CN1249354A

CN1249354A - Process for efficiently extracting cobalt compound from leftover containing cobalt

Info

Publication number: CN1249354A
Application number: CN98111506A
Authority: CN
Inventors: 孔令树
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-09-25
Filing date: 1998-09-25
Publication date: 2000-04-05
Anticipated expiration: 2018-09-25
Also published as: CN1059241C

Abstract

A process for effecient extraction of cobalt compound from the leftover containing cobalt features that the acidic solution of said cobalt-containing leftover is ammoniated by excess ammonia water, the solution of cobalt-ammonia complex is then separated out,and the cobalt oxide is finally separated out by adding alkali and thermal precipitation. Its advantages are high extraction rate and high purity of cobalt oxide.

Description

Novel process for efficiently extracting cobalt compound from cobalt-containing leftovers

The invention relates to a preparation process of chemical raw materials, namely a novel process for extracting cobalt compounds from leftovers containing cobalt.

Cobalt is a rare element in nature, and cobalt resources are relatively scarce in the world; with the continuous development of industrial technology, the usage of cobalt compounds is more and more extensive, and the demand is increasingly higher. Due to the lack of resources, the recycling of cobalt element in the waste metal containing cobalt becomes important work for the leftovers containing cobalt generated in industrial production. The current state of the art for cobalt recovery is: the leftover containing cobalt produced in industrial production is often mixed with elements such as iron, manganese and the like in cobalt-containing waste metal, and cobalt in the leftover is required to be separated from the iron and the manganese to prepare a high-purity cobalt compound, so that the cobalt is extracted to prepare a useful cobalt compound, for example: cobalt acetate, cobalt oxide, cobalt chloride, basic cobalt carbonate, and the like. The extraction method of most manufacturers at present is to dissolve the waste cobalt-containing metal and cobalt waste metal into mixed salt solution by using sulfuric acid, hydrochloric acid and nitric acid, then adjust the pH value of the solution, oxidize metal ions such as iron and manganese into high-valence iron and manganese hydroxides or oxides by using strong oxidants such as hydrogen peroxide and sodium chlorate, and remove the formed precipitate. This approach has two disadvantages: firstly, the extraction rate is low: the cobalt is partially oxidized into higher oxides or hydroxides during oxidation and is removed together with the precipitate. Secondly, the purity is low: the residual soluble ions of ferromanganese are more, so the purity of the proposed cobalt is low, the field for preparing high-purity cobalt compounds is still unavailable, and the high-purity cobalt compounds can be prepared only by using high-purity cobalt metal at present.

The invention aims to efficiently extract high-purity cobalt oxide from leftovers containing cobalt so as to prepare a high-purity cobalt compound.

In order to achieve the purpose, the process steps and related chemical reaction formulas of the technical scheme are as follows:

1. acid dissolution:

the pH value of the acid solution formed by pretreatment or direct dissolution in sulfuric acid or hydrochloric acid is kept between 2 and 3 according to the properties of the leftovers

Co is CoSO₄CoCl₂In solution

Mn is MnSO₄MnCl₂In solution

Fe is FeSO₄FeCl₂In solution

Fe₂(SO₄)₃FeCl₃In solution

Separating the insoluble substances with separation equipment (centrifuge, filter, etc.) to obtain clear solution.

2. Ammoniation separation:

adding acid-soluble clear mixed acid solution into ammonia water, and maintaining pH at 8-9. The following reactions occur:

co is complexed into cobalt-ammonia complex ions under the action of excessive ammonia and is dissolved in water

Under the action of oxygen in the air, Co (NH)₃)₄ ⁺⁺Is oxidized to more stable Co (NH)₃)₆ ⁺⁺⁺The complex ions are also soluble in water.

In this case, Fe (OH)₂And most of Mn (OH)₂Is a precipitate.

The suspension was separated, and the resulting liquid contained a small amount of Mn (OH)₂Dissolved in an excess of aqueous ammonia.

Adding Na into the solution₂CO₃Or NH₄HCO₃The solution gave the following reaction:

mixing MnCO₃The precipitate was separated off. Because of Mn (OH)₂Mn (OH) which oxidizes in ammonia solution to produce a brown color when exposed to air₄The precipitate is also removed. Only the Co compound remains in solution, separating the cobalt from the ferromanganese.

3. Adding alkali and heat sink:

NaOH is added to the solution and heated to boiling, the following reaction takes place

This resulted in the formation of a cobalt oxide precipitate, ammonia gas evolution, and the liquid was NaCl solution.

4. Absorption:

the ammonia sent from the heating precipitation is absorbed by water and cooled to prepare 120TT (namely 6N) ammonia water for ammoniation.

5. Separation:

the hot precipitate is sent to the suspension where the cobalt oxide is separated from the NaCl solution using a separation device.

6. Washing:

washing the separated cobalt oxide with high-purity water, and further separating to obtain the cobalt oxide with high purity for preparing various cobalt compounds.

