SU1135134A1 - Method of cleaning waste water of cyanides - Google Patents

Abstract

1. METHOD OF CLEANING. WATER FROM CYANIDES, which includes treatment with ferrous sulfate in the presence of an alkaline reagent, characterized in that, in order to increase the degree of purification, reduce reagent consumption and simplify the process, an alkali or alkaline earth metal hydroxide is used as an alkaline reagent gland. 2 o The method according to p. 1, about t l and u and so that the process is carried out at a pH of 8.0-11.0. i

Description

00

cd 1 The invention relates to the field of sewage treatment and can be used)) ano for the disposal of industrial sewage containing cyanide in ferrous and ferrous metallurgy, chemical, galvanic and other industries. from cyanide by treatment with vitriol, with a fourfold excess for at least two hours. To remove excess bivalent iron cations in the form of hydroxide, milk of lime is added to the wastewater for five minutes before the end of the reaction. This milk is characterized by a long duration, high consumption of reagents and low efficiency of purification from cyanides - only up to 2, 0 mg / l, most closely. The technical essence and the achieved result is the method of purification of cyanide wastewater, which consists in the fact that concentrated lime milk and part of the sludge formed from purification process, then treated with iron-containing solution with subsequent flocculation .i sgugtseniem slurry for circulating pain necks part. The application of this method is complicated by the high consumption of reagents, the complexity of the instrumentation of the process and the insufficient purification efficiency (70-99%). The aim of the invention is to increase the degree of purification, reduce the consumption of reagents and simplify the process. The aim is to achieve that in the known method of purification of wastewater from cyanides by treating them with ferrous sulfate iron in the presence of an alkaline reagent, cleaning is carried out while simultaneously introducing hydroxide into wastewater alkaline or alkaline earth metal pH during cleaning, mg / l 7.0 8.0 9.5

Cyanide concentration after

3.25 1.30 0.10 0.08 0.60 purification, mg / l

7.00 and ferrous sulphate to stabilize the pH of the wastewater. The cleaning process is carried out at a pH of 8.0-11.0, preferably 9.5-10.5. The essence of the proposed method lies in the fact that the introduction of alkali into the wastewater simultaneously with the iron salt to stabilize the pH at a level of 8.0-11.0 contributes to a more complete and rapid binding of cyanide ions to iron cations. This leads to a reduction in the processing time and a decrease in the consumption of iron-containing reagent, a significant increase in the degree of purification. EXAMPLE 1 Sewage water containing 100 mg / l of lane ions was treated with ferrous sulphate in an amount of 0.5 kg / m of wastewater while simultaneously introducing 1% sodium hydroxide solution to stabilize the pH at various levels. After stirring for 15 minutes, the concentration of cyanide in purified water was determined (Table 1). Example 2. Sewage water containing 100 mg / l cyanide ions was treated with ferrous sulphate in an amount of 0.5 kg / m wastewater while simultaneously introducing 1% sodium hydroxide solution (potassium and calcium) to stabilize the pH at 11.0 . After stirring for 15 minutes, the concentration of cyanide in the purified water was determined (score 2). Wastewater treatment according to the described method can significantly increase the degree of purification while reducing reagent consumption and simplifying the process (Table 3). The main advantage of this method is the ability to effectively clean cyanide wastewater using such cheap and non-deficient reagents as ferrous sulphate, calcium oxide or caustic soda. Table 1 10.5 11.0 -12.0

11: 55134

  t a b l u 11 a 2

Prime

Naem NaOH KOH SaOH) hydroxide

Concentration

cyanide.

after cleaning, mg / l 0.02 0.02 0, OBA

Features- CleaningClear

tic of pro-pre-lime process-0.06 1.86

0.3 5.54 0.5 1.89

14

Table 3

mu spo- (US Pat.

tel number 3847867)

Claims (2)

1. METHOD FOR WASTE CLEANING. WATER FROM CYANIDES, including treatment with ferrous sulfate in the presence of an alkaline reagent, characterized in that, in order to increase the degree of purification, reduce the consumption of reagents and simplify the process, alkaline or alkaline earth metal hydroxide is used as the alkaline reagent, which is introduced simultaneously with divalent sulfate gland. 2 o The method of claim 1, wherein the process is carried out at a pH of 8.0-11.0.