RU2013380C1 - Method of purifying sewage against metal ions - Google Patents

Abstract

FIELD: purification of sewage. SUBSTANCE: sewage is treated by ultradisperse powder of aluminium and/or iron which are prepared by electric explosion of conductor. Quantity of powder is 200-500 mg/l. After mixing within 0.5 h precipitate is removed. Thus purification against Cr, Pb, Th and Sr is carried out. EFFECT: improves efficiency of the method. 3 tbl

Description

 The invention relates to methods for treating wastewater from ions of heavy and radioactive metals and can be used in wastewater treatment of galvanic plants and non-ferrous metallurgy enterprises, as well as for cleaning solutions of ions of radioactive metals.

 The closest in technical essence to the proposed method is a method for treating wastewater from heavy metal ions, according to which effluents containing zinc, copper, nickel, hexavalent and trivalent chromium ions are treated, heavy metals are converted to their hydroxides, and the precipitate is separated. The disadvantage of this method is the complexity of its implementation, since when degreasing heavy metal ions by converting them into the form of insoluble hydroxides, ions of various heavy metals are most fully converted to the form of hydroxide at various pH values. For this reason, a pH range in which a complete conversion of heavy metal ions to the form of insoluble hydroxides is simultaneously ensured cannot be chosen. Therefore, it is necessary to work in a certain pH range, as well as additionally introduce iron hydroxide in an amount of 50-250 mg / l in terms of iron. After separation of the metal hydroxide from the treated water, the effluent must be neutralized to a certain pH. Iron hydroxide used in this method is unstable in air and requires special storage conditions (Akhmetov N. S. Inorganic chemistry. M.: Higher school, 1975, p. 624).

 The purpose of the invention is to simplify the process of wastewater treatment from metal ions.

 This goal is achieved by the fact that in the method of treating wastewater from metal ions, including treating wastewater with a metal-containing reagent and subsequent separation of the precipitate, ultrafine aluminum and / or iron powders obtained by electric explosion of conductors in an amount of 200-500 are used as a reagent mg / l Cleaning is carried out at any pH in the range of ≥3. The required pH value of water is established during the cleaning process due to the ongoing chemical processes between the powders of aluminum, iron and water.

 The method is as follows.

PRI me R. Wastewater containing chromium, thorium and strontium ions with a concentration of 100 MAC is subjected to treatment. The treatment is carried out in a reactor with a volume of 10 m ³ . Ultrafine aluminum powder obtained by the method of electric explosion of conductors in argon, with a particle size of 0.23 microns in an amount of 200; 350; 500 mg / l is sucked into a reactor filled with water, stirred, left for 0.5 hours. Then the precipitate is separated by settling. The residual content of metal ions in water is determined. Radioactive metals are determined by the method of radioactive indicators. Heavy metals are determined by the photocolorimetric method (physicochemical methods of analysis. L.: Chemistry, 1974, p. 89).

 The results of the analyzes are given in table. 1.

 As can be seen from the table. 1, when treating water, an almost complete purification of water from metal ions is achieved when aluminum is added in an amount of 200-500 mg / l. If aluminum is added less than 200 mg / l, then water purification is insufficient and the number of metal ions exceeds the MPC. It is not advisable to add more than 500 mg / l of aluminum, since cleaning already occurs when 500 mg / l is added.

 In the table. 2 shows the test results of water purification from metal ions by an ultrafine iron powder with a particle size of 0.15 microns.

 As can be seen from the table. 2, during water treatment an almost complete purification of water from metal ions is achieved if iron is added in an amount of 200-500 mg. More than 500 mg / l is impractical to add. If you add less than 200 mg / l, then there is not enough water purification from metal ions.

 When a mixture of aluminum and iron powders is used as a metal-containing reagent, ion removal is carried out similarly to that when aluminum and iron are added separately. The results are shown in table. 3.

 As can be seen from the table. 3, during water treatment, almost complete purification is achieved if 200-500 mg / l of reagent is added. In this case, the mixture of powders contains aluminum and iron in equal parts. If you add the reagent in an amount of less than 200 mg / l, then there is not enough cleaning from metal ions. It is not advisable to add more than 500 mg / l of reagent, since even with the addition of 500 mg / l, water is purified from impurities of metal ions.

 Thus, when treating water containing ions of both heavy (Cr, Pb) and radioactive (Th, Sr) metals, almost complete removal of metal ions occurs if the reagent is added in an amount of 200-500 mg / l. The proposed method is simple to perform, does not require additional operations to establish the pH of the water and chemical processing. The absence of these operations simplifies the method of wastewater treatment from metal ions and reduces the cost of treating water from metal ions in comparison with the prototype.

Claims (1)

 METHOD FOR WASTE WATER CLEANING FROM METAL IONS, including treatment with a reagent, mixing and separation of sludge, characterized in that, in order to simplify the cleaning process, ultrafine powders of aluminum and / or iron obtained by electric explosion of conductors are used in the amount of 200-500 mg / l

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