What is the dry residue

The dry residue is one of the main criteria for determining the quality of water, which reveals the degree of its mineralization. Ion-salt residue is used to determine the type of water.

dry residue

Features of the remainder

As the main ions, due to whichyou can determine the dry residue, act: sulfates, chlorides, carbonates, nitrates, bicarbonates. There is their subdivision into organic and mineral residues, which differ in their boiling points. A dry residue means the presence of dissolved, non-volatile solids in water. There is a special methodology for its calculation.

determination of the dry residue

Gravimetric calculation method

With its help, the dry residue in the test sample is determined. To conduct such a study, it is necessary to filter the sample and separate it from organic impurities.

Water is used in almost all industriesmodern production. For example, in the cosmetics industry, it is used as drinking water, as raw material for making semi-finished products, as a substance for washing industrial containers.

It is with water associated organolepticindicators of products produced at the enterprise: stability, odor, taste, color. For example, the appearance and taste of syrups are directly related to the mineral substances contained in the water. If the dry residue contains sodium chloride, then the water acquires some salty taste.

mass fraction of dry residue

Sanitary norms

There are certain standards thatconform water. If the content of the dry residue does not satisfy them, then it can not be used. There are special physicochemical laboratories that are equipped with special measuring instruments.

In them, the mass fraction of the dry residue is determinedAccording to GOST "Drinking water" 18164-72. Use water in production only after it is fully controlled for compliance with all quality indicators.

If in the course of the research inconsistencies are detected for any indicators, it is necessary to draw up a protocol on non-compliance, and to carry out the necessary corrective measures.

dry residue content

Methods for determining the dry residue

There are several methods for determining the dry residue. GOST allows the procedure with the addition of soda or using salt. Let's consider both options in more detail.

In the first case, the sample is evaporated fromusing a water bath. First, the container to be used for evaporation is dried to a constant mass. Next, the filtered water is poured into the porcelain container. After completion of evaporation of the last sample, the cup is dried in a thermostat to constant weight at a temperature of.

To determine the dry residue, a special formula is used. It connects the mass of an empty container with a dry residue, as well as the amount of water that is taken for research.

The application of this method leads to the production ofexaggerated results. This situation is due to increased hygroscopicity, as well as the course of hydrolysis of calcium and magnesium chloride, the complexity of water transfer by sulfates of calcium and magnesium.

To eliminate this drawbackA pure sodium carbonate is added to the test sample. During the addition of calcium and magnesium chlorides, they are converted to anhydrous carbonates. To completely remove the crystallization water, dry the resulting dried residue at an elevated temperature until a constant mass is obtained in the thermostat.

dry residue

Method with a solution of soda

This option involves a preliminaryfiltering water using a paper filter. After drying the sample until a constant weight is obtained, the cup should be placed on a water bath. Here, the water samples taken for analysis are evaporated. As soon as the last portion of water is introduced, a solution of carbon dioxide is pipetted. Given that the weight of the soda taken refers to the mass of the dry residue as 2 to 1, perform mathematical calculations.

To carry out further evaporation,It is necessary to mix the sample, destroying the resulting crust. For mixing, use a glass rod. Then wash with a distilled water stick. Then the formed dry residue with soda in the cup is placed in a thermostat, dried at a temperature of about 150 degrees Celsius until a constant mass is obtained.

The average evaporation time isfrom two to five hours. Determine the difference in weight between the capacity of the precipitate formed and the initial weight of the cup and soda. This difference determines the amount of dry residue in the determined amount of water. Determine the dry residue by the formula that connects the mass of an empty container, added soda, and also the volume of water chosen for analysis.

This analysis from the hygienic point of viewlies in the fact that it is possible to carry out a technical adjustment of the analyzed water, using filtration systems, while decreasing the degree of mineralization.

Conclusion

The taste is balanced if in waterthe total salt content is 600 mg per liter. If it contains more than 1 g / l, it is considered unsuitable for drinking, as it has a bitter-salty taste.

If you constantly use this kind of water,the body can have serious physiological problems. First of all, there is an increase in the motor and secret functions of the intestine and stomach, at an elevated temperature the body overheats.

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