Method for preparing sludge conditioner through resource utilization of aluminum sludge and sludge conditioner

Abstract

The invention relates to the technical field of water purification and sludge treatment, in particular to a method for preparing a sludge conditioner through resource utilization of aluminum sludge and the sludge conditioner. The method comprises the following steps: (1) uniformly mixing hydrochloric acid and aluminum sludge for reaction to obtain sludge conditioner primary liquid; (2) adding a precipitator into the sludge conditioner primary liquid to remove impurities, and then adding calcium aluminate powder to react to obtain a sludge conditioner crude product; and (3) carrying out filter pressing on the sludge conditioner crude product, cooling and removing impurities to obtain the sludge conditioner. The method provided by the invention realizes efficient resource comprehensive utilization of the aluminum sludge, solves the problem of secondary residues caused by crystallization precipitation of a sludge conditioner product prepared from the aluminum sludge, can effectively improve the dehydration performance of the product on the sludge, further reduces the overall cost of subsequent sludge treatment, and is simple in process, simple and convenient to operate, low in cost and suitable for industrial production. The industrial production is realized, and the method has important economic and environmental significance.

Description

Technical Field

[0001] The invention relates to the technical field of water purification and sludge treatment, and in particular to a method for preparing a sludge conditioner by resource utilization of aluminum sludge and the sludge conditioner. Background Art

[0002] Aluminum sludge is a solid waste generated during the production and processing of aluminum. It is composed of fine aluminum particles, inorganic salts, organic additives and water. With the increasingly stringent environmental regulations, the requirements for the treatment and disposal of aluminum sludge are getting higher and higher. At the same time, aluminum sludge contains valuable metal aluminum and other resources, which has the potential for reuse. Therefore, turning aluminum sludge into resources and converting environmental risks into economic value has become an important research topic.

[0003] In the existing technology, the use of chemical treatment to convert aluminum sludge into sludge conditioner has been proven to achieve the recycling of aluminum resources, thereby reducing the pressure on the disposal of aluminum sludge and also helping to save limited aluminum resources. However, in the process of preparing aluminum sludge into sludge conditioner products, there is a crystallization problem, that is, sulfate crystals gradually precipitate and may cause blockage of pipelines, pumps and drug storage tanks, and seriously affect the stability and use effect of the product. How to solve this crystallization problem is a key problem in the current industry, which is still in the experimental exploration stage and has not yet been applied to actual production.

[0004] Therefore, it is of great economic and environmental significance to develop efficient and low-cost aluminum mud resource utilization technology and solve the crystallization problem. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. The method provided by the present invention makes full use of the resource advantage of solid waste aluminum sludge as a raw material, and innovatively designs the purification process for the crystallization problem of the prepared product, solves the secondary residue problem caused by the crystallization of the sludge conditioner product prepared from aluminum sludge, and can effectively improve the dehydration performance of the product on the sludge, thereby reducing the overall cost of subsequent sludge disposal, realizing the efficient resource utilization of aluminum sludge, helping to improve the recycling rate of aluminum sludge resources, reducing adverse effects on the environment, and promoting technological progress in the field of sludge conditioners. The preparation method has simple process, easy operation, low cost, and realizes industrial production. It has broad application prospects and important economic and environmental significance.

[0006] In a first aspect, the present invention provides a method for preparing a sludge conditioner by utilizing aluminum sludge as a resource, the method comprising:

[0007] (1) mixing hydrochloric acid and aluminum sludge to react and obtain a primary liquid of sludge conditioning agent;

[0008] (2) adding a precipitant to the primary liquid of the sludge conditioner to remove impurities, and then adding calcium aluminate powder to react to obtain a crude sludge conditioner;

[0009] (3) The crude product of the sludge conditioner is subjected to filter pressing, cooling and impurity removal to obtain the sludge conditioner.

