CN114318014A - A kind of method for double-flow feeding of vanadium slag pressure leaching reaction kettle - Google Patents

Abstract

The invention provides a method for double-flow feeding of a vanadium slag pressure leaching reaction kettle, which comprises the following steps: mixing the first alkali liquor and the vanadium slag to obtain slurry; conveying the slurry obtained in the step (1) and the preheated second alkali liquor to a pressurized reaction kettle for oxidation leaching reaction to realize extraction of vanadium; the method adopts a double-flow feeding method to feed materials into the pressurized reaction kettle, thereby not only reducing the loss of conveying equipment, but also improving the leaching rate of vanadium, and leading the leaching rate to reach more than 90 percent and to reach more than 97 percent at most; in addition, the second alkali liquor is preheated by adopting a pipeline preheating mode, so that the energy consumption in the heating process can be saved, and the service life of equipment is prolonged. The method disclosed by the invention is efficient and environment-friendly, is suitable for industrial production, and has a good application prospect.

Description

A kind of method for double-flow feeding of vanadium slag pressure leaching reaction kettle

technical field

The invention belongs to the technical field of vanadium chemical industry and metallurgy, and in particular relates to a method for double-flow feeding of a vanadium slag pressure leaching reaction kettle.

Background technique

Vanadium slag is a kind of vanadium enriched material smelted from vanadium-containing molten iron in the presence of oxygen-containing gas. Vanadium slag produced from vanadium titanomagnetite in the iron and steel industry is the main raw material for vanadium extraction. Enterprises that use vanadium titanomagnetite as raw materials to produce iron and vanadium products currently use the traditional vanadium slag sodium roasting process to extract vanadium from vanadium slag, such as my country's Pangang and Chenggang, South Africa's Highveld, New Zealand's Steel company etc. The basic principle of the sodium roasting process is to use Na ₂ CO ₃ as an additive, and through high temperature sodium roasting (750-850 ℃), the low-valence vanadium is converted into the sodium salt of water-soluble pentavalent vanadium, and then the sodium roasting product is Direct water leaching to obtain vanadium-containing leaching solution, then adding ammonium salt to prepare ammonium polyvanadate precipitation, and obtaining vanadium oxide product after reduction roasting. However, the recovery rate of vanadium in the sodium roasting process is low, the recovery rate of vanadium in a single roasting is about 70%, and the recovery rate of vanadium after multiple roasting is only 80%; and the roasting temperature is high (750-850 ° C), and requires Repeated roasting will result in high energy consumption; in the roasting process, harmful corrosive gases such as HCl and Cl ₂ will also be produced, polluting the environment. Therefore, it is of great significance to provide a vanadium extraction process from vanadium slag with low energy consumption, simple process flow, safety and environmental protection.

CN102531056A discloses a method for pressurized leaching of vanadium slag in a pressurized reactor. The method firstly stirs and mixes NaOH solution and vanadium slag in a preparation tank to prepare a slurry with a liquid-solid ratio of 4-6:1, and then passes All the pumps with alkali resistance, high temperature resistance and wear resistance are transported to the pressurized and pressurized reactor for leaching reaction. However, this method has relatively high requirements on the equipment, and the corrosion and wear of the equipment is relatively serious, and the feeding time is long by using a single feeding pump. The whole reaction cycle is also prolonged, and the energy consumption is higher.

CN110760687A discloses a low-cost vanadium slag cleaning and vanadium extraction method, which includes four steps of vanadium slag roasting, alkali leaching, purification and vanadium precipitation. The vanadium slag and calcium oxide are mixed and roasted to obtain roasted clinker, and the roasted clinker is subjected to alkali leaching. The residue and vanadium-containing leachate are obtained. After the residue is washed, the washing solution is concentrated and mixed with the vanadium-containing leachate to obtain a vanadium-containing mixed solution. The vanadium-containing mixed solution is mixed with calcium chloride to obtain a sodium vanadate solution. The sodium vanadate solution is added to the solid-liquid ammonium chloride solution The ammonium metavanadate precipitation and the vanadium precipitation wastewater are obtained by separation, and the vanadium precipitation wastewater is returned to the alkaline leaching step for alkaline leaching of the roasting clinker. Although this method does not use the sodium roasting process, but is mixed with calcium oxide for roasting, the roasting temperature is also high, and the energy consumption is relatively high.

