CN106430312A - Preparation method of monoclinic system tungsten trioxide - Google Patents

Abstract

The invention provides a method for preparing monoclinic tungsten trioxide by using copper-tungsten alloy waste as a raw material, which includes the steps of acid leaching, roasting, ammoniation and acidolysis. The present invention uses copper-tungsten alloy waste as a raw material to prepare a high-value product monoclinic tungsten trioxide with photocatalytic degradation of organic matter, realizes the recycling of waste metal resources, and can utilize renewable energy (solar energy) to recycle The product is used in the aspect of environmental pollution control, which conforms to the national strategy of energy conservation, environmental protection and resource regeneration; the preparation method of the invention has easy-to-obtain raw materials, low cost and simple process, and is suitable for industrial production.

Description

A kind of preparation method of monoclinic tungsten trioxide

technical field

The invention relates to a preparation method of tungsten trioxide, in particular to the preparation of tungsten trioxide by using copper-tungsten alloy waste.

Background technique

Metal tungsten is widely used in alloy manufacturing industry, shipbuilding industry, anti-corrosion coating, gas sensor, photocatalysis and display because of its good properties such as high hardness, high melting point, and no air corrosion at room temperature. During the process of tungsten product preparation and waste product elimination, a large amount of tungsten-containing secondary resources will be formed. Recovering tungsten from secondary resources will not only improve the grade of tungsten but also realize resource recycling. At present, the recycling of tungsten slag is mainly divided into three parts: (1) recovery of valuable metals; (2) use of tungsten slag as mineral raw material to produce wear-resistant materials; (3) production of tungsten slag glass-ceramics.

Chinese patent CN201310002669.X uses sodium tungstate dihydrate and sodium chloride as raw materials to prepare tungsten trioxide; Chinese patent CN201310742106.4 uses saturated ammonium tungstate solution, ammonium chloride, tartaric acid, ethylenediamine tetrapropionic acid, etc. as raw materials Tungsten trioxide powder was prepared. The raw materials of the above technologies are relatively expensive and costly, and are not suitable for industrial production; and no research has been conducted on product performance.

The existing patents for preparing tungsten trioxide basically use analytically pure ammonium tungstate, sodium tungstate, ammonium paratungstate, etc. as raw materials. The process is complicated and the production cost is high, which is not conducive to industrial production.

In view of the above-mentioned defects, the designers actively researched and innovated in order to create a preparation method of monoclinic tungsten trioxide to make it more valuable in industry.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a method for preparing monoclinic tungsten trioxide using copper-tungsten alloy waste as raw material, which has low cost and simple process, and is suitable for industrial production.

A kind of preparation method of monoclinic tungsten trioxide of the present invention is characterized in that, comprises the following steps:

(1) Dissolve tungsten trioxide in alkali solution, and ammonium to obtain ammonium paratungstate or ammonium tungstate;

(2) ammonium paratungstate or ammonium tungstate in step (1) obtains tungstic acid colloid through acidolysis;

(3) The tungstic acid colloid is aged, washed and dried to obtain the monoclinic tungsten trioxide.

Further, before the step (1), it also includes the steps of removing copper in the copper-tungsten alloy by acid leaching to obtain tungsten slag, and roasting the tungsten slag to obtain tungsten trioxide.

Further, the acid used in the acid leaching method is selected from one or more of nitric acid, hydrochloric acid and sulfuric acid.

Further, the tungsten slag is fired at 400-600°C.

Further, the acid hydrolysis is acid hydrolysis with reducing acid.

specific,

(1) The copper in the copper-tungsten alloy is removed by nitric acid leaching to obtain tungsten slag, the mass percentage of copper in the tungsten slag is at least less than 0.5%, preferably less than 0.05%, and the tungsten slag is roasted at 400-600°C to obtain three Tungsten oxide;

(2) Dissolving tungsten trioxide in alkali solution, and ammonium to obtain ammonium paratungstate or ammonium tungstate;

(3) Ammonium paratungstate or ammonium tungstate is prepared into 1-2mol/L aqueous solution, and slowly added to 3-4mol/L reducing acid for acidolysis, and stirred to obtain yellow tungstic acid colloid;

(4) Aging the yellow tungstic acid colloid at 20-35°C (room temperature) for 16-24h, filtering and washing, then drying at 100°C for 6h to obtain monoclinic tungsten trioxide, and yellow monoclinic crystal after grinding Department of tungsten trioxide powder.

