CN110760703B

CN110760703B - Method for recovering tungsten from waste APT powder

Info

Publication number: CN110760703B
Application number: CN201911144029.6A
Authority: CN
Inventors: 谢泉文
Original assignee: Cnmc Guangxi Pgma Co ltd
Current assignee: Cnmc Guangxi Pgma Co ltd
Priority date: 2019-11-20
Filing date: 2019-11-20
Publication date: 2021-09-03
Anticipated expiration: 2039-11-20
Also published as: CN110760703A

Abstract

The invention discloses a method for recovering tungsten from waste APT powder, which comprises the following steps: pumping a crude sodium tungstate solution into an ammonia still, and heating to 85 ℃ under stirring; adding the waste APT powder into an ammonia still, continuously stirring for 2 hours, and adding hydrogen peroxide into the ammonia still to remove sulfur; step three, raising the internal temperature of the ammonia still to 95-100 ℃, keeping the temperature for 8 hours under stirring, stopping heating, collecting ammonia gas at the top of the ammonia still and spraying hydrochloric acid to recover the ammonia gas; and step four, filtering the mixed liquid in the ammonia still, and collecting filtrate, namely the recovered sodium tungstate solution. The method has the advantages of simple process operation, low energy consumption, low production cost and easy realization of tungsten recovery from the waste APT powder.

Description

Method for recovering tungsten from waste APT powder

Technical Field

The invention relates to the field of tungsten smelting production. More particularly, the invention relates to a method for recovering tungsten from waste APT powder.

Background

As is known, tungsten ore is a non-renewable resource, but secondary resources of tungsten are recyclable. Tungsten, a refractory rare metal, is widely used in important industrial fields such as military industry, electronics, metallurgy, petrochemical industry and the like due to its specific physical and chemical properties, and is an important strategic metal in many countries of the world. In the current secondary resource recovery of tungsten, tungsten is mainly recovered from waste materials such as tungsten leaching slag, molybdenum removal precipitation slag, tungsten-containing alloy waste materials, APT waste powder and the like. However, the APT waste powder is mainly derived from waste materials such as rice crust generated by crystallization and drying of ammonium paratungstate, wet APT precipitated in a crystallization mother liquor tank and a washing water tank, screen heads generated by powder mixing, polluted APT and the like.

At present, a waste APT treatment method of a tungsten smelting manufacturer mainly adopts a rotary calciner to burn tungsten trioxide at high temperature, then alkali is added to dissolve the tungsten trioxide and the tungsten trioxide returns to the main flow for use, the treatment process cost is high, the production cost of enterprises is increased, and the economical practicability is poor.

Disclosure of Invention

An object of the present invention is to solve at least the above problems and to provide at least the advantages described later.

Still another object of the present invention is to provide a method for recovering tungsten from waste APT powder, which has the advantages of simple process operation, low energy consumption, low production cost, and easy realization of tungsten recovery from waste APT powder.

To achieve these objects and other advantages in accordance with the purpose of the invention, there is provided a method for recovering tungsten from waste APT powder, comprising the steps of:

pumping a crude sodium tungstate solution into an ammonia still, and heating to 85 ℃ under stirring;

adding the waste APT powder into an ammonia still, continuously stirring for 2 hours, and adding hydrogen peroxide into the ammonia still to remove sulfur;

step three, raising the internal temperature of the ammonia still to 95-100 ℃, keeping the temperature for 8 hours under stirring, stopping heating, collecting ammonia gas at the top of the ammonia still and spraying hydrochloric acid to recover the ammonia gas;

and step four, filtering the mixed liquid in the ammonia still, and collecting filtrate, namely the recovered sodium tungstate solution.

Preferably, in the method for recovering tungsten from waste APT powder, the heating in the ammonia still adopts steam heating; the steam pressure in the third step is 0.1-0.4 MPa.

