A combined pulping process for gasification fine slag and low-rank / oxidized coal slime

Abstract

The present invention discloses a combined slurrying process for gasification fine slag and low-rank / oxidized coal slime, specifically comprising the following steps: slurrying the gasification fine slag, feeding it into an interference bed separator for sorting and deashing, feeding it into a high-frequency screen for screening and grading to obtain oversize concentrate, oversize tailings, and undersize fine slag; mixing the obtained undersize fine slag with low-rank / oxidized coal slime, and performing reverse flotation to obtain flotation concentrate and flotation tailings; mixing the oversize concentrate and flotation concentrate to obtain a mixed pulp; feeding the mixed pulp into a ball mill for grinding to obtain a finished water-coal slurry; mixing the flotation tailings with the oversize tailings, and feeding it into a filter press for dehydration to obtain a high-ash product. In the present invention, the gasification fine slag is deashed and screened and then mixed with the low-rank / oxidized coal slime after reverse flotation to prepare the water-coal slurry, achieving the comprehensive utilization of two low-value-added products. At the same time, the slurrying process does not require deep dehydration of the gasification fine slag, solving the problem of difficult dehydration of the gasification fine slag and achieving its economic benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal chemical industry, and in particular relates to a combined pulping process of gasified fine slag and low-rank / oxidized coal slime. Background Art

[0002] Coal-water slurry is a low-pollution, high-efficiency, pipeline-transportable coal-based fluid fuel that replaces oil. Its calorific value is equivalent to half that of fuel oil. It can replace fuel oil in boilers, power plants, industrial furnaces and kilns, and can be used to replace coal. It has the advantages of high combustion efficiency, convenient load adjustment, reduced environmental pollution, improved working conditions and coal saving. From the perspective of the long-term development of the coal-water slurry industry, the raw materials for slurry production should be based on low-priced long flame coal, weakly sticky coal, non-sticky coal, lignite and other low-rank coals and high-rank coals such as anthracite, lean coal, lean coal or various solid wastes such as municipal sludge, industrial sludge, flotation coal slime, etc. This will not only improve the economic efficiency of coal-water slurry, but also comply with the national policy of rationally utilizing coal and waste resources.

[0003] Coal gasification fines are solid waste generated during the coal gasification process. They contain some ungasified carbon, heavy metals, and fine particulate matter. Currently, they are primarily disposed of via landfill. However, due to their high carbon content, they still have significant potential for utilization, and carbon-ash separation is key to their reduction and resource utilization. However, gasification fines have a high water content and complex processing, and the separated high-carbon components are difficult to dehydrate due to their well-developed pores. Therefore, the efficient and integrated utilization of solid waste gasification fines and low-rank / oxidized coal slime to prepare coal-water slurries is an economical and environmentally friendly approach to solid waste reuse. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a combined slurrying process for gasification fine slag and low-rank / oxidized coal slime, wherein the gasification fine slag is deashed and pre-screened, and then mixed with low-rank / oxidized coal slime for reverse flotation to prepare water-coal slurry, thereby realizing the comprehensive utilization of two low-value-added products. At the same time, there is no need to deeply dehydrate the gasification fine slag, thereby solving the problem of difficult dehydration of the gasification fine slag and achieving its economic benefits.

[0005] To achieve the above object, the technical solution adopted by the present invention is to provide a combined slurrying process of gasified fine slag and low-rank / oxidized coal slime, comprising the following steps:

[0006] Step 1: Mix the gasified fine slag with water to prepare a slurry, and then send it to an interference bed separator for separation and deashing to obtain concentrate slurry and tailings slurry;

[0007] Step 2: feeding the concentrate slurry obtained in step 1 into a high-frequency sieve for screening and grading, wherein the oversize is the concentrate, and the undersize is the first undersize fine slag; feeding the tailings slurry obtained in step 1 into a high-frequency sieve for screening, wherein the oversize is the tailings, and the undersize is the second undersize fine slag;

[0008] Step 3: mixing the low-rank / oxidized coal slime with the first undersize fine residue and the second undersize fine residue obtained in Step 2, and then performing reverse flotation to obtain flotation concentrate and flotation tailings;

[0009] Step 4: The flotation concentrate obtained in step 3 is sent to a concentrate tank for gravity sedimentation to obtain overflow water and concentrated underflow. The overflow water enters the reverse flotation process in step 3 for recycling. The concentrated underflow and the oversize concentrate obtained in step 2 are sent to a mixing tank for mixing and stirring to obtain a mixed slurry.

