Carbon powder waste residue recycling method, cement clinker raw material and application

Abstract

The invention provides a carbon powder waste residue recycling method, a cement clinker raw material and application. The method comprises the following steps: mixing the carbon powder waste residue and a mineral material, and then stacking and curing to obtain a cement clinker raw material; wherein the mineral material comprises at least one of calcium carbonate, calcium oxide, calcium hydroxide, carbide slag and bauxite. According to the method, the acidic substances in the carbon powder waste residues are neutralized and fixed by using the mineral materials, the acidic substances are fully neutralized and fixed through the stacking and curing step, and the finally prepared material can be used as a cement clinker raw material.

Description

Technical Field

[0001] The invention belongs to the technical field of battery recycling and relates to a method for recycling carbon powder waste residue, cement clinker raw materials and applications. Background Art

[0002] Lithium iron phosphate battery is a lithium-ion battery with lithium iron phosphate as the positive electrode material, and the negative electrode material is usually carbon material, such as graphite. With the development of technology and the expansion of market scale, the cost of lithium iron phosphate battery has gradually decreased. Compared with other lithium batteries, its raw material cost and manufacturing cost are relatively low, and it has better economy. In high temperature environment, the performance of lithium iron phosphate battery is relatively stable, and it can maintain low internal resistance and high cycle life. It can still provide stable battery performance under high temperature conditions and is not prone to problems such as thermal runaway. It does not contain rare metals and toxic substances, is environmentally friendly, and the materials can be recycled, which meets the requirements of sustainable development.

[0003] When recycling lithium iron phosphate batteries, the positive and negative electrodes are usually processed together to obtain lithium iron phosphate black powder, the main components of which include lithium iron phosphate, carbon powder and binder, and may also contain a small amount of electrolyte and metal impurities. Usually, lithium is first extracted from the lithium iron phosphate black powder, and the lithium element is extracted for recycling to obtain lithium extraction liquid and lithium extraction waste residue; then the lithium extraction waste residue is used as a raw material for acid leaching to obtain acid leaching liquid and a large amount of carbon powder waste residue, and then a series of operations are performed on the acid leaching liquid to prepare iron phosphate, realizing resource recycling. However, the treatment method for the generated carbon powder waste residue has yet to be developed. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for recycling carbon powder waste, a cement clinker raw material and its application. The present invention uses mineral materials to neutralize and fix the acidic substances in the carbon powder waste, and the acidic substances are fully neutralized and fixed through the steps of stacking and maturation, and the final material can be used as a cement clinker raw material.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for recycling carbon powder waste residue, the method comprising:

[0007] The carbon powder waste residue is mixed with mineral materials, and then piled and matured to obtain cement clinker raw materials; wherein the mineral materials include at least one of calcium carbonate, calcium oxide, calcium hydroxide, carbide slag and bauxite.

[0008] It should be noted that after acid leaching using lithium extraction waste residue as raw material, the obtained carbon powder waste residue must contain acidic substances.

[0009] For example, when sulfuric acid is used for acid leaching, the acidic substances in the carbon powder waste residue are mainly phosphates (such as iron phosphate, aluminum phosphate, etc.) and adsorbed sulfuric acid and sulfates (such as iron sulfate, aluminum sulfate, etc.). When hydrochloric acid is used for acid leaching, the acidic substances in the carbon powder waste residue are mainly phosphates (such as iron phosphate, aluminum phosphate, etc.) and adsorbed hydrochloric acid and chlorides (such as iron chloride, aluminum chloride, etc.). If other acids are used for acid leaching, the acidic substances in the obtained carbon powder waste residue are similar.

[0010] The present invention utilizes mineral materials to neutralize and fix the acidic substances in the carbon powder waste slag, and focuses on neutralizing and fixing the phosphate therein; the acidic substances are fully neutralized and fixed through the stacking and aging steps, and the finally obtained material can be used as cement clinker raw material.

[0011] Preferably, the toner waste residue is pre-treated before being mixed with the mineral material.

