CN106276989B - The method that magnesium prepares magnesium hydroxide is reclaimed from cobalt nickel industry magnesium solution containing cobalt - Google Patents

Abstract

The invention provides a method for recovering magnesium from a cobalt-containing magnesium solution in the cobalt-nickel industry to prepare magnesium hydroxide, comprising the following steps: Step 1: taking the cobalt-containing magnesium solution, adding 3 to 6 mol/L of sodium hydroxide to adjust the pH value, Control temperature and stir to make cobalt fully precipitate; Step 2: Filtrate to obtain filtrate 1 and filter cake 1, add water to slurry 1, and then filter to obtain filtrate 2; Step 3: Mix filtrate 2 and filtrate 1 to obtain filtrate 3. Add sodium sulfide solution, control temperature, stir, then add polyaluminium chloride, and then filter to obtain filtrate 4; Step 4: Add filtrate 4 to alkali solution, adjust pH value, control temperature, and stir; Step 5: Chen process 6: slurry and wash the filter cake 3, and then filter to obtain the filter cake 4; process 7: slurry and wash the filter cake 4, then filter, dry, and pulverize to obtain the finished product. The method of the invention can simply and efficiently recover magnesium from the cobalt-nickel production process to prepare magnesium hydroxide.

Description

The method that reclaims magnesium and prepares magnesium hydroxide from cobalt-nickel industry cobalt-containing magnesium solution

technical field

The invention belongs to the technical field of resource recycling and hydrometallurgy, and in particular relates to a method for separating cobalt from an extracted cobalt-containing magnesium solution and recovering magnesium to prepare magnesium hydroxide.

technical background

As an industrial monosodium glutamate, cobalt-nickel has been widely used in the manufacture of high-energy batteries, functional ceramics, and artificial diamonds. Usually the preparation of cobalt-nickel materials uses laterite ore with high magnesium content as the raw material. During the preparation process, the liquid after acid immersion will contain a large amount of magnesium, which will not only cause a large amount of inclusions in the subsequent cobalt-nickel extraction process. Magnesium, which brings inconvenience to the extraction, and the discharge of high-magnesium-containing wastewater into the water body will also cause the water body to be too salinized, causing pollution to the environment, and is also detrimental to the subsequent sewage treatment.

Therefore, it is very necessary to recover the magnesium in the cobalt-containing magnesium solution in the industrial production process.

At present, magnesium hydroxide is the most widely used in magnesium-containing compounds and has the largest demand. Therefore, if the magnesium recovered from the cobalt-containing magnesium solution in the cobalt-nickel industry can be used to prepare magnesium hydroxide products, it will not only reduce the impact of magnesium on cobalt. The impact of nickel extraction, the enrichment of magnesium in the extraction system and the pollution caused by its discharge to the environment can also turn waste into wealth and create economic value by using waste magnesium resources.

However, in the prior art, the preparation of magnesium hydroxide is mostly extracted from dolomite, and the separation of calcium and magnesium is realized by various methods such as carbonization, ammonium chloride extraction or sulfuric acid dissolution, and then magnesium hydroxide is obtained by adding alkali to precipitate magnesium. Or use magnesium sulfate or magnesium chloride plus alkali precipitation to generate magnesium hydroxide. Dehydration is very difficult due to the fine particles of magnesium hydroxide generated during the magnesium precipitation process. For this reason, it is usually necessary to use ammonia water to precipitate magnesium, or to hydrothermally treat the formed magnesium hydroxide gel to improve its dehydration performance. Through these treatments Measures can then be filtered to obtain the magnesium hydroxide product.

At present, there is no method that can effectively separate cobalt and magnesium from the cobalt-containing magnesium solution in the cobalt-nickel industry, so as to recover magnesium and prepare magnesium hydroxide.

Contents of the invention

The present invention is carried out in order to solve the above problems, and the purpose is to provide a simple and efficient method for preparing magnesium hydroxide from reclaiming magnesium in the production process of cobalt and nickel.

