SU806614A1 - Method of purifying waste water of metallurgical producting products and synthetic surface-active substances - Google Patents

Description

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This invention relates to wastewater treatment of metallurgical industries.

A known method of sewage treatment of metallurgical industries, for example, from a mouse with the help of salts of iron, titanium, manganese. Purification occurs by capturing the mouse with metal hydroxides when the pH is changed il.

However, coprecipitation with hydroxides is applicable only for small concentrations of mice.

There is also a known method for the purification of waste waters of metallurgical industries from mouse 2, lead and zinc with the use of highly basic metallurgical slags: ferrochrome, electric steelmaking, open-hearth and blast furnace.

Purification of arsenic, lead, and zinc occurs due to their sorption by calcium silicate with the help of slag.

The known method is also applicable to the treatment of wastewater with only low initial content of arsenic lead and zinc. In addition, the ability of harmful slag constituents

leaching with water limits their use.

Closest to the proposed

is a wastewater treatment method for metallurgical plants by treating it with an alkaline reagent followed by filtration. The method consists in that the wastewater is treated with lime to a pH of 11-12, the precipitate is separated by filtration. Purification from the mouse occurs due to the formation of arsenates and arsenites of the mouse, and heavy metals are precipitated as hydroxides.

5 However, despite its widespread use, the method has several significant drawbacks:

1. The method does not provide the necessary depth of cleaning from the mouse,

0 since the most insoluble calcium salts of mice are solubility 3-4 mg / l, which is 15-20 times higher than the maximum permissible concentration;

5 2. Large specific consumption of deficient lime (9-12 kg / m), greater yield of toxic sediment, requiring special disposal;

3. Purified wastewater cannot be used in the circulating water supply due to overgrowing of pipelines and equipment with calcium salts. The purpose of the invention is to increase the cleaning efficiency and reduce the number of toxic waste dumps, as well as eliminate the use of deficient reagents and reduce the cost of the process. The goal is achieved by the fact that the wastewater is treated first with a mixture of a felite-type slag with concentrated sulfuric acid, taken in a ratio of 1: 1-2, at 40-60 ° C for 15-20 minutes, then the effluent is treated with an alkaline reagent followed by filtration . A distinctive feature of the present invention is the pretreatment of wastewater a mixture of a felite-type slag with sulfuric acid under the indicated conditions. The basis of the felite-type slag is iron oxide-2-orthosilicate (FeO-SiOj) - f. As a result, the purification of minerals is released into the sediment in the form of arsenates or arsenites of metals, and zinc, copper, lead and. other heavy metals are in the form of hydroxides and ferrites. The use of the proposed method of wastewater treatment provides the following advantages over the lime process: a) a higher degree of purification (the content in As effluents is 0.02 mg / l, 2n 0.1 mg / l, Cu 0.01 mg Pb 0.02 mg / l, while when cleaning with lime As 0.1 mg / l, Zn 3 mg / l, Cu 0.8 mg / l Pb 0.3 mg / l; b) the lower yield of toxic dump material (2 -3 kg with 1 m-wastewater, instead of 9-12 kg when cleaning with lime); c) elimination of the use of scarce building lime; d) a significant reduction in the cost of cleaning. (The cost of cleaning 1 meter of wastewater is 1.24 rubles, instead of 1.74 rubles when cleaning with lime; e) treated wastewater can be used in recycled water supply, since they practically do not contain calcium ions. Wastewater containing 200 mg / l of sugar, 800 mg / l of zinc, 400 mg / l of copper, 15 mg / l of lead is treated with a mixture of slag composition: 50-55% FeO, 30-35% SiOj, 3-5% 6 -10% CaO, 3-5% Zn, 0.1-0.2% As, 0.5-0.6% Cu, 0.01-0.02% Pb with concentrated sulfuric acid, taken in a ratio of 1 : 1-2. Mixture consumption 5-6 kg per 1 m of waste. The treatment time is 1520 minutes at 40-60 seconds. The pH of the solution after treatment is 4-5. Next, the wastewater is treated with an alkaline reagent — a 20–30% solution of soda ash in an amount necessary to apply a pH of 4–5 to 7.5–8–8, then purge air for 40–50 min. The precipitate is separated by filtration. The following results are presented in the table.

Claims (3)

As 0.02, As 0.02, Zn Content of inZn 0.1, Cu 0.01 Cu 0.01, ingredients in Pb 0.02 Pb 0.02 treated wastewater, mg / l Amount of waste product with 1 m wastewater, kg Formula of the Invention The method of purification of waste waters of metallurgical production by treating them with an alkaline reagent followed by filtration, characterized in that, in order to increase the cleaning efficiency and reduce the amount of toxic waste dump products, the wastewater is pretreated with a mixture of a felite-type slag with concentrated sulfuric acid, vz, 1, As 0,1, Zn 2,0 Cu 0,6, Pb 0,3 those in weight with ratio 1: 1-2 ,. at 40-60 ° C fl for 15-20 minutes Sources of information taken into account during the examination 1.Nikolaev A.V. and others. Disposal of waste in the production of nonferrous metals and its use in the national economy. - Non-ferrous metals, 1, 1972, p. 15-17. 2.Rashchuk N.L. et al. Conditions for the use of metallurgical slags 5 for wastewater treatment. Proceedings of the Institute VODGEO. M., issue. 42.1973. 3. Nikolaev A.V. and others. Problems of use and neutralization of 8066146 ml in the production of non-ferrous metals. Alma-Ata, Methods of purification of industrial wastewater, Proceedings of the Institute Kaemehanobr, Coll. 8, t. I, 1972, p. 46 (prototype).