CN105908223A - Alkaline electrolyte and method for preparing bright nickel by means of electrolysis in alkaline electrolyte - Google Patents

Abstract

The invention discloses an alkaline electrolyte and a method for electrolytically preparing bright nickel in the alkaline electrolyte. The alkaline electrolyte comprises nickel chloride, ammonium chloride, ammonia water, sodium benzenesulfinate and water, wherein the concentration of nickel chloride is 50-400g/L, the concentration of ammonium chloride is 80-450g/L, and the concentration of ammonia water is 30~350g/L, sodium benzene sulfinate concentration 0.03~1g/L. A method for electrolytically preparing bright nickel in an alkaline electrolyte, comprising: (1) preparing an alkaline electrolyte; (2) removing a surface oxide layer and degreasing treatment on a cathode material, and soaking the anode material in nitric acid Removing the surface oxide layer and impurities; (3) placing the pretreated cathode material and anode material in an electrolytic tank equipped with an alkaline electrolyte for electrodeposition to obtain a bright and flat nickel layer. The alkaline electrolyte of the invention can effectively solve the problem that the deposited nickel layer is black and brittle, and successfully prepares bright nickel. The method has the advantages of high current efficiency, bright nickel, good toughness, and the like.

Description

A kind of alkaline electrolytic solution and the method for electrolytically preparing bright nickel in the alkaline electrolytic solution

(1) Technical field

The invention relates to an alkaline electrolyte and a method for electrolytically preparing bright nickel in the alkaline electrolyte, belonging to the technical field of nonferrous metallurgy.

(2) Background technology

In the current electrolytic industrial production of nickel, the bright nickel is mainly prepared by electrolysis with the Watts nickel plating solution of the boric acid system. This process has been continuously improved and matured after decades of transformation and innovation. The progress of the traditional electrolytic nickel process is increasingly revealing its shortcomings in production. The disadvantages of the traditional electrolytic nickel process are as follows:

1. Using acidic system electrolytic nickel process, using boric acid as a buffer, it is necessary to strictly control the pH within the range of 4.5 to 5.4. If the pH is too low, the efficiency of the cathode will decrease, and if the pH is too high, it will lead to the formation of nickel hydroxide. Physical properties and morphology deteriorate.

2. The electrolytic nickel current density is low by using the sulfate-chloride mixed system, which makes it difficult to strengthen production and the production capacity is too low.

3. To obtain the raw materials of electrolytic nickel, coarse nickel, nickel sulfide, and high nickel matte, need to go through a complicated production process, which has a long cycle, a lot of waste, and high energy consumption. Moreover, diaphragm electrolysis is used, the cell voltage is high, energy consumption is increased, the process of the purification system is long, and the operation is difficult.

Therefore, it is self-evident that it is of great significance for nickel industrial production to study a relatively efficient and green electrolytic method with relatively simple process flow, which can be applied to mechanized and automated production, increase production capacity, and expand the pH range of buffer additives to prepare bright nickel. It is also in line with the current green production policy advocated by the state. Using ammonia leaching solution directly as the electrolyte to electrolyze nickel has high research value, but compared with the current mature electrolytic nickel system in the nickel industry, the research in this area is almost blank, and there are many deficiencies in related applications.

The invention describes the research on the preparation of bright nickel by electrolysis in an alkaline system, which has great prospects, environmental and economic benefits.

(3) Contents of the invention

The purpose of the present invention is to address the deficiency of the existing boric acid system and the problem that nickel is blackened and brittle by electrolysis of the nickel-ammonia complex alkaline system, and proposes an alkaline electrolyte and a method for electrolytically preparing bright nickel in the alkaline system. method, the alkaline electrolyte can effectively solve the problem that the deposited nickel layer is black and brittle by adding an appropriate amount of sodium benzenesulfinate to the nickel-ammonia complex alkaline system, and successfully prepares bright nickel. This method has current efficiency High, the prepared nickel is bright, good toughness and other advantages.

To achieve the above object, the present invention adopts the following technical solutions:

An alkaline electrolyte, which includes nickel chloride, ammonium chloride, ammonia water, sodium benzenesulfinate and water, wherein the concentration range of nickel chloride is 50-400g/L, and the concentration range of ammonium chloride is 80-450g/L L. The concentration of ammonia water (calculated as NH ₃ ·H ₂ O) ranges from 30 to 350 g/L, and the concentration of sodium benzenesulfinate ranges from 0.03 to 1 g/L.

