RU2339584C1 - Method of waste water purification from ions of heavy metals in production of ballistic powder - Google Patents

Abstract

FIELD: chemistry, technological processes.

SUBSTANCE: waste water of ballistic powder production, polluted with ions of heavy metals, is treated with sodium carbonate at pH=9-10, polyacrylamide is added, and heated with vapour during 25-35 minutes. Formed insoluble carbonates of heavy metals are filtered and clarified water is passed through absorber, filled in sections with wooden chips, activated coal, ion-exchanging resins. Then purified water is discharged on treatment facilities. In preferable version of method realisation 1% solution of polyacrylamide in amount 0.015-0.030 % is added to treated water. As ion-exchanging resins cationite "КУ-2-8" and anionite "АН-31" are used, as activated coal, coal of brands "БАУ" and "АГ-3" is used. For purposes of environment protection sediment is burned and introduced into cement-gravel mixtures for repairing of roads, floors and different non-load-carrying constructions.

EFFECT: virtually complete purification of waste production water and waste-free, ecologically clean technology.

4 cl, 2 dwg, 3 tbl

Description

The invention relates to the field of purification of waste industrial water and environmental protection from industrial emissions.

The method is intended for purification of waste industrial water from heavy metal ions in the production of ballistic gunpowder.

The literature contains a significant number of publications on methods for purifying industrial water from heavy metals in various industrial fields. Reagent treatment methods are applied - “A method for treating wastewater from heavy metal compounds” SU 1386584 A1 (Chelyabinsk branch of VODGEO), published 07.04.88 - treatment with an inorganic coagulant in an alkaline medium. As an inorganic coagulant, galvanic wastewater containing water-soluble salts of Fe, Zn, Cu and Ni is used, followed by the introduction of polyacrylamide. These methods are economically disadvantageous and require the use of equipment that is difficult to manufacture and maintain.

RJ Chemistry No. 6, 2006, 19H380-D1 (Separ and Purif. Technol, 2004, 39, No. 3, pp. 181-188) “Removing Nickel from Wastewater from Galvanic Plants by Combination of Ion Exchange and Deposition”. The results of the experiments showed that the use of ion exchange allows you to remove 74.8% of Nickel from wastewater. The addition of a precipitation step allows the removal of 94.2-98.3%. The subsequent stages are the establishment of a pH of 10.5, ion exchange using clinoptilolite, and deposition for 2 hours. The disadvantage of this method is the lack of cleaning efficiency and the use of scarce clinoptilolite, as well as the fact that the process is periodic. A disadvantage should be considered that the sediment is not removed from the process, which leads to a decrease in the absorption capacity of clinoptilolite, and the question remains of its further use or discharge of sediment into the environment.

The objective of the invention is to provide a more efficient, waste-free, environmentally friendly method of purification of waste industrial water from heavy metal ions in the production of ballistic gunpowder.

The task is achieved by organizing a two-stage process:

- waste industrial water is treated in the presence of polyacrylamide when heated with sodium carbonate to a pH of 9-10 in order to obtain insoluble carbonates of heavy metals and filtered off;

- clarified water is passed through an adsorber filled in sections with wood shavings, activated carbon, ion-exchange resins and sent to wastewater treatment plants.

The filtered sediment is burned in furnaces and disposed of in cement-gravel mixtures when repairing floors in industrial buildings, roads on the premises and other load-bearing structures, which eliminates its ingress into the environment.

Figure 1 shows the "Schematic diagram of the wastewater in the production of ballistic gunpowder." Wastewater contaminated with heavy metals is fed to a neutralization tank (1), sodium carbonate (soda ash) is also fed there to bind heavy metal ions to insoluble carbonates and a 1% solution of polyacrylamide in an amount of 0.015-0.030% to accelerate precipitation . The mixture is heated by supplying hot steam to the tank for 25-35 minutes. After this, the solution is settled, the clarified upper part is pumped (2) to the adsorber (3). Water passing through the adsorber is purified from mechanical impurities (section a, filling with wood shavings), possible residues of organic substances (section b, coal filling BAU and AG-3), residues of cations of soluble salts and heavy metals (sections c, d, filling KU-2-8 cation exchanger), residues of anions of dissolved salts of heavy metals (section d, e, filling with AN-31 anion exchanger). A suspension of heavy metal carbonates from the lower part of the neutralization tank is fed to the suction filter (4) with the same pump, the filtrate is collected in a collector (6) using a vacuum pump (5) and sent to an adsorber (3). The precipitate is periodically unloaded in a container and sent for burning from the residues of nitrocellulose to the installation for the destruction of special technological waste (7) or any other furnace. The obtained calcined sludge is sent to a concrete mixer (8) for introduction into cement-gravel mixtures.