[0010] The method provided by the present invention is based on the resource utilization of aluminum sludge to prepare sludge conditioners. Through technological innovation, the product is purified, and the impurity removal by precipitant and cooling is combined to substantially solve the subsequent crystallization precipitation problem caused by the preparation of sludge conditioner products by aluminum sludge. It can also effectively improve the dewatering performance of the product on sludge, thereby reducing the overall cost of subsequent sludge disposal, realizing the efficient resource utilization of aluminum sludge, and promoting technological progress in the field of sludge conditioners. The method has simple process, easy operation, and low cost, and realizes industrial production, providing a new solution for the high-efficiency water purifier and sludge treatment industries, with broad application prospects and important economic and environmental significance.

[0011] As a preferred technical solution of the present invention, the basicity of the primary solution of the sludge conditioner is -10 to 10%, for example, -10%, -5%, 5%, 10%, etc.

[0012] When the basicity of the primary solution of the sludge conditioner is within the above range of the present invention, it is helpful to filter out more secondary crystal residues, so that the sludge conditioner finally prepared by the present invention has a more excellent sludge conditioning performance. If the primary solution of the sludge conditioner does not reach the above index, it can be adjusted by adding an appropriate amount of hydrochloric acid or aluminum mud until the basicity index of the primary solution of the sludge conditioner is within the above range.

[0013] As a preferred technical solution of the present invention, the mass ratio of HCl in the hydrochloric acid to the equivalent alumina in the aluminum mud is 1.9 to 3:1, for example, 1.9:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, etc.

[0014] The preparation method of the sludge conditioner provided by the invention has realized industrialized production and has low requirements on raw materials, wherein the hydrochloric acid can be selected from by-product hydrochloric acid, synthetic hydrochloric acid, etc., with a wide source and low cost.

[0015] As a preferred technical solution of the present invention, the mass concentration of the hydrochloric acid is 30-37%, such as 30%, 32%, 34%, 37%, etc., preferably 32%.

[0016] As a preferred technical solution of the present invention, the equivalent alumina content in the aluminum mud is ≥9wt%.

[0017] When the converted alumina content and the hydrochloric acid concentration in the aluminum mud are within the above ranges, the mass ratio of the hydrochloric acid to the aluminum mud can be 0.6 to 1.1:1, for example, 0.6:1, 0.8:1, 1.0:1, 1.1:1, etc.

[0018] As a preferred technical solution of the present invention, the precipitant is selected from calcium salt or barium salt. The precipitant is added to the primary liquid of the sludge conditioner in the present invention to form crystals with sulfate ions therein, thereby reducing subsequent sulfate crystallization precipitation.

[0019] As a preferred technical solution of the present invention, the calcium salt includes calcium chloride and / or calcium nitrate.

[0020] As a preferred technical solution of the present invention, the barium salt includes barium chloride and / or barium nitrate.

[0021] As a preferred technical solution of the present invention, the precipitant is selected from calcium chloride.

[0022] As a preferred technical solution of the present invention, the mass ratio of the precipitant to the aluminum mud is 1 to 2:100, for example, 1:100, 1.2:100, 1.4:100, 1.6:100, 1.8:100, 2:100, etc.

[0023] In the present invention, calcium aluminate powder is added 30-40 minutes after the precipitant is added to carry out a salt-base reaction, so as to provide sufficient time to remove as much sulfate as possible. The amount of calcium aluminate powder used in the present invention is related to the amount of hydrochloric acid used, and the calcium aluminate powder can be used to deeply remove sulfate in the system.

[0024] As a preferred technical solution of the present invention, the mass ratio of HCl to calcium aluminate powder in the hydrochloric acid is 1.1 to 1.8:1, for example, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, etc.

[0025] When the concentration of hydrochloric acid is within the above range of 30-37%, the mass ratio of hydrochloric acid to calcium aluminate powder may be 3 to 5:1, such as 3:1, 4:1, 5:1, etc.

[0026] After the crude sludge conditioner is prepared in the present invention, it is filtered to filter out the acid insoluble residue and the sulfate insoluble matter purified by precipitation, and then cooled to remove impurities.