Preferably, in the method for recovering tungsten from waste APT powder, the volume of the addition amount of the crude sodium tungstate solution in the first step is 50-60% of the internal volume of the ammonia still; the concentration of tungsten in the crude sodium tungstate solution is 100-150 g/L, and the concentration of alkali is 100-120 g/L.

Preferably, in the method for recovering tungsten from waste APT powder, the adding amount of waste APT in the second step is controlled as follows: the total molar quantity of tungsten contained in the waste APT powder is 45-48% of the total molar quantity of the deionization alkali contained in the crude sodium tungstate solution in the step I.

Preferably, in the method for recovering tungsten from waste APT powder, the stirring speed in the first step is 30 r/min; and in the second step and the third step, the stirring speed is 50-60 r/min.

Preferably, in the method for recovering tungsten from the waste APT powder, the waste APT powder is a mixture consisting of one or more of rice crust generated by crystallizing and drying ammonium paratungstate, wet APT precipitated in a crystallization mother liquor tank and a washing water tank, screen heads generated by mixing powder and polluted APT waste.

Preferably, in the method for recovering tungsten from waste APT powder, adding hydrogen peroxide in the second step to remove sulfur specifically comprises the following steps: and after continuously stirring for 2 hours, sampling from the ammonia still to detect the content amol of sulfur in the mixed liquid in the ammonia still, adding 1.1-1.2 amol of hydrogen peroxide into the ammonia still, continuously stirring for 20-30 min, and then entering the third step.

Preferably, in the method for recovering tungsten from waste APT powder, the ammonia gas in step three is further subjected to purification treatment before being sprayed and recovered with hydrochloric acid, specifically:

introducing ammonia gas discharged from the top of the ammonia still into the adsorption tank from the lower part of one side of the adsorption tank, discharging the ammonia gas into the hydrochloric acid spray tower from the top of the adsorption tank, and introducing nitrogen gas into the bottom of the adsorption tank;

the adsorption tank is characterized in that the pressure in the adsorption tank is normal pressure, the temperature is 20-25 ℃, a plurality of adsorption fillers are horizontally connected in the adsorption tank from top to bottom at intervals, any adsorption filler comprises activated carbon fiber particles loaded with ferric oxide hydrate, gauze wrapping the activated carbon fiber particles and two layers of plastic nets sequentially wrapping the outer surfaces of the gauze, a plurality of condensation pipes are arranged on the outer surfaces of the two plastic nets at intervals, and polypropylene polyurethane particles are filled between the inner layer plastic net and the gauze; a refrigerant medium with the temperature of 0-3 ℃ is introduced into any one of the condensation pipes; any plastic net is made of PP material.

Preferably, the method for recovering tungsten from waste APT powder comprises the following steps:

step S1, taking 20-30 parts by weight of activated carbon fiber, cleaning, soaking in boiling distilled water, keeping the temperature for 20-24 hours, taking out the activated carbon fiber, placing the activated carbon fiber in running water, washing for 10-20 min, and drying the activated carbon fiber to obtain activated carbon fiber;

s2, preparing 10 parts of ferric chloride solution with the molar concentration of ferric ions of 0.15-1.8 mol/L, dropwise adding the ferric chloride solution into boiling distilled water with the volume 4 times that of the ferric chloride solution, after dropwise adding, keeping the temperature and stirring until the solution turns brown, stopping heating, and naturally cooling to obtain the ferric solution;

and S3, adding the activated carbon fiber obtained in the step S1 into the iron solution obtained in the step S2, fully stirring for 2-4 hours, standing, performing filter pressing after 1-2 hours, collecting filter residues, and drying and crushing the filter residues to obtain the activated carbon fiber.