[0012] The present invention removes part of the acidic substances in the carbon powder waste residue, mainly adsorbed acid and adsorbed salt, through the pretreatment step. Then, the remaining acidic substances in the carbon powder waste residue, mainly phosphate and adsorbed acid and adsorbed salt remaining after the pretreatment, are fully neutralized and fixed by using mineral materials and stacking and aging operations, with the focus on neutralizing and fixing phosphate.

[0013] Preferably, the pretreatment comprises washing and solid-liquid separation performed sequentially.

[0014] Preferably, the pretreatment specifically includes the following steps: washing the carbon powder waste residue until the conductivity of the washing liquid is less than 200 μS / cm (for example, it can be 190 μS / cm, 150 μS / cm, 100 μS / cm or 50 μS / cm, etc.), and then performing solid-liquid separation until the liquid mass content in the solid product is less than 30% (for example, it can be 29%, 25%, 20%, 15% or 10%, etc.).

[0015] In the present invention, if the conductivity of the washing liquid after washing the carbon powder waste residue is too high, the adsorbed acid and adsorbed salt content in the washed carbon powder waste residue is relatively high, which has a certain impact on the back-end processing equipment and application.

[0016] In the present invention, if the liquid mass content in the solid product after solid-liquid separation is too high, it will lead to difficulty in mixing with mineral materials and difficulty in grinding during back-end application; at the same time, it will reduce the calorific value of the material.

[0017] Preferably, the detergent used in the washing comprises water.

[0018] Preferably, the particle size of the mineral material is less than 100 cm, for example, it can be 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm or 90 cm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] In the present invention, if the particle size of the mineral material is too large, it will lead to difficulties in mixing and grinding in the back-end application.

[0020] Preferably, the mass ratio of the pretreated carbon powder waste residue to the mineral material is 1:(0.5-2), for example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 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 or 1:2, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] In the present invention, when the mass ratio of the pretreated carbon powder waste slag and the mineral material meets the above range, it is conducive to fully neutralizing and fixing the acidic substances in the carbon powder waste slag, making it easier to grind when used in the back end; at the same time, it ensures that the applied product has a higher calorific value. If the mass ratio of the pretreated carbon powder waste slag and the mineral material is low, it will affect the calorific value of the applied product; if the mass ratio is high, although it will increase the calorific value of the applied product, the viscosity of the obtained cement clinker raw material is too high, resulting in too much difficulty in grinding, and easy blockage when making the applied product.

[0022] Preferably, the stacking and maturation time is 5 to 30 days, for example, it can be 5 days, 6 days, 8 days, 10 days, 12 days, 15 days, 18 days, 20 days, 22 days, 25 days, 28 days or 30 days, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] The stacking and aging step of the present invention is mainly used for volatilization and homogenization of water, and fully neutralization and fixation of acidic substances in the carbon powder waste residue.

[0024] In the present invention, if the stacking and aging time is too long, additional stacking space is required, which increases costs; if the stacking and aging time is too short, the materials are unevenly mixed and the water volatilization is poor, which affects the calorific value. Considering the site cost and calorific value, the time range specified in this application is preferred.

[0025] It should be noted that the present invention does not limit the temperature of the stacking and aging, and the stacking can be placed in a natural environment. For example, the stacking can be placed in a natural environment with a temperature of -15 to 40°C.

[0026] Preferably, after the stacking and ripening, a crushing step is performed.

[0027] Preferably, the particle size of the cement clinker raw material is less than 30 cm, for example, it can be 29 cm, 28 cm, 25 cm, 20 cm, 15 cm, 10 cm or 5 cm, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] As a preferred technical solution of the present invention, the method specifically comprises the following steps:

[0029] (1) The carbon powder waste residue is washed with water until the conductivity of the washing liquid is less than 200 μS / cm, and then filtered until the water content in the filter cake is less than 30% by weight.