[0027] As a preferred technical solution of the present invention, the cooling and impurity removal method is: the filtrate obtained by pressure filtration is quickly cooled to below 75°C and continuously cooled for 24 to 48 hours, for example, 24 hours, 30 hours, 36 hours, 42 hours, 48 ​​hours, etc., so that the remaining sulfate therein can be fully crystallized and precipitated.

[0028] The present invention cools and removes impurities from the filtrate obtained by pressure filtration, which can accelerate the precipitation of residual sulfate insolubles in the product, thereby reducing subsequent sulfate crystallization precipitation of the product. The combination of a precipitant for impurity removal can effectively solve the subsequent crystallization precipitation problem of the sludge conditioner product prepared from aluminum sludge.

[0029] As a preferred technical solution of the present invention, the method of rapid cooling is to use water cooling or brine cooling for cooling.

[0030] The present invention allows the filtrate to be rapidly cooled through a cooler equipment pipeline and flow into a cooling pool for cooling for 24 to 48 hours. The cooler may be a graphene tube cooler.

[0031] As a preferred technical solution of the present invention, the cooling and impurity removal is followed by secondary filter pressing to obtain the sludge conditioner.

[0032] The secondary filtration of the present invention removes the remaining precipitated crystalline impurities, and finally obtains a clear and transparent qualified sludge conditioner product.

[0033] As a preferred technical solution of the present invention, the reaction temperature in step (1) is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, etc., and the reaction time is 1.5-3h, for example, 1.5h, 2h, 2.5h, 3h, etc.

[0034] As a preferred technical solution of the present invention, the reaction temperature in step (1) is 70° C. and the reaction time is 2 h.

[0035] As a preferred technical solution of the present invention, the reaction temperature in step (2) is 95-100°C, for example, 95°C, 96°C, 97°C, 98°C, 99°C, 100°C, etc., and the reaction time is 1-2h, for example, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2.0h, etc.

[0036] As a specific embodiment of the present invention, the method comprises:

[0037] (1) adding hydrochloric acid and aluminum sludge into a reaction kettle in a measured amount, reacting at 60-80° C. for 1.5-3 hours to obtain a primary solution of sludge conditioner having a basicity of -10 to 10%;

[0038] (2) adding a precipitant to the primary liquid of the sludge conditioner to remove impurities, and then adding calcium aluminate powder to react at 95-100° C. for 1-2 hours to obtain a crude sludge conditioner;

[0039] (3) The crude sludge conditioner is subjected to filter pressing to obtain a filtrate, and the filtrate is rapidly cooled to below 75° C. by water cooling or brine cooling and continuously cooled for 24 to 48 hours to cool and remove impurities, and then subjected to secondary filter pressing to obtain the sludge conditioner.

[0040] Wherein, the amount of hydrochloric acid used is preferably 30-35% of the volume of the reactor.

[0041] The method provided by the present invention realizes the efficient resource comprehensive utilization of aluminum sludge, solves the secondary residue problem caused by crystallization precipitation of sludge conditioner products prepared from aluminum sludge, and has simple process, easy operation, low cost, and realizes industrial production, which has important economic and environmental significance.

[0042] In a second aspect, the present invention provides a sludge conditioner, which is prepared by the method described in the first aspect.

[0043] As a preferred technical solution of the present invention, the aluminum oxide content in the sludge conditioner is 9-13wt%, for example, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, etc., and the basicity is 55-70%, for example, 55%, 60%, 65%, 70%, etc.

