CN101545112B

CN101545112B - An electrolytic method of electrolytic manganese dioxide

Info

Publication number: CN101545112B
Application number: CN200910043286.0A
Authority: CN
Inventors: 竹原尚夫; 崔璀
Original assignee: HUNAN SUNSHINE ELECTROCHEMICAL CO Ltd
Current assignee: HUNAN SUNSHINE ELECTROCHEMICAL CO Ltd
Priority date: 2009-05-04
Filing date: 2009-05-04
Publication date: 2014-04-23
Anticipated expiration: 2029-05-04
Also published as: CN101545112A

Abstract

An electrolytic method of electrolytic manganese dioxide, wherein the electrolytic process of electrolytic manganese dioxide controls the concentration of anionic surfactant in electrolyte at 0.1-100ppm. According to the actual situation, the surfactant may also be used together with heat and acid resistant resin or paraffin. In this way, the voltage of electrobath may be reduced by about 0.5V and the unit electricity consumption of electrolysis may be reduced by about 20%.

Description

The electrolysis process of electrolytic manganese dioxide

Technical field

The present invention relates to a kind of electrolysis process of electrolytic manganese dioxide, especially relate to a kind of electrolysis process of adjusting the electrolytic manganese dioxide of bath voltage by the surfactant concentration in adjustment electrolyzer.

Background technology

In electrolytic manganese dioxide (hereinafter to be referred as " EMD ") is produced, reduce as much as possible the unit power consumption of electrolysis, it is extremely important reducing bath voltage.Conventionally, be exactly reduce by every means bath voltage and theoretical decomposition voltage (1.23V) poor, be about to overpotential and reduce as much as possible.But, in actual process control procedure, when anodic current density reaches 0.7A/dm ²time, bath voltage reaches 3.5V sometimes, and overpotential reaches 2.2V.Electrolysis overpotential consists of anode overpotential, cathode overpotential, electrode ohmic loss, electrolytic solution ohmic loss etc., and major influence factors comprises length of electrode surface state, current density, temperature, stirring, pH value of solution, electrolysing period etc.Control past attempts to these factors was taked a lot of measures, such as, take to change the rough degree in surface of anode, the material that changes male or female, reduction current density, strengthening stirring, shortened the measures such as electrolysing period, but because its result also has impact to quality and whole cost, in practice, be restricted.And in actual production process, the improvement of electric power unit consumption is limited, generally in 30% left and right.

In general, anode overpotential is maximum, accounts for 50% of whole overpotentials.

In the EMD of China industry, in electrolyzer, add tensio-active agent only for preventing electrolytic solution evaporation this purpose, therefore, there is the tendency of excessively using.Material impact about surperficial anion active agent to electrolytic reaction itself, until before present inventor completes the present invention, seem not yet to cause that people pay close attention to.

And using electrolyzer to carry out in the industry of electrolysis production, the object of conventionally using tensio-active agent is in order to improve electrolytic reaction mostly.For example, in anodizing of aluminium field, use be the anion surfactant (ROSO identical with Chinese EMD industry ₃na), but its objective is in order to allow R base be adsorbed and to separate out on aluminium surface, and be not intended to avoid evaporating (referring to No. 1997-31690, day disclosure special permission, open day on February 4th, 1997, the treatment process > > of denomination of invention < < anodizing of aluminium film).

On electrolytic polishing is produced, can use tensio-active agent to regulate the overpotential of metal (referring to < < chemical grinding and electrolytic polishing > >, Omaki bookstore, version in 1997, Japan).

On metallide is produced, by using cats product, can make the nickel Evolution overpotential of negative electrode reach 300mV.It is introduced, its reason is because tensio-active agent is adsorbed on negative electrode (referring to < < sufacing > > Vo1.57 (2006), No7, Japan).

Summary of the invention

The object of the present invention is to provide a kind of use tensio-active agent effectively to reduce the method for overpotential in electrolytic manganese dioxide (hereinafter to be referred as EMD) production process.