[0010] Step 5: Grinding the mixed slurry obtained in step 4 into a ball mill, adding a dispersant and a stabilizer to obtain a finished coal water slurry;

[0011] Step 6: The flotation tailings obtained in step 3 are sent to a tailings pond, mixed with the oversize tailings obtained in step 2, and then sent to a filter press for dehydration to obtain a high-ash product.

[0012] Furthermore, it is characterized in that the sieve hole sizes of the concentrate high-frequency screen and the tailings high-frequency screen in step 2 are both 0.074mm-0.1mm.

[0013] Furthermore, the reverse flotation process in step three includes the following steps:

[0014] Step 301: The low-rank / oxidized coal slime, the first undersize fine residue, and the second undersize fine residue obtained in step 2 are fed into a mixing barrel, water is added, and mixed to obtain a low-rank / oxidized coal slime slurry having a mass percentage concentration of 8% to 15%. A flotation agent is added to the low-rank / oxidized coal slime slurry, and the mixture is fully stirred in a mixing barrel to obtain a stirred low-rank / oxidized coal slime slurry.

[0015] Step 302: feeding the stirred low-rank / oxidized coal slime slurry obtained in step 301 into a flotation machine for aeration and stirring to obtain a foam product and a pulp portion, wherein the pulp portion is a flotation concentrate and the foam portion is a flotation tailings.

[0016] Furthermore, it is characterized in that the flotation agent is an amine collector and an alcohol foaming agent, the amine collector is used to capture the mineral components in the low-order / oxidized coal slime slurry and change the hydrophobicity of the mineral components; the alcohol foaming agent is used to generate bubbles that can float the mineral components.

[0017] Furthermore, the amine collector is dodecylamine, octadecylamine, a mixed amine or coconut amine, and the amount of the amine collector is 0.1-1 kg / t of the dry ore obtained by mixing the low-rank / oxidized coal slime, the first undersize fine slag and the second undersize fine slag; the alcohol foaming agent is 2-octanol or n-butanol, and the mass ratio of the amount of the alcohol foaming agent to the amine collector is 1:5-10.

[0018] Furthermore, the gravity sedimentation in step 4 is to increase the concentration of the flotation concentrate by allowing solid particles in the flotation concentrate to naturally sink under the action of gravity. The mass percentage concentration of the concentrated underflow obtained after gravity sedimentation of the flotation concentrate is 30%-50%.

[0019] Furthermore, the water content in the oversize concentrate obtained in step 2 is 60%-70% by mass.

[0020] Furthermore, the average particle size of the solid particles in the finished coal-water slurry obtained by grinding in the ball mill is less than or equal to 50 μm, wherein particles with a particle size of 74 μm account for 10%-15% of the total mass of the solid particles in the coal-water slurry.

[0021] Furthermore, the mass percentage concentration of the finished coal water slurry obtained in step 5 is 55%-65%, wherein the total mass of the dispersant and the stabilizer accounts for 1%-2% of the mass percentage of the finished coal water slurry.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention combines the characteristics of large specific surface area, high water content, porosity and high ash content of gasification fine slag, adopts gravity sorting method to deash the gasification fine slag, and uses high-frequency screen to dehydrate and grade the gasification fine slag, thereby increasing the carbon content of the concentrate on the screen.

[0024] 2. The present invention improves the utilization rate of carbon components in low-rank / oxidized coal slime and gasification fine slag by mixing the undersize after screening gasification fine slag with low-rank / oxidized coal slime and then performing reverse flotation.