The invention at least comprises the following beneficial effects:

the method has the advantages of simple process operation, low energy consumption and low production cost, and is easy to realize the recovery of tungsten from the waste APT powder; decomposing waste APT powder at a certain temperature by using free excess alkali of primary filter pressing concentrated material (crude sodium tungstate solution) for decomposing black and white tungsten concentrates to ensure that WO in APT₃Conversion to Na₂WO₄And ammonia nitrogen, the crude sodium tungstate solution is adopted to dissociate the surplus alkali to decompose the waste APT powder, the alkali is secondarily utilized, the tungsten in the waste APT is separated and recovered, and the investment cost of tungsten recovery is reduced; the method strictly controls the input proportion of each raw material and the processing technological parameters (temperature and stirring speed), reduces the consumption of alkali and ammonia, reduces the production cost of enterprises, and greatly improves the recovery rate of tungsten;

aiming at the technical problems that ammonia nitrogen in the wastewater is not further recovered and the ammonia nitrogen in the treated wastewater exceeds the standard so as to cause environmental pollution in the prior art, the invention further carries out ammonia distillation on the recovered and treated wastewater, controls the ammonia distillation temperature and the ammonia distillation time in the ammonia distillation process, reduces the ammonia nitrogen concentration in the wastewater as much as possible, simultaneously carries out purification treatment on the ammonia gas, and adopts hydrochloric acid for spray recovery, finally obtains an ammonia nitrogen product which can be directly put into production and application, and further reduces the production cost of enterprises;

the ammonia purification process with simple structure and good impurity removal effect is arranged, other impurities such as hydrogen sulfide in ammonia gas can be removed as far as possible, the direct production and application of ammonia are prevented from being influenced by the mixing of hydrogen sulfide, and the safety and reliability of secondary application of ammonia are ensured; the ammonia gas discharged from the top of the ammonia still carries harmful gas hydrogen sulfide, the hydrogen sulfide gas needs to be removed before the ammonia is put into production and application, the ammonia gas to be purified is introduced from the lower part of an adsorption tank, the ammonia gas moves upwards and sequentially passes through a plurality of adsorption fillers, nitrogen is introduced into the bottom of the adsorption filler, the ammonia gas can be promoted to move upwards, two layers of plastic nets outside any adsorption filler are used as crystallization places, the reaction product of the ammonia gas and the hydrogen sulfide can be crystallized and adsorbed on a plastic PP net at 0-3 ℃, the aim of removing the hydrogen sulfide is further achieved, further, when the ammonia gas passes through activated carbon fiber particles loaded with hydrated iron oxide, the hydrated iron oxide reacts with the hydrogen sulfide, so that the hydrogen sulfide is removed again, polypropylene urethane particles are filled between the inner layer plastic net and gauze, moisture carried in the ammonia gas can be removed, and moisture generated by the reaction of the hydrated iron oxide and the hydrogen sulfide can also be removed, further promoting the forward reaction of the hydrated ferric oxide and the hydrogen sulfide, and improving the adsorption efficiency of the hydrated ferric oxide to the hydrogen sulfide; the ammonia purification treatment process is simple, the purification effect is good, and the aim of reducing the production cost of enterprises is further fulfilled.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

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

Detailed Description

The present invention is further described in detail below with reference to the drawings and examples so that those skilled in the art can practice the invention with reference to the description.

It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

It is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified.

The chemical equation related to the invention is as follows:

5(NH₄)₂O·12WO₃·5H₂O+24NaOH=12Na₂WO₄+10NH₃·H₂O+12H₂O （1）

S^2-＋4H₂O₂=SO₄ ^2-＋4H₂O （2）

NH₄ ⁺ + OH^-=NH₃ + H₂O （3）

NH₃+ H₂O =NH₄OH （4）

NH₄OH + HCl = NH₄Cl + H₂O （5）

NH₃+ H₂S = (NH₄)₂S （6）

FeCl₃+3H₂O = Fe(OH)₃(colloid) +3HCl (7)

Fe₂O₃·H₂O+ 3H₂S = Fe₂S₃+ 4H₂O （8）

(1) Decomposing sodium paratungstate in the waste APT powder by using free alkali in the crude sodium tungstate solution;

(2) in the second step, hydrogen peroxide is used for removing sulfur;

(3) collecting ammonia gas for ammonia distillation;

(4) spraying hydrochloric acid to recover ammonia;

(6) reacting ammonia with hydrogen sulfide;

(7) converting ferric chloride into iron solution colloid;

(8) reaction of hydrated iron oxide with hydrogen sulfide.

