A unique feature of Aragon cartridges is that, with hard water, two mechanisms of scale elimination operate simultaneously: removal of hardness salts by the classical ion-exchange mechanism and the quasi-softening effect (patent 2004138606/15).
What is the quasi-softening effect and what are its unique features?
In common water, calcium carbonate is present in the form of calcite. On heating, it precipitates to form a dense deposit (scale). Calcite crystals have a rectangular shape. Therefore, they tightly adhere to each other and to surrounding surfaces like small bricks. However, calcium carbonate also exists in another modification, aragonite, with rhombic crystal shape. Common water contains virtually no aragonite. Rhombic crystals of aragonite tend to agglutinate and adhere to surfaces to a considerably lesser extent than do rectangular crystals of common calcite.
As a result, friable aragonite deposit is readily broken and washed away with water flow. Appearance of aragonite in water results in breakdown of the already formed scale, because aragonite crystals become centers of recrystallization. This is the essence of the quasi-softening effect exerted by Aragon cartridge. The quasi-softening effect was theoretically substantiated by researchers of the Vienna State University and was confirmed on the quantitative level at the Fedorovskii Russian Research Institute of Mineral Resources.
The essence of this process is as follows: Due to Coulomb attraction forces, dipoles of water molecules and ions of hardness salts form cluster structures. These are relatively large metastable formations. As water flows through the porous structure of the Aragon material, the pressure that steadily grows owing to channel narrowing compresses and breaks down the clusters. The salts get free of the shell of water molecules and interact with the filtering material. Its specific properties create conditions for the formation from the dissolved carbonates of carbon dioxide which is sorbed by channel walls. At the exit from the filtering material, the pressure grows to a maximum and then sharply decreases to zero. As a result, carbon dioxide is intensely released, and it rapidly volatilizes from water.
The same phenomenon can be observed when opening a bottle with carbonated water. The release of carbon dioxide increases pH of water, creating favorable conditions for the formation of calcium carbonates in the form of aragonite, which saturates the purified water.
The formation of the aragonite structure of hardness salts was confirmed experimentally. The appearance of aragonite can be seen both under a microscope at a large magnification and in X-ray diffraction patterns taken at the Russian Research Institute of Mineral Resources.
Quantitative data of X-ray phase analysis show that the content of the aragonite form of calcium carbonate in water after passing through Aragon material increases considerably (by a factor of 8–10).