[0044] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0045] The method provided by the present invention makes full use of the resource advantage of solid waste aluminum mud as raw material, and innovatively designs the purification process for the crystallization problem of the prepared product, thereby solving the secondary residue problem caused by the crystallization precipitation of the sludge conditioner product prepared from aluminum mud, and can effectively improve the dehydration performance of the product on the sludge, thereby reducing the overall cost of subsequent sludge disposal, realizing the efficient resource comprehensive utilization of aluminum mud, helping to improve the recycling rate of aluminum mud resources, reducing adverse effects on the environment, and promoting technological progress in the field of sludge conditioners. The method has simple process, easy operation, low cost, and realizes industrial production. It has broad application prospects and important economic and environmental significance. DETAILED DESCRIPTION

[0046] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0048] The following embodiments of the present invention involve the content of aluminum oxide and basicity. The present invention provides a method for determining the content of aluminum oxide and basicity:

[0049] 1. Determination of alumina content

[0050] 1.1 Method Summary

[0051] The sample was depolymerized with nitric acid, and when the pH value was about 3, an excess of disodium ethylenediaminetetraacetate solution was added to make it complex with aluminum ions. With xylenol orange as an indicator, the excess disodium ethylenediaminetetraacetate solution was back-titrated with a standard zinc chloride titration solution.

[0052] 1.2 Analysis steps:

[0053] Weigh about 8g of liquid sample or 2.5g of solid sample to an accuracy of 0.2g. Dissolve it with deionized water, transfer it into a 250mL volumetric flask, dilute to the mark, and shake well. The supernatant is sample A.

[0054] Pipette 10mL of sample A solution and place it in a 250mL conical flask. Add 10mL of nitric acid solution and boil for one minute. After cooling to room temperature, add 20mL of EDTA, add 3-4 drops of thymol blue solution, neutralize with ammonia solution until the solution changes from red to yellow, and boil for two minutes. After cooling, add 10mL of acetic acid-sodium acetate buffer solution and 2 drops of xylenol orange indicator, add 50mL of water, and titrate with zinc chloride standard solution until the solution changes from light yellow to slightly red. At the same time, make a blank.

[0055] 1.3. Calculation of results:

[0056]

[0057] In the formula

[0058] V0: blank volume of zinc chloride consumed, mL;

[0059] V: volume of zinc chloride consumed by the sample, mL;

[0060] c: concentration of zinc chloride titration solution, mol / L;

[0061] m: mass of the sample, g;

[0062] M: molar mass of aluminum oxide, g / moL (M = 101.96);

[0063] V1: volume of sample A pipetted, mL (V1=5);

[0064] V A : Total volume of sample A, mL, (V A =250).

[0065] 2 Determination of basicity

[0066] 2.1 Method Summary

[0067] Add excess hydrochloric acid solution to the sample, use potassium fluoride to mask aluminum ions and iron ions, and back-titrate the excess hydrochloric acid solution with a standard sodium hydroxide solution.

[0068] 2.2 Analysis steps

[0069] Take 25mL of test solution A (test sample) and place it in a 250mL conical flask. Add 20mL of hydrochloric acid standard solution, cover with a watch glass, heat on an electric stove until boiling, then remove immediately and cool to room temperature. Add 20mL of potassium fluoride solution, shake well, add five drops of phenolphthalein indicator solution, and immediately titrate with sodium hydroxide standard titration solution until the solution turns slightly red, which is the end point. At the same time, use water without carbon dioxide for a blank test.

[0070] 2.3. Calculation of results:

[0071]

[0072] Where:

[0073] V0: The volume of the sodium hydroxide standard titration solution consumed in the blank test (mL);

[0074] V: the volume of sodium hydroxide standard titration solution consumed by the sample, (mL);

[0075] c: The exact value of the actual concentration of the sodium hydroxide standard titration solution, (mol / L);

[0076] M: numerical value of the molar mass of hydroxide, (g / mol), (M=16.99);

[0077] m: the mass of the sample, (g);

[0078] w1: mass fraction of aluminum oxide measured above, %;

[0079] V1: the volume of test solution A pipetted, (mL), (V1 = 25);

[0080] V A : The total volume of test solution A, (mL), (V A =250);

[0081] M1: numerical value of the molar mass of aluminum, (g / mol), (M1=26.98);

[0082] M2: numerical value of the molar mass of aluminum oxide, (g / mol), (M2=101.96).