[0025] 3. The present invention prepares a water-coal slurry product by mixing the flotation concentrate of low-rank / flotation coal with the concentrate on the screen of gasification fine slag, which does not require deep dehydration of the gasification fine slag and solves the problem of difficult dehydration of the gasification fine slag.

[0026] 4. The present invention mixes the oversize tailings and flotation tailings and then sends them to a filter press for dehydration. The particle size of the oversize tailings is relatively coarse, and the coarse tailings are dehydrated to effectively solve the problem of difficult dehydration of fine particles. The high-ash product obtained after dehydration can be reused as a building material.

[0027] The present invention is further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0029] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0030] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] like Figure 1 As shown, the present invention provides a combined pulping process for gasified fine slag and high carbon components of low-rank / oxidized coal slime, comprising the following steps:

[0032] Step 1: After the gasified fine slag with a particle size of -0.5mm is fed into a mixing barrel and mixed with water to form a gasified fine slag slurry, the gasified fine slag slurry is fed into an interference bed separator for sorting and deashing to obtain concentrate slurry and tailings slurry. The particle size range of the concentrate slurry and the tailings slurry is both -0.5mm. The overflow product of the interference bed separator is a low-density concentrate slurry, and the underflow product is a high-density tailings slurry. The concentrate slurry separated by the interference bed separator has a high carbon content and is an optimal raw material for preparing water-coal slurry.

[0033] Step 2: The concentrate slurry is fed into a high-frequency concentrate screen for screening and grading. The high-frequency concentrate screen is a high-frequency screen with an adjustable sieve hole size within the range of 0.074 mm to 0.1 mm. The obtained oversize is the concentrate on the sieve, and the undersize is the first undersize fine slag. The tailings slurry is fed into a high-frequency tailings screen for screening. The high-frequency tailings screen is a high-frequency screen with an adjustable sieve hole size within the range of 0.074 mm to 0.1 mm. The obtained oversize is the tailings on the sieve, and the undersize is the second undersize fine slag. Since the high-frequency screen has the functions of dehydration and classification, the high-ash materials that are difficult to separate in the gasification fine slag can be removed through screening and classification, thereby obtaining gasification fine slag with a high carbon content. However, due to the high water content of the gasification fine slag, the water cannot be completely removed by dehydration through the high-frequency screen, so there is still unremoved water in the obtained oversize concentrate. The water content of the oversize concentrate is 60%-70%, while the particle size of the first undersize fine slag and the second undersize fine slag is smaller than the sieve hole size and exists in the form of ore pulp.

[0034] Step 3: Mix the low-rank / oxidized coal slime with the first undersize fine slag and the second undersize fine slag obtained in step 2 and then perform reverse flotation to obtain flotation concentrate and flotation tailings. In order to improve the selectivity of flotation and achieve better flotation effect, the particle size of the low-rank / oxidized coal slime used in the present invention is -0.5 mm. The low-rank / oxidized coal slime can be low-rank coal slime or oxidized coal slime, or a mixed slime of low-rank coal slime and oxidized coal slime in any proportion. In this step, the utilization rate of the gasified fine slag is improved by further reverse flotation deashing of the first undersize fine slag and the second undersize fine slag. Normal flotation of low-rank coal / oxidized coal slime is difficult. Reverse flotation is performed by utilizing its hydrophilicity to further improve flotation efficiency. The flotation concentrate obtained by reverse flotation exists in the form of slurry, which is convenient for concentration adjustment when preparing water-coal slurry product.

[0035] Step 4: The flotation concentrate obtained in step 3 is sent to a concentrate tank for gravity sedimentation to obtain overflow water and concentrated underflow. The overflow water enters the reverse flotation process in step 3 for recycling. The concentrated underflow and the oversize concentrate obtained in step 2 are sent to a mixing tank for mixing and stirring to obtain a mixed slurry. The purpose of gravity sedimentation is to adjust the mass percentage concentration of the flotation concentrate to 30%-50%, that is, the mass percentage concentration of the concentrated underflow is 30%-50%. The gravity sedimentation is carried out in a concentrate tank used for dehydrating high-fine particle materials. The concentration of the flotation concentrate is increased by the natural sinking of solid particles in the flotation concentrate under the action of gravity, thereby achieving the purpose of concentrating the flotation concentrate.