Further, the preferred concentration of the nickel chloride is 80-200g/L.

Further, the preferred concentration of the ammonium chloride is 100-350 g/L.

Further, the preferred concentration of the ammonia water is 50-250 g/L.

Further, the preferred concentration of the sodium benzene sulfinate is 0.05-0.4 g/L.

Further, the alkaline electrolyte is prepared from nickel chloride, ammonium chloride, ammonia water, sodium benzenesulfinate and water.

Furthermore, the preparation steps of the alkaline electrolyte are as follows: adding nickel chloride and ammonium chloride into a small amount of water for heating and dissolving, adding ammonia water and water to mix after the solution is cooled, stirring evenly at a constant temperature of 25-65°C, adding Sodium benzenesulfinate is finally prepared to obtain an alkaline electrolyte.

The present invention further provides a method for electrolytically preparing bright nickel in an alkaline electrolyte, the method comprising the following steps:

(1) prepare alkaline electrolyte;

(2) Remove the surface oxide layer and degreasing treatment on the cathode material, and soak the anode material in 1-5mol/L nitric acid for 10-60min to remove the surface oxide layer and impurities;

(3) placing the cathode material and the anode material after the pretreatment in step (2) in an electrolytic cell equipped with an alkaline electrolyte, controlling the electrodeposition temperature to 25-65° C. and the stirring speed of the electrolyte to 250-650 r/min, Adopt constant current method, control the current density to -100～-500A/m ² , electrodeposit for 0.5～100h, take out the cathode, wash it with water, and dry it with cold wind to obtain a bright and flat nickel layer.

Further, in step (2), the cathode material can be an electrode material that can be used as a cathode in the existing electrolysis technology field, preferably the cathode material is stainless steel, nickel or copper. In cathode pretreatment, surface oxides can generally be removed by sandpaper grinding, and then degreasing and cleaning are carried out with a cleaning solvent. The cleaning solvent can be acetone, ethanol, water, etc.

Further, in step (2), the anode material can be an electrode material that can be used as an anode in the existing electrodeposition technology field, preferably the anode material is thick nickel, nickel sulfide or high matte nickel. In anodic pretreatment, the concentration of nitric acid is preferably 2-4 mol/L, and the soaking time is preferably 20-40 min.

Further, in step (2), the electrolysis temperature range is preferably 40-60°C.

Further, in step (2), the stirring speed of the electrolyte solution is preferably 300-500 r/min.

Furthermore, in step (2), the current density is preferably -200 to -400A/m ² .

Further, in step (2), the electrolysis time is preferably 1-40 h.

Further, in step (2), the bright nickel layer obtained by electrolysis is high-purity nickel

Further, the preparation consists of steps (1) to (3).

The beneficial effects of the present invention are: the present invention solves the problem of blackening and brittle electrolytic nickel in the nickel-ammonia alkaline system, and the bright nickel prepared in the alkaline system has better toughness and can meet industrial demands. The electrolyte required by the invention can be obtained by an ammonia leaching process, the process flow is simple, the anode does not produce toxic chlorine gas, the invention is green and environmentally friendly, and has huge prospects, environmental and economic benefits.

(4) Description of drawings

Fig. 1 is the scanning electron micrograph of embodiment 3 electrolytic nickel.

(5) Specific implementation methods

The present invention will be further described below through specific examples, but the protection scope of the present invention is not limited thereto.

Example 1

Configure 250 mL of electrolyte solution containing 50 g/L of nickel chloride, 80 g/L of ammonium chloride, 30 g/L of ammonia water, and 0.03 g/L of sodium benzenesulfinate. Take the anode of the thick nickel electrode and immerse it in 1mol/L nitric acid for 60 minutes to remove the surface oxide layer and impurities, take it out, rinse it with deionized water, and dry it with cold air. Using stainless steel as the cathode material, after grinding with 1#, 3#, and 5# sandpaper, degreasing with absolute ethanol, washing with deionized water and drying with cold air, put the cathode and anode into the electrolytic cell at the same time, and control the electrodeposition temperature to 25°C, the current density is -500A/m ² , the speed of stirring the electrolyte is 650r/min, after 0.5h of electrodeposition, take out the cathode, rinse the residual electrolyte on the surface with water, dry it with cold air, and peel off the nickel from the stainless steel. High-purity nickel with bright surface and high toughness is obtained.

The current efficiency of electrolytic nickel based on Example 1 is 98.35%.