In summary, how to provide a vanadium extraction process from vanadium slag with low energy consumption, simple process flow, safety and environmental protection has become an urgent problem to be solved at present.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the object of the present invention is to provide a method for double-flow feeding of a vanadium slag pressure leaching reaction kettle. The method is efficient and environmentally friendly, and is suitable for industrial production.

For this purpose, the present invention adopts the following technical solutions:

The invention provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, the method comprises the following steps:

(1) the first alkali liquor is mixed with vanadium slag to obtain slurry;

(2) The slurry obtained in step (1) and the preheated second lye solution are transported to a pressurized reaction kettle for oxidative leaching reaction to realize the extraction of vanadium.

In the present invention, the first lye solution and the second lye solution may be divided into two strands of the same lye solution, or may be prepared independently.

In the present invention, the traditional method of first batching and then feeding is optimized, the lye is divided into two streams, one part is formed into a slurry with vanadium slag, and the other part is then fed with the formed slurry in two streams. This method can effectively compare The loss of low material flow to the conveying pump can prolong the service life of the equipment, save energy and high efficiency, and has good economic benefits, which is conducive to industrial application.

The following are the preferred technical solutions of the present invention, but not as limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical purpose and beneficial effects of the present invention can be better achieved and realized.

As a preferred technical solution of the present invention, the first alkali solution in step (1) includes NaOH solution.

Preferably, the first alkali liquor in step (1) includes fresh alkali liquor and/or circulating alkali liquor after evaporation and concentration.

Preferably, the concentration of the first alkali solution in step (1) is 40-50wt%, such as 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49 wt % or 50 wt %, etc., but not limited to the recited values, and other unrecited values within the numerical range are also applicable.

Preferably, the initial temperature of the first alkali solution in step (1) is 80-120°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C etc., but are not limited to the recited numerical values, and other unrecited numerical values within the numerical range are equally applicable.

As a preferred technical solution of the present invention, the proportion of particles passing through a 200-mesh sieve in the vanadium slag in step (1) is 70-90wt%, such as 70wt%, 72wt%, 74wt%, 76wt%, 78wt%, 80wt%, 82 wt %, 84 wt %, 86 wt %, 88 wt % or 90 wt %, etc., but not limited to the recited values, and other unrecited values within the numerical range are also applicable.

As a preferred technical solution of the present invention, the liquid-solid ratio of the slurry in step (1) is (1.0-2):1, such as 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, etc., but not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Preferably, the temperature of the slurry in step (1) does not exceed 95°C, such as 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 93°C, or 95°C, etc., but not limited to those listed value, other non-recited values within this value range also apply.

In the present invention, the slurry in step (2) is transported by a diaphragm pump, because the diaphragm pump has no shaft seal, no leakage, wide flow channel, no impeller, and small wear of the pump itself, so the transport contains particles, which are easy to volatilize and corrode When using a sexual medium, it will not cause environmental pollution and endanger personal safety. However, the diaphragm pump has requirements on the feeding temperature, which should not be higher than 95°C, so the liquid-solid ratio of the slurry is very important. The method of the present invention controls the slurry temperature by adjusting the liquid-solid ratio. If the liquid-solid ratio is too large, the slurry temperature will be too high. If the temperature exceeds 95°C, the diaphragm pump will be corroded and the service life will be affected. If the liquid-solid ratio is too small, the solid content of the slurry will be too high, and the slurry cannot be transported normally. Blocked feed line.

As a preferred technical solution of the present invention, the second alkali solution in step (2) includes NaOH solution.

Preferably, the second alkali liquor in step (2) includes fresh alkali liquor and/or circulating alkali liquor after evaporation and concentration.

Preferably, the concentration of the second alkali solution in step (2) is 40-50wt%, such as 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49 wt % or 50 wt %, etc., but not limited to the recited values, and other unrecited values within the numerical range are also applicable.

