CN112708773A

CN112708773A - Treatment method of petroleum coke hydrogen production ash

Info

Publication number: CN112708773A
Application number: CN202011543320.3A
Authority: CN
Inventors: 叶阑珊; 吕灵灵; 王沿森; 于维钊; 张新功
Original assignee: Qingdao Hui Cheng Environmental Technology Co ltd
Current assignee: Qingdao Hui Cheng Environmental Technology Co ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-04-27
Anticipated expiration: 2040-12-23
Also published as: CN112708773B

Abstract

The application provides a treatment method of petroleum coke hydrogen production ash, and belongs to the technical field of petroleum coke hydrogen production ash treatment. The processing method comprises the following steps: mixing the ash with 2-10% alkali liquor, and carrying out alkali dissolution treatment at 125-180 ℃ to obtain alkali dissolution slag. And (3) placing the alkali-soluble slag in a chlorination reactor, and reacting with chlorine at the temperature of 400-650 ℃ to obtain the flue gas and the chlorination slag. Condensing and recovering the flue gas, and/or adding alkali into the chloride slag washing liquid for recovery. Through alkali treatment, the reaction specific surface area of ash particles during chlorination can be increased, the reaction efficiency of chlorination is improved, and the reaction temperature is reduced at the same time, so that the reaction temperature during chlorination is reduced to be within the melting point temperature of alkali metal chloride, material adhesion is avoided, and heavy metals can be recovered conveniently.

Description

Treatment method of petroleum coke hydrogen production ash

Technical Field

The application relates to the technical field of petroleum coke hydrogen production ash treatment, in particular to a treatment method of petroleum coke hydrogen production ash.

Background

For coal gasification ash or other ash with similar properties, the main treatment mode is secondary utilization after stabilization. The main components of the coal gasification ash comprise carbon, silicon oxide, aluminum oxide, calcium oxide and the like; the main components of the petroleum coke hydrogen production ash comprise carbon, silicon oxide, aluminum oxide, calcium oxide, vanadium oxide, nickel oxide, iron oxide, sodium oxide and the like. Although the petroleum coke hydrogen production process is consistent with the coal hydrogen production process, due to the difference of raw materials, the components of petroleum coke hydrogen production ash and coal gasification ash are different, the components have different forms, heavy metals in petroleum are enriched in the petroleum coke hydrogen production ash, if the heavy metals are directly stabilized, the heavy metals cannot be recovered, so that the resource waste is caused, and the energy consumption of direct stabilization treatment is higher.

Disclosure of Invention

The application aims to provide a treatment method of petroleum coke hydrogen production ash, which can recover heavy metals.

In a first aspect, the present application provides a method for treating petroleum coke hydrogen production ash, comprising: alkali treatment: mixing the ash and the alkali liquor, and carrying out alkali dissolution treatment at the temperature of 125-180 ℃ to obtain alkali dissolution slag, wherein the mass concentration of the alkali liquor is 2-10%. Chlorination treatment: and (3) placing the alkali-soluble slag in a chlorination reactor, and reacting with chlorine at the temperature of 400-650 ℃ to obtain the flue gas and the chlorination slag. And (3) recovery treatment: condensing and recovering the flue gas, and/or adding alkali into the chloride slag washing liquid for recovery.

The temperature of alkali treatment is higher (within the range of 125-180 ℃), and the concentration of alkali liquor in the alkali treatment is lower (the mass concentration is 2-10%), so that on one hand, the silicon-aluminum structure can be improved, the stable aggregation structure in the particles can be damaged, the heavy metal wrapped in the ash particles can be exposed, the specific surface area of subsequent reaction is increased, and the deep removal of the subsequent heavy metal is facilitated; on the other hand, the granular structure with irregular shape can be converted into a particle structure with a sphere-like shape, the fluidization property of the material is improved, the subsequent treatment in a boiling bed chlorination reactor is more suitable, the continuous feeding and continuous deslagging can be realized, the treatment capacity is large, the treatment efficiency is high, the temperature of the chlorination reaction can be reduced, and the temperature is reduced to be within the melting point temperature of the alkali metal chloride, so that the material adhesion in the chlorination reaction is avoided. In the chlorination treatment, the temperature of the chlorination reaction is 400-650 ℃, and the treatment temperature is lower, so that the alkali metal chloride is prevented from being fused and bonded at high temperature; on the other hand, the conversion rate of silicon and aluminum can be greatly reduced, and the primary separation of heavy metal and a matrix is realized. And can obtain flue gas with lower boiling point (vanadium oxychloride, aluminum trichloride, ferric trichloride, and the like) and chloride with higher boiling point (nickel chloride, calcium chloride, sodium chloride, and the like) so as to recover the flue gas and the chloride slag respectively in the following steps, thereby recovering heavy metals.