[0030] (2) The filter cake and the mineral material are mixed, and then piled in a natural environment for aging for 5 to 30 days, and then crushed to obtain a cement clinker raw material with a particle size of less than 30 cm; wherein the mineral material includes at least one of calcium carbonate, calcium oxide, calcium hydroxide, carbide slag and bauxite; the particle size of the mineral material is less than 100 cm; and the mass ratio of the filter cake to the mineral material is 1:(0.5-2).

[0031] In a second aspect, the present invention provides a cement clinker raw material, which is prepared by the method described in the first aspect.

[0032] In a third aspect, the present invention provides a cement clinker, wherein the raw material of the cement clinker includes the cement clinker raw material described in the second aspect.

[0033] The cement clinker raw material prepared by the present invention is added to raw materials to prepare cement clinker. Since the carbon powder contained in the cement clinker raw material itself has a calorific value (not less than 4000 kcal / kg), the coal consumption can be effectively reduced, and the calorific value of the cement clinker product can be increased. The calorific value of the prepared cement clinker product is not less than 1000 kcal / kg.

[0034] Preferably, the raw material also includes a calcium source, an iron source, a silicon source and an aluminum source.

[0035] The present invention does not limit the specific types of calcium source, iron source, silicon source and aluminum source. For example, the calcium source may be limestone or carbide slag; the iron source may be iron powder, steel slag or iron ore tailings; the silicon source may be clay, sandstone or fly ash; the aluminum source may be clay, bauxite or coal gangue.

[0036] Preferably, based on the total mass of the raw materials as 100%, the mass fraction of the cement clinker raw materials is 10-20%, for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Exemplarily, the present invention provides a method for preparing cement clinker, comprising the following steps:

[0038] The calcium source, iron source, silicon source, aluminum source and the cement clinker raw material are mixed and ground to obtain raw meal; and then the raw meal is sintered in stages to obtain cement clinker.

[0039] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention utilizes mineral materials to neutralize and fix the acidic substances in the carbon powder waste slag, with an emphasis on neutralizing and fixing the phosphates (such as iron phosphate, aluminum phosphate, etc.) therein; the acidic substances are fully neutralized and fixed through the steps of stacking and maturation, and the final material obtained can be used as a cement clinker raw material.

[0042] The cement clinker raw material prepared by the present invention is added to raw materials to prepare cement clinker. Since the carbon powder contained in the cement clinker raw material itself has calorific value, coal consumption can be effectively reduced, and the calorific value of the cement clinker product can be increased. The calorific value of the prepared cement clinker product is not less than 1000 kcal / kg. DETAILED DESCRIPTION

[0043] The technical scheme of the present invention is further described below by specific implementation methods. For ease of understanding the present invention, the present invention lists the following embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0044] Example 1

[0045] This embodiment provides a method for recycling carbon powder waste residue, comprising the following steps:

[0046] (1) The carbon powder waste residue is washed with water until the conductivity of the washing liquid is 150 μS / cm to remove impurities therein, and then filtered until the water content in the filter cake is 20% by weight.

[0047] (2) Mechanically mixing the filter cake and calcium carbonate with a particle size of less than 100 cm, with a mass ratio of the filter cake to calcium carbonate being 1:1.5, and then stacking and aging in a natural environment at a temperature of 25±5°C for 18 days, and then crushing to obtain a cement clinker raw material with a particle size of less than 30 cm.

[0048] Example 2

[0049] This embodiment provides a method for recycling carbon powder waste residue, comprising the following steps:

[0050] (1) The carbon powder waste residue is washed with water until the conductivity of the washing liquid is 100 μS / cm to remove impurities therein, and then filtered until the water content by mass in the filter cake is 25%.

[0051] (2) The filter cake and calcium oxide with a particle size of less than 80 cm are mechanically mixed in a mass ratio of 1:1, and then piled and matured in a natural environment at a temperature of 25±5°C for 20 days, and then crushed to obtain a cement clinker raw material with a particle size of less than 30 cm.