Preferably, the initial temperature of the second alkali solution in step (2) is 80-120°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C etc., but are not limited to the recited numerical values, and other unrecited numerical values within the numerical range are equally applicable.

As a preferred technical solution of the present invention, the second alkali solution in step (2) is preheated by a pipeline preheater.

Preferably, the heating medium used by the pipeline preheater includes saturated steam.

Preferably, the pressure of the saturated steam is not less than 2.0 MPa, such as 2.0 MPa, 2.2 MPa, 2.3 MPa, 2.5 MPa, 3.0 MPa, 3.2 MPa, 3.5 MPa, 3.8 MPa or 4.0 MPa, etc., but not limited to those listed Numerical values, other non-recited values within the numerical range also apply.

Preferably, the preheated temperature of the second lye solution in step (2) is 180-220°C, such as 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C or 220°C °C, etc., but are not limited to the listed numerical values, and other unlisted numerical values within the numerical range are also applicable.

In the present invention, the traditional pressurized oxidation reaction adopts steam direct heating or electromagnetic induction heating. Direct steam heating will cause the lye slurry of the reactor to be diluted, thereby affecting the extraction effect of vanadium; The kettle body then transfers the heat to the slurry. The kettle body has large heat dissipation and low thermal efficiency, and the energy consumption cost of electric heating is higher than that of steam. The steam pipeline preheating of the invention can not only improve the heat exchange efficiency of steam heating and reduce the preheating cost, but also does not affect the alkali concentration of the slurry through the indirect heat exchange of the steam, and is an efficient and energy-saving heating method.

As a preferred technical solution of the present invention, the added amount of the second alkali solution described in step (2) is 3-5 times the mass of the vanadium slag described in step (1), such as 3.0 times, 3.2 times, 3.4 times, 3.6 times, 3.8 times, 4.0 times, 4.2 times, 4.4 times, 4.6 times, 4.8 times, or 5.0 times, etc., but not limited to the listed numerical values, and other unlisted numerical values within the numerical range are also applicable.

As a preferred technical solution of the present invention, the slurry in step (2) is transported by a diaphragm pump.

Preferably, the second alkali solution in step (2) is transported by a centrifugal pump.

Preferably, the impeller material of the centrifugal pump includes Ni-based alloy.

Preferably, the Ni-based alloy includes any one of Ni-Cr alloy, Ni-Cr-Mo-Cu alloy, Ni-Cr-Mo(W) alloy or Ni-Cr-W alloy, preferably Ni-Cr alloy.

As a preferred technical solution of the present invention, the pressure of the oxidative leaching reaction in step (2) is 0.6-1.0 MPa, such as 0.60 MPa, 0.65 MPa, 0.70 MPa, 0.75 MPa, 0.80 MPa, 0.85 MPa, 0.90 MPa, 0.95 MPa or 1.00 MPa, etc., but not limited to the listed numerical values, and other unlisted numerical values within the numerical range are also applicable.

Preferably, the temperature of the oxidative leaching reaction in step (2) is 160-180°C, such as 160°C, 163°C, 166°C, 169°C, 172°C, 175°C, 178°C or 180°C, etc., but not limited to Recited values apply equally well to other non-recited values within this range of values.

In the present invention, the temperature of the preheated second lye solution and the slurry can reach the set reaction temperature of 160-180° C. The reaction kettle does not need to add heating equipment, and the leaching temperature can be guaranteed by the reaction exotherm of the oxidative leaching process. , thereby saving energy consumption and reducing investment in reactor equipment.

Preferably, the oxidizing gas used in the oxidative leaching reaction in step (2) includes any one or a combination of at least two of oxygen, air or ozone.

Preferably, the oxygen partial pressure of the oxidative leaching reaction in step (2) is 0.3-0.5 MPa, such as 0.30 MPa, 0.33 MPa, 0.36 MPa, 0.39 MPa, 0.42 MPa, 0.45 MPa, 0.48 MPa, or 0.50 MPa, etc., but Not limited to the recited values, other non-recited values within the range of values apply equally.