The object of the invention is to be achieved through the following technical solutions: at the electrowinning process of EMD, the surfactant concentration of electrolytic solution is controlled to 0.1～100ppm.

Preferred electrolyte surface surfactant concentration scope is to be controlled at 0.5～75ppm.

Preferred tensio-active agent is anion surfactant (ROSO for example ₃na).

Concrete control method, can in a planned way adjust the concentration of anion surfactant first by pilot study, grasps the Changing Pattern of bath voltage.

Pilot study can be selected following condition: in having the 3L beaker of attemperator, insert the pure anode titanium plate of a 50 * 150mm, insert the negative electrode carbon plate of two 50 * 150mm; Interpolation sulfuric acid concentration is the solution that 0.45M/L, manganese concentration are 0.55M/L, and by electrothermal heater, controlling temperature is 93 ℃; In current density, be 0.2A/dm ²under condition, electrolysis is after one hour, and (why electrolysis time is set as one hour to the voltage of mensuration electrolyzer, is because now electrolysis voltage roughly tends towards stability; Current density is set in to lower level, is that current density is high in order to hold as much as possible the one-side impact of tensio-active agent, has a plurality of factors and exerts an influence, and overpotential also can become greatly, and it is large that error likely can become)

Because the cell surface surfactant concentration in actual production is at present 100～300ppm, so present inventor's above-mentioned experiment, from the concentration of 300pp, reduces successively concentration and test, its result is as shown in the table:

Surfactant concentration (ppm)	Corresponding electrolysis voltage (V)
		300	1.81
150	1.80
		100	1.77
75	1.69
		50	1.64
10	1.52
		1	1.43
0.5	1.42
		0.1	1.41

From the test-results of upper table, electrolysis voltage is along with surfactant concentration reduces and reduces, and surfactant concentration is lower than 100ppm, and particularly lower than after 75ppm, effect is obvious.Overpotential has been reduced to 0.18V from the highest 0.58V, has reduced 0.4V.When concentration is during lower than 0.4ppm, the foaming effect of tensio-active agent declines to a great extent, and this is inappropriate.Therefore, according to above experimental result, the concentration of tensio-active agent should be controlled at 0.1～100ppm, optimally should be controlled at 0.5～75ppm.

In actual production operation, along with the rising of current density, the ohmic loss under different situations is not identical yet, thus cannot treat different things as the same, and need to consider the impact of dosage of surfactant deficiency on electrolytic solution evaporation.But to this situation, can be by by heat-resisting acid-proof resin or paraffin and tensio-active agent and with being solved, at electrolyte surface also suspend heat-resisting acidproof tree resin or the melt paraffin of 2-30mm thickness.Why upper thickness limit being defined as to 30mm, is because as the countermeasure that prevents electrolytic solution evaporation, although the heat-resisting acidproof tree resin of suspension or melt paraffin are more thick better, blocked uply can reduce the useful area of electrode again and has influence on turnout; And thickness is lower than 2mm, prevent that electrolytic solution evaporation effect is poor again.

The also use of heat-resisting acid-proof resin or paraffin and tensio-active agent, can also expect following subsidiary effect.The tensio-active agent and the paraffin that use now respectively have relative merits, and in the patent of applying for before this according to present inventor, about the calculating of electrolyzer heat balance, from the effect avoiding evaporating, tensio-active agent only has 30% of paraffin; But on the other hand, because melting point of paraffin wax is higher, in the more difficult cleaning of postprocessing working procedures, its cleaning equipment is also comparatively complicated and comparatively expensive, this is the weak point of paraffin.But pass through and use, because tensio-active agent can reduce exposing of interface, thereby can expect to improve the effect avoiding evaporating; Meanwhile because by and by the usage quantity that has reduced paraffin (foaming effect relatively), can expect that the aftertreatment meeting of product becomes comparatively simple and easy.

Embodiment

The invention will be further described by the following examples.But these embodiment must not be interpreted as to limiting the scope of the invention.