[0036] Step 5: After the mixed ore pulp is fed into a ball mill for grinding, a dispersant and a stabilizer are added to obtain a finished water-coal slurry with a mass percentage concentration of 55%-65%. The average particle size of the water-coal slurry obtained by grinding in the ball mill is less than or equal to 50 μm, and particles with a particle size of 74 μm account for 10%-15% of the total mass of solid particles in the water-coal slurry. The dispersant is added to change the hydrophilicity of the coal surface, reduce the coal-water interfacial tension, and make the coal particles fully wetted and evenly dispersed. The dispersant can be a sulfonate. The stabilizer is added to stably suspend the coal particles in water without hard precipitation. The stabilizer can be a polyacrylate. The total mass of the dispersant and stabilizer accounts for 1%-2% of the mass percentage of the finished water-coal slurry.

[0037] Step 6: Send the flotation tailings into the tailings pond and mix them with the oversize tailings to obtain feed slurry. The particle size of the feed slurry is less than 0.5 mm. The feed slurry is sent to a filter press for dehydration to obtain a high-ash product. The high-ash product refers to a product with an ash content greater than 80%. The high-ash product can be used as a raw material for building materials. The flotation tailings are foam products. Since the preparation of the feed slurry involves a stirring process, the flotation tailings foam can be eliminated by stirring. Therefore, there is no need to perform special defoaming treatment on the foam product. It is only necessary to allow the flotation tailings to defoam naturally during the flow process and to defoam by the mechanical force generated when it falls from a high place into the tailings pond.

[0038] Specifically, the reverse flotation in step 3 is to select the high carbon components in the fine residue under the first sieve, the fine residue under the second sieve, and the low-rank / oxidized coal slime, and separate the useless mineral components in the form of foam, and specifically includes the following steps:

[0039] (1) feeding the first sieve undersize fine residue, the second sieve undersize fine residue and the low-rank / oxidized coal slime into a mixing barrel, adding water and mixing to obtain a low-rank / oxidized coal slime slurry with a mass percentage concentration of 8%-15%, adding a flotation agent to the low-rank / oxidized coal slime slurry and fully stirring in the mixing barrel to obtain a stirred low-rank / oxidized coal slime slurry;

[0040] (2) The stirred low-rank / oxidized coal slime slurry is fed into a flotation machine for aeration and stirring to obtain a foam product and a pulp portion, wherein the pulp portion is a flotation concentrate and the foam portion is a flotation tailing. Aeration refers to the process in which the pulp in the tank is sucked into the impeller blades from all sides through the bottom of the tank by the lower end of the impeller when the impeller rotates. At the same time, the low-pressure air supplied by the blower enters the impeller cavity through the air duct, the air regulating valve, and the hollow main shaft to achieve an aeration effect. The purpose of flotation aeration is to ensure that sufficient air can enter, form bubbles and evenly disperse in the flotation tank, react with the pulp, and separate the minerals from the pulp with the help of bubbles; stirring is to ensure that the pulp entering the flotation machine is fully dispersed in the tank under the stirring action of the impeller, so that the mineral particles in the pulp are suspended without precipitation and evenly distributed, ensuring that they can fully contact with the air reagent and mineralize.