In order to achieve the above object, the present invention adopts the following scheme:

The invention provides a method for preparing magnesium hydroxide by reclaiming magnesium from a cobalt-containing magnesium solution in the cobalt-nickel industry. sodium hydroxide to adjust the pH value to 7.3~8.2, the temperature is controlled at 40~55°C, the stirring speed is 150~250rpm, and the pH value is kept constant for 10~30min, so that the cobalt is fully precipitated, and the cobalt in the solution after the cobalt precipitation The concentration is not more than 500mg/L; Step 2: filter to obtain filtrate 1 and filter cake 1, add water to the filter cake 1 for slurry, add water to adjust the slurry concentration to 10~15wt.%, water temperature 40~60°C, slurry When the stirring speed is 150~250rpm, stir for 5~10min, then filter to obtain filtrate 2 and filter cake 2, filter cake 2 continues to wash, and is used for subsequent recovery of cobalt; process three: combine filtrate 2 and filtrate 1 to obtain filtrate 3. Add 20~60g/L sodium sulfide solution to the filtrate 3, the addition is 2.5~3.8 times of the cobalt content in the filtrate 3, the temperature is controlled at 40~55°C, the stirring speed is 150~250rpm, and the reaction time is 5~3. 10min, then add polyaluminum chloride, the dosage is 10~30mg/L, and then filter to obtain the filtrate 4; Step 4: Slowly add the filtrate 4 to 2~7mol/L alkali solution, adjust the pH value to 10.8~11.5, The temperature is controlled at 40~60°C to precipitate magnesium, the stirring speed is 150~250rpm, and the reaction is 15~30min; Step 5: The solution obtained in Step 4 is aged at 75~85°C for 3~8h, and the formed magnesium hydroxide particles are laser Particle size _D50 is 4~8 microns, and then filtered to obtain filter cake 3; Step 6: Slurry and wash filter cake 3 with hot water at 40~60°C for 3~4 times, and the slurry concentration during washing is 10~15wt. %, stirring 150~250rpm, stirring time 5~10min, and then filtering to obtain filter cake 4; Step 7: Slurry and wash the filter cake 4 once with absolute ethanol, the slurry concentration is 35~45wt.%, and the temperature is 20~ 30°C, stirring 150-250rpm, stirring time 10-15min, then filtering to obtain filter cake 5, drying and crushing filter cake 5 at 120-140°C to obtain the finished product, the purity of magnesium hydroxide in the finished product is not less than 97.5 %.

Further, the method for preparing magnesium hydroxide by recovering magnesium from cobalt-nickel industrial cobalt-containing magnesium solution provided by the present invention may also have the following characteristics: in process one, the concentration of sodium hydroxide is 6mol/L, and the pH value is adjusted to 7.8 , the temperature was controlled at 40°C, the stirring speed was 250rpm, and the pH value was kept constant for 20min. Precipitation of cobalt works best under these conditions.

Further, the method for preparing magnesium hydroxide by recovering magnesium from cobalt-nickel industrial cobalt-containing magnesium solution provided by the present invention may also have the following characteristics: in process one, the concentration of sodium hydroxide is 6mol/L, and the pH value is adjusted to 7.8 , the temperature was controlled at 40°C, the stirring speed was 250rpm, and the pH value was kept constant for 20min.

Further, the method for preparing magnesium hydroxide by recovering magnesium from the cobalt-nickel industrial cobalt-containing magnesium solution provided by the present invention may also have the following characteristics: in the second step, when adding water to the filter cake 1 to make slurry, add water to adjust the concentration of the slurry %, the water temperature is 60°C, the stirring speed during slurrying is 250rpm, and stirred for 5min.