The method has the advantages that: 1. the extraction rate is high: due to Co (NH)₃)₆Cl₃Is highly soluble and complex ion stable, and therefore Co (OH)₂The precipitate is basically dissolved, so that the invention has high extraction rate, and the experiment proves that the extraction rate can reach more than 95%. 2. The purity is high: at NH₃In the presence of Mn (OH)₂-MnCO₃Very easy to carry out, Fe (OH)₃、Fe(OH)₂、MnCO₃The solubility product is very small, and the manganese ions and the iron ions in the solution are very tiny. Therefore, the high purity of the cobalt sesquioxide is ensured, and pilot scale experiments prove that the Co content in the basic cobalt carbonate prepared by the cobalt oxide reaches 46.9 percent; prepared cobalt acetate Co (CH)₃COO)₂4H₂The cobalt acetate content of O reaches 99 percent, which is comparable with the product prepared by high-purity metal cobalt. 3. The conventional preparation of other cobalt compounds from cobalt oxides is easy to carry out.

An embodiment of the invention is described below with reference to the accompanying drawings:

FIG. 1 is a schematic process flow diagram of the present invention.

The method provided by the invention is adopted by the inventor to perform a pilot test in a certain fine chemical plant of Jiangpu, and the specific method is as follows:

1. the raw material is cobalt manganese material recovered by sodium carbonate from waste liquid of terephthalic acid generated by chemical plants of Yangzi group company. The main component of the material is CoCO₃、MnCO₃The Co content is 10%.

2. The auxiliary raw materials are all market products, and the ammonia water is industrial ammonia water.

3. The description of the examples is carried out according to the inventive procedure.

(1) Acid dissolution: dissolving cobalt and manganese materials in a reaction kettle by using industrial sulfuric acid, and removing residues insoluble in dilute acid organic acid to obtain clear CoSO₄、MnSO₄The solution was mixed.

(2) Ammoniation: adding industrial ammonia water into an ammoniation device according to the requirements of the invention, slowly adding acid solution, and keeping the pH value above 8-9.

(3) Separation: separating out the precipitate by using a 800 centrifugal machine, adding a sodium carbonate solution into the liquid for precipitation and clarification, and then sending the liquid into a reaction kettle.

(4) Adding alkali and heat sink: NaOH was added to the kettle and heated to boiling temperature of 100 ℃ for 5 minutes.

(5) Separation and washing: the suspension of the heat sink was cooled to 60 degrees and sent to a 800 centrifuge to separate the cobalt oxide and the filter cake was washed five times with high purity water.

(6) Dissolving: the filter cake cobalt oxide was dissolved and diluted with concentrated sulfuric acid in a reaction kettle.

(7) Separation: separating the dissolved cobalt sulfate solution by a centrifugal machine to obtain a clear solution, wherein the filter cake is undissolved Co₂O₃And putting the mixture into a kettle for redissolving.

(8) And (3) precipitation: feeding the cobalt sulfate solution into a precipitation tank (3 cubic meters of stainless steel stirring tank) and adding Na₂CO₃The solution was brought to pH 8 and a purple-red precipitate formed.

(9) Separation: the suspension containing the purplish red precipitate was sent to 800 centrifuges, Na was added₂SO₄The solution was isolated and the purple filter cake was washed three times with high purity water.

(10) Washing: and (4) sending the filter cake into a washing tank, adding high-purity water, stirring and washing.

(11) Separating the washed suspension in 800-type centrifuge, washing with high-purity water for several times, and adding BaCl into the filtrate₂The solution did not precipitate white.

(12) Drying and crushing: and drying the filter cake in a tray and crushing the filter cake into a green bean large-grain basic cobalt carbonate product.

(13) The product has a cobalt content of 46.9% as analyzed by a chemical university analysis and research laboratory.

Claims

1. A process for efficiently extracting cobalt compound from the leftover containing cobalt includes ammoniating the acidic solution of said leftover containing cobalt with excessive ammonia, separating out the solution of cobalt-ammonia complex, and thermal deposition with alkali to separate out cobalt oxide.

2. The method of claim 1 wherein the cobalt-containing leftovers are cobalt-containing waste metals containing cobalt, iron and manganese.

3. The method of claim 1 or 2, wherein the acid dissolution treatment of the cobalt-containing tailings is carried out by pre-treating the tailings or directly dissolving the tailings in sulfuric acid or hydrochloric acid, and the pH value of the acid solution is maintained at 2-3.

4. The process according to any of the preceding claims, wherein the ammoniated separation is carried out by adding an excess of aqueous ammonia to the acid-soluble clear mixed acid solution, maintaining the pH at 8-9.

5. A method according to any one of the preceding claims wherein the alkalising heat sink is heated to boiling by adding caustic soda to a solution based on cobalt ammine complexes.

6. A process according to any one of the preceding claims wherein ammonia gas evolved in the caustic heat sink step is made into 120TT (i.e. 6N) ammonia by water absorption cooling for ammoniation.