< example 1>

As shown in FIG. 1, the invention provides a method for recovering tungsten from waste APT powder, which comprises the following steps:

pumping a crude sodium tungstate solution into an ammonia still, stirring at a stirring speed of 30r/min, heating to 85 ℃, wherein the crude sodium tungstate solution is a primary filter-pressing concentrated material for decomposing black tungsten concentrate; the volume of the addition amount of the crude sodium tungstate solution is 50 percent of the internal volume of the ammonia still, the tungsten concentration in the crude sodium tungstate solution is 100g/L, the alkali concentration is 100g/L, wherein the alkali concentration is lower than 100g/L, and the addition amount can be supplemented to 100g/L by additionally adding solids (such as alkali sodium hydroxide);

step two, adding waste APT powder (APT is an abbreviation of ammonium paratungstate) into an ammonia still, adjusting the stirring speed to 50r/min, continuously stirring for 2 hours, and adding hydrogen peroxide into the ammonia still for removing sulfur: sampling from an ammonia still, detecting the content amol of sulfur in the mixed liquid in the ammonia still, adding 1.1amol of hydrogen peroxide into the ammonia still, and continuing stirring for 20 min; the waste APT powder is rice crust generated by crystallization and drying of ammonium paratungstate; the adding amount of the waste APT powder is controlled as follows: the total molar quantity of tungsten contained in the waste APT powder is 45 percent of the total molar quantity of free alkali contained in the crude sodium tungstate solution;

step three, raising the internal temperature of the ammonia still to 95 ℃, keeping the temperature for 8 hours at a stirring speed of 50r/min, and stopping heating, wherein ammonia gas at the top of the ammonia still is collected and is sprayed by hydrochloric acid to recover the ammonia gas;

filtering the mixed solution in the ammonia still, and collecting filtrate, namely the recovered sodium tungstate solution;

wherein, in the above steps, the heating in the ammonia still adopts steam heating; the vapor pressure in the third step is 0.1 MPa.

< example 2>

pumping a crude sodium tungstate solution into an ammonia still, stirring at a stirring speed of 30r/min, heating to 85 ℃, wherein the crude sodium tungstate solution is a primary filter-pressing concentrated material for decomposing scheelite concentrate; the volume of the addition amount of the crude sodium tungstate solution is 60 percent of the internal volume of the ammonia still, the tungsten concentration in the crude sodium tungstate solution is 150g/L, the alkali concentration is 120g/L, wherein the alkali concentration is lower than 120g/L, and the addition amount can be made up to 120g/L by additionally adding solids (such as alkali sodium hydroxide);

step two, adding waste APT powder (APT is an abbreviation of ammonium paratungstate) into an ammonia still, adjusting the stirring speed to 60r/min, continuing stirring for 2 hours, and adding hydrogen peroxide into the ammonia still for removing sulfur: sampling from an ammonia still, detecting the content amol of sulfur in the mixed liquid in the ammonia still, adding 1.2amol of hydrogen peroxide into the ammonia still, and continuing stirring for 30 min; the waste APT powder is a mixture consisting of wet APT precipitated in a crystallization mother liquor tank and a washing water tank and a sieve head generated by powder mixing; the adding amount of the waste APT powder is controlled as follows: the total molar quantity of tungsten contained in the waste APT powder is 48 percent of the total molar quantity of free alkali contained in the crude sodium tungstate solution;

step three, raising the internal temperature of the ammonia still to 100 ℃, keeping the temperature for 8 hours at a stirring speed of 60r/min, and stopping heating, wherein ammonia gas at the top of the ammonia still is collected and is sprayed by hydrochloric acid to recover the ammonia gas;

wherein, in the above steps, the heating in the ammonia still adopts steam heating; the vapor pressure in the third step is 0.4 MPa.

