Method for separating tungsten, molybdenum and copper from tungsten smelting molybdenum removal slag

Abstract

The invention discloses a method for separating tungsten, molybdenum and copper from tungsten smelting molybdenum removal slag, which comprises the following steps of: firstly, separating the molybdenum removal slag from a tungstate solution by using one or more filter presses or centrifugal solid-liquid separation devices; and then washing the separated molybdenum-removed slag with dilute ammonia water at the low temperature of less than or equal to 70 DEG C to dissolve tungsten mixed in the molybdenum-removed slag. The method is low in investment, low in cost, less in pollution, small in occupied area and easy to industrialize, copper sulfide and molybdate obtained by separating and recycling molybdenum removal slag can be directly sold, an ammonium tungstate solution formed by separated tungsten can be returned to the original process to be directly evaporated and crystallized, water vapor can be generated in the whole treatment process of molybdenum removal crystallization, and the treatment effect is good. No new three wastes are generated, and the transformation and harmless utilization of hazardous wastes is realized.

Description

Technical Field

[0001] The invention relates to the technical field of tungsten smelting, and in particular to a method for removing molybdenum slag from tungsten smelting to separate tungsten, molybdenum and copper. Background Art

[0002] In the tungsten smelting production process, the harmful impurity element molybdenum in the raw material tungsten concentrate enters the solution together with tungsten during the smelting process. In order to reduce the molybdenum content in tungsten smelting products such as sodium tungstate, ammonium paratungstate, ammonium metatungstate, and tungsten oxide, most manufacturers will use selective precipitation to remove molybdenum during the tungsten smelting process. The process flow of selective precipitation to remove molybdenum is: add soluble sulfide to the tungstate solution with a pH value of 7-9 for sulfidation, and add soluble copper salt after sulfidation to precipitate the impurity molybdenum to achieve tungsten and molybdenum separation. The resulting precipitate is the molybdenum removal slag.

[0003] On June 14, 2016, the National Environmental Protection Department issued Order No. 39, which clearly listed molybdenum slag as hazardous waste and took effect on August 1, 2016.

[0004] Chinese patents have disclosed several patents, including "A method for recovering tungsten from molybdenum removal slag", "A method for treating molybdenum removal slag produced during tungsten smelting", "A method for recovering molybdenum and copper from molybdenum removal slag from tungsten smelting", "A method for separating and extracting metallic tungsten and molybdenum from molybdenum removal slag produced from tungsten smelting", and "A device for recovering molybdenum removal slag".

[0005] The above patents have shortcomings: first, most of the patents do not recover the three valuable metals in the molybdenum removal slag separately, but only separate one or two of the metals, resulting in a waste of resources; second, some patents use volatile hydrochloric acid in the separation process, and the reaction process produces toxic hydrogen sulfide, and the process is not environmentally friendly; third, some patents not only use high-temperature roasting in the separation process, but also use organic reagents for extraction, and it is necessary to carry out pollution control of tail gas containing sulfur dioxide, dust, etc.; fourth, although the patent "Method for treating molybdenum removal slag produced in tungsten smelting process" recovers the three valuable metals separately, the highly volatile concentrated ammonia water is used in the treatment process for high-temperature leaching and separation of molybdenum and copper is not thorough, the operating environment is harsh, the pollution is serious, and the recovered ammonium molybdate solution has ammonia volatilization that pollutes the environment and is difficult and inconvenient to transport.

[0006] Therefore, it is very necessary to improve the molybdenum slag recovery process, especially to achieve a complete and thorough separation of the three valuable metals tungsten, molybdenum and copper with a short process and less pollution, which is beneficial to all the production companies involved. Summary of the invention

[0007] In view of the defects of the prior art, the purpose of the present invention is to provide a method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum, so as to solve the problems raised in the above background technology.