Further, the method for preparing magnesium hydroxide by reclaiming magnesium from the cobalt-containing magnesium solution in the cobalt-nickel industry provided by the present invention can also have the following characteristics: in step three, the sodium sulfide solution added is 45g/L, and the addition amount is 3 3 times the cobalt content in the medium, the temperature is controlled at 55°C, the stirring speed is 150rpm, the reaction time is 7min, and then the amount of polyaluminum chloride added is 10mg/L.

Further, the method for preparing magnesium hydroxide by reclaiming magnesium from the cobalt-nickel industrial cobalt-containing magnesium solution provided by the present invention can also have the following characteristics: in step four, the alkali solution is any one of sodium hydroxide solution and ammonia solution .

Further, the method for preparing magnesium hydroxide by recovering magnesium from cobalt-nickel industrial cobalt-containing magnesium solution provided by the present invention may also have the following characteristics: in step 4, the concentration of the added ammonia solution is 3mol/L, and the pH value is adjusted to 10.8 , the temperature is controlled at 60° C., the stirring speed is 200 rpm, and the reaction time is 15 minutes.

Furthermore, the method for preparing magnesium hydroxide by recovering magnesium from the cobalt-containing magnesium solution in the cobalt-nickel industry provided by the present invention may also have the following features: in step five, the solution is aged at 75° C. for 6 hours.

Further, the method for preparing magnesium hydroxide by recovering magnesium from cobalt-nickel industrial cobalt-containing magnesium solution provided by the present invention may also have the following characteristics: In step six, the filter cake is slurried and washed with hot water at 40°C for 4 times, and after washing When the slurry concentration is 15wt.%, the stirring speed is 150rpm, the stirring time is 10min, and then filtered.

Further, the method for preparing magnesium hydroxide from the cobalt-nickel industry cobalt-containing magnesium solution provided by the present invention can also have the following characteristics: in step six, the slurry concentration is 45wt.%, the stirring speed is 250rpm, and the stirring time For 10min, the filter cake is dried at 140°C.

Function and Effect of Invention

The method provided by the present invention is to reclaim magnesium from the cobalt-containing magnesium solution in the cobalt-nickel industry to prepare magnesium hydroxide, utilize the cobalt-containing magnesium solution in the cobalt-nickel industry to reclaim magnesium, and prepare the recovered magnesium into a magnesium hydroxide product, so that not only It can reduce the impact of magnesium on the extraction of cobalt and nickel, and can effectively reduce the discharge of magnesium and the enrichment in the extraction system, and can also use the recovered magnesium to prepare magnesium hydroxide products simply and efficiently, thereby bringing economic benefits. A win-win situation of environmental protection and economic benefits has been achieved.

In addition, because the laser D ₅₀ of the obtained magnesium hydroxide product particles is 4-8 μm, the filtration is very smooth and fast, saving time and effort, and improving the preparation efficiency.

Description of drawings

Figure 1 is a process flow diagram of an embodiment of the present invention.

detailed description

The specific embodiment of recovering magnesium from cobalt-nickel production process to prepare magnesium hydroxide involved in the present invention will be described in detail below in conjunction with the accompanying drawings.

<Example 1>

As shown in Figure 1, the method for preparing magnesium hydroxide by reclaiming magnesium from the cobalt-nickel industry cobalt-containing magnesium solution provided by the present embodiment 1 includes the following steps:

Process one (P1):

Get cobalt-containing magnesium solution after extracting nickel, its cobalt content 30g/L, magnesium content 25g/L, at first adjust pH value to 7.3 with the sodium hydroxide of 3mol/L, temperature is controlled at 55 ℃, stirring speed 150rpm, and maintain Keep the pH value unchanged for 10 minutes, so that the cobalt is fully precipitated, and the concentration of cobalt in the solution after cobalt precipitation is 490mg/L;

Process two (P2):