[0083] Example 1

[0084] This embodiment provides a method for preparing a sludge conditioner by utilizing aluminum sludge resources and a sludge conditioner. This embodiment uses a sludge conditioner production line of an environmental protection enterprise in Shandong for production. The main equipment on the production line is 50m 3 2 reactors, 30m 3 1 reactor, 200m 2 1 filter press. Before starting the operation, ensure that all relevant valves (including the inlet and outlet valves of the hydrochloric acid feed pump, the outlet valve of the hydrochloric acid storage tank, the hydrochloric acid feed pipeline valve on the reactor and the acid mist absorption pipeline valve) are in the open state.

[0085] The method comprises the following steps:

[0086] (1) Open all relevant valves, start the hydrochloric acid feed pump, and feed 50m 3 18.5t of hydrochloric acid with a mass fraction of 32% is added to the reactor (33.2% of the reactor capacity). The stirring in the reactor is turned on, and 22.4t of aluminum sludge in the form of ton bags (equivalent to 10.5% alumina mass content) is measured and added to the reactor using the crane system (addition is based on the mass ratio of hydrochloric acid: aluminum sludge = 0.83:1). The reactor temperature is controlled at 65°C, and the aluminum sludge and hydrochloric acid react in the reactor for 1.5h. After the reaction is completed, the primary liquid of the sludge conditioner in the reactor is taken and sent to the laboratory for testing of alumina and basicity indicators. The test results show that the alumina content is 5.47% and the basicity is -5.35%, which meets the subsequent production indicators (basicity between ±10%).

[0087] (2) Continue to add 225 kg of calcium chloride into the reactor and continue stirring the reaction for 0.5 h to precipitate some sulfate ions and reduce subsequent sulfate crystallization.

[0088] (3) 5 tons of calcium aluminate powder was added into the reactor in sequence by means of a crane system (the mass ratio of hydrochloric acid to calcium powder was 3.7:1), and the reaction temperature was controlled at 95°C and the reaction time was controlled at 1.5 hours. After the reaction was fully completed, a crude sludge conditioner was obtained.

[0089] (4) The crude sludge conditioner in the reactor is pumped into a filter press for a primary filtration. The final filtrate is rapidly cooled to 72°C through a water-cooled cooler pipeline and then flows into a cooling pool for continuous cooling for 24 hours to allow the sulfate to cool and crystallize as quickly as possible.

[0090] (5) The product obtained in step (4) is pumped into the filter press again for secondary filtration, and the secondary filtrate product flows into the product storage tank by gravity, thus obtaining a clear and transparent sludge conditioner product. Sludge conditioner product quality control: alumina content 10.10%, basicity 60.21%.

[0091] Example 2

[0092] This embodiment provides a method for preparing a sludge conditioner by utilizing aluminum sludge resources and a sludge conditioner. This embodiment uses a sludge conditioner production line of an environmental protection enterprise in Shandong for production. The main equipment on the production line is 50m 3 2 reactors, 30m 3 1 reactor, 200m 2 1 filter press. Before starting the operation, ensure that all relevant valves (including the inlet and outlet valves of the hydrochloric acid feed pump, the outlet valve of the hydrochloric acid storage tank, the hydrochloric acid feed pipeline valve on the reactor and the acid mist absorption pipeline valve) are in the open state.

[0093] The method comprises the following steps:

[0094] (1) Open all relevant valves, start the hydrochloric acid feed pump, and feed 30m 3 10.62t of hydrochloric acid with a mass fraction of 33% is added to the reactor (30.0% of the reactor capacity). The stirring in the reactor is turned on, and 15.4t of aluminum sludge in the form of ton bags (equivalent to 9.5% alumina mass content) is measured and added to the reactor using the crane system (addition is based on the mass ratio of hydrochloric acid: aluminum sludge = 0.69:1). The reactor temperature is controlled at 75°C, and the aluminum sludge and hydrochloric acid react in the reactor for 2.0h. After the reaction is completed, the primary liquid of the sludge conditioner in the reactor is taken and sent to the laboratory for testing of alumina and basicity indicators. The test results show that the alumina content is 5.53% and the basicity is 0.88%, which meets the subsequent production indicators (basicity between ±10%).