[0008] The present invention solves the technical problem by adopting the following technical solution:

[0009] The present invention provides a method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum, comprising the following steps:

[0010] First, the molybdenum removal slag is separated from the tungstate solution by using a single or multiple filter presses or centrifuge solid-liquid separation devices, and then the separated molybdenum removal slag is washed with dilute ammonia water at a low temperature of ≤70°C to dissolve the tungsten contained in the molybdenum removal slag;

[0011] Then the molybdenum removal slag and the dilute ammonia water are separated into solid and liquid, and the separated dilute ammonia water can be used for the next cycle of molybdenum removal slag tungsten removal, until the tungsten concentration in the dilute ammonia water reaches more than 10g / l, and ammonium paratungstate is directly prepared by evaporation and crystallization, or other methods are adopted to recover the tungsten therein;

[0012] After tungsten is separated, one or more strong bases such as sodium hydroxide and potassium hydroxide are added to the molybdenum removal slag to decompose at above 25°C. After the reaction is complete, solid-liquid separation is performed to obtain solid-phase copper sulfide, which can be directly sold to copper smelting enterprises as copper concentrate;

[0013] The obtained liquid molybdate solution is further evaporated and crystallized. After reaching the crystallization end point, solid-liquid separation is performed again. The crystallized molybdate can be directly sold to a molybdenum chemical plant. The mother liquor is an alkaline solution containing a small amount of molybdate, which can be directly added with alkali and used again for decomposition of molybdenum removal slag after tungsten separation.

[0014] Preferably, the separated molybdenum-removing slag is further modified by stirring with chitosan modification liquid.

[0015] Preferably, the stirring temperature of the stirring modification treatment is 48-52° C., the stirring speed is 450-500 r / min, and the stirring time is 30-40 min.

[0016] Preferably, the preparation method of chitosan modified liquid is:

[0017] The chitosan solution is added to a dodecylbenzene sulfonic acid solution which is 3-5 times the total amount of the chitosan solution, and then a silane coupling agent which is 10-15% of the total amount of the chitosan solution is added, and the mixture is stirred thoroughly. Finally, a sodium alginate agent which is 2-5% of the total amount of the chitosan solution is added, and the mixture is stirred thoroughly to obtain a chitosan modified solution.

[0018] Preferably, the mass fraction of the chitosan solution is 4-8%; the mass fraction of the dodecylbenzenesulfonic acid solution is 10-15%.

[0019] Preferably, the silane coupling agent is silane coupling agent KH560.

[0020] Preferably, the sodium alginate agent is prepared by mixing sodium alginate in a sufficient amount of potassium permanganate solution, and then washing with water and drying.

[0021] Preferably, the mass fraction of the potassium permanganate solution is 10-15%.

[0022] The chitosan modified liquid uses chitosan solution in combination with dodecylbenzenesulfonic acid solution, silane coupling agent and other raw materials to moisten the molybdenum removal slag, thereby optimizing the subsequent process efficiency of separating tungsten, molybdenum and copper.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The invention has the advantages of low investment, low cost, less pollution, small footprint, and easy industrialization. The copper sulfide and molybdate obtained by separating and recovering the molybdenum slag can be sold directly, and the separated tungsten forms an ammonium tungstate solution which can be returned to the original process for direct evaporation and crystallization. In the whole treatment process, water vapor will be generated except for the crystallization process of molybdate, and no new three wastes will be generated, thus realizing the transformation of hazardous waste into harmless utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] A method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum, comprising the following steps:

[0028] First, the molybdenum removal slag is separated from the tungstate solution by using a single or multiple filter presses or centrifuge solid-liquid separation devices, and then the separated molybdenum removal slag is washed with dilute ammonia water at a low temperature of ≤70°C to dissolve the tungsten contained in the molybdenum removal slag;