Further, the reducing acid is one or more of hydrochloric acid, sulfurous acid, hydrogen sulfide, and HBr.

Further, the alkaline solution is ammonia water, ammonium paratungstate is obtained by ammonification and crystallization of tungsten trioxide, specifically, tungsten trioxide is dissolved in ammonia solution with a mass percentage of 25-28%, wherein the mixture of tungsten trioxide and ammonia solution The mass ratio of solid to liquid is 1:5-10, dissolve slowly for 12-24 hours, take the supernatant, evaporate and crystallize to obtain white crystal ammonium paratungstate.

Further, tungsten trioxide is dissolved in NaOH or KOH solution, crystallized to obtain sodium tungstate or potassium tungstate, sodium tungstate or potassium tungstate is ammoniated to obtain ammonium tungstate, specifically, tungsten trioxide is dissolved In 5-10mol/L NaOH or KOH solution, wherein the solid-to-liquid mass ratio of tungsten trioxide to NaOH or KOH solution is 1:5-10, stir and dissolve at 40-80°C for 5-10h to obtain sodium tungstate or tungstic acid Potassium solution, filtered, evaporated and crystallized to obtain sodium tungstate or potassium tungstate crystals.

Further, the sodium tungstate or potassium tungstate obtained by crystallization is added to nitric acid before ammonification to obtain a precipitate of yellow tungstate, which is dissolved in an aqueous ammonia solution, and ammonium tungstate is obtained after ammoniation, specifically Add the obtained sodium tungstate crystals to 1-3mol/L nitric acid, wherein the solid-to-liquid ratio of sodium tungstate crystals to nitric acid is 1:2-4, filter the solution to obtain yellow tungstic acid precipitation, add yellow tungstic acid to 25 - In 28% ammonia solution, the solid-to-liquid ratio of yellow tungstic acid to ammonia solution is 1:5-10, after slowly dissolving for 12-24 hours, filter the supernatant, and distill ammonia at 60-100°C for 30-60 minutes , until the pH of the solution is about 6-7, the ammonium tungstate solution is obtained.

By means of the above scheme, the present invention has at least the following beneficial effects:

The present invention uses copper-tungsten alloy waste as a raw material to prepare a high-value product monoclinic tungsten trioxide with photocatalytic degradation of organic matter, realizes resource recycling of waste metals, and utilizes renewable energy solar energy to recycle products In terms of environmental pollution control, it conforms to the country's energy-saving and environmental protection strategy; the preparation method of the invention has easy-to-obtain raw materials, low cost and simple process, and is suitable for industrial production.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the following is a detailed description of the preferred embodiments of the present invention with accompanying drawings.

Description of drawings

Figure 1 is the XRD pattern of orthorhombic tungsten trioxide;

Fig. 2 is the monoclinic tungsten trioxide XRD figure prepared in embodiment 1 of the present invention;

Fig. 3 is the monoclinic tungsten trioxide XRD figure prepared in embodiment 2 of the present invention;

Fig. 4 is the monoclinic tungsten trioxide XRD figure prepared in embodiment 3 of the present invention;

Fig. 5 is the monoclinic tungsten trioxide XRD figure prepared in Example 4 of the present invention;

Fig. 6 is a characterization diagram of the monoclinic tungsten trioxide degradation methylene blue solution prepared in Examples 1 to 4 of the present invention.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