Filter with a plate and frame filter press to obtain filtrate 1 and filter cake 1, add water to filter cake 1 for slurry, add water to adjust the slurry concentration to 15wt.%, water temperature 60 ° C, stirring speed during slurry is 250rpm, stir for 5min , and then filter with a plate and frame filter press to obtain filtrate 2 and filter cake 2, and filter cake 2 continues to be washed and used for subsequent recovery of cobalt;

Process three (P3):

Filtrate 2 and filtrate 1 are merged to obtain filtrate 3, and 20g/L sodium sulfide solution is added in filtrate 3, and the addition is 2.5 times of cobalt content in filtrate 3, and temperature is controlled at 40 ℃, stirring speed 150rpm, reaction time 5min , then add polyaluminum chloride, dosage 10mg/L, then filter to obtain filtrate 4;

Process four (P4):

Slowly add 7mol/L sodium hydroxide solution to the filtrate 4, adjust the pH value to 11.0, control the temperature at 50°C to precipitate magnesium, stir at 150rpm, and react for 15min;

Process five (P5):

Aging the solution obtained in step 4 at 85°C for 3 hours, and then filtering to obtain filter cake 3, and the filtrate was directly discharged after adding acid to adjust pH=6~9;

Process six (P6):

The filter cake 3 obtained in step 5 was slurried and washed 3 times with hot water at 60°C, the slurry concentration was 10wt.% during washing, stirred at 200rpm for 10min, and then filtered by a plate and frame filter press to obtain the filter cake 4. filtrate discharge;

Process seven (P7):

Finally, the filter cake 4 is slurried and washed once with absolute ethanol, the slurry concentration is 35wt.%, the temperature is 20° C., the stirring time is 150 rpm, and the stirring time is 15 min. Then filter cake 5 is obtained by filtering with a plate and frame filter press, and the filter cake 5 is Dry and grind at 120°C to get the finished product.

In Example 1, the recovery rate of magnesium can reach 82.5wt.%, the purity of the magnesium hydroxide product can reach 97.9wt.%, the particle size distribution is between 1.2-11.9 μm, and the particle laser particle size D ₅₀ is 7.82 μm.

<Example 2>

As shown in Figure 1, the method for preparing magnesium hydroxide by reclaiming magnesium from the cobalt-nickel industry cobalt-containing magnesium solution provided by the second embodiment includes the following steps:

Process one (P1):

Get cobalt-containing magnesium solution after extracting nickel, its cobalt content 56g/L, magnesium content 30g/L, at first adjust pH value to 7.8 with the sodium hydroxide of 6mol/L, temperature is controlled at 40 ℃, stirring speed 250rpm, and maintain Keep the pH value unchanged for 20 minutes, so that the cobalt is fully precipitated, and the concentration of cobalt in the solution after cobalt precipitation is 327mg/L;

Process two (P2):

Filter with a plate and frame filter press to obtain filtrate 1 and filter cake 1, add water to slurry the filter cake 1, add water to adjust the slurry concentration to 10wt.%, water temperature 60 ° C, stirring speed during slurrying is 250rpm, stir for 5min , and then filter with a plate and frame filter press to obtain filtrate 2 and filter cake 2, and filter cake 2 continues to be washed and used for subsequent recovery of cobalt;

Process three (P3):

Filtrate 2 and filtrate 1 are merged to obtain filtrate 3, and 45g/L sodium sulfide solution is added in filtrate 3, and the addition is 3 times of cobalt content in filtrate 3, and temperature is controlled at 55 ℃, stirring speed 150rpm, reaction time 7min , then add polyaluminum chloride, dosage 10mg/L, then filter to obtain filtrate 4;

Process four (P4):

Add the filtrate 4 slowly to 3mol/L sodium hydroxide solution, adjust the pH value to 10.8, control the temperature at 60°C to precipitate magnesium, stir at 200rpm, and react for 15min;

Process five (P5):

Aging the solution obtained in step 4 at 75°C for 6 hours, and then filtering to obtain filter cake 3, the filtrate was directly discharged after adding acid to adjust pH=6~9;

Process six (P6):