[0095] (2) Continue to add 250 kg of calcium chloride into the reactor and continue stirring the reaction for 0.5 h to precipitate some sulfate ions and reduce subsequent sulfate crystallization.

[0096] (3) 3 tons of calcium aluminate powder was added to the reactor in sequence using the crane system (addition was carried out at a mass ratio of hydrochloric acid to calcium powder = 3.54:1), and the reaction temperature was controlled at 95°C and the reaction time was controlled at 1.5 hours. After the reaction was fully completed, a crude sludge conditioner was obtained.

[0097] (4) The final product of the filtrate is rapidly cooled to 70°C through a water-cooled cooler pipe and then flows into a cooling pool for continuous cooling for 24 hours to allow the sulfate to cool and crystallize as quickly as possible.

[0098] (5) The product obtained in step (4) is pumped into the filter press again for secondary filtration, and the secondary filtrate product flows into the product storage tank by gravity, thus obtaining a clear and transparent sludge conditioner product. Sludge conditioner product quality control: alumina content 9.74%, basicity 66.37%.

[0099] Example 3

[0100] This embodiment provides a method for preparing a sludge conditioner by utilizing aluminum sludge resources and a sludge conditioner. This embodiment uses a sludge conditioner production line of an environmental protection enterprise in Shandong for production. The main equipment on the production line is 50m 3 3 reactors, 100m 2 2 filter presses. Before starting the operation, ensure that all relevant valves (including the inlet and outlet valves of the hydrochloric acid feed pump, the outlet valve of the hydrochloric acid storage tank, the hydrochloric acid feed pipeline valve on the reactor and the acid mist absorption pipeline valve) are in the open state.

[0101] The method comprises the following steps:

[0102] (1) Open all relevant valves, start the hydrochloric acid feed pump, and feed 50m 3 19.47t of hydrochloric acid with a mass fraction of 31% is added to the reactor (33.0% of the reactor capacity). The stirring in the reactor is turned on, and 17.8t of aluminum sludge in the form of ton bags (equivalent to 11% alumina mass content) is measured and added to the reactor using the crane system (addition is based on the mass ratio of hydrochloric acid: aluminum sludge = 1.09:1). The reactor temperature is controlled at 70°C, and the aluminum sludge and hydrochloric acid react in the reactor for 2.0h. After the reaction is completed, the primary liquid of the sludge conditioner in the reactor is taken and sent to the laboratory for testing of alumina and basicity indicators. The test results show that the alumina content is 6.21% and the basicity content is -7.82%, which meets the subsequent production indicators (basicity between ±10%).

[0103] (2) Continue to add 300 kg of calcium chloride into the reactor and continue stirring the reaction for 0.5 h to precipitate some sulfate ions and reduce subsequent sulfate crystallization.

[0104] (3) 4 tons of calcium aluminate powder were metered and added into the reactor in sequence using the crane system (the mass ratio of hydrochloric acid to calcium powder was 4.87:1), and the reaction temperature was controlled at 95°C and the reaction time was controlled at 1.5 hours. After the reaction was fully completed, a crude sludge conditioner was obtained.

[0105] (4) The crude sludge conditioner in the reactor is pumped into a filter press for a primary filtration. The final filtrate product is rapidly cooled to 72° C. through a water-cooled cooler pipeline and then flows into a cooling pool for continuous cooling for 48 hours to allow the sulfate to cool and crystallize as quickly as possible.

[0106] (5) The product obtained in step (4) is pumped into the filter press again for secondary filtration, and the secondary filtrate product flows into the product storage tank by gravity, thus obtaining a clear and transparent sludge conditioner product. Sludge conditioner product quality control: alumina content 10.26%, basicity content 58.11%.