In one possible embodiment, the time of the alkali-dissolving treatment is 2 to 3 hours. The ash particles can be reacted with the alkali liquor sufficiently to increase the specific surface area of the ash particles and to spheroidize the particle shape for subsequent chlorination.

In one possible embodiment, the lye comprises one or more of a sodium hydroxide solution, a potassium hydroxide solution and a quaternary ammonium base solution. Which can perform alkali dissolution treatment on ash particles to increase the comparative area of the ash particles and spheroidize the particle shape.

In a possible embodiment, before the alkali dissolution treatment, the method further comprises the step of crushing the petroleum coke hydrogen production ash into particles with the average particle size of 50-150 mu m. So that the subsequent ash particles react with the alkali liquor to obtain spherical particles with large specific surface area for subsequent chlorination treatment.

In one possible implementation mode, in the chlorination treatment, the alkali soluble slag is placed in a chlorination reactor, inert gas is introduced into the chlorination reactor, the temperature of the chlorination reactor is raised to 400-650 ℃, and then a gas source is switched to chlorine gas to react to obtain the flue gas and the chlorination slag. Before the reaction temperature is reached, inert gas is firstly introduced to avoid the generation of low-temperature side reaction so as to obtain chloride which is convenient for subsequent treatment.

In one possible embodiment, the alkali soluble slag is continuously fed into the boiling bed chlorination reactor, and the chlorination slag is continuously discharged from the chlorination reactor. After the alkali dissolution treatment, the alkali dissolution slag forms a spheroidal particle structure, so that the fluidization property of the material is improved, the continuous feeding and the continuous slag discharge are facilitated, the treatment capacity is large, and the treatment efficiency is high.

In one possible embodiment, the condensing recovery of the flue gas comprises: and introducing the flue gas generated by the chlorination reactor into a condensing system, and absorbing residual chlorine by using alkali liquor. The flue gas is low-boiling-point chloride (mainly comprising vanadium oxychloride, aluminum trichloride, ferric trichloride and the like), and according to the boiling point difference of each substance, various chlorinated products can be roughly enriched by a condensing system and then further refined and recovered.

In one possible embodiment, the recycling of the chlorination residue washing liquid with alkali comprises: firstly, chlorination residues in a chlorination reactor are placed in water to be mixed to obtain an aqueous solution, the aqueous solution is filtered, and alkali is added into filtrate for precipitation. The chlorination residue contains high boiling point chlorides (mainly including nickel chloride, calcium chloride, sodium chloride and the like), which are all dissolved in water, but unreacted substances such as silicon and aluminum are not dissolved in water, alkali is added into the filtrate for precipitation, so that a crude product of nickel hydroxide can be obtained, and the nickel chloride can be recovered and roughly separated from each alkali metal chloride.

In one possible embodiment, the base comprises one or more of a sodium hydroxide solution, a potassium hydroxide solution, and a quaternary ammonium base solution. So as to precipitate nickel chloride.

In a possible embodiment, after the alkali treatment and before the chlorination treatment, the method further comprises the step of washing and drying the alkali soluble slag. So as to wash the alkali slag completely, remove redundant alkali liquor on the surface and avoid the influence of alkali on chlorination treatment.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments are briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive efforts and also belong to the protection scope of the present application.