The filter cake 3 obtained in step 5 was slurried and washed 4 times with hot water at 40°C, the slurry concentration was 15wt.% during washing, stirred at 150 rpm for 10 minutes, and then filtered by a plate and frame filter press to obtain the filter cake 4. filtrate discharge;

Process seven (P7):

Finally, the filter cake 4 is slurried and washed once with absolute ethanol, the slurry concentration is 45wt.%, the temperature is 30° C., the stirring time is 250 rpm, and the stirring time is 10 min. Then the plate and frame filter press is filtered to obtain the filter cake 5, and the filter cake 5 is Drying and crushing at 140°C to obtain the finished product;

In Example 2, the recovery rate of magnesium can reach 82.7wt.%, the purity of the magnesium hydroxide product can reach 98.3wt.%, the particle size distribution is between 0.9-32 μm, and the particle laser particle size D ₅₀ is 5.68 μm.

<Example Three>

As shown in Figure 1, the method for preparing magnesium hydroxide by recovering magnesium from the cobalt-nickel industry cobalt-containing magnesium solution provided by the present embodiment three includes the following steps:

Process one (P1):

Get cobalt-containing magnesium solution after extracting nickel, its cobalt content 90g/L, magnesium content 30g/L, at first adjust pH value to 8.2 with the sodium hydroxide of 6mol/L, temperature is controlled at 50 ℃, stirring speed 250rpm, and maintain Keep the pH value unchanged for 30 minutes, so that the cobalt is fully precipitated, and the concentration of cobalt in the solution after cobalt precipitation is 251mg/L;

Process two (P2):

Filter with a plate and frame filter press to obtain filtrate 1 and filter cake 1, add water to slurry the filter cake 1, add water to adjust the slurry concentration to 10wt.%, water temperature 50 ° C, stirring speed during slurrying is 200rpm, stir for 10min , and then filter with a plate and frame filter press to obtain filtrate 2 and filter cake 2, and filter cake 2 continues to be washed and used for subsequent recovery of cobalt;

Process three (P3):

Filtrate 2 and filtrate 1 are merged to obtain filtrate 3, and 60g/L sodium sulfide solution is added in filtrate 3, and the addition is 3.8 times of cobalt content in filtrate 3, and temperature is controlled at 50 ℃, stirring speed 250rpm, reaction time 10min , then add polyaluminum chloride, dosage 30mg/L, then filter to obtain filtrate 4;

Process four (P4):

Slowly add 7mol/L sodium hydroxide solution to the filtrate 4, adjust the pH value to 11.5, control the temperature at 50°C to precipitate magnesium, stir at 250rpm, and react for 20min;

Process five (P5):

Aging the solution obtained in step 4 at 75°C for 8 hours, and then filtering to obtain filter cake 3, the filtrate was directly discharged after adding acid to adjust pH=6~9;

Process six (P6):

Slurry and wash the filter cake 3 obtained in step 5 with hot water at 60°C for 3 times, the slurry concentration during washing is 10wt.%, stir at 150rpm for 10min, and then filter with a plate and frame filter press to obtain filter cake 4 , filtrate discharge;

Process seven (P7):

Finally, the filter cake 4 is slurried and washed once with absolute ethanol, the slurry concentration is 40wt.%, the temperature is 25° C., the stirring time is 150 rpm, and the stirring time is 15 min. Then the plate and frame filter press is filtered to obtain the filter cake 5, and the filter cake 5 is Drying and crushing at 130°C to obtain the finished product;

In Example 3, the recovery rate of magnesium can reach 80.9wt.%, the purity of the magnesium hydroxide product can reach 97.9wt.%, the particle size distribution is between 1.6-45 μm, and the particle laser particle size D ₅₀ is 6.17 μm.