[0029] Then the molybdenum removal slag and the dilute ammonia water are separated into solid and liquid, and the separated dilute ammonia water can be used for the next cycle of molybdenum removal slag tungsten removal, until the tungsten concentration in the dilute ammonia water reaches more than 10g / l, and ammonium paratungstate is directly prepared by evaporation and crystallization, or other methods are adopted to recover the tungsten therein;

[0030] After tungsten is separated, one or more strong bases such as sodium hydroxide and potassium hydroxide are added to the molybdenum removal slag to decompose at above 25°C. After the reaction is complete, solid-liquid separation is performed to obtain solid-phase copper sulfide, which can be directly sold to copper smelting enterprises as copper concentrate;

[0031] The obtained liquid molybdate solution is further evaporated and crystallized. After reaching the crystallization end point, solid-liquid separation is performed again. The crystallized molybdate can be directly sold to a molybdenum chemical plant. The mother liquor is an alkaline solution containing a small amount of molybdate, which can be directly added with alkali and used again for decomposition of molybdenum removal slag after tungsten separation.

[0032] The separated molybdenum-removing slag in this embodiment is also subjected to modification treatment by stirring with chitosan modification liquid.

[0033] The stirring temperature of the stirring modification treatment in this embodiment is 48-52° C., the stirring speed is 450-500 r / min, and the stirring time is 30-40 min.

[0034] The preparation method of the chitosan modified liquid of this embodiment is:

[0035] The chitosan solution is added to a dodecylbenzene sulfonic acid solution which is 3-5 times the total amount of the chitosan solution, and then a silane coupling agent which is 10-15% of the total amount of the chitosan solution is added, and the mixture is stirred thoroughly. Finally, a sodium alginate agent which is 2-5% of the total amount of the chitosan solution is added, and the mixture is stirred thoroughly to obtain a chitosan modified solution.

[0036] The mass fraction of the chitosan solution in this embodiment is 4-8%; the mass fraction of the dodecylbenzenesulfonic acid solution is 10-15%.

[0037] The silane coupling agent of this embodiment is silane coupling agent KH560.

[0038] The sodium alginate agent of this embodiment is prepared by stirring sodium alginate in a sufficient amount of potassium permanganate solution, and then washing with water and drying.

[0039] The mass fraction of the potassium permanganate solution in this embodiment is 10-15%.

[0040] The chitosan modified liquid uses chitosan solution in combination with dodecylbenzenesulfonic acid solution, silane coupling agent and other raw materials to moisten the molybdenum removal slag, thereby optimizing the subsequent process efficiency of separating tungsten, molybdenum and copper.

[0041] A method for separating tungsten, molybdenum and copper from tungsten smelting slag. It includes the following three steps: (1) separating tungsten with dilute ammonia water; (2) separating copper sulfide with alkaline leaching; (3) crystallizing molybdate. Figure 1 shown.

[0042] The separated molybdenum-removing slag in this example is also subjected to modification treatment by stirring with chitosan modification liquid.

[0043] The stirring temperature of the modification treatment in this embodiment is 50° C., the stirring speed is 470 r / min, and the stirring time is 35 min.

[0044] The preparation method of the chitosan modified liquid of this embodiment is:

[0045] The chitosan solution was added to a dodecylbenzenesulfonic acid solution of 4 times the total amount of the chitosan solution, followed by adding a silane coupling agent of 12.5% ​​of the total amount of the chitosan solution, stirring thoroughly, and finally adding a sodium alginate agent of 3.5% of the total amount of the chitosan solution, continuing to mix thoroughly to obtain a chitosan modified solution.

[0046] The mass fraction of the chitosan solution in this embodiment is 6%; the mass fraction of the dodecylbenzenesulfonic acid solution is 12%.

[0047] The silane coupling agent of this embodiment is silane coupling agent KH560.

[0048] The sodium alginate agent of this embodiment is prepared by stirring sodium alginate in a sufficient amount of potassium permanganate solution, and then washing with water and drying.

[0049] The mass fraction of the potassium permanganate solution in this embodiment is 12.5%.