12g of copper-tungsten alloy waste, first separate the copper and tungsten by the secondary nitric acid leaching method, and obtain 8.3g of tungsten slag, which contains less than 0.05% copper, and roast the tungsten slag at 400°C to obtain about 10g of yellow-green tungsten trioxide powder. The product is orthorhombic tungsten trioxide, as shown in the XRD schematic diagram in Figure 1; add orthorhombic tungsten trioxide into ammonia water with a mass percentage of 25-28%, the solid-liquid ratio is 1:5, and slowly dissolve for 18 hours , the dissolution rate is about 90%, take the supernatant, evaporate and crystallize, and obtain 9.71g of white crystal ammonium paratungstate; make ammonium paratungstate into 1mol/L aqueous solution, slowly add it into 3mol/L hydrochloric acid, stir for 1h, and obtain yellow tungstic acid colloid , aged at room temperature for 16 hours, filtered and washed, and dried at 100°C for 6 hours to obtain solid tungsten trioxide, which was ground to obtain 8.5 g of yellow tungsten trioxide powder. According to XRD analysis, the product is monoclinic tungsten trioxide, as shown in Figure 2; through experimental research, under the condition of 500W xenon lamp irradiation for 3 hours, 0.10g monoclinic tungsten trioxide powder can make 10mg/L/methylene blue solution The degradation rate reached 98.74%, as shown in Figure 6.

Example 2

50g of copper-tungsten alloy waste, first separate the copper and tungsten by the secondary nitric acid leaching method to obtain 34.1g of tungsten slag, which contains less than 0.05% copper, and roast the tungsten slag at 600°C to obtain about 41g of yellow-green tungsten trioxide powder. The product is orthorhombic tungsten trioxide; add it to 25-28% ammonia water, the solid-liquid ratio is 1:10, dissolve slowly for 24 hours, and the dissolution rate is about 90%. Take the supernatant, evaporate and crystallize, and obtain 40.12 g white crystal ammonium paratungstate; make ammonium paratungstate into 2mol/L aqueous solution, slowly add it into 4mol/L hydrochloric acid, stir for 2h, and obtain yellow tungstic acid colloid, age at room temperature for 24h, filter and wash, then dry at 100°C for 6h , to obtain solid tungsten trioxide, and after grinding, 34.05 g of yellow tungsten trioxide powder was obtained. According to XRD analysis, the product is monoclinic tungsten trioxide, as shown in Figure 3; through experimental research, under the condition of 500W xenon lamp irradiation for 3 hours, 0.25g monoclinic tungsten trioxide powder can make 50mg/L/methylene blue solution The degradation rate reached 96.51%, as shown in Figure 6.

Example 3

12g of copper-tungsten alloy waste, first separate the copper and tungsten by the secondary nitric acid leaching method to obtain 8.3g of tungsten slag, which contains less than 0.5% copper, and roast the tungsten slag at 400°C to obtain about 10g of yellow-green tungsten trioxide powder. The product is orthorhombic tungsten trioxide; add it to 50ml of 5mol/L sodium hydroxide solution, stir at 40°C for 5 hours, the dissolution rate of tungsten trioxide is about 90%, filter the supernatant, evaporate and crystallize 12.80g sodium tungstate crystals; add sodium tungstate crystals to 23ml of 1mol/L nitric acid solution, stir for 0.5h, and filter to obtain 9.68g yellow tungstic acid precipitate; add yellow tungstic acid to 50ml concentrated ammonia water (25-28% ) solution, after slowly dissolving for 12 hours, take the supernatant, distill ammonia at 60°C until the pH of the solution is about 7, and obtain ammonium tungstate solution; add this ammonium tungstate solution to 50ml 3mol/L hydrochloric acid solution, and stir for 1 hour , aged at room temperature for 16 hours, filtered and washed, and then dried at 100°C for 6 hours to obtain solid tungsten trioxide. After grinding, 8.5g of yellow tungsten trioxide powder was obtained. According to XRD analysis, the product is monoclinic tungsten trioxide, as shown in Figure 4; through experimental research, under the condition of 500W xenon lamp irradiation for 3 hours, 0.10g tungsten trioxide powder can make the degradation rate of 10mg/L/methylene blue solution reach 98.74 %,As shown in Figure 6.

