RU148901U1 - DEVICE FOR ELECTROCHEMICAL WASTE WATER TREATMENT FROM COMPOUNDS OF NON-FERROUS AND RARE-EARTH METALS - Google Patents

Abstract

A device for the electrochemical treatment of wastewater from non-ferrous and rare-earth metal compounds, comprising a housing with an electrolyzer and an electroflotation chamber, characterized in that the side anode chambers of the electrolyzer are equipped with nozzles for introducing and discharging wastewater and pipelines connecting them to the cathode chamber, this inside the lateral anode chambers additionally placed anion-exchange membrane and cathode.

Description

The proposed utility model relates to devices for the electrochemical treatment of wastewater from compounds of non-ferrous and rare-earth metals and can be used in enterprises of non-ferrous and ferrous metallurgy, mechanical engineering, instrument making, radio electronics, and the electrical industry.

A device for electrochemical wastewater treatment, which is a housing divided into sections of preliminary water treatment (in the form of a two-chamber diaphragm electrolyzer with an anion exchange membrane) and electroflotation treatment [A.S. USSR No. 1675215 A1, IPC C02F 1/46, C02F 1/465; declared 10/13/1989; publ. 09/07/1991, bull. No. 33].

The disadvantage of this device is the low productivity, due to the small area of the electrodes and membrane.

It is known that the device selected as a prototype contains a housing with an electrolyzer placed in it in the form of an anode and two side cathode chambers and an electroflotation chamber [Electroflotation technology for wastewater treatment of industrial enterprises / V.A. Kolesnikov, V.I. Ilyin, Yu.I. Kapustin et al .; under the editorship of V.A. Kolesnikova. - M .: Chemistry, 2007. - S. 224-226 s].

The disadvantage of this device is the insufficient productivity of the processes of membrane electrolysis, due to the small area of the electrodes and membranes.

The technical problem and the result, the solution of which the claimed device is directed from compounds of non-ferrous and rare-earth metals is to increase the productivity of membrane electrolysis processes.

The technical result is achieved by the fact that the device comprises a housing placed in it and an electrolyzer in the form of a cathode and two side anode chambers and an electroflotation chamber. According to the proposed utility model, the side anode chambers of the electrolyzer are equipped with nozzles for input and output of wastewater and pipelines connecting them to the cathode chamber, while an anion-exchange membrane and the cathode are additionally placed inside the side anode chambers.

The proposed utility model of the device is illustrated in the figure, where in FIG. 1 is a top view.

The device consists of a housing 1, divided by an overflow partition 2 into an electrolyzer 3 and an electroflotation chamber 4. The electrolyzer is made in the form of a cathode 5 and two side anode chambers 6.

The cathode chamber of the electrolyzer is separated from the anode by anion-exchange membranes 7.

Insoluble plate cathodes 8 are installed in the cathode chamber, and insoluble plate anodes 11 are installed in the anode chambers.

In the cathode chamber 5 of the electrolyzer there are nozzles 13 for introducing neutralized wastewater.

Inside the anode chambers 6 of the electrolyzer are anion-exchange membranes 9, forming cathode sections 10, in which plate insoluble cathodes 12 are installed and there are nozzles 14 for introducing acidic wastewater and 15 for outputting neutralized wastewater. In this case, the cathode sections 10 of the electrolyzer are equipped with pipelines 16 connecting them to the cathode chamber 5.

In the electroflotation chamber horizontal insoluble electrodes 17 (cathodes and anodes) are placed in the form of a comb and there are nozzles 18 for removing purified water. From the opposite end of the electroflotation chamber from the electrolyzer is a foam collector 19.

In the upper part of the device located above the water level, a foam collecting device 20 is placed, driven by a gear motor 21.

The device operates as follows. Acid wastewater containing non-ferrous ions (copper, nickel, zinc, cadmium, cobalt, manganese) and rare-earth (cerium, yttrium, terbium) metals individually or in a mixture enters through nozzles 14 into the cathode sections 10 of the side anode chambers 6 of the electrolyzer, into which under the influence of the current load on the insoluble cathodes 12, the electrochemical cathodic reaction of the reduction of hydroxonium ions occurs with the formation of hydrogen and water molecules (2H ₃ O ⁺ → H ₂ + 2H ₂ O). Next, the neutralized wastewater flows through pipelines 16 into the cathode chamber 5 of the electrolyzer, in which, under the influence of a current load, cathodes 8 carry out the electrochemical cathodic reaction of the discharge of water molecules with the formation of hydrogen and hydroxyl ions (2H ₂ O → H ₂ ↑ + 2OH ^- ), as a result, the pH of wastewater rises (alkalizes) to 9-10, at which due to chemical reactions (Me + 2OH ^- = Me (OH) ₂ ↓), the formation of particles of the dispersed phase of poorly soluble non-ferrous and rare-earth metal compounds in the form of hydroxides and their flotation belly rkami hydrogen on the surface of water.