<Example 4>

As shown in Figure 1, the method for preparing magnesium hydroxide by reclaiming magnesium from the cobalt-nickel industry cobalt-containing magnesium solution provided by the present embodiment four includes the following steps:

Process one (P1):

Get cobalt-containing magnesium solution after extracting nickel, its cobalt content 60g/L, magnesium content 15g/L, at first adjust pH value to 8.2 with the sodium hydroxide of 4.5mol/L, temperature is controlled at 55 ℃, stirring speed 250rpm, and Keep the pH value unchanged for 15 minutes, so that the cobalt is fully precipitated, and the concentration of cobalt in the solution after cobalt precipitation is 382mg/L;

Process two (P2):

Filter with a plate and frame filter press to obtain filtrate 1 and filter cake 1, add water to slurry to filter cake 1, add water to adjust the slurry concentration to 10wt.%, water temperature 60 ° C, stirring speed during slurry is 150rpm, stir for 10min , and then filter with a plate and frame filter press to obtain filtrate 2 and filter cake 2, and filter cake 2 continues to be washed and used for subsequent recovery of cobalt;

Process three (P3):

Filtrate 2 is combined with filtrate 1 to obtain filtrate 3, and 50g/L sodium sulfide solution is added in filtrate 3, and the addition is 3.2 times of cobalt content in filtrate 3, and temperature is controlled at 50 ℃, stirring speed 200rpm, reaction time 8min , then add polyaluminum chloride, dosage 25mg/L, then filter to obtain filtrate 4;

Process four (P4):

Slowly add the filtrate 4 to 2mol/L sodium hydroxide solution, adjust the pH value to 11.2, control the temperature at 50°C to precipitate magnesium, stir at 150rpm, and react for 30min;

Process five (P5):

Aging the solution obtained in step 4 at 85°C for 6 hours, and then filtering to obtain filter cake 3, and the filtrate was directly discharged after adding acid to adjust pH=6~9;

Process six (P6):

The filter cake 3 obtained in step 5 was slurried and washed 4 times with hot water at 50°C, the slurry concentration was 10wt.% during washing, stirred at 200rpm for 5min, and then filtered by a plate and frame filter press to obtain the filter cake 4. filtrate discharge;

Process seven (P7):

Finally, the filter cake 4 is slurried and washed once with absolute ethanol, the slurry concentration is 45wt.%, the temperature is 20° C., the stirring time is 150 rpm, and the stirring time is 10 min. Then, the filter cake 5 is obtained by filtering with a plate and frame filter press, and the filter cake 5 is Drying and crushing at 120°C to obtain the finished product;

In Example 4, the recovery rate of magnesium can reach 81.5wt.%, the purity of the magnesium hydroxide product can reach 98.0wt.%, the particle size distribution is between 1.3-38 μm, and the particle laser particle size D ₅₀ is 7.82 μm.

<Embodiment 5>

As shown in Figure 1, the method for preparing magnesium hydroxide by reclaiming magnesium from the cobalt-nickel industry cobalt-containing magnesium solution provided by the present embodiment five includes the following steps:

Process one (P1):

Get cobalt-containing magnesium solution after extracting nickel, its cobalt content 63g/L, magnesium content 32g/L, at first adjust pH value to 8.0 with the sodium hydroxide of 5mol/L, temperature is controlled at 40 ℃, stirring speed 200rpm, and maintain Keep the pH value unchanged for 20 minutes, so that the cobalt is fully precipitated, and the cobalt concentration in the solution after cobalt precipitation is 366mg/L;

Process two (P2):

Filter with a plate and frame filter press to obtain filtrate 1 and filter cake 1, add water to slurry to filter cake 1, add water to adjust the slurry concentration to 10wt.%, water temperature 40 ° C, stirring speed during slurry is 200rpm, stir for 5min , and then filter with a plate and frame filter press to obtain filtrate 2 and filter cake 2, and filter cake 2 continues to be washed and used for subsequent recovery of cobalt;

Process three (P3):