As the preferred technical solution of the present invention, the method comprises the following steps:

(1) Mix the first alkali solution with an initial temperature of 80-120°C and a concentration of 40-50wt% and vanadium slag with a particle ratio of 70-90wt% passing through a 200-mesh sieve to obtain a liquid-solid ratio of (1-2) :1 slurry;

(2) using a pipeline preheater to preheat the second alkali liquid to 180-220°C, wherein the heating medium is saturated steam with a pressure of not less than 2.0MPa;

Then, the slurry obtained in step (1) is transported to the reactor by a diaphragm pump, and the preheated second lye is transported to the pressurized reactor by a centrifugal pump. The addition amount of the second lye It is 3-5 times the quality of the vanadium slag described in step (1), and after mixing the two, the oxidation leaching reaction is carried out under the conditions of 0.6-1.0MPa, 160-180 ° C, and oxygen partial pressure of 0.3-0.5MPa, so as to realize the vanadium leaching reaction. extract.

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

(1) the vanadium slag pressurized leaching reaction kettle double-flow feeding method of the present invention optimizes the traditional method of first batching and then feeding, mixing part of the lye with the vanadium slag to form a slurry, and then mixing another part of the lye Realize dual-stream feeding with the obtained slurry, making the feeding process simpler and more efficient;

(2) The method of the present invention controls the temperature of the slurry to not exceed 95°C by preparing a vanadium slag slurry with a low liquid-solid ratio, so as to meet the requirements of the diaphragm pump for the material conveying temperature, and ensure that the vanadium slag slurry can use a durable diaphragm The pump is used as the feed pump for the pressurized reactor;

(3) The method of the present invention utilizes the diaphragm pump to transport the slurry to the reaction kettle, which can avoid the loss of the slurry to the impeller of the traditional transport pump and prolong the service life of the equipment;

(4) The method of the present invention adopts the pipeline preheating method to preheat the second lye to the reaction temperature. Since the liquid caustic does not contain solid particles, the wear of the impeller of the pump for transporting the lye is greatly reduced, and it can also be used. The lifespan can be significantly extended;

(5) The second alkali liquid of the method of the present invention is heated by the method of steam pipeline preheating, which can not only improve the heat exchange efficiency of steam heating and reduce the preheating cost, but also the indirect heat exchange of steam will not affect the alkali concentration of the slurry. An efficient and energy-saving heating method;

(6) The method of the present invention can make the recovery rate of vanadium reach more than 90%, and the highest can reach more than 97%.

Description of drawings

Fig. 1 is the process flow diagram of a kind of vanadium slag pressure leaching reaction kettle double-stream feeding method provided in the embodiment 1 of the present invention.

Detailed ways

In order to better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, the present invention is further described in detail below. However, the following embodiments are only simple examples of the present invention, and do not represent or limit the protection scope of the present invention, and the protection scope of the present invention is subject to the claims.

The following are typical but non-limiting examples of the present invention:

Example 1:

The present embodiment provides a method for double-flow feeding of vanadium slag pressurized leaching reaction kettle, and the process flow of the method is shown in FIG. 1 .

The method includes the following steps:

Provide an evaporated circulating NaOH solution with an initial temperature of 90 °C and a concentration of 45 wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 80 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.6:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 180°C, wherein the heating medium is saturated steam with a pressure of 3.0MPa;

Then, the slurry obtained in step (1) is transported into the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported into the pressurized reaction kettle by a centrifugal pump whose impeller material is Ni-Cr alloy, so that the The added amount of the second NaOH solution is 3.4 times the quality of the vanadium slag described in step (1). After the two are mixed, the oxidative leaching reaction is carried out under the conditions of 0.8MPa, 160° C., and an oxygen partial pressure of 0.4MPa to achieve vanadium extract.

Example 2:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide a freshly prepared NaOH solution with an initial temperature of 86 ° C and a concentration of 48 wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 84 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 2.0:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 210°C, wherein the heating medium is saturated steam with a pressure of 3.6MPa;

Then, the slurry obtained in step (1) is transported into the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported into the pressurized reaction kettle by a centrifugal pump whose impeller material is Ni-Cr alloy, so that the The added amount of the second NaOH solution is 3.0 times the mass of the vanadium slag described in step (1). extract.