< example 3>

pumping a crude sodium tungstate solution into an ammonia still, stirring at a stirring speed of 30r/min, heating to 85 ℃, wherein the crude sodium tungstate solution is a primary filter-pressing concentrated material for decomposing black tungsten concentrate; the volume of the addition amount of the crude sodium tungstate solution is 55 percent of the internal volume of the ammonia still, the tungsten concentration in the crude sodium tungstate solution is 125g/L, the alkali concentration is 110g/L, wherein the alkali concentration is lower than 110g/L, and the addition amount can be made up to 110g/L by additionally adding solids (such as alkali sodium hydroxide);

step two, adding waste APT powder (APT is an abbreviation of ammonium paratungstate) into an ammonia still, adjusting the stirring speed to 55r/min, continuing stirring for 2 hours, and adding hydrogen peroxide into the ammonia still for removing sulfur: sampling from an ammonia still, detecting the content amol of sulfur in the mixed liquid in the ammonia still, adding 1.15amol of hydrogen peroxide into the ammonia still, and continuing stirring for 25 min; (ii) a The waste APT powder is polluted APT waste; the adding amount of the waste APT powder is controlled as follows: the total molar quantity of tungsten contained in the waste APT powder is 47 percent of the total molar quantity of free alkali contained in the crude sodium tungstate solution;

step three, raising the internal temperature of the ammonia still to 98 ℃, stirring and preserving heat for 8 hours at a stirring speed of 55r/min, and then stopping heating, wherein ammonia gas at the top of the ammonia still is collected and is sprayed by hydrochloric acid to recover the ammonia gas;

wherein, in the above steps, the heating in the ammonia still adopts steam heating; the vapor pressure in the third step is 0.3 Mpa.

< example 4>

wherein, in the above steps, the heating in the ammonia still adopts steam heating; the steam pressure in the third step is 0.1 Mpa;

in the third step, the ammonia gas is purified before being sprayed and recovered by hydrochloric acid, and the method specifically comprises the following steps:

the adsorption tank is characterized in that the pressure in the adsorption tank is normal pressure, the temperature is 20 ℃, a plurality of adsorption fillers are horizontally connected in the adsorption tank from top to bottom at intervals, any adsorption filler comprises activated carbon fiber particles loaded with ferric oxide hydrate, gauze wrapping the activated carbon fiber particles and two layers of plastic nets sequentially wrapping the outer surfaces of the gauze, a plurality of condensation pipes are arranged on the outer surfaces of the two plastic nets at intervals, and polypropylene polyurethane particles are filled between the inner layer plastic net and the gauze; a refrigerant medium with the temperature of 0 ℃ is introduced into any one of the condensation pipes; any plastic net is made of PP material.

< example 5>

wherein, in the above steps, the heating in the ammonia still adopts steam heating; the steam pressure in the third step is 0.4 Mpa;

the adsorption tank is characterized in that the pressure in the adsorption tank is normal pressure, the temperature is 25 ℃, a plurality of adsorption fillers are horizontally connected in the adsorption tank from top to bottom at intervals, any adsorption filler comprises activated carbon fiber particles loaded with ferric oxide hydrate, gauze wrapping the activated carbon fiber particles and two layers of plastic nets sequentially wrapping the outer surfaces of the gauze, a plurality of condensation pipes are arranged on the outer surfaces of the two plastic nets at intervals, and polypropylene polyurethane particles are filled between the inner layer plastic net and the gauze; a refrigerant medium with the temperature of 3 ℃ is introduced into any one of the condensation pipes; any plastic net is made of PP material.