Filtrate 2 and filtrate 1 are merged to obtain filtrate 3, and 45g/L sodium sulfide solution is added in filtrate 3, and the addition is 3 times of cobalt content in filtrate 3, and temperature is controlled at 55 ℃, stirring speed 150rpm, reaction time 7min , then add polyaluminum chloride, dosage 10mg/L, then filter to obtain filtrate 4;

Process four (P4):

Slowly add 4mol/L sodium hydroxide solution to the filtrate 4, adjust the pH value to 11, control the temperature at 40°C to precipitate magnesium, stir at 200rpm, and react for 15min;

Process five (P5):

Aging the solution obtained in step 4 at 80°C for 6 hours, and then filtering to obtain filter cake 3, the filtrate was directly discharged after adding acid to adjust pH=6~9;

Process six (P6):

The filter cake 3 obtained in step 5 was slurried and washed 4 times with 55°C hot water, the slurry concentration was 10wt.% during washing, stirred at 250rpm for 10min, and then filtered by a plate and frame filter press to obtain the filter cake 4. filtrate discharge;

Process seven (P7):

Finally, the filter cake 4 is slurried and washed once with absolute ethanol, the slurry concentration is 40wt.%, the temperature is 25° C., the stirring time is 200 rpm, and the stirring time is 10 min. Then the plate and frame filter press is filtered to obtain the filter cake 5, and the filter cake 5 is Drying and crushing at 140°C to obtain the finished product;

In Example 5, the recovery rate of magnesium can reach 80.9wt.%, the purity of the magnesium hydroxide product can reach 98.1wt.%, the particle size distribution is between 1.1 and 39 μm, and the particle laser particle size D ₅₀ is 6.39 μm.

Function and effect of embodiment:

The method for preparing magnesium hydroxide by reclaiming magnesium from the cobalt-containing magnesium solution in the cobalt-nickel industry provided in the above-mentioned embodiments, because the cobalt-containing magnesium solution in the cobalt-nickel industry can be utilized to reclaim magnesium, and the reclaimed magnesium can be prepared into hydrogen Magnesium oxide products, the resulting products meet the requirements of the "Industrial Magnesium Hydroxide" HG/T 3607-2007 standard, which can not only reduce the impact of magnesium on the extraction of cobalt and nickel, but also effectively reduce the discharge of magnesium and the enrichment in the extraction system , and can also use the recovered magnesium to prepare magnesium hydroxide products simply and efficiently so as to bring economic benefits and achieve a win-win situation of environmental protection and economic benefits.

In addition, since the particle size of the obtained magnesium hydroxide product is generally 1-60 μm, and the particle laser particle size D ₅₀ is 4-8 μm, the filtration is very smooth and fast, saving time and effort, and improving the preparation efficiency.

The above embodiments are merely illustrations for the technical solution of the present invention. The method for preparing magnesium hydroxide by recovering magnesium from the cobalt-nickel industrial cobalt-containing magnesium solution involved in the present invention is not only limited to the content described in the above examples, but is based on the scope defined in the claims. Any modifications, supplements or equivalent replacements made by those skilled in the art of the present invention on the basis of the embodiments are within the protection scope of the claims of the present invention.

In the above-mentioned embodiments, the plate and frame filter press is used for filtering, and the present invention can also use belt filter press and other filtering equipment to realize the separation of solid and liquid.

Claims (9)

1. the method that magnesium prepares magnesium hydroxide is reclaimed in a kind of magnesium solution containing cobalt from cobalt nickel industry, it is characterised in that including following Process：

Process one：

Magnesium solution containing cobalt after extraction of nickel is taken, adjusts pH value to 7.3 ~ 8.2 with 3 ~ 6mol/L sodium hydroxide first, temperature control exists 40 ~ 55 °C, 150 ~ 250rpm of mixing speed, and pH value 10 ~ 30min of constant holding is maintained, cobalt is fully precipitated, solution after heavy cobalt In the concentration of cobalt be no more than 500mg/L；