At the same time, in the lateral anode chambers 6, when water molecules are discharged on the surface of the insoluble anodes 11, oxygen is released and the background electrolyte is acidified due to the formation of hydrogen ions H ⁺ .

The separation of the products of the cathodic and anodic reaction by anion-exchange membranes 7 and 9 prevents the transport of OH ^- ions in the treated wastewater and their chemical interaction with H ⁺ ions with the formation of neutral water molecules.

Further, wastewater containing particles of the dispersed phase of sparingly soluble compounds of non-ferrous and rare-earth metals overflows through a partition 2 and enters the electroflotation chamber 4, in which under the action of gas bubbles (hydrogen and oxygen) formed on insoluble electrodes (anodes and cathodes) 17 at electrolysis of water flotation separation of particles of the dispersed phase of poorly soluble compounds of non-ferrous and rare earth metals from waste water. The purified water is discharged from the device through the nozzles 18.

The dispersed phase of poorly soluble non-ferrous and rare-earth metal compounds that has surfaced during electroflotation onto the water surface is formed into a foam layer, which is removed by the foam collecting device 20 into the collector 19 and then removed from the device.

, Кл/л), которая может быть определена по формуле [Яковлев СВ., Краснобородько И.Г., Рогов В.М. Технология электрохимической очистки воды. - Л.: Стройиздат, 1987. С. 289-291.]An increase in the productivity of membrane electrolysis processes is achieved due to the additional placement of cathodes and anion-exchange and membranes in the lateral anode chambers, which increases the total working surface area of their surface in the cell. In this case, the productivity of the process or device (Q, m ³ / h) will be determined by the change in pH (acidity) of the treated water. The main calculated value for the required change in the pH of the wastewater is the current consumption (

, CL / l), which can be determined by the formula [Yakovlev SV., Krasnoborodko IG, Rogov VM Technology of electrochemical water treatment. - L .: Stroyizdat, 1987. S. 289-291.]

,

,

- удельное изменение кислотности на 100 Кл/л, мг-экв/л.where K _K and K _N - the required final and initial acidity of water, respectively;

- specific change in acidity per 100 C / l, mEq / L.

The performance of the process will be

,

,

where S _e - the surface area of the electrodes; I _e - current density at the electrodes.

Thus, with an increase in the surface area of the electrodes S _{e, the} productivity of the process will increase.

The productivity of the process is also affected by the rate of ion transfer through the ion-exchange membrane, which is determined by the change in the concentration of ions H ⁺ (C _ref / C _con ), which can be calculated by the formula [Bogatyrev A.E., Vartsov V.V., Shulpin G. P. Membrane electrodialysis technologies for electroplating. Issue 3 (1697). -M.: Central Research Institute "Electronics", 1993. - S. 57.]:

,

,

where C _ref is the initial concentration of ions; C _ref is the final concentration of ions; D is the diffusion coefficient of ions; δ is the thickness of the limiting diffusion layer; Smb - the area of ion-exchange membranes; i _mb is the current density on the ion-exchange membrane; W _n - linear flow rate of the treated water along the membranes.

Thus, with an increase in the area of ion exchange membranes Smv, the productivity of the process (mass transfer rate) will also increase.

The technical result in solving the problem is achieved by increasing the total working surface area of the anion-exchange membranes and cathodes.

The proposed design of a utility model of a device for electrochemical wastewater treatment of compounds of non-ferrous and rare-earth metals can improve the performance of membrane electrolysis processes.

Claims (1)

A device for electrochemical treatment of wastewater from non-ferrous and rare-earth metal compounds, comprising a housing with an electrolytic cell and an electroflotation chamber, characterized in that the side anode chambers of the electrolyzer are equipped with nozzles for introducing and discharging wastewater and pipelines connecting them to the cathode chamber, this inside the lateral anode chambers additionally placed anion-exchange membrane and cathode.

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