Abstract: The invention describes a method and a device for the continual and, in particular, for a fast detection of changes of the concentration of radon gas dissolved in water by means of a transfer into a measuring gas (Rn-222), which can be adopted for a variety of monitoring, control and regulation assignments. The invention is based on the fact that a membrane, which is permeable for the radioactive noble gas radon but extensively non-permeable for water, is circum-flushed on the one side of radon-containing water and on the other side of the carrier gas with, in each case, optimised flow velocities either in parallel or in counter-flow When stable peripheral conditions are ensured, the concentration of radon in the measuring gas is directly proportional to the concentration of radon in the water.

Abstract: The invention describes a method and a device for the continual and, in particular, for a fast detection of changes of the concentration of radon gas dissolved in water by means of a transfer into a measuring gas (Rn-222), which can be adopted for a variety of monitoring, control and regulation assignments. The invention is based on the fact that a membrane, which is permeable for the radioactive noble gas radon but extensively non-permeable for water, is circum-flushed on the one side of radon-containing water and on the other side of the carrier gas with, in each case, optimised flow velocities either in parallel or in counter-flow When stable peripheral conditions are ensured, the concentration of radon in the measuring gas is directly proportional to the concentration of radon in the water.

Abstract: A method for producing a material for heavy metal absorption or for analytically detecting heavy metals, especially uranium and radium, comprises the steps of: providing a material containing nitrogen which is organically bonded in a polymer; treating said material with potassium permanganate in an alkaline solution; and treating the material with iron(II) hydroxide in an alkaline solution. The material produced in this way is suitable for being used for a method of analytically detecting heavy metals and heavy metal istopes in a sample liquid as well as for a method of cleaning contaminated liquids.

Abstract: In the treatment of a zeolite suspension to separate solids from the mother and/or washing liquor, a vibrator is used in the suction drying zone of a vacuum filter in order to partially liquefy the filter cake material through the introduction of shear forces into the solidified filter cake, so that further separation of the pure liquid phase can take place in the suction drying zone of the vacuum filter.

Abstract: This invention relates to the preparation of sodium metasilicate. More particularly, this invention relates to a process for the preparation of solid, crystalline, substantially anhydrous sodium metasilicate which comprises the steps of:(a) reacting an SiO.sub.2 -containing material with a concentrated aqueous solution of sodium hydroxide in an SiO.sub.2 to Na.sub.2 O molar ratio of from about 1.2:1 to 1:1.2 under elevated pressure and at an elevated temperature, to form a sodium metasilicate suspension;(b) filtering the suspension from step (a) to obtain a filter cake and filtrate;(c) crushing the filter cake from step (b) at elevated temperature;(d) removing water from the crushed filter cake to recover substantially anhydrous sodium metasilicate;(e) concentrating the filtrate from step (b); and(f) returning the concentrated filtrate from step (e) to the reaction mixture of step (a).

Abstract: A process for the reduction of the particle size of coarse grain, crystalline zeolitic sodium aluminosilicate of the NaA type obtained in an aqueous alkaline suspension by crystallization of a reaction mixture suspension formed from sodium aluminate solution and sodium silicate solution, said sodium aluminosilicate having a large cation exchange capacity consisting essentially of subjecting said aqueous alkaline suspension of the crystallized sodium aluminosilicate to treatment on a vibrating screen having a substantially uniform mesh size between 25 to 100 .mu.m, the number of vibrations per minute and the amplitude of oscillation of said screen being so selected that at least 99.95 percent by weight, based on the anhydrous weight, of sodium aluminosilicate particles recovered have a particle size of less than 100 .mu.m, the said aqueous alkaline suspension of the crystallized sodium aluminosilicate having a molar ratio of 2.5-5 Na.sub.2 O:1 Al.sub.2 O.sub.3 :1.8 to 2 SiO.sub.2 :50-100 H.sub.2 O.