Process two：

Filtrate 1 and filter cake 1 are filtrated to get, to the filter cake 1 plus water slurry, adds runoff investigation concentration of slurry to 10 ~ 15wt.%, water 40 ~ 60 °C of temperature, mixing speed during pulp be 150 ~ 250rpm, 5 ~ 10min of stirring, then filters, obtains filtrate 2 and filter cake 2, The filter cake 2 continues to wash, and is used for follow-up Call Provision；

Process three：

The filtrate 2 is merged into obtain filtrate 3 with the filtrate 1,20 ~ 60g/L sodium sulfide solutions are added into the filtrate 3, is added Measure as 2.5 ~ 3.8 times of cobalt content in the filtrate 3, temperature control is at 40 ~ 55 °C, 150 ~ 250rpm of mixing speed, reaction Between 5 ~ 10min, then add aluminium polychloride, 10 ~ 30mg/L of dosage, then filtered, obtain filtrate 4；

Process four：

2 ~ 7mol/L aqueous slkalis will be slowly added in the filtrate 4, regulation pH value is to 10.8 ~ 11.5, and temperature control is at 40 ~ 60 DEG C Magnesium sinking, 150 ~ 250rpm of mixing speed, react 15 ~ 30min；

Process five：

The solution of gained in the process four is aged 3 ~ 8h, the magnesium hydroxide particle laser particle D of formation at 75 ~ 85 DEG C₅₀ For 4 ~ 8 microns, then filter, obtain filter cake 3；

Process six：

By the filter cake 3 40 ~ 60 DEG C of hot water pulping and washings 3 ~ 4 times, pulp concentration is 10 ~ 15wt% during washing, stirring 150 ~ 250rpm, 5 ~ 10min of mixing time, is then filtered, and obtains filter cake 4；

Process seven：

With absolute ethyl alcohol to the pulping and washing of filter cake 4 once, pulp concentration is 35 ~ 45wt%, 20 ~ 30 DEG C of temperature, stirring 150 ~ 250rpm, 10 ~ 15min of mixing time, then filtering obtain filter cake 5, filter cake 5 are dried at 120 ~ 140 DEG C, crushes and produces into Product, the purity of magnesium hydroxide is not less than 97.5% in finished product.

2. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, in the process one, the concentration of sodium hydroxide is 6mol/L, regulation pH value to 7.8, temperature control at 40 °C, Mixing speed is 250rpm, maintains the constant holding 20min of pH value.

3. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, in the process two, to the filter cake 1 plus during water slurry, it is 10wt.% to add runoff investigation concentration of slurry, water temperature For 60 °C, mixing speed during pulp is 250rpm, stirs 5min.

4. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, in the process three, the sodium sulfide solution of addition is 45g/L, and addition is 3 of cobalt content in the filtrate 3 Times, for temperature control at 55 °C, mixing speed 150rpm, reaction time 7min, the amount for then adding aluminium polychloride is 10mg/L.

5. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, in the process four, the aqueous slkali is any one in sodium hydroxide solution and ammonia spirit.

6. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, in the process four, the ammonia spirit concentration of addition is 3mol/L, and pH value is adjusted to 10.8, and temperature control exists 60 DEG C of magnesium sinkings, mixing speed 200rpm, reaction time 15min.

7. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, it is that solution is aged 6h at 75 DEG C in the process five.

8. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, in the process six, the filter cake is with 40 DEG C of hot water pulping and washings 4 times, and pulp concentration is during washing 15wt.%, mixing speed 150rpm, mixing time 10min, then filter.

9. reclaiming the method that magnesium prepares magnesium hydroxide in containing the cobalt magnesium solution according to claim 1 from cobalt nickel industry, it is special Sign is：

Wherein, in the process six, pulp concentration is 45wt.%, mixing speed 250rpm, mixing time 10min, is filtered Cake is dried at 140 DEG C.