[0052] Example 3

[0053] This embodiment provides a method for recycling carbon powder waste residue, comprising the following steps:

[0054] (1) The carbon powder waste residue is washed with water until the conductivity of the washing liquid is 80 μS / cm to remove impurities therein, and then filtered until the water content by mass in the filter cake is 15%.

[0055] (2) The filter cake and bauxite with a particle size of less than 50 cm are mechanically mixed, with a mass ratio of the filter cake to the bauxite being 1:1.8, and then piled and aged in a natural environment at a temperature of 25±5°C for 10 days, and then crushed to obtain a cement clinker raw material with a particle size of less than 30 cm.

[0056] Example 4

[0057] The difference between this embodiment and embodiment 1 is that in step (1), washing is performed until the conductivity of the washing liquid is 250 μS / cm.

[0058] The remaining parameters remain the same as those in Example 1.

[0059] Example 5

[0060] The difference between this embodiment and embodiment 1 is that the water content by mass in the filter cake after pressure filtration in step (1) is 35%.

[0061] The remaining parameters remain the same as those in Example 1.

[0062] Example 6

[0063] The difference between this embodiment and embodiment 1 is that in step (2), the mass ratio of filter cake to calcium carbonate is 1:2.2.

[0064] The remaining parameters remain the same as those in Example 1.

[0065] Example 7

[0066] The difference between this embodiment and embodiment 1 is that the stacking and aging time is 3 days.

[0067] The remaining parameters remain the same as those in Example 1.

[0068] Example 8

[0069] The difference between this embodiment and embodiment 1 is that the carbon powder waste residue is not washed with water and filtered, but is directly mixed with the mineral material.

[0070] The remaining parameters remain the same as those in Example 1.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 3 is that bauxite is replaced by kaolin.

[0073] The remaining parameters remain the same as those in Example 3.

[0074] Application Example 1

[0075] This application example provides a method for preparing cement clinker, comprising the following steps:

[0076] The cement clinker raw material, limestone, iron powder and clay of Example 1 are mixed and ground to obtain raw material; wherein, based on the total mass of the cement clinker raw material, limestone, iron powder and clay being 100%, the mass fraction of the cement clinker raw material is 10%; and the mass ratio of limestone, iron powder and clay is 80:5:15.

[0077] The raw material is fed into a rotary kiln for sintering, wherein the temperature of the feed preheating section is 200°C, the temperature of the middle equalizing section is 600°C, and the temperature of the outlet sintering section is 1450°C; after sintering, cement clinker is obtained.

[0078] Application Example 2-8

[0079] The difference from Application Example 1 is that the cement clinker raw material of Example 1 is replaced by the cement clinker raw materials of Example 2, Example 3, Example 4, Example 5, Example 6, Example 7 and Example 8 respectively.

[0080] Comparative application example 1

[0081] The difference between this comparative application example and application example 1 is that the cement clinker raw material of embodiment 1 is replaced by the cement clinker raw material of comparative example 1.

[0082] test

[0083] The calorific value of the cement clinker prepared in the above application example and the comparative application example was tested by oxygen bomb calorimetry.

[0084] The specific method is as follows: weigh 1g of cement clinker sample and grind it thoroughly to ensure its complete combustion. Put the sample into the crucible of the oxygen bomb, connect the ignition wire, then seal the oxygen bomb and fill it with 2.5MPa of oxygen. Put the oxygen-filled oxygen bomb into the inner cylinder of the calorimeter, add a certain amount of water, connect the temperature sensor and stirrer and other devices, start the test program, and record the temperature change data.

[0085] Data processing: Based on the measured temperature change, specific heat capacity of water, heat capacity of oxygen bomb and sample mass and other parameters, the calorific value of cement clinker is calculated according to the corresponding calculation formula.

[0086] The test results are shown in Table 1.

[0087] Table 1

[0088] Calorific value (kcal / kg) Application Example 1 1700 Application Example 2 1800 Application Example 3 1300 Application Example 4 1650 Application Example 5 1530 Application Example 6 1100 Application Example 7 1500 Application Example 8 980 Comparative application example 1 900

[0089] analyze:

[0090] It can be seen from Application Examples 1-3 that the cement clinker product prepared by the present invention is added to raw materials and has a higher calorific value.