FIG. 1 is a flow chart of a method for processing petroleum coke hydrogen production ash provided by the embodiment of the application;

FIG. 2 is an apparent structural view of pulverized ash particles;

FIG. 3 is an apparent structural view of ash particles after washing of alkali slag;

FIG. 4 shows the conversion of the main metal elements after the ash particles are treated by the direct chlorination process.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

In the prior art, titanium dioxide is usually extracted by a chlorination method, and the specific method is as follows: adding TiO into the mixture₂Placing titanium ore (such as natural rutile ore, artificial rutile or high titanium slag) with the content of more than 90% and coke in a fluidized bed chlorination reactor, and introducing chlorine gas into the fluidized bed chlorination reactor, wherein the reaction formula is as follows: TiO 2₂+Cl₂+C→TiCl₄+CO(CO₂). Meanwhile, impurities in the ore also participate in chlorination reaction to generate FeCl₃、SiCl₄、AlCl₃、VOCl₃、MnCl₂、NbCl₅、SnCl₂、MgCl₂And after the gas discharged from the fluidized bed chlorination reactor is cooled to about 200 ℃, most of the chloride containing impurities is condensed on furnace ash and settled, the gas is further condensed to about-12 ℃ through filtration to recover titanium tetrachloride, and the non-condensable gas (CO, CO2, residual chlorine and the like) is absorbed by alkali liquor through a gaseous treatment device and then discharged. However, there are existingIn the technology, the chlorination method is not used for treating the petroleum coke hydrogen production ash.

The petroleum coke hydrogen production ash is ash generated in the petroleum coke hydrogen production process, and mainly comprises carbon, silicon oxide, aluminum oxide, calcium oxide, vanadium oxide, nickel oxide, iron oxide, sodium oxide and the like. The inventor researches and discovers that if the ash is directly subjected to chlorination treatment, the main reaction equation of the chlorination process is as follows:

6NiO+6Cl₂+3C→6NiCl₂+3CO₂

2V₂O₅+6Cl₂+3C→4VOCl₃+3CO₂

2Fe₂O₃+6Cl₂+3C→4FeCl₃+3CO₂

6CaO+6Cl₂+3C→6CaCl₂+3CO₂

Na₂O+Cl₂+C→2NaCl+CO₂

2Al₂O₃+6Cl₂+3C→4AlCl₃+3CO₂

among them, heavy metal chlorides (e.g., VOCl)₃) The boiling point is relatively low, the catalyst can be removed at the chlorination temperature, and the difference of the boiling points is large; the chlorides of nickel, calcium, iron, sodium and the like have high boiling points and can be remained in the chloride slag under the reaction condition and removed in a washing mode.

The ash slag is produced under the reaction condition of high-temperature quenching, so that the ash slag has the characteristics of high carbon content, low specific surface area, high calcium and magnesium content, irregular apparent form, high heavy metal nickel and vanadium content and the like. If the ash is treated by a direct chlorination method, the reaction specific surface area of the ash is small, and part of metal is wrapped by silicate, so that high recovery rate is difficult to obtain.

Furthermore, in order to ensure high recovery rate of each heavy metal, the chlorination reaction temperature needs to be increased, and in the early stage of the chlorination reaction, because alkali metal preferentially generates chlorination reaction, the generated alkali metal chloride has low melting point and high boiling point, and cannot be diffused to a subsequent condensing system at the chlorination reaction temperature, and can be enriched in reaction slag in the reaction process to be in a molten state, so that material adhesion is caused, the contact area between the material and chlorine is reduced, the reaction efficiency is lowered, the material fluidity is poor, even slag can not be discharged, and the continuous operation of the fluidized bed reactor is not facilitated.

Therefore, the application provides a processing method of petroleum coke hydrogen production ash, which can increase the reaction specific surface area of ash particles, improve the reaction efficiency and reduce the temperature required by the reaction at the same time, so that the reaction temperature during the chlorination reaction is reduced to be within the melting point temperature of alkali metal chloride, thereby avoiding material bonding and facilitating the recovery of heavy metals wrapped in a silicon-aluminum structure.