[0107] Example 4

[0108] This embodiment provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. This embodiment uses a sludge conditioner production line of an environmental protection enterprise in Shandong for production. The main equipment on the production line is 40m 3 2 reactors, 80m 2 2 filter presses. Before starting the operation, ensure that all relevant valves (including the inlet and outlet valves of the hydrochloric acid feed pump, the outlet valve of the hydrochloric acid storage tank, the hydrochloric acid feed pipeline valve on the reactor and the acid mist absorption pipeline valve) are in the open state.

[0109] The method comprises the following steps:

[0110] (1) Open all relevant valves and start the hydrochloric acid feed pump to 40m 3 18.01t of 30% hydrochloric acid (35.0% of the reactor capacity) was added to the reactor. The stirring in the reactor was turned on, and 21.5t of aluminum sludge (equivalent to 13% alumina mass content) in the form of ton bags was added to the reactor using the crane system (addition was based on the mass ratio of hydrochloric acid: aluminum sludge = 0.84:1). The reactor temperature was controlled at 70°C, and the aluminum sludge and hydrochloric acid reacted in the reactor for 3.0h. After the reaction was completed, the primary liquid of the sludge conditioner in the reactor was taken and sent to the laboratory for testing of alumina and basicity indicators. The test results showed that the alumina content was 9.25% and the basicity content was 1.30%, which met the subsequent production indicators (basicity between ±10%).

[0111] (2) Continue to add 250 kg of calcium chloride into the reactor and continue stirring the reaction for 1.0 h to precipitate some sulfate ions and reduce subsequent sulfate crystallization.

[0112] (3) 4 tons of calcium aluminate powder were metered and added into the reactor in sequence using the crane system (the mass ratio of hydrochloric acid to calcium powder was 4.50:1), and the reaction temperature was controlled at 95°C and the reaction time was controlled at 1.5 hours. After the reaction was fully completed, a crude sludge conditioner was obtained.

[0113] (4) The crude sludge conditioner in the reactor is pumped into a filter press for a first filtration. The final filtrate product is rapidly cooled to 68° C. through a water-cooled cooler pipeline and then flows into a cooling pool for continuous cooling for 36 hours to allow the sulfate to cool and crystallize as quickly as possible.

[0114] (5) The product obtained in step (4) is pumped into the filter press again for secondary filtration, and the secondary filtrate product flows into the product storage tank by gravity, thus obtaining a clear and transparent sludge conditioner product. Sludge conditioner product quality control: alumina content 12.81%, basicity content 55.45%.

[0115] Example 5

[0116] This embodiment provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. This embodiment uses the sludge conditioner production line of Example 1 for production.

[0117] The method described in this embodiment is the same as that in embodiment 1, and the difference from embodiment 1 is that in this embodiment, the basicity of the sludge conditioner in the primary liquid in step (1) is -25%.

[0118] It was found that the crude sludge conditioner in the reactor could not be pumped into the filter press for primary filtration, and the filtration could not be performed. The secondary crystallization residue still existed in the crude sludge conditioner, i.e., a clear and transparent sludge conditioner product could not be obtained.

[0119] Example 6

[0120] This embodiment provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. This embodiment uses the sludge conditioner production line of Example 1 for production.

[0121] The method described in this embodiment is the same as that in Example 1, except that in this embodiment, the amount of aluminum mud used is 12.3 t.

[0122] The results showed that the amount of aluminum sludge added was small, resulting in a liquid salt basicity of -34% for the sludge conditioner. By continuing to add 6 tons of aluminum sludge and continuing the reaction for 2 hours, after the reaction was completed, the liquid salt basicity was measured again until the basicity was between -10 and 10%.

[0123] Example 7

[0124] This embodiment provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. This embodiment uses the sludge conditioner production line of Example 1 for production.