< example 6>

wherein, in the above steps, the heating in the ammonia still adopts steam heating; the steam pressure in the third step is 0.3 Mpa;

the adsorption tank is characterized in that the pressure in the adsorption tank is normal pressure, the temperature is 23 ℃, a plurality of adsorption fillers are horizontally connected in the adsorption tank from top to bottom at intervals, any adsorption filler comprises activated carbon fiber particles loaded with ferric oxide hydrate, gauze wrapping the activated carbon fiber particles and two layers of plastic nets sequentially wrapping the outer surfaces of the gauze, a plurality of condensation pipes are arranged on the outer surfaces of the two plastic nets at intervals, and polypropylene polyurethane particles are filled between the inner layer plastic net and the gauze; a cold medium with the temperature of 2 ℃ is introduced into any one of the condensation pipes; any plastic net is made of PP material.

< example 7>

The preparation method of the hydrated ferric oxide activated carbon fiber comprises the following steps:

step S1, 20 parts by weight of activated carbon fibers are taken and cleaned, then soaked in boiling distilled water, kept warm for 20 hours, taken out and placed under running water for washing for 10 minutes, and then dried to obtain activated carbon fibers;

s2, preparing 10 parts of ferric chloride solution with the ferric ion molar concentration of 0.15 mol/L, dropwise adding the ferric chloride solution into boiling distilled water with the volume 4 times that of the ferric chloride, after dropwise adding, keeping the temperature and stirring until the solution turns brown, stopping heating, and naturally cooling to obtain the ferric solution;

and S3, adding the activated carbon fiber obtained in the step S1 into the iron solution obtained in the step S2, fully stirring for 2 hours, standing, performing pressure filtration after 1 hour, collecting filter residue, drying and crushing the filter residue to obtain the activated carbon fiber.

< example 8>

the adsorption tank is characterized in that the pressure in the adsorption tank is normal pressure, the temperature is 25 ℃, a plurality of adsorption fillers are horizontally connected in the adsorption tank from top to bottom at intervals, any adsorption filler comprises activated carbon fiber particles loaded with ferric oxide hydrate, gauze wrapping the activated carbon fiber particles and two layers of plastic nets sequentially wrapping the outer surfaces of the gauze, a plurality of condensation pipes are arranged on the outer surfaces of the two plastics at intervals, and polypropylene polyurethane particles are filled between the inner layer of plastic net and the gauze; a refrigerant medium with the temperature of 3 ℃ is introduced into any one of the condensation pipes; any plastic net is made of PP material.

step S1, according to the parts by weight, after 30 parts of activated carbon fibers are cleaned, the activated carbon fibers are soaked in boiling distilled water, the temperature is kept for 24 hours, the activated carbon fibers are taken out and placed under running water for washing for 20 minutes, and then the activated carbon fibers are dried to obtain activated carbon fibers;

s2, preparing 10 parts of ferric chloride solution with the ferric ion molar concentration of 1.8 mol/L, dropwise adding the ferric chloride solution into boiling distilled water with the volume 4 times that of the ferric chloride, after dropwise adding, keeping the temperature and stirring until the solution turns brown, stopping heating, and naturally cooling to obtain the ferric solution;

and S3, adding the activated carbon fiber obtained in the step S1 into the iron solution obtained in the step S2, fully stirring for 4 hours, standing, performing pressure filtration after 2 hours, collecting filter residue, drying and crushing the filter residue to obtain the activated carbon fiber.

