SU1239101A1 - Method of removing metallic mercury from waste water - Google Patents

Description

The invention relates to methods for purifying wastewater from metallic mercury and can be used to purify wastewater generated in the production of chlorine and caustic soda, in electrolysis processes, carried out by Mbix using mercury electrodes, in electroplating, in the manufacture of dyes, cyanide, hydrocarbons, acetaldehyde, vinyl chloride and luminescent materials, as well as in plants using as a catalyst.

The aim of the invention is to increase the degree of purification and reduce the duration of the process. .

Example: A 1 liter hydrosol of dispersed mercury containing 25 mg / l of metal having a temperature of 20 ° C, pH 9 is placed in the chamber of a flotation machine, and 200 mg of AAA is injected as an aqueous solution and 275 mg of bentonite, i.e. 19 mg of hydrophobized bentonite per 1 mg of mercury. Then the solution is floated for 10 minutes. Final mercury concentration 0.2 mg / l

When comparing laboratory tests of the known and proposed water purification methods, it has been established that when the flow rate of the flotation agent is changed for values greater and less than proposed, there is a significant change in the degree of mercury recovery.

The effect of sorbent consumption on mercury recovery is shown in Table 1,

Recovery rate,% 53.7 68.3 92.8 95.2 99.4 99.4 99.4

From Table 2 it follows that in order to extract the mercury as much as possible by the proposed method, it is necessary to conduct the flotation process for min. In less time mercury does not have time to quantitatively go to the surface of the solution. Increasing the time of 15 minutes is not advisable, since it does not lead to additional mercury removal.

Table 1

The effect of flotation time on mercury recovery is shown in

Table 2.

table 2

When bentonite is hydrophobized, it is necessary to strictly maintain the ratio of bentonite: AAK 1: (O, 7-0.75). When AAK lacks, the recovery rate drops sharply, while its excess is not practical, since the degree of mercury recovery also decreases (Table. 3).

The effect of reagents on the degree of extraction of mercury is shown in Table 3.

The degree of extraction,% 32.8 99, D 99.4 99.4 80.4

The whole cleaning process by the proposed method lasts 10-15 minutes and ensures the purification of waste water from metallic mercury by 99-99.4%. The residual concentration (at an initial concentration of 10–50 mg / l of metallurgical mercury) of purified water is 0.25 mg / l. Known cleaning methods

Editor N. Gunko

Compiled by A.Zhuravleva Tehred I.Popovich Proofreader M.Pojo

Order 3350/19, Circulation 864 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

T-face 3

from metallic mercury are based on multistage processes, in particular, preliminary oxidation of mercury, its precipitation in the form of sulfide and subsequent flotation in the presence of a collector. The total duration of such processes is usually 5 - 6 hours.

Claims (1)

METHOD OF WASTE WATER TREATMENT FROM METAL MERCURY, including the introduction of a sorbent followed by flotation, characterized in that, in order to increase the degree of purification and reduce the duration of the process, bentonite, hydrophobized with rosin amine acetate (AAA), taken in an amount of 19-21, is used as a sorbent g per 1 g of mercury with a ratio of bentonite: AAA equal to 1:: (0.7-0.75).