Example 4

50g of copper-tungsten alloy waste, firstly separate the copper and tungsten by the secondary nitric acid leaching method to obtain 34.1g of tungsten slag, which contains less than 0.5% copper, and roast the tungsten slag at 600°C to obtain about 41g of yellow-green tungsten trioxide powder. This product is orthorhombic tungsten trioxide; add it to 100ml 10mol/L sodium hydroxide solution, stir at 80°C for 10 hours, the dissolution rate of tungsten trioxide is about 90%, filter the supernatant, evaporate and crystallize Obtain 52.48g of sodium tungstate crystals; add it to 200ml of 3mol/L nitric acid solution, stir for 0.5h, and filter to obtain 39.68g of yellow tungstic acid precipitate; add yellow tungstic acid to 400ml with a mass percentage of 25%-28% After slowly dissolving in ammonia water for 24 hours, take the supernatant, distill ammonia at 100°C until the pH of the solution is about 7, and obtain an ammonium tungstate solution; add this ammonium tungstate solution to 280ml 4mol/L hydrochloric acid solution, and stir for 2 hours , aged at room temperature for 16 hours, filtered and washed, and then dried at 100°C for 6 hours to obtain solid tungsten trioxide. After grinding, 34.84g of yellow tungsten trioxide powder was obtained. According to XRD analysis, the product is monoclinic tungsten trioxide, as shown in Figure 5; through experimental research, under the condition of 500W xenon lamp irradiation for 3 hours, 0.25g of tungsten trioxide powder can make the degradation rate of 50mg/L/methylene blue solution reach 92.18 %,As shown in Figure 6.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the technical principle of the present invention. and modifications, these improvements and modifications should also be considered as the protection scope of the present invention.

Claims (9)

1. a kind of preparation method of monoclinic system tungstic acid is it is characterised in that comprise the following steps：

(1) tungstic acid is dissolved in aqueous slkali, obtains ammonium paratungstate or ammonium tungstate through ammonification；

(2) ammonium paratungstate in step (1) or ammonium tungstate obtain wolframic acid colloid through acidolysis；

(3) wolframic acid colloid aged, washing, dry after obtain described monoclinic system tungstic acid.

2. preparation method according to claim 1 it is characterised in that：Before step (1), also include adopting acid leaching process The copper removing in copper-tungsten obtains tungsten slag, the step that tungsten slag roasting obtains tungstic acid.

3. preparation method according to claim 2 it is characterised in that：Acid leaching process use acid be selected from nitric acid, hydrochloric acid and One or more of sulfuric acid.

4. preparation method according to claim 2 it is characterised in that：Described tungsten slag roasting at 400-600 DEG C.

5. preparation method according to claim 1 it is characterised in that：In step (2), described acidolysis is through reproducibility acid acid Solution.

6. preparation method according to claim 5 it is characterised in that：Described reproducibility acid is hydrochloric acid, sulfurous acid, sulfuration One or more of hydrogen, HBr.

7. preparation method according to claim 1 it is characterised in that：In step (1), described aqueous slkali is ammoniacal liquor, three oxygen Change tungsten and obtain ammonium paratungstate through ammonification, crystallization.

8. preparation method according to claim 1 it is characterised in that：In step (1), by tungstic acid be dissolved in NaOH or In KOH solution, crystallization obtains sodium tungstate or potassium tungstate, and sodium tungstate or potassium tungstate obtain ammonium tungstate after ammonification.

9. preparation method according to claim 8 it is characterised in that：Crystallize the described sodium tungstate obtaining or potassium tungstate adds To in nitric acid, obtain yellow wolframic acid precipitation, yellow wolframic acid precipitation is dissolved in ammonia spirit, after ammonification, obtains ammonium tungstate.