Example 3:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide an evaporated circulating NaOH solution with an initial temperature of 80°C and a concentration of 50wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 86 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.8:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 220°C, wherein the heating medium is saturated steam with a pressure of 3.7MPa;

Then, the slurry obtained in step (1) is transported to the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported to the pressurized reaction by a centrifugal pump whose impeller material is Ni-Cr-Mo-Cu alloy In the kettle, the added amount of the second NaOH solution is 3.2 times the quality of the vanadium slag described in step (1), and after mixing the two, the oxidative leaching reaction is carried out under the conditions of 0.8 MPa, 180 ° C, and an oxygen partial pressure of 0.50 MPa , to achieve vanadium extraction.

Example 4:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide a freshly prepared NaOH solution with an initial temperature of 88 °C and a concentration of 48 wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 76 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.0:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 215°C, wherein the heating medium is saturated steam with a pressure of 3.0MPa;

Then, the slurry obtained in step (1) is transported into the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported into the pressurized reaction kettle by a centrifugal pump whose impeller material is Ni-Cr alloy, so that the The added amount of the second NaOH solution is 4.0 times the mass of the vanadium slag described in step (1). extract.

Example 5:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide an evaporated circulating NaOH solution with an initial temperature of 110° C. and a concentration of 47wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 70 wt % passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.4:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 200°C, wherein the heating medium is saturated steam with a pressure of 2.0MPa;

Then, the slurry obtained in step (1) is transported into the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported into the pressurized reaction kettle by a centrifugal pump whose impeller material is Ni-Cr alloy, so that the The added amount of the second NaOH solution is 3.6 times the mass of the vanadium slag described in step (1). extract.

Example 6:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide an evaporated circulating NaOH solution with an initial temperature of 105° C. and a concentration of 48wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 88 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.5:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 190°C, wherein the heating medium is saturated steam with a pressure of 3.2MPa;

Then, the slurry obtained in step (1) is transported into the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported into the pressurized reaction kettle by a centrifugal pump whose impeller material is Ni-Cr alloy, so that the The added amount of the second NaOH solution is 3.5 times the mass of the vanadium slag described in step (1). After the two are mixed, the oxidative leaching reaction is carried out under the conditions of 0.95MPa, 165° C., and an oxygen partial pressure of 0.35MPa to achieve vanadium extract.

Example 7:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide an evaporated circulating NaOH solution with an initial temperature of 90° C. and a concentration of 46 wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 72 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.3:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 185°C, wherein the heating medium is saturated steam with a pressure of 2.5MPa;

Then, the slurry obtained in step (1) is transported to the reactor by a diaphragm pump, and the preheated second NaOH solution is transported to the pressurized reactor by a centrifugal pump whose impeller material is Ni-Cr-Mo alloy , the added amount of the second NaOH solution is 3.7 times the mass of the vanadium slag described in step (1), and after the two are mixed, the oxidative leaching reaction is carried out under the conditions of 0.75MPa, 163 ° C, and an oxygen partial pressure of 0.30MPa to achieve Extraction of vanadium.

Example 8:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide an evaporated circulating NaOH solution with an initial temperature of 120 ° C and a concentration of 50 wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 90 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.0:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 220°C, wherein the heating medium is saturated steam with a pressure of 4.0MPa;

Then, the slurry obtained in step (1) is transported into the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported into the pressurized reaction kettle by a centrifugal pump whose impeller material is Ni-Cr alloy, so that the The added amount of the second NaOH solution is 4.0 times the quality of the vanadium slag described in step (1). extract.