Each embodiment test conditions is identical with described pilot study.Tensio-active agent used is Sodium Lauryl Sulphate BP/USP (sodium lauryl sulfate), and its molecular formula is C ₁₂h ₂₅oSO ₃na.

Embodiment 1

Current density is by the 0.5A/dm of common actual production operation ², electrolysis time 7 hours.Surfactant concentration is pressed 300ppm, 50ppm, 10ppm, tetra-levels of 1ppm, start voltage as follows respectively with final voltage: 300ppm (2.10V → 2.31V), 50ppm (1.85V → 1.92V), 10ppm (1.83V → 1.87V), 1ppm (1.81V → 1.84V), result has identical tendency with aforementioned pilot study.

Embodiment 2

Current density is pressed 0.7A/dm ², then test.Result is as follows: 300ppm (2.39V → 2.70V), 50ppm (1.99V → 2.10V), 10ppm (1.96V → 2.05V), 1ppm (1.89V → 1.92V).Also there is identical tendency with aforementioned pilot study.

Under the current density of described degree, even if in actual long-term production operation, the voltage change of electrolyzer should be less.So the electric power unit consumption that can infer electrolysis roughly can reduce 0.5V ÷ 2.5V * 100=20%.

Surfactant causes the impact of excessive vaporization to be analyzed by quantity not sufficient, by weighting method (supplementing liquid storage in liquid, discharge opeing, beaker), measured the steam output before and after test, as shown in the table, between 10ppm and 1ppm, do not have large steam output to change.

In addition, by analyzing the current curve diagram of automatic temperature-controlled heat exchanger, before the concentration of discovery tensio-active agent is down to 10ppm, electric current is stabilized in 0.50 ± 0.05Amp always, does not almost change.Irrelevant with current density, during 1ppm, be 0.53 ± 0.10Amp.Can infer, for holding temperature is 93 ℃, because making up the thermosteresis of excessive vaporization, the current value of heat exchanger and fluctuation thereof understand that some is large.

Embodiment 3

0.7A/dm ²the condition of current density, surfactant concentration 0.5ppm under, use ball resin material, 3mm diameter simultaneously, ball suspension thickness is 3mm; Steam output is 5%, with the data comparison of embodiment 2, successful.The electric current of heat exchanger is with this understanding identical when 10ppm is above with concentration, is all stabilized in 0.47 ± 0.05Amp, and can maintain the temperature of 93 ℃.Its groove is pressed as 1.91V → 1.92V, has identical tendency with embodiment 2.

Embodiment 4

0.7Amp/dm ², 0.5ppm tensio-active agent and paraffin (60 ℃ of fusing points) use, paraffin suspension thickness 2mm.Steam output 3%, is all better than embodiment 2, successful.Heat exchanger electric current is identical with the above concentration of 10ppm, is stabilized in 0.45 ± 0.05Amp, and temperature can maintain 93 ℃, successful.Its groove is pressed as 1.89V → 1.90V, has identical tendency with embodiment 2.

Because the proneness of EMD testing laboratory electrolyzer data and the data of actual electrolyzer have stronger dependency, can think, the utilizability of these information in EMD actual production is larger.

Claims

1. the electrolysis process of an electrolytic manganese dioxide, it is characterized in that, at the electrowinning process of electrolytic manganese dioxide, the electrolytic solution anionic surfactant concentration of electrolyzer is controlled to 0.1 ~ 100ppm, effectively to reduce the overpotential in electrolytic manganese dioxide production process.

2. the electrolysis process of electrolytic manganese dioxide according to claim 1, is characterized in that, the electrolytic solution anionic surfactant concentration of electrolyzer is controlled at 0.5 ~ 75ppm.

3. the electrolysis process of electrolytic manganese dioxide according to claim 1 and 2, is characterized in that, at the electrolyte surface 2-that also suspends 30heat-resisting acid-proof resin pearl or the melt paraffin of mm thickness.