Fig. 1 is a flow chart of a method for processing petroleum coke hydrogen production ash provided in an embodiment of the present application, please refer to fig. 1, and the method includes the following steps:

s10, preprocessing: the petroleum coke hydrogen production ash is crushed into particles with the average particle size of 50-150 mu m. So that the subsequent ash particles react with the alkali liquor to obtain spherical particles with large specific surface area for subsequent chlorination treatment.

S20, alkali treatment: mixing the petroleum coke hydrogen production ash with alkali liquor, and carrying out alkali dissolution treatment at the temperature of 125-180 ℃ to obtain alkali dissolution slag, wherein the mass concentration of the alkali liquor is 2-10%.

The temperature of alkali treatment is higher (within the range of 125-180 ℃), and the concentration of alkali liquor in the alkali treatment is lower (the mass concentration is 2-10%), so that on one hand, the silicon-aluminum structure can be improved, the stable aggregation structure in the particles can be damaged, the heavy metal wrapped in the ash particles can be exposed, the specific surface area of subsequent reaction is increased, and the deep removal of the subsequent heavy metal is facilitated; on the other hand, the granular structure with irregular shape can be converted into a particle structure with a sphere-like shape, the fluidization property of the material is improved, the subsequent treatment in a boiling bed chlorination reactor is more suitable, the continuous feeding and continuous deslagging can be realized, the treatment capacity is large, the treatment efficiency is high, the temperature of the chlorination reaction can be reduced, and the temperature is reduced to be within the melting point temperature of the alkali metal chloride, so that the material adhesion in the chlorination reaction is avoided. Wherein the alkali solution comprises one or more of sodium hydroxide solution, potassium hydroxide solution and quaternary ammonium base solution. For example: the alkali liquor is sodium hydroxide solution, or potassium hydroxide solution, or quaternary ammonium base solution, or a mixture of sodium hydroxide solution and potassium hydroxide solution, or a mixture of sodium hydroxide solution and quaternary ammonium base solution, or a mixture of quaternary ammonium base solution and potassium hydroxide solution, or a mixture of sodium hydroxide solution, potassium hydroxide solution and quaternary ammonium base solution.

Illustratively, the temperature of the alkali-dissolving treatment may be 125 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃ or 180 ℃; the mass concentration of the alkali liquor can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

Further, the time of the alkali dissolution treatment is 2-3 h. The ash particles can be reacted with the alkali liquor sufficiently to increase the specific surface area of the ash particles and to spheroidize the particle shape for subsequent chlorination. For example: the time of the alkali dissolution treatment is 2h, 2.5h or 3 h.

S30, cleaning: and washing the alkali soluble residue and drying. Optionally, the alkali-soluble residue is washed by water (or directly soaked and washed), excess alkali liquor on the surface of the alkali-soluble residue is removed, and then the alkali-soluble residue is dried for chlorination treatment.

S40, chlorination: and (3) placing the alkali dissolving slag (optionally, the cleaned alkali dissolving slag; but not limited to the cleaned alkali dissolving slag) into a chlorination reactor, and reacting with chlorine at 400-650 ℃ to obtain the flue gas and the chlorinated slag.

In the chlorination treatment, the temperature of the chlorination reaction is controlled to be 400-650 ℃, which is lower than the temperature of the ordinary chlorination reaction (lower than the melting point of high-boiling-point chlorides), so that the high-boiling-point low-melting-point chlorides (such as calcium chloride with the melting point of 772 ℃ and sodium chloride with the melting point of 801 ℃) are prevented from being melted and bonded; on the other hand, the conversion rate of silicon and aluminum can be greatly reduced. And can obtain flue gas with lower boiling point (vanadium oxychloride, aluminum trichloride, ferric trichloride, and the like) and chloride with higher boiling point (nickel chloride, calcium chloride, sodium chloride, and the like) so as to recover the flue gas and the chloride slag respectively in the following steps, thereby recovering heavy metals.

Wherein, chlorination is a dry treatment process, and can avoid the problem of wastewater treatment brought by a wet recovery process to a certain extent.

Optionally, the alkali-soluble slag is placed in a chlorination reactor, inert gas (such as argon or/and nitrogen) is introduced, the temperature of the chlorination reactor is raised to 400-650 ℃, and then the gas source is switched to chlorine gas to react to obtain the flue gas and the chlorination slag. For example, the temperature of the chlorination treatment may be 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃ or 650 ℃.