[0041] Wherein, the flotation agent used in reverse flotation is an amine collector and an alcohol foaming agent, the amine collector is a cationic collector, which can be dodecylamine, octadecylamine, mixed amines or coconut amine, and is used to capture the mineral components in the low-order / oxidized coal slime slurry and change the hydrophobicity of the mineral components. The dosage of the amine collector is 0.1-1kg / t of dry ore after mixing the low-order / oxidized coal slime, the first undersize fine slag and the second undersize fine slag. When the amine collector is used, it needs to be made into a water-soluble ammonium salt and then be made into water. The solution is added, and the amine collector has a certain foaming effect. However, since the particle size of the fine residue under the screen is relatively fine, a certain amount of foaming agent still needs to be added. The alcohol foaming agent is used to generate bubbles that can float the mineral components. The foaming agent is directionally adsorbed and distributed on the water-air interface to reduce the surface tension of the aqueous solution, so that the air filled into the water is dispersed into bubbles, making the bubbles more stable. The foaming agent can be 2-octanol or n-butanol. The mass ratio of the amount of the foaming agent to the amount of the collector is 1:5-10.

[0042] Example 1

[0043] Step 1: Mix the gasified fine slag with a particle size of -0.5mm and a water content of 40% with water, prepare a slurry, and then send it into an interference bed separator for separation and deashing to obtain concentrate slurry and tailings slurry;

[0044] Step 2: The concentrate slurry obtained in step 1 is fed into a high-frequency sieve for sieving and grading, and the obtained oversize is the oversize concentrate, and the undersize is the first undersize fine slag, and the water content of the oversize concentrate is 60% by mass; the tailings slurry obtained in step 1 is fed into a high-frequency sieve for sieving, and the obtained oversize is the oversize tailings, and the undersize is the second undersize fine slag;

[0045] Step 3: The low-rank / oxidized coal slime and the first undersize fine slag and the second undersize fine slag obtained in step 2 are fed into a mixing barrel and mixed with water to obtain a low-rank / oxidized coal slime slurry with a mass percentage concentration of 8%. Dodecylamine and 2-octanol are added to the low-rank / oxidized coal slime slurry, wherein the amount of dodecylamine is 0.1 kg / t of the dry ore after the low-rank / oxidized coal slime, the first undersize fine slag and the second undersize fine slag are mixed, and the amount of 2-octanol is 0.02 kg / t of the dry ore after the low-rank / oxidized coal slime, the first undersize fine slag and the second undersize fine slag are mixed. After that, the mixture is fully stirred in a mixing barrel to obtain a stirred low-rank / oxidized coal slime slurry; the stirred low-rank / oxidized coal slime slurry is fed into a flotation machine for aeration and stirring to obtain a foam product and a pulp part, wherein the pulp part is a flotation concentrate and the foam part is a flotation tailings.

[0046] Step 4: The flotation concentrate obtained in step 3 is sent to a concentrate tank for gravity sedimentation to obtain overflow water and a concentrated underflow with a mass percentage concentration of 30%. The overflow water enters the reverse flotation process in step 3 for recycling, and the concentrated underflow and the oversize concentrate obtained in step 2 are sent to a mixing tank for mixing and stirring to obtain a mixed slurry;

[0047] Step 5: Grinding the mixed slurry obtained in step 4 into a ball mill, adding a dispersant and a stabilizer to obtain a finished coal water slurry with a mass percentage concentration of 55%, wherein the total mass of the dispersant and the stabilizer accounts for 1% of the mass percentage of the finished coal water slurry, and the average particle size of the solid particles in the finished coal water slurry is less than 50 μm, wherein particles with a particle size of 74 μm account for 10% of the total mass of the solid particles in the coal water slurry;

[0048] Step 6: The flotation tailings obtained in step 3 are sent to a tailings pond, mixed with the oversize tailings obtained in step 2, and then sent to a filter press for dehydration to obtain a high-ash product.

[0049] Example 2

[0050] Step 1: Mix the gasified fine slag with a particle size of -0.5mm and a water content of 50% with water, prepare a slurry, and then send it into an interference bed separator for separation and deashing to obtain concentrate slurry and tailings slurry;

[0051] Step 2: The concentrate slurry obtained in step 1 is fed into a high-frequency sieve for sieving and grading, the oversize is the oversize concentrate, the undersize is the first undersize fine slag, and the water content of the oversize concentrate is 70% by mass; the tailings slurry obtained in step 1 is fed into a high-frequency sieve for sieving, the oversize is the oversize tailings, and the undersize is the second undersize fine slag;