[0091] It can be seen from Application Examples 1 and 4 that if the conductivity of the washing liquid after washing in step (1) is too high, the calorific value of the cement clinker product produced will decrease.

[0092] It can be seen from Application Examples 1 and 5 that if the moisture content of the filter cake after the pressure filtration in step (1) is too high, the calorific value of the cement clinker product produced will be reduced.

[0093] It can be seen from Application Examples 1 and 6 that if the mass ratio of filter cake to calcium carbonate is too low, the calorific value of the cement clinker product will decrease.

[0094] It can be seen from Application Examples 1 and 7 that if the stacking and maturation time is too short, the materials will be unevenly mixed and the water will evaporate poorly, thus affecting the calorific value of the cement clinker product.

[0095] It can be seen from Application Examples 1 and 8 that if the carbon powder waste residue is not washed and filtered, but directly mixed with mineral materials, the calorific value of the final cement clinker product will decrease.

[0096] It can be seen from Application Example 3 and Comparative Application Example 1 that when kaolin is mixed with filter cake for stacking and maturation, it is difficult for kaolin to fix phosphate, so the prepared cement clinker raw materials still contain acidic substances, which have too high viscosity, making grinding too difficult and easily causing blockage when making cement clinker products; at the same time, the remaining acidic substances will react with other raw materials, resulting in a lower calorific value of the final cement clinker product.

[0097] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recycling carbon powder waste residue, characterized in that: The method comprises: The carbon powder waste residue is mixed with mineral materials, and then piled and aged to obtain cement clinker raw materials; Wherein, the mineral material includes at least one of calcium carbonate, calcium oxide, calcium hydroxide, carbide slag and bauxite.

2. The method according to claim 1, characterized in that Before mixing the toner waste residue with the mineral material, pre-treating the toner waste residue; Preferably, the pretreatment comprises washing and solid-liquid separation performed sequentially.

3. The method according to claim 2, characterized in that The pretreatment specifically comprises the following steps: The carbon powder waste residue is washed until the conductivity of the washing liquid is less than 200 μS / cm, and then solid-liquid separation is performed until the liquid mass content in the solid product is less than 30%.

4. The method according to any one of claims 1 to 3, characterized in that: The particle size of the mineral material is <100 cm.

5. The method according to any one of claims 2 to 4, characterized in that: The mass ratio of the pretreated carbon powder waste residue to the mineral material is 1:(0.5-2).

6. The method according to any one of claims 1 to 5, characterized in that: The stacking and aging time is 5 to 30 days; Preferably, after the stacking and aging, a crushing step is performed; Preferably, the particle size of the cement clinker raw material is less than 30 cm.

7. The method according to any one of claims 1 to 6, characterized in that: The method specifically comprises the following steps: (1) washing the carbon powder waste residue with water until the conductivity of the washing liquid is less than 200 μS / cm, and then filtering the residue with pressure until the water content in the filter cake is less than 30% by weight; (2) The filter cake and the mineral material are mixed, and then piled in a natural environment for aging for 5 to 30 days, and then crushed to obtain a cement clinker raw material with a particle size of less than 30 cm; wherein the mineral material includes at least one of calcium carbonate, calcium oxide, calcium hydroxide, carbide slag and bauxite; the particle size of the mineral material is less than 100 cm; and the mass ratio of the filter cake to the mineral material is 1:(0.5-2).

8. A cement clinker raw material, characterized in that: The cement clinker raw material is prepared by the method described in any one of claims 1-7.

9. A cement clinker, characterized in that: The raw material of the cement clinker includes the cement clinker raw material according to claim 8.

10. The cement clinker according to claim 9, characterized in that: The raw material also includes a calcium source, an iron source, a silicon source and an aluminum source; Preferably, based on the total mass of the raw materials being 100%, the mass fraction of the cement clinker raw materials is 10-20%.