Example 9:

The present embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle, and the method comprises the following steps:

Provide an evaporated circulating NaOH solution with an initial temperature of 80 °C and a concentration of 45 wt%, and divide it into A shares and B shares, wherein the A shares are the first NaOH solution, and the B shares are the second NaOH solution;

(1) mixing the first NaOH solution with the vanadium slag with a particle ratio of 74 wt% passing through a 200-mesh sieve to obtain a slurry with a liquid-solid ratio of 1.9:1;

(2) using a pipeline preheater to preheat the second NaOH solution to 180°C, wherein the heating medium is saturated steam with a pressure of 3.5MPa;

Then, the slurry obtained in step (1) is transported into the reaction kettle by a diaphragm pump, and the preheated second NaOH solution is transported into the pressurized reaction kettle by a centrifugal pump whose impeller material is Ni-Cr alloy, so that the The added amount of the second NaOH solution is 3.1 times the mass of the vanadium slag described in step (1). After the two are mixed, the oxidation leaching reaction is carried out under the conditions of 0.60 MPa, 160 ° C, and an oxygen partial pressure of 0.30 MPa, so as to realize the vanadium extract.

Example 10:

The present embodiment provides a method for dual-stream feeding of vanadium slag pressurized leaching reactor, and the method refers to the method in Example 4, and the difference is only that: the liquid-solid ratio of the slurry obtained in step (1) is 0.5: 1.

Example 11:

The present embodiment provides a method for dual-stream feeding of vanadium slag pressurized leaching reactor, and the method refers to the method in Example 2, and the difference is only that: the liquid-solid ratio of the slurry obtained in step (1) is 2.5: 1.

Example 12:

This embodiment provides a method for double-flow feeding of vanadium slag pressure leaching reaction kettle. The method refers to the method in Example 1, except that the impeller of the centrifugal pump in step (2) is made of 316L stainless steel.

The leaching rate of vanadium in Examples 1-12 was measured, and the results are shown in Table 1.

Table 1

Embodiments 1-9 adopt the method of the present invention, and by optimizing the feeding method, the service life of the equipment is improved, and the leaching rate of vanadium is ensured to reach more than 90%, and the maximum can reach more than 97%; The liquid-solid ratio of the slurry formed by mixing alkali liquor and vanadium slag is too small, which makes the slurry transportation very difficult, and the frequency of blockage of the feed pipeline is very high; in Example 11, the slurry liquid-solid ratio formed by mixing the first alkali liquor and vanadium slag If the ratio is too large, the temperature of the slurry reaches 110 °C, and the service life of the rubber diaphragm in the diaphragm pump is shortened from one year to 3 months; Although it has no effect on the vanadium leaching rate, the service life of the impeller of the centrifugal pump is shortened from 6 months to 2 months, which increases the equipment cost.

It can be seen from the above examples that, in the first aspect, the double-stream feeding method of the vanadium slag pressurized leaching reaction kettle of the present invention optimizes the traditional method of first batching and then feeding, and mixes part of the lye with the vanadium slag to form Slurry, and then another part of the lye and the obtained slurry are fed into two streams, so that the feeding process is simpler and more efficient; in the second aspect, the method controls the temperature of the slurry by preparing a vanadium slag slurry with a low liquid-solid ratio. The temperature exceeds 95 °C, so as to meet the requirements of the diaphragm pump for the material conveying temperature, and ensure that the vanadium slag slurry can use a durable diaphragm pump as the feed pump for the pressurized reaction kettle; thirdly, the method uses the diaphragm pump to transport the slurry. In the reaction kettle, it can avoid the loss of the impeller of the traditional conveying pump and prolong the service life of the equipment. The method also adopts the pipeline preheating method to preheat the second lye to the reaction temperature. Containing solid particles, the wear of the impeller of the pump transporting the lye is greatly reduced, and the service life of the pump can also be significantly prolonged; in the fourth aspect, the second lye of the method is heated by the method of steam pipeline preheating, which can not only improve the steam The heating and heat exchange efficiency reduces the preheating cost, and the indirect heat exchange of steam will not affect the alkali concentration of the slurry, so it is an efficient and energy-saving heating method; in the fifth aspect, the vanadium leaching rate guaranteed by the method can be as high as More than 90%, up to more than 97%.

The applicant declares that the present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the present invention's operation, the addition of auxiliary operations, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims (10)

1. A method for double-flow feeding of a vanadium slag pressure leaching reaction kettle is characterized by comprising the following steps:

(1) mixing the first alkali liquor and the vanadium slag to obtain slurry;

(2) and (3) conveying the slurry obtained in the step (1) and the preheated second alkali liquor to a pressurized reaction kettle for oxidation leaching reaction to realize extraction of vanadium.

