower (6) for receiving a stream of once processed gas (5) from the first washing tower (2), and a third washing tower (9) for receiving a stream of twice processed gas (23) from the second washing tower (6) and configured for discharging a stream of cleaned gas (12).

Abstract: The invention relates to a method and to an arrangement for removing gaseous elementary mercury from a stream of gas and to an arrangement for carrying out the method. The arrangement comprises a first washing tower (2) for receiving a stream of gas, a second washing tower (6) for receiving a stream of once processed gas (5) from the first washing tower (2), and a third washing tower (9) for receiving a stream of twice processed gas (23) from the second washing tower (6) and configured for discharging a stream of cleaned gas (12).

Abstract: A method of an essentially complete elimination of remaining traces of mercury in gases, such as roaster gases containing SO2, and which have been treated in a chloride washer for removing elementary Hg,. It is characterized in that the gas is introduced to a scrubber plant where the same is washed with a washing liquid such that any content of gaseous HgCl2. The gas is absorbed by the washing liquid and is subjected to a turbulent and mechanical action in the scrubber so as to physically put together any Hg, HgCl2 and Hg2Cl2 and other compounds of Hg present in particle or drop form into bigger aggregates or agglomerates. Thus formed aggregates or agglomerates and present bigger particles are brought to be separated from the gas and then be collected and removed. The invention may be completed with further steps for the elimination of any remaining mercury.

Abstract: A method for purifying aqueous solutions having varying concentrations of contaminants and/or various contaminants including ions of several metals and elements by conducting precipitation in a first precipitation stage by adding lime in a surplus quantity whereby a pH of about 12 is established and maintained in the solution and a major part of the contaminant content is precipitated so as to form a solution having a substantially constant composition and to form a precipitate that is isolated and removed together with residual lime. Precipitation is then conducted in a second precipitation stage by adding a reagent for precipitation at a pH in the range of 4-11 wherein residual contaminant in the formed solution from the first precipitation stage is precipitated the precipitate is isolated and returned to the first precipitation stage.

Abstract: The invention relates to a method for purifying aqueous solutions containing at least one impurity element from the group consisting of arsenic, phosphorus, mercury and other heavy metals and solid matter by precipitation in at least two stages with the aid of precipitation reagents possessing ions capable of forming not-readily dissolved hydroxide precipitate. In accordance with the invention the main part of the precipitation reagent is introduced to the stage or stages following the first stage. The impurity element-containing precipitate formed in the aqueous solution subsequent to adding the reagent is separated therefrom substantially completely, and is returned so as to be present in the first precipitation stage, while that part of the solution which has been freed from precipitate in a later stage is withdrawn from the system. Substantially all the impurity element amount present in the ingoing aqueous solution are separated therefrom in the form of a sludge prior to the second precipitation stage.

Abstract: A method of extraction of mercury from gases containing gaseous elementary mercury comprising treating said gases in a closed circuit with an aqueous solution containing 0.1-300 mmol/l mecury(II)-ions and at least double that content of ions with the ability to form soluble complexes with mercury(II)-ions whereafter mercury absorbed in solution is recovered and the solution recirculated.