And continuously feeding the alkali-soluble slag into a chlorination reactor, and continuously discharging the chlorination slag from the chlorination reactor. The reaction is a continuous reaction, the ash particles after alkali treatment have better fluidity, so that the continuous feeding can be realized, and after the reaction, the chlorination slag is continuously discharged, so that the feeding is performed again and the reaction is performed with the introduced chlorine, and the continuous production is realized.

S50, recovery treatment: condensing and recovering the flue gas, and adding alkali into the chlorination residue washing liquid for recovery.

Wherein, the mode of flue gas condensation recovery is as follows: and introducing the flue gas generated by the chlorination reactor into a condensing system, and absorbing residual chlorine by using alkali liquor. The flue gas is low-boiling-point chloride (mainly comprising vanadium oxychloride, aluminum trichloride, ferric trichloride and the like), and different substances can be respectively condensed in sequence through a condensing system according to the boiling point difference of each substance, so that the metal chlorides can be enriched and collected.

Optionally, as the main components in the flue gas are vanadium oxychloride, aluminum trichloride, ferric trichloride and the like, the boiling points of the aluminum trichloride and the ferric trichloride are relatively close, and the aluminum trichloride and the ferric trichloride can be condensed together to obtain a mixture, and then the mixture is separated in a sublimation-desublimation mode. Vanadium oxytrichloride can be separately condensed so as to recover the heavy metal vanadium.

The chloride slag washing liquid alkali recovery mode is as follows: firstly, chlorination residues in a chlorination reactor are placed in water to be mixed to obtain an aqueous solution (pulping and washing), filtration is carried out, and alkali is added into filtrate for precipitation.

The chlorination residue comprises substances such as silicon aluminum and the like which are not subjected to chlorination conversion and high-boiling-point chlorides (mainly comprising nickel chloride, calcium chloride, sodium chloride and the like), the high-boiling-point chlorides are completely dissolved in water during pulping and washing, and the filtered residue is the substances such as silicon aluminum and the like which are not subjected to chlorination conversion, and the substances are separated out and can be used as common solid waste or building materials for secondary utilization.

Adding alkali into the filtered filtrate for precipitation to obtain crude nickel hydroxide (nickel chloride reacts to form nickel hydroxide), and separating the nickel chloride from each alkali metal chloride so as to recover heavy metal nickel.

Wherein the base comprises one or more of a sodium hydroxide solution, a potassium hydroxide solution, and a quaternary ammonium base solution. In order to precipitate the heavy metal nickel. Since the water washing is performed in the early stage, a high-concentration alkali solution (for example, the concentration of the alkali solution is 30% -50%, for example, an industrial alkali solution) can be added by a delivery pump. Of course, solid base may also be added, and this application is not limited.

Alternatively, the amount of base added may be controlled, such as: when the pH of the obtained solution is 7 to 10 after the alkali is added to the aqueous solution, the recovery rate of nickel in the aqueous solution is higher.

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Experimental example 1: influence of alkali treatment on apparent structure of ash particles

The petroleum coke hydrogen production ash is crushed into ash particles. Mixing the ash particles with a sodium hydroxide solution with the mass concentration of 4%, and carrying out alkali dissolution at the temperature of 145 ℃ for 2.5h to obtain alkali dissolution slag.

The samples of 3 batches were treated in the above manner, and the specific surface area before and after the alkali treatment of each sample was measured to obtain table 1.

TABLE 1 change in specific surface area of samples before and after alkali treatment

Sample name	Specific surface area/m before alkali treatment²/g	Specific surface area/m after alkali treatment²/g
			Sample
1	3.8	89
			Sample 2	2.3	76
Sample 3	6	103

FIG. 2 is an apparent structural view of pulverized ash particles; FIG. 3 is an apparent structural view of ash particles after washing of alkali slag. As can be seen from fig. 2 and 3, the sample before the alkali treatment is in a block shape, has a smooth surface and a non-porous structure, and is converted into a spherical shape after the alkali treatment, and a large number of porous channels are formed on the surface, and as can be seen from the change of the front and rear specific surface areas of the sample in several experiments in table 1, the specific surface area of the sample can be increased by the alkali treatment, and the fluidity of the sample can be improved by the improvement of the shape of microscopic particles of the sample, so that the sample is more beneficial to the operation of a subsequent fluidized bed chlorination.