< example 9>

the adsorption tank is characterized in that the pressure in the adsorption tank is normal pressure, the temperature is 23 ℃, a plurality of adsorption fillers are horizontally connected in the adsorption tank from top to bottom at intervals, any adsorption filler comprises activated carbon fiber particles loaded with ferric oxide hydrate, gauze wrapping the activated carbon fiber particles and two layers of plastic nets sequentially wrapping the outer surfaces of the gauze, a plurality of condensation pipes are arranged on the outer surfaces of the two plastic nets at intervals, and polypropylene polyurethane particles are filled between the inner layer plastic net and the gauze; a cold medium with the temperature of 2 ℃ is introduced into any one of the condensation pipes; any plastic net is made of PP material;

step S1, according to the parts by weight, 25 parts of activated carbon fiber is taken and cleaned, then is soaked in boiling distilled water, is kept warm for 22 hours, is taken out and is placed under running water for washing for 15 minutes, and then is dried to obtain activated carbon fiber;

s2, preparing 10 parts of ferric chloride solution with the ferric ion molar concentration of 0.9mol/L, dropwise adding the ferric chloride solution into boiling distilled water with the volume 4 times that of the ferric chloride, after dropwise adding, keeping the temperature and stirring until the solution turns brown, stopping heating, and naturally cooling to obtain the ferric solution;

and S3, adding the activated carbon fiber obtained in the step S1 into the iron solution obtained in the step S2, fully stirring for 3 hours, standing, performing pressure filtration after 1.5 hours, collecting filter residues, drying and crushing the filter residues, and thus obtaining the activated carbon fiber iron-base composite material.

< comparative example 1>

As shown in fig. 1, the present invention provides a method for recovering tungsten from waste APT powder, which is different from example 9 in that activated carbon fiber is not subjected to the activation treatment of step S1, and the remaining conditions and parameters are the same as those of example 9.

< comparative example 2>

As shown in fig. 1, the present invention provides a method for recovering tungsten from spent APT powder, which is different from example 6 in that activated carbon fiber particles loaded with hydrated iron oxide in an adsorption tank are replaced with the same amount of activated carbon fiber particles (not loaded with hydrated iron oxide), and the remaining conditions and parameters are the same as example 6.

< comparative example 3>

As shown in fig. 1, the present invention provides a method for recovering tungsten from waste APT powder, which is different from example 6 in that the adsorption packing in the adsorption tank comprises activated carbon fiber particles loaded with hydrated iron oxide, gauze wrapping the activated carbon fiber particles, i.e., two plastic nets are not provided outside the gauze; the remaining conditions and parameters were the same as in example 6.

< comparative example 4>

As shown in fig. 1, the present invention provides a method for recovering tungsten from waste APT powder, which is different from example 6 in that a condensation duct is not provided on the outer surface of any plastic net; the remaining conditions and parameters were the same as in example 6.

< comparative example 5>

As shown in fig. 1, the present invention provides a method for recovering tungsten from waste APT powder, which is different from example 6 in that the space between the inner plastic net and the gauze is not filled with the granules of polyurethane polypropylene; the remaining conditions and parameters were the same as in example 6.

< Experimental example >

1. In the embodiments 1-3, the heating is stopped after the heat preservation is carried out for 8 hours in the third step, the ammonia nitrogen concentration in the mixed liquid in the ammonia still is detected, and the ammonia nitrogen concentrations in the embodiments 1-3 are respectively 4.8g/L, 4.9g/L and 4.7 g/L. After the heat preservation is carried out for 8 hours, the ammonia distillation is finished, and therefore the ammonia nitrogen in the recovery liquid can be reduced to be below 5g/L in the embodiments 1-3 of the invention, and the recovery rate of the ammonia nitrogen is up to more than 95%.

2. The recovery rate of tungsten in examples 1 to 3 of the present invention was calculated according to the following formula: the recovery rate of tungsten = the content of tungsten in the filtrate obtained by filtering the mixed solution in the fourth step/the content of tungsten in the waste APT powder added into the ammonia still in the second step; the tungsten recovery rates of examples 1 to 3 were 98.9%, 99.2% and 99.3%, respectively. Therefore, the method for recovering tungsten provided by the invention can be used for basically recovering tungsten in the waste APT powder, and has higher recovery rate.