[0052] Step 3: The low-rank / oxidized coal slime and the first under-sieve fine slag and the second under-sieve fine slag obtained in step 2 are fed into a mixing barrel and mixed with water to obtain a low-rank / oxidized coal slime slurry with a mass percentage concentration of 15%. Octadecylamine and n-butanol are added to the low-rank / oxidized coal slime slurry, wherein the amount of octadecylamine is 1 kg / t of the dry ore after the low-rank / oxidized coal slime, the first under-sieve fine slag and the second under-sieve fine slag are mixed, and the amount of n-butanol is 0.1 kg / t of the dry ore after the low-rank / oxidized coal slime, the first under-sieve fine slag and the second under-sieve fine slag are mixed. After that, the mixture is fully stirred in a mixing barrel to obtain a stirred low-rank / oxidized coal slime slurry; the stirred low-rank / oxidized coal slime slurry is fed into a flotation machine for aeration and stirring to obtain a foam product and a pulp part, wherein the pulp part is a flotation concentrate and the foam part is a flotation tailings.

[0053] Step 4: The flotation concentrate obtained in step 3 is sent to a concentrate tank for gravity sedimentation to obtain overflow water and a concentrated underflow with a mass percentage concentration of 40%. The overflow water enters the reverse flotation process in step 3 for recycling, and the concentrated underflow and the oversize concentrate obtained in step 2 are sent to a mixing tank for mixing and stirring to obtain a mixed slurry;

[0054] Step 5: Grinding the mixed slurry obtained in step 4 into a ball mill, adding a dispersant and a stabilizer to obtain a finished coal water slurry with a mass percentage concentration of 60%, wherein the total mass of the dispersant and the stabilizer accounts for 2% of the mass percentage of the finished coal water slurry, and the average particle size of the solid particles in the finished coal water slurry is less than 50 μm, wherein particles with a particle size of 74 μm account for 15% of the total mass of the solid particles in the coal water slurry;

[0055] Step 6: The flotation tailings obtained in step 3 are sent to a tailings pond, mixed with the oversize tailings obtained in step 2, and then sent to a filter press for dehydration to obtain a high-ash product.

[0056] Example 3

[0057] Step 1: Mix the gasified fine slag with a particle size of -0.5mm and a water content of 60% with water, prepare a slurry, and then send it into an interference bed separator for separation and deashing to obtain concentrate slurry and tailings slurry;

[0058] Step 2: The concentrate slurry obtained in step 1 is fed into a high-frequency sieve for sieving and grading, and the obtained oversize is the oversize concentrate, and the undersize is the first undersize fine slag, and the water content of the oversize concentrate is 65% by mass; the tailings slurry obtained in step 1 is fed into a high-frequency sieve for sieving, and the obtained oversize is the oversize tailings, and the undersize is the second undersize fine slag;

[0059] Step 3: The low-rank / oxidized coal slime and the first undersize fine slag and the second undersize fine slag obtained in step 2 are fed into a mixing barrel and mixed with water to obtain a low-rank / oxidized coal slime slurry with a mass percentage concentration of 10%. A mixed amine and 2-octanol are added to the low-rank / oxidized coal slime slurry, wherein the amount of the mixed amine is 0.5 kg / t of the dry ore after the low-rank / oxidized coal slime, the first undersize fine slag and the second undersize fine slag are mixed, and the amount of the 2-octanol is 0.1 kg / t of the dry ore after the low-rank / oxidized coal slime, the first undersize fine slag and the second undersize fine slag are mixed. After that, the mixture is fully stirred in a mixing barrel to obtain a stirred low-rank / oxidized coal slime slurry; the stirred low-rank / oxidized coal slime slurry is fed into a flotation machine for aeration and stirring to obtain a foam product and a pulp part, wherein the pulp part is a flotation concentrate and the foam part is a flotation tailings.