Experimental example 2: influence of alkaline treatment on Chlorination

Ball-milling and sieving the hydrogen-making ash of the petroleum coke, controlling different granularity, respectively placing the raw materials with different granularity in a chlorination reactor, introducing nitrogen, heating the chlorination reactor to 600 ℃, and then switching an air source into chlorine gas to react to obtain flue gas and chlorinated slag. And introducing the flue gas into a condensation system for condensation, and absorbing residual chlorine through alkali liquor. And (3) placing the chlorination residues in water to be mixed to obtain an aqueous solution, filtering to obtain filter residues and filtrate, adding alkali into the filtrate for precipitation, drying the filter residues, weighing the total mass of the filter residues and detecting the content of various substances in the filter residues. The conversion of ash with different particle sizes is shown in table 2, and the conversion of main metal elements is shown in figure 4.

TABLE 2 Total conversion of ash of different particle sizes in chlorination

Average particle diameter/. mu.m	Total conversion%
		2.154	29.38
38.313	15.03
		43.588	9.45
56.004	8.57
		77.316	7.96

The particle size distribution of ash from table 2 for different particle sizes is shown in table 3:

TABLE 3 particle size distribution of ash having different particle sizes

Sample name	0-20μm	20-40μm	40-110μm	＞110μm	Dv0.5
						＜10μm	96.88	0.79	2.07	0.26	2.154
30～40μm	16.2	37.13	46.67	0	38.313
						40-50μm	11.87	31.43	56.61	0.09	43.588
50-60μm	8.44	17.05	70.05	4.46	56.004
						70-80μm	5.73	1.74	68.91	23.62	77.316

As can be seen from table 2, the conversion increases gradually with decreasing particle size. As seen from FIG. 4, since the conversion rate of each metal element is generally high at a particle size of 56.004 μm, it is considered that this point does not conform to the general rule, and after removal analysis, the conversion rate of each metal element is significantly high at a particle size of less than 10 μm, and when the particle size is greater than 30 μm, the conversion rate of each metal element decreases gently as the particle size increases. From other total conversion rates, the total conversion rate is obviously higher when the granularity is less than 10 mu m, and the other granularities have small difference. In conclusion, if direct chlorination is selected, the particle size is less than 10 μm to achieve a more desirable conversion.

In the experimental example, the petroleum coke hydrogen production ash is crushed into ash particles with the particle size of about 91.806 μm. The particle size distribution of the ash particles is shown in Table 4:

TABLE 4 particle size distribution of ash particles

Sample name	0-20μm	20-40μm	40-110μm	＞110μm	Dv0.5
						Alkali slag	0	1.14	66.29	33.71	91.806

Mixing the ash particles with a sodium hydroxide solution with the mass concentration of 4%, and carrying out alkali dissolution at the temperature of 145 ℃ for 2.5h to obtain alkali dissolution slag. And washing the alkali soluble residue and drying. And (3) placing the washed alkali-soluble slag into a chlorination reactor, introducing nitrogen, heating the chlorination reactor to 500 ℃, 600 ℃ or 650 ℃, and then switching a gas source into chlorine gas to react to obtain the flue gas and the chlorination slag. And introducing the flue gas into a condensation system for condensation, and absorbing residual chlorine through alkali liquor. The chlorination residue was mixed in water to obtain an aqueous solution, filtered to obtain a residue and a filtrate, an alkali was added to the filtrate to precipitate, the residue was washed and dried, and the total mass of the residue and the contents of various substances thereof (content detection was performed by fluorescence analysis using a fluorescence element analyzer) were measured to obtain table 5.