3. NH obtained in examples 1 to 9 and comparative examples 1 to 5 of the present invention was measured₄The content of sulfur ions in Cl; recording the detection result, which is detailed in table 1;

	content of sulfide ion (g/L)
		Example 1	0.472
Example 2	0.512
		Example 3	0.523
Example 4	0.0901
		Example 5	0.0897
Example 6	0.0904
		Example 7	--
Example 8	--
		Example 9	--
Comparative example 1	0.015
		Comparative example 2	0.163
Comparative example 3	0.156
		Comparative example 4	0.651
Comparative example 5	0.489

Remarking: - -is lower than the detection line, and is not detected when the content is lower than 0.001 g/L.

As can be seen from table 1, the ammonia gas in examples 7 to 9 of the present invention can substantially remove hydrogen sulfide in the ammonia gas through purification treatment by the adsorption filler, and comparing examples 7 to 9 with examples 4 to 6, examples 1 to 3, and comparative examples 1 to 5, it is demonstrated that the removal effect of hydrogen sulfide in ammonia gas can be improved by subjecting the activated carbon fiber to activation treatment, loading hydrated iron oxide on the activated carbon fiber, filling polypropylene urethane particles between the gauze and the plastic mesh, providing two layers of plastic meshes, and providing a condensation pipe on the outer surface of the plastic mesh.

The number of apparatuses and the scale of the process described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be apparent to those skilled in the art.

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims

1. The method for recovering tungsten from waste APT powder is characterized by comprising the following steps:

wherein, ammonia has still undergone purification treatment before spraying with hydrochloric acid and retrieving in step three, specifically is:

the adsorption tank is characterized in that the pressure in the adsorption tank is normal pressure, the temperature is 20-25 ℃, a plurality of adsorption fillers are horizontally connected in the adsorption tank from top to bottom at intervals, any adsorption filler comprises activated carbon fiber particles loaded with ferric oxide hydrate, gauze wrapping the activated carbon fiber particles and two layers of plastic nets sequentially wrapping the outer surfaces of the gauze, a plurality of condensation pipes are arranged on the outer surfaces of the two plastic nets at intervals, and polypropylene polyurethane particles are filled between the inner layer plastic net and the gauze; a refrigerant medium with the temperature of 0-3 ℃ is introduced into any one of the condensation pipes; any plastic net is made of PP material;

2. The method for recovering tungsten from waste APT powder according to claim 1, wherein the heating in the ammonia still is steam heating; the steam pressure in the third step is 0.1-0.4 MPa.

3. The method for recovering tungsten from waste APT powder according to claim 2, wherein the volume of the addition amount of the crude sodium tungstate solution in the first step is 50-60% of the internal volume of the ammonia still; the concentration of tungsten in the crude sodium tungstate solution is 100-150 g/L, and the concentration of alkali is 100-120 g/L.

4. The method for recovering tungsten from waste APT powder according to claim 3, wherein the addition amount of the waste APT in the second step is controlled as follows: the total molar quantity of tungsten contained in the waste APT powder is 45-48% of the total molar quantity of free alkali contained in the crude sodium tungstate solution in the first step.

5. The method for recovering tungsten from spent APT powder according to claim 4 wherein the stirring speed in the first step is 30 r/min; and in the second step and the third step, the stirring speed is 50-60 r/min.

6. The method of claim 5, wherein the APT waste powder is a mixture of one or more of rice crust generated by ammonium paratungstate crystallization and drying, wet APT precipitated from a crystallization mother liquor tank and a washing water tank, screen heads generated from powder mixing, and contaminated APT waste.

7. The method for recovering tungsten from waste APT powder according to claim 6, wherein the step two of adding hydrogen peroxide for sulfur removal specifically comprises the following steps: and after continuously stirring for 2 hours, sampling from the ammonia still to detect the content amol of sulfur in the mixed liquid in the ammonia still, adding 1.1-1.2 amol of hydrogen peroxide into the ammonia still, continuously stirring for 20-30 min, and then entering the third step.