Example 2

Prepare 250 mL of electrolyte solution containing 400 g/L of nickel chloride, 450 g/L of ammonium chloride, 350 g/L of ammonia water, and 1 g/L of sodium benzenesulfinate. Take the anode of the thick nickel electrode, soak it in 5mol/L nitric acid for 10min to remove the surface oxide layer and impurities, take it out, rinse it with deionized water, and dry it with cold air. Using stainless steel as the cathode material, after grinding with 1#, 3#, and 5# sandpaper, degreasing with absolute ethanol, washing with deionized water and drying with cold air, put the cathode and anode into the electrolytic cell at the same time, and control the electrodeposition temperature to 65℃, the current density is -100A/m ² , the speed of stirring the electrolyte is 250r/min, after 100 hours of electrodeposition, take out the cathode, rinse the residual electrolyte on the surface with water, dry it with cold air, and peel off the nickel from the stainless steel to obtain Bright and ductile high-purity nickel.

The current efficiency of electrolytic nickel based on Example 2 is 97.73%.

Example 3

Configure 250 mL of electrolyte containing 80 g/L of nickel chloride, 100 g/L of ammonium chloride, 50 g/L of ammonia water, and 0.05 g/L of sodium benzenesulfinate. Take the anode of the thick nickel electrode and immerse it in 2mol/L nitric acid for 40min to remove the surface oxide layer and impurities, take it out, rinse it with deionized water, and dry it with cold air. Using stainless steel as the cathode material, after grinding with 1#, 3#, and 5# sandpaper, degreasing with absolute ethanol, washing with deionized water and drying with cold air, put the cathode and anode into the electrolytic cell at the same time, and control the electrodeposition temperature to 40℃, the current density is -400A/m ² , the speed of stirring the electrolyte is 500r/min, after electrodeposition for 1 hour, take out the cathode, rinse the residual electrolyte on the surface with water, dry it with cold air, and peel the nickel from the stainless steel to obtain Bright and ductile high-purity nickel.

The current efficiency of electrolytic nickel based on Example 3 is 96.98%.

Example 4

Configure 250 mL of electrolyte containing 200 g/L of nickel chloride, 350 g/L of ammonium chloride, 250 g/L of ammonia water, and 0.4 g/L of sodium benzenesulfinate. Take the anode of the thick nickel electrode and immerse it in 4mol/L nitric acid for 20min to remove the surface oxide layer and impurities, take it out, rinse it with deionized water, and dry it with cold air. Using stainless steel as the cathode material, after grinding with 1#, 3#, and 5# sandpaper, degreasing with absolute ethanol, washing with deionized water and drying with cold air, put the cathode and anode into the electrolytic cell at the same time, and control the electrodeposition temperature to 60℃, the current density is -200A/m ² , the speed of stirring the electrolyte is 500r/min, after 40 hours of electrodeposition, take out the cathode, rinse the residual electrolyte on the surface with water, dry it with cold air, and peel off the nickel from the stainless steel to obtain Bright and ductile high-purity nickel.

The current efficiency of electrolytic nickel based on Example 4 is 97.55%.

Example 5

Configure 250 mL of electrolyte solution containing 130 g/L of nickel chloride, 212 g/L of ammonium chloride, 126 g/L of ammonia water, and 0.2 g/L of sodium benzenesulfinate. Take the anode of the thick nickel electrode and immerse it in 3mol/L nitric acid for 30min to remove the surface oxide layer and impurities, take it out, rinse it with deionized water, and dry it with cold air. Using stainless steel as the cathode material, after grinding with 1#, 3#, and 5# sandpaper, degreasing with absolute ethanol, washing with deionized water and drying with cold air, put the cathode and anode into the electrolytic cell at the same time, and control the electrodeposition temperature to 50℃, the current density is -300A/m ² , the speed of stirring the electrolyte is 400r/min, after 15 hours of electrodeposition, take out the cathode, rinse the residual electrolyte on the surface with water, dry it with cold air, and peel off the nickel from the stainless steel to obtain Bright and ductile high-purity nickel.

The current efficiency of electrolytic nickel based on Example 5 is 98.69%.