TABLE 5 results of alkali dissolution-chlorination experiment (average particle size about 91.806 μm)

Remarking: alkali dissolution Process V₂O₅The dissolution rate was about 17%, and the total vanadium conversion was calculated to be 74.76% (500 ℃), 78.53% (600 ℃), 82.16% (650 ℃).

Wherein the total mass of the ash before the alkali treatment is a (the total mass of the raw materials), and the content percentage x of each component is the ratio of the content of each component to a. After alkali treatment and chlorination treatment, the total mass of the finally obtained filter residue is b, and the content percentage y of each component after treatment is the ratio of the content of each component to b. The conversion is calculated as: z is 100% × (a × x-b × y)/a × x.

It should be noted that the silica conversion rate may be negative because the silica is not substantially reacted, and the result may be negative due to the error of fluorescence analysis, which is an inevitable error of experiment, but the experimental data is not problematic.

Through the data in table 5, the total conversion rate can be calculated, which indicates that the ash particles with the average particle size of 90 μm can be directly chloridized (ground to 10 μm) at 600 ℃ after alkali treatment and then chlorinated at 500 ℃, and indicates that the chlorination reaction efficiency is greatly improved by improving the specific surface and improving the apparent form of the raw materials in the alkali treatment process.

As can be seen from comparison of FIG. 4 with Table 5, in FIG. 4, the ash particles having an average particle size of about 30 μm were chlorinated at 600 ℃ to give a vanadium conversion of about 71% and a nickel conversion of about 74%. In Table 5, the conversion of vanadium was 74.13% and the conversion of nickel was 73.63% after alkali treatment and chlorination at 600 ℃ of ash particles having an average particle size of about 90 μm, which almost reached the conversion of vanadium and nickel of ash particles having an average particle size of 30 μm in the direct chlorination reaction. The treatment method provided by the application can effectively improve the conversion rate of chlorination treatment, improve the reaction effect and be beneficial to the recovery of heavy metals.

The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Claims

1. The method for treating the petroleum coke hydrogen production ash is characterized by comprising the following steps:

alkali treatment: mixing the ash and alkali liquor, and carrying out alkali dissolution treatment at the temperature of 125-180 ℃ to obtain alkali dissolution slag, wherein the mass concentration of the alkali liquor is 2-10%;

chlorination treatment: placing the alkali-soluble slag in a chlorination reactor, and reacting with chlorine at the temperature of 400-650 ℃ to obtain smoke and chlorination slag;

and (3) recovery treatment: condensing and recovering the flue gas, and/or adding alkali into the chlorination residue washing liquid for recovery.

2. The treatment process according to claim 1, characterized in that the time of the alkaline dissolution treatment is 2-3 h.

3. The process of claim 1, wherein the lye comprises one or more of a sodium hydroxide solution, a potassium hydroxide solution and a quaternary ammonium base solution.

4. The process of claim 1, further comprising the step of pulverizing the ash to particles having an average particle size of 50 to 150 μm before the alkali-dissolving treatment.

5. The treatment method according to any one of claims 1 to 4, wherein in the chlorination treatment, the alkali-soluble slag is placed in a chlorination reactor, inert gas is introduced into the chlorination reactor, the temperature is raised to 650 ℃, and then a gas source is switched to chlorine gas to react to obtain the flue gas and the chlorination slag.

6. The process according to claim 5, characterized in that said alkaline slag is continuously fed into an ebullated bed chlorination reactor, from which said chlorination slag is continuously discharged.

7. The treatment method according to claim 5, wherein condensing and recovering the flue gas comprises: and introducing the flue gas generated in the chlorination reactor into a condensing system, and absorbing residual chlorine by using alkali liquor.

8. The process of claim 5, wherein the caustic recovery of the chloride slag wash solution comprises: firstly, placing the chlorination residues in the chlorination reactor into water, mixing to obtain an aqueous solution, filtering, and adding alkali into the filtrate for precipitation.

9. The process of claim 8, wherein the base comprises one or more of a sodium hydroxide solution, a potassium hydroxide solution, and a quaternary ammonium base solution.

10. The treatment process according to any one of claims 1 to 4, further comprising, after the alkali treatment and before the chlorination treatment: and washing and drying the alkali soluble slag.