[0050] The chitosan modified liquid uses chitosan solution in combination with dodecylbenzenesulfonic acid solution, silane coupling agent and other raw materials to moisten the molybdenum removal slag, thereby optimizing the subsequent process efficiency of separating tungsten, molybdenum and copper.

[0051] The raw material is molybdenum-removing slag, and the analysis results are as follows:

[0052] Ingredients WO3 QUR Mo content,% 8.2 32.1 15.6

[0053] The analysis results of the molybdenum-removing slag after washing and separating tungsten with dilute ammonia water at a low temperature of ≤70°C are as follows:

[0054]

[0055] The above molybdenum-removing slag after tungsten separation by dilute ammonia water was decomposed with alkali at above 25°C for 3 hours, and the analysis results of the copper sulfide obtained were as follows:

[0056]

[0057] The analysis results of molybdate obtained by evaporation crystallization are as follows:

[0058]

[0059]

[0060] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0061] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for separating tungsten, molybdenum and copper from tungsten smelting slag. It is characterized in that The following steps are involved: First, the molybdenum removal slag is separated from the tungstate solution by using a single or multiple filter presses or centrifuge solid-liquid separation devices, and then the separated molybdenum removal slag is washed with dilute ammonia water at a low temperature of ≤70°C to dissolve the tungsten contained in the molybdenum removal slag; Then the molybdenum removal slag and the dilute ammonia water are separated into solid and liquid, and the separated dilute ammonia water can be used for the next cycle of molybdenum removal slag tungsten removal, until the tungsten concentration in the dilute ammonia water reaches more than 10g / l, and ammonium paratungstate is directly prepared by evaporation and crystallization, or other methods are adopted to recover the tungsten therein; After tungsten is separated, one or more strong bases such as sodium hydroxide and potassium hydroxide are added to the molybdenum removal slag to decompose at above 25°C. After the reaction is complete, solid-liquid separation is performed to obtain solid-phase copper sulfide, which can be directly sold to copper smelting enterprises as copper concentrate; The obtained liquid molybdate solution is further evaporated and crystallized. After reaching the crystallization end point, solid-liquid separation is performed again. The crystallized molybdate can be directly sold to a molybdenum chemical plant. The mother liquor is an alkaline solution containing a small amount of molybdate, which can be directly added with alkali and used again for decomposition of molybdenum removal slag after tungsten separation.

2. The method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum according to claim 1, It is characterized in that The separated molybdenum-removing slag is also subjected to a stirring modification treatment using a chitosan modification liquid.

3. The method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum according to claim 2, It is characterized in that The stirring temperature of the modified treatment is 48-52°C, the stirring speed is 450-500r / min, and the stirring time is 30-40min.

4. The method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum according to claim 2, It is characterized in that The preparation method of chitosan modified liquid is: The chitosan solution is added to a dodecylbenzene sulfonic acid solution which is 3-5 times the total amount of the chitosan solution, and then a silane coupling agent which is 10-15% of the total amount of the chitosan solution is added, and the mixture is stirred thoroughly. Finally, a sodium alginate agent which is 2-5% of the total amount of the chitosan solution is added, and the mixture is stirred thoroughly to obtain a chitosan modified solution.

5. The method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum according to claim 4, It is characterized in that The mass fraction of the chitosan solution is 4-8%; the mass fraction of the dodecylbenzenesulfonic acid solution is 10-15%.

6. The method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum according to claim 4, It is characterized in that The silane coupling agent is silane coupling agent KH560.

7. The method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum according to claim 4, It is characterized in that The sodium alginate agent is prepared by mixing sodium alginate with a sufficient amount of potassium permanganate solution, and then washing with water and drying.

8. The method for separating tungsten, molybdenum and copper from tungsten smelting slag by removing molybdenum according to claim 7, It is characterized in that The mass fraction of potassium permanganate solution is 10-15%.

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