Examples of experimental verification results under experimental conditions are given in tables 1, 2.

Table 1 The results of the treatment of waste water from heavy metals using soda and 1% PAA Cleaning conditions Dose of reagent 1% rr PAA,% The concentration of heavy metals in water, mg / l Cleaning efficiency, Before cleaning After cleaning % one 2 3 four 5 1. Processing soda and PAA pH 10.27 0.010 4.02 2,58 64,2 2. Treatment with soda and PAA pH 10.27 0,025 6.56 0.3 95.4 3. Processing soda and PAA pH 10.27 0,050 6.56 1,63 75.16

From table 1 it follows that the optimal cleaning effect of 95.4% is achieved at a pH of 10.27 and a flow rate of 1% PAA 0.025%, while the concentration of heavy metals in the treated water decreases from 6.56 to 0.3 mg / L. Based on the results obtained, it is necessary to add 1% polyacrylamide solution in the amount of 0.015-0.030% to the treated water.

table 2 Data on the treatment of waste water from Cu and Pb generated in the manufacture of semi-finished products Waste Water Treatment Method Concentration in water, mg / l The cleaning effect,% Before cleaning After cleaning Pb ²⁺ Cu ²⁺ Pb ²⁺ Cu ²⁺ Pb ²⁺ Cu ²⁺ one 2 3 four 5 6 7 1. The original waste water pH 4 after boiling with soda to a pH of 6.32 2400 542.6 10.9 85.9 99.55 84 2. Water after treatment with soda to pH 9.97 10.9 85.9 2,5 12,2 77.06 85.79 3. Water after treatment with soda pH 10.0 10.9 85.9 4,5 7.3 58.71 91.5 4. Water after treatment with 1% PAA and Na ₂ CO ₃ at pH 10.0, t = 30 ° C 2400 542.62 3 107.14 99.8 80,43 5. Post-treatment at KU-2-8 3 107.14 but 0.12 one hundred 99.8 6. Post-treatment on the AN-31 3 0.12 but but one hundred one hundred

From table 2 it follows that in the first stage of purification - only by treatment with sodium carbonate - it is not possible to obtain stable results and the required efficiency. At the second stage - the passage of water through ion-exchange resins - complete extraction of the remains of ions of soluble salts of heavy metals is achieved. The use of two-stage cleaning can significantly increase the cleaning efficiency and increase the life of ion-exchange resins in the adsorber.

Table 3 The test results of samples of "building" materials No. p / p Composition,% (g) Water ml Sediment input method Tensile strength, kg / cm ² Cement River sand Sludge, in excess of 100% one 2 3 four 5 6 7 one 67.39 32.61 0 25 Control; a mixture of cement and sand mixed with water and cured for 5 days in special forms 109 2 67.39 32.61 0.3 25 A calcined precipitate was introduced into the mixture of cement and sand, the mixture was mixed, then water was introduced into the resulting mixture. Curing was carried out for 5 days in special forms to obtain samples d = 15 mm and h = 20 mm 106 3 67.39 32.61 2.0 25 70.5 four 67.39 32.61 3,5 25 15.9

Table 3 and figure 2 shows the dependence of the tensile strength of building materials on the content of calcined sludge, which shows that the amount of injected sludge should be in the range of 0.1-0.5%, which does not significantly affect the strength characteristics of building materials. However, it is advisable to use sediment in non-load bearing structures. This is dictated by environmental protection requirements: the sediment is not discharged to the soil, but is closed in insoluble concrete materials.

Claims (4)

1. The method of purification of waste water from heavy metal ions in the production of ballistic gunpowder, which consists in the fact that the waste production water is treated with sodium carbonate to a pH of 9-10, polyacrylamide is added, steam is heated for 25-35 minutes, and the insoluble heavy carbonates are filtered off. metals and clarified water are passed through an adsorber filled in sections with wood shavings, activated charcoal, ion-exchange resins, after which the purified water is discharged to treatment facilities. 2. The method according to claim 1, characterized in that a 1% solution of polyacrylamide in an amount of 0.015-0.030% is added to the treated water. 3. The method according to claim 1, characterized in that cation exchanger KU-2-8 and anion exchanger AN-31 are used as ion-exchange resins. 4. The method according to claim 1, characterized in that the activated carbon used is coal of the BAU and AG-3 grades.

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