2. The method of claim 1, wherein the first lye of step (1) comprises NaOH solution;

preferably, the first alkali liquor in the step (1) comprises fresh alkali liquor and/or circulating alkali liquor after evaporation concentration;

preferably, the concentration of the first alkali liquor in the step (1) is 40-50 wt%;

preferably, the initial temperature of the primary alkali solution in the step (1) is 80-120 ℃.

3. The method according to claim 1 or 2, characterized in that the proportion of particles passing through a 200-mesh sieve in the vanadium slag in the step (1) is 70-90 wt%.

4. The method according to any one of claims 1 to 3, wherein the slurry of step (1) has a liquid-to-solid ratio of (1-2) to 1;

preferably, the temperature of the slurry of step (1) does not exceed 95 ℃.

5. The method of any one of claims 1-4, wherein the second alkaline solution of step (2) comprises NaOH solution;

preferably, the second alkali liquor in the step (2) comprises fresh alkali liquor and/or circulating alkali liquor after evaporation concentration;

preferably, the concentration of the second alkali liquor in the step (2) is 40-50 wt%;

preferably, the initial temperature of the second alkali liquor in the step (2) is 80-120 ℃.

6. The method according to any one of claims 1 to 5, wherein the second alkaline solution of step (2) is preheated by a pipeline preheater;

preferably, the heating medium adopted by the pipeline preheater comprises saturated steam;

preferably, the pressure of the saturated steam is not less than 2.0 MPa;

preferably, the temperature of the second alkali liquor after preheating in the step (2) is 180-220 ℃.

7. The method according to any one of claims 1 to 6, characterized in that the amount of the second alkali liquor added in the step (2) is 3 to 5 times of the mass of the vanadium slag in the step (1).

8. The method according to any one of claims 1 to 7, wherein the slurry of step (2) is delivered using a diaphragm pump;

preferably, the second alkaline solution in the step (2) is delivered by a centrifugal pump;

preferably, the impeller of the centrifugal pump is made of Ni-based alloy;

preferably, the Ni-based alloy includes any one of a Ni-Cr alloy, a Ni-Cr-Mo-Cu alloy, a Ni-Cr-Mo alloy, or a Ni-Cr-W alloy, preferably a Ni-Cr alloy.

9. The process according to any one of claims 1 to 8, wherein the pressure of the oxidative leaching reaction of step (2) is 0.6 to 1.0 MPa;

preferably, the temperature of the oxidation leaching reaction in the step (2) is 160-180 ℃;

preferably, the oxidizing gas used in the oxidizing leaching reaction in the step (2) comprises any one or a combination of at least two of oxygen, air or ozone;

preferably, the oxygen partial pressure of the oxidative leaching reaction of step (2) is 0.3-0.5 MPa.

10. Method according to any of claims 1-9, characterized in that the method comprises the steps of:

(1) mixing a first alkali solution with the initial temperature of 80-120 ℃ and the concentration of 40-50 wt% with vanadium slag with the proportion of particles passing through a 200-mesh sieve of 70-90 wt% to obtain slurry with the liquid-solid ratio (1-2): 1;

(2) preheating a second alkali solution with the initial temperature of 80-120 ℃ and the concentration of 40-50 wt% to 180-220 ℃ by adopting a pipeline preheater, wherein the heating medium is saturated steam with the pressure of not less than 2.0 MPa;

and (2) then, conveying the slurry obtained in the step (1) to a reaction kettle by using a diaphragm pump, conveying the preheated second alkali liquor to a pressurized reaction kettle by using a centrifugal pump, wherein the addition amount of the second alkali liquor is 3-5 times of the mass of the vanadium slag in the step (1), and after mixing the second alkali liquor and the vanadium slag, carrying out oxidation leaching reaction under the conditions of 0.6-1.0MPa, 160-180 ℃ and 0.3-0.5MPa of oxygen partial pressure to realize extraction of vanadium.

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