[0125] The method described in this embodiment is the same as that in Embodiment 1, and the difference from Embodiment 1 is that in this embodiment, the amount of calcium aluminate powder used is 3 t.

[0126] It was found that the quality control index of the final clear and transparent sludge conditioner product was 9.2%, and the basicity was 40%, which could not meet the quality control range.

[0127] Example 8

[0128] This embodiment provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. This embodiment uses the sludge conditioner production line of Example 1 for production.

[0129] The method described in this embodiment is the same as that in Embodiment 1, except that in this embodiment, the amount of calcium aluminate powder used is 9 t.

[0130] It was found that the crude sludge conditioner in the reactor could not be pumped into the filter press for primary filtration, i.e. it could not be filtered, and the secondary crystallization residue still existed in the crude sludge conditioner, and a clear and transparent sludge conditioner product could not be obtained.

[0131] Comparative Example 1

[0132] This comparative example provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. This comparative example uses the sludge conditioner production line of Example 1 for production.

[0133] The method described in this comparative example is the same as that in Example 1, except that step (2) is omitted in this comparative example.

[0134] The results showed that the final sludge conditioner still had crystalline residue precipitated, affecting the sludge conditioning performance of the product.

[0135] Comparative Example 2

[0136] This comparative example provides a method for preparing a sludge conditioner by resource utilization of aluminum sludge and a sludge conditioner. This comparative example uses the sludge conditioner production line of Example 1 for production.

[0137] The method described in this comparative example is the same as that in Example 1. The difference from Example 1 is that steps (4) and (5) are omitted in this comparative example, and the filtrate is directly used as the final product.

[0138] The results showed that the final sludge conditioner still had crystalline residue precipitated, affecting the sludge conditioning performance of the product.

[0139] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0140] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments described herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a sludge conditioner by utilizing aluminum sludge as a resource, characterized in that: The method comprises: (1) mixing hydrochloric acid and aluminum sludge to react and obtain a primary liquid of sludge conditioning agent; (2) adding a precipitant to the primary liquid of the sludge conditioner to remove impurities, and then adding calcium aluminate powder to react to obtain a crude sludge conditioner; (3) The crude sludge conditioner is subjected to filter pressing, cooling and impurity removal to obtain the sludge conditioner.

2. The method according to claim 1, characterized in that The basicity of the primary solution of the sludge conditioner is -10 to 10%.

3. The method according to claim 1 or 2, characterized in that: The mass ratio of HCl in the hydrochloric acid to the equivalent aluminum oxide in the aluminum mud is 1.9 to 3:1; And / or, the equivalent alumina content in the aluminum mud is ≥9wt%.

4. The method according to claim 1 or 2, characterized in that: The precipitant is selected from calcium salts or barium salts, the calcium salts include calcium chloride and / or calcium nitrate, and the barium salts include barium chloride and / or barium nitrate; And / or, the mass ratio of the precipitant to the aluminum mud is 1 to 2:

100.

5. The method according to claim 1 or 2, characterized in that: The mass ratio of HCl to calcium aluminate powder in the hydrochloric acid is 1.1-1.8:

1.

6. The method according to claim 1 or 2, characterized in that: The cooling and impurity removal method is: the filtrate obtained by pressure filtration is quickly cooled to below 75° C. and continuously cooled for 24 to 48 hours.

7. The method according to claim 6, characterized in that The method for rapid cooling is to use water cooling or brine cooling for cooling.

8. The method according to claim 1 or 2, characterized in that: After cooling and removing impurities, secondary filter pressing is performed to obtain the sludge conditioner.

9. The method according to claim 1 or 2, characterized in that: The reaction temperature in step (1) is 60-80° C. and the reaction time is 1.5-3 h. And / or, the reaction temperature in step (2) is 95-100° C., and the reaction time is 1-2 h.

10. A sludge conditioner, characterized in that: The sludge conditioner is prepared by the method according to any one of claims 1 to 9.

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