[0060] Step 4: The flotation concentrate obtained in step 3 is sent to a concentrate tank for gravity sedimentation to obtain overflow water and a concentrated underflow with a mass percentage concentration of 50%. The overflow water enters the reverse flotation process in step 3 for recycling, and the concentrated underflow and the oversize concentrate obtained in step 2 are sent to a mixing tank for mixing and stirring to obtain a mixed slurry;

[0061] Step 5: Grinding the mixed slurry obtained in step 4 into a ball mill, adding a dispersant and a stabilizer to obtain a finished coal water slurry with a mass percentage concentration of 65%, wherein the total mass of the dispersant and the stabilizer accounts for 1.5% of the mass percentage of the finished coal water slurry, and the average particle size of the solid particles in the finished coal water slurry is less than 50 μm, wherein particles with a particle size of 74 μm account for 13% of the total mass of the solid particles in the coal water slurry;

[0062] Step 6: The flotation tailings obtained in step 3 are sent to a tailings pond, mixed with the oversize tailings obtained in step 2, and then sent to a filter press for dehydration to obtain a high-ash product.

[0063] Example 4

[0064] Step 1: Mix the gasified fine slag with a particle size of -0.5mm and a water content of 60% with water, prepare a slurry, and then send it into an interference bed separator for separation and deashing to obtain concentrate slurry and tailings slurry;

[0065] Step 2: The concentrate slurry obtained in step 1 is fed into a high-frequency sieve for sieving and grading, and the obtained oversize is the oversize concentrate, and the undersize is the first undersize fine slag, and the water content of the oversize concentrate is 62% by mass; the tailings slurry obtained in step 1 is fed into a high-frequency sieve for sieving, and the obtained oversize is the oversize tailings, and the undersize is the second undersize fine slag;

[0066] Step 3, the low-order / oxidized coal slime and the first undersieve fine slag and the second undersieve fine slag obtained in step 2 are fed into a stirring barrel and mixed with water to obtain a low-order / oxidized coal slime slurry with a mass percentage concentration of 12%, and coconut amine and n-butanol are added to the low-order / oxidized coal slime slurry, the amount of coconut amine is 0.35kg / t of the dry ore after the low-order / oxidized coal slime, the first undersieve fine slag and the second undersieve fine slag are mixed, and the amount of n-butanol is 0.05kg / t of the dry ore after the low-order / oxidized coal slime, the first undersieve fine slag and the second undersieve fine slag are mixed, and then fully stirred in a stirring barrel to obtain a stirred low-order / oxidized coal slime slurry; the stirred low-order / oxidized coal slime slurry is fed into a flotation machine for aeration and stirring to obtain a foam product and a pulp part, the pulp part is a flotation concentrate, and the foam part is a flotation tailings;

[0067] Step 4: The flotation concentrate obtained in step 3 is sent to a concentrate tank for gravity sedimentation to obtain overflow water and a concentrated underflow with a mass percentage concentration of 45%. The overflow water enters the reverse flotation process in step 3 for recycling, and the concentrated underflow and the oversize concentrate obtained in step 2 are sent to a mixing tank for mixing and stirring to obtain a mixed slurry;

[0068] Step 5: Grinding the mixed slurry obtained in step 4 into a ball mill, adding a dispersant and a stabilizer to obtain a finished coal water slurry with a mass percentage concentration of 58%, wherein the total mass of the dispersant and the stabilizer accounts for 1.8% of the mass percentage of the finished coal water slurry, and the average particle size of the solid particles in the finished coal water slurry is less than 50 μm, wherein particles with a particle size of 74 μm account for 12% of the total mass of the solid particles in the coal water slurry;

