SU785220A1 - Method of waste water purification - Google Patents

Description

one

This invention relates to the treatment of waste water containing alkaline earth metal compounds,; and can be used in wastewater treatment of the chemical industry and wastewater treatment plants of non-ferrous metals.

Methods are known for removing alkaline earth metals from solutions, where solutions are treated with sulphate-containing reagents followed by: settling. in the separation of the posture of sparingly soluble alkaline earth metal sulfates LlJ.

The precipitation of alkaline earth metals in the form of sulphates in relation to wastewater cannot provide the necessary degree of purification of wastewater from wastewater, which in the form of sulphate is not sufficiently removed.

The closest in technical significance and the achieved result to the proposed method is the purification of cTOf4 water, including the treatment of alkali metal with carbonate and the separation of carblossa of earth-earth metals

M) Yes, the well-known method does not exclude

Oj3 formations of alkaline earth metal bicarbonates, whose solubility significantly exceeds the solubility of carbonates, which invariably entails an increased content of strontium in the water being purified.

The aim of the invention is to increase the degree of purification of waste water from strontium.

This goal is achieved by the fact that the waste water is pretreated with phelochny and sulphate-containing reagents, then with an alkali metal carbonate, and then the precipitate is separated.

The starting point of the proposed method is the preliminary treatment with alkali and sulphate-containing reagents.

The process is carried out as follows.

Claims (2)

Sewage water containing alkaline earth metals is treated successively with an alkaline reagent, for example calcium hydroxide, a sulphate-containing reagent, for example sodium sulphate, the precipitate is formed, then the carbonate metal is read and the sediment is removed. Example 1. Wastewater iodine-bromine plants containing g / l: calcium - 10: magnesium - 2j sodium - SO; potassium — 5j of the salt of the xlot; y — 0.4–, strontium — 0.5, is alkalinized with calcium hydroxide at a rate of 8.9 g / l. This calcium hydroxide precipitates magnesium hydroxide, neutralizes hydrochloric acid, and raises the pH to 11. Then, 143 g of deshydrous sulfate is introduced into the stream (Glauber's salt). As a result, a portion of calcium and 75% strontium passes into the sediment. The drain after settling contains a significant amount of strontium (25%), which is pre-precipitated, added soda ash to the drain (4.5 g per liter of solution). After 24 hours of settling, the content of strontium is reduced to 10 mg / l, and after 48 hours, the amount of strontium does not exceed 3 mg / l, which corresponds to the sanitary standards for this element. , Example 2. Water containing the same I components as in the previous P1 example is treated with calcium hydroxide in a volume of 8.9 g / l. In this case, the magnesium is precipitated in the form of a hydroxide, pI of the solution rises to 11. 143 g / l of sodium hydrogen sulphate is added, 95% of calcium is precipitated. The drain after settling, containing 0.5 g / l of calcium, is treated with soda ash of 4.5 g / l. After 24 hours of settling, the calcium content is 20 mg / l. "The proposed method allows to reduce the strontium content in the wastewater to 0.6% and calcium to 0.2% and at the same time to Reduce the consumption of soda ash from 40 g / l to 4.5 g / l compared with the known method. DETAILED DESCRIPTION OF THE INVENTION A method for purifying waste water from alkaline earth metals, including treating alkali metal with carbonate and separating the formed sludge, so that with the aim of increasing the degree of purification from striction, the waste water is pretreated reagents. Sources of information taken into account in the examination 1. Remi G. Course of inorganic chemistry, M., IL, 1963, p. 314. 2. For Japan No. 52-89576, 13 47) O 43, 1977 (prototype).