Example 6

Configure 250 mL of electrolyte solution containing 130 g/L of nickel chloride, 212 g/L of ammonium chloride, 126 g/L of ammonia water, and 0.2 g/L of sodium benzenesulfinate. Use the anode of nickel sulfide electrode to immerse in 3mol/L nitric acid for 30 minutes to remove the surface oxide layer and impurities, take it out, rinse it with deionized water, and dry it with cold air. Taking copper as the cathode material, after grinding with 1#, 3#, and 5# sandpaper, degreasing with absolute ethanol, washing with deionized water and drying with cold air, put the cathode and anode into the electrolytic cell at the same time, and control the electrodeposition temperature to 50℃, the current density is -300A/m ² , the speed of stirring the electrolyte is 400r/min, after 15 hours of electrodeposition, take out the cathode, rinse the residual electrolyte on the surface with water, dry it with cold air, and peel off the nickel from the stainless steel to obtain Bright and ductile high-purity nickel.

The current efficiency of electrolytic nickel based on Example 6 is 96.88%.

Example 7

Configure 250 mL of electrolyte solution containing 130 g/L of nickel chloride, 212 g/L of ammonium chloride, 126 g/L of ammonia water, and 0.2 g/L of sodium benzenesulfinate. Use the anode of high ice nickel electrode, immerse in 3mol/L nitric acid for 30min to remove the surface oxide layer and impurities, take it out, rinse it with deionized water, and dry it with cold wind. Using nickel as the cathode material, after grinding with 1#, 3#, and 5# sandpaper, degreasing with absolute ethanol, washing with deionized water and drying with cold air, put the cathode and anode into the electrolytic cell at the same time, and control the electrodeposition temperature to 50℃, the current density is -300A/m ² , the speed of stirring the electrolyte is 400r/min, after 15 hours of electrodeposition, take out the cathode, rinse the residual electrolyte on the surface with water, dry it with cold air, and peel off the nickel from the stainless steel to obtain Bright and ductile high-purity nickel.

The current efficiency of electrolytic nickel based on Example 7 is 97.52%.

Claims (10)

1. an alkaline electrolyte, it is characterised in that: described alkaline electrolyte include Nickel dichloride., ammonium chloride, Ammonia, benzene sulfinic acid sodium salt and water, wherein Nickel dichloride. concentration range be 50～400g/L, ammonium chloride concentration scope be 80～450g/L, ammonia concn scope be 30～350g/L, benzene sulfinic acid sodium salt concentration range be 0.03～1g/L.

2. alkaline electrolyte as claimed in claim 1, it is characterised in that: described alkaline electrolyte is by chlorination Nickel, ammonium chloride, ammonia, benzene sulfinic acid sodium salt and water are formulated.

3. alkaline electrolyte as claimed in claim 1 or 2, it is characterised in that: described Nickel dichloride. concentration is 80～200g/L.

4. alkaline electrolyte as claimed in claim 1 or 2, it is characterised in that: described ammonium chloride concentration is 100～350g/L.

5. alkaline electrolyte as claimed in claim 1 or 2, it is characterised in that: described ammonia concn is 50～250g/L.

6. alkaline electrolyte as claimed in claim 1 or 2, it is characterised in that: described benzene sulfinic acid sodium salt is dense Degree is 0.05～0.4g/L.

7. a method for electrolytic preparation bright nickel in alkaline electrolyte, said method comprising the steps of:

(1) alkaline electrolyte as claimed in claim 1 is prepared；

(2) cathode material is removed surface oxide layer, oil removal treatment, anode material is placed in 1～5mol/L Nitric acid in soak 10～60min removal surface oxide layers and impurity；

(3) cathode material after step (2) pre-treatment and anode material are placed in equipped with alkaline electrolyte Electrolysis bath in, control electrodeposition temperature 25～65 DEG C and electrolyte mixing speed 250～650r/min, use The mode of constant current, controlling electric current density electric current density is-100～-500A/m², electro-deposition 0.5～100h, take Go out that negative electrode washes, cold wind i.e. obtains the smooth nickel dam of light after drying up.

8. the method for electrolytic preparation bright nickel in alkaline electrolyte as claimed in claim 7, its feature exists In: in step (2), cathode material is rustless steel, nickel or copper；Anode material is thick nickel, nickel sulfide or height Ice nickel.

9. the method for electrolytic preparation bright nickel in alkaline electrolyte as claimed in claim 7 or 8, it is special Levying and be: in step (2), electrolysis temperature scope is 40～60 DEG C；Electrolyte mixing speed is 300～500r/min； Electric current density is-200～-400A/m²；Electrolysis time is 1～40h.

10. the method for electrolytic preparation bright nickel in alkaline electrolyte as claimed in claim 7 or 8, its It is characterised by: described preparation is made up of step (1)～(3).