[0069] Step 6: The flotation tailings obtained in step 3 are sent to a tailings pond, mixed with the oversize tailings obtained in step 2, and then sent to a filter press for dehydration to obtain a high-ash product.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A combined slurrying process of gasified fine slag and low-rank / oxidized coal slime, characterized in that: The following steps are involved: Step 1: Mix the gasified fine slag with water to prepare a slurry, and then send it to an interference bed separator for separation and deashing to obtain concentrate slurry and tailings slurry; Step 2: feeding the concentrate slurry obtained in step 1 into a high-frequency sieve for screening and grading, wherein the oversize is the concentrate, and the undersize is the first undersize fine slag; feeding the tailings slurry obtained in step 1 into a high-frequency sieve for screening, wherein the oversize is the tailings, and the undersize is the second undersize fine slag; Step 3: mixing the low-rank / oxidized coal slime with the first undersize fine residue and the second undersize fine residue obtained in Step 2, and then performing reverse flotation to obtain flotation concentrate and flotation tailings; Step 4: The flotation concentrate obtained in step 3 is sent to a concentrate tank for gravity sedimentation to obtain overflow water and concentrated underflow. The overflow water enters the reverse flotation process in step 3 for recycling. The concentrated underflow and the oversize concentrate obtained in step 2 are sent to a mixing tank for mixing and stirring to obtain a mixed slurry. Step 5: Grinding the mixed slurry obtained in step 4 into a ball mill, adding a dispersant and a stabilizer to obtain a finished coal water slurry; Step 6: The flotation tailings obtained in step 3 are sent to a tailings pond, mixed with the oversize tailings obtained in step 2, and then sent to a filter press for dehydration to obtain a high-ash product.

2. The pulping process according to claim 1, characterized in that: The sieve hole sizes of the concentrate high-frequency screen and the tailings high-frequency screen in the step 2 are both 0.074mm-0.1mm.

3. The pulping process according to claim 1, characterized in that: The reverse flotation process in step 3 comprises the following steps: Step 301: The low-rank / oxidized coal slime, the first undersize fine residue, and the second undersize fine residue obtained in step 2 are fed into a mixing barrel, water is added, and mixed to obtain a low-rank / oxidized coal slime slurry having a mass percentage concentration of 8% to 15%. A flotation agent is added to the low-rank / oxidized coal slime slurry, and the mixture is fully stirred in a mixing barrel to obtain a stirred low-rank / oxidized coal slime slurry. Step 302: feeding the stirred low-rank / oxidized coal slime slurry obtained in step 301 into a flotation machine for aeration and stirring to obtain a foam product and a pulp portion, wherein the pulp portion is a flotation concentrate and the foam portion is a flotation tailings.

4. The pulping process according to claim 3, characterized in that: The flotation agents are amine collectors and alcohol foaming agents. The amine collectors are used to capture mineral components in low-order / oxidized coal slime slurry and change the hydrophobicity of the mineral components; the alcohol foaming agents are used to generate bubbles that can float the mineral components.

5. The pulping process according to claim 4, characterized in that: The amine collector is dodecylamine, octadecylamine, a mixed amine or coconut amine, and the amount of the amine collector is 0.1-1 kg / t of the dry ore obtained by mixing the low-rank / oxidized coal slime, the first undersize fine slag and the second undersize fine slag; the alcohol foaming agent is 2-octanol or n-butanol, and the mass ratio of the amount of the alcohol foaming agent to the amine collector is 1:5-10.

6. The pulping process according to claim 1, characterized in that: The gravity sedimentation in step 4 is to increase the concentration of the flotation concentrate by allowing solid particles in the flotation concentrate to naturally sink under the action of gravity. The mass percentage concentration of the concentrated underflow obtained after gravity sedimentation of the flotation concentrate is 30%-50%.

7. The pulping process according to claim 6, characterized in that: The water content in the oversize concentrate obtained in step 2 is 60%-70% by mass.

8. The pulping process according to claim 7, characterized in that: The average particle size of solid particles in the finished coal-water slurry obtained by grinding with the ball mill is less than or equal to 50 μm, wherein particles with a particle size of 74 μm account for 10%-15% of the total mass of solid particles in the coal-water slurry.

9. The pulping process according to any one of claims 1 to 8, characterized in that: The mass percentage concentration of the finished coal water slurry prepared in step 5 is 55%-65%, wherein the total mass of the dispersant and the stabilizer accounts for 1%-2% of the mass percentage of the finished coal water slurry.

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