Treatment method of sulfate radical high-salinity wastewater

Abstract

The invention relates to a treatment method of sulfate radical high-salinity wastewater. The treatment method comprises the following steps: providing the sulfate radical high-salinity wastewater in an aluminum oxide preparation process; carrying out deamination treatment on the sulfate radical high-salinity wastewater to obtain deamination tail liquid; and the deamination tail liquid is sent to a bauxite ore grinding procedure, so that the deamination tail liquid finally enters ore pulp formed by bauxite ore grinding. According to the method, the deamination tail liquid obtained after the sulfate radical high-salinity wastewater is subjected to deamination treatment is fed to the bauxite grinding procedure, so that the deamination tail liquid finally enters the ore pulp formed by bauxite grinding, and finally sulfate radical ions in the ore pulp are mingled in the red mud; and other substances in the sulfate radical high-salinity wastewater can be recovered or treated in the aluminum oxide preparation process flow.

Description

Technical Field

[0001] The present application relates to the field of environmental protection, and in particular to industrial wastewater treatment. Background Art

[0002] Sulfate high-salt wastewater refers to wastewater that mainly contains sulfate. The usual treatment method is to recover part of the sulfate and then further treat the remaining wastewater. The market demand for recovered sulfate is small, and the remaining wastewater has a complex composition and usually contains a large amount of harmful elements, so the treatment cost is high. For example, the sulfate high-salt wastewater in the alumina preparation process is a typical sulfate high-salt wastewater. In addition to sodium sulfate and ammonium sulfate, it also contains some impurities such as arsenic, fluorine, chlorine, and oxalate. The cost of purifying and disposing of the vanadium precipitation tail liquid in the alumina process is high and the process is complex. The market demand for sodium sulfate is small and the economic value is low. Summary of the invention

[0003] The embodiment of the present application provides a method for treating sulfate high-salt wastewater to solve the technical problem of difficulty in treating sulfate high-salt wastewater.

[0004] The present invention provides a method for treating sulfate high-salt wastewater, and the method for treating sulfate high-salt wastewater comprises the following steps:

[0005] Provide sulfate high-salinity wastewater;

[0006] Deammoniation treatment is performed on the sulfate high-salt wastewater to obtain a deammoniation tail liquid;

[0007] The deammoniation tail liquid is sent to the bauxite grinding process, so that the deammoniation tail liquid finally enters the slurry formed by the bauxite grinding.

[0008] In some embodiments of the present application, the sulfate high-salt wastewater is the tail liquid of vanadium extraction in the Bayer process for producing alumina.

[0009] In some embodiments of the present application, the method for treating sulfate high-salt wastewater further comprises the following steps:

[0010] Determine whether the total silicon-sulfur ratio of the deammoniation tail liquid and the bauxite in the grinding process reaches 6 or more, and if the silicon-sulfur ratio does not reach 6 or more, add a raw material containing silicon dioxide to the bauxite until the silicon-sulfur ratio reaches 6 or more;

[0011] The deammoniation tail liquid is finally introduced into the slurry formed by bauxite grinding;

[0012] The ore pulp is subjected to a dissolution treatment.

[0013] In some embodiments of the present application, the method for treating sulfate high-salt wastewater further comprises the following steps:

[0014] Determine whether the total silicon-sulfur ratio of the deammoniation tail liquid and the bauxite in the grinding process reaches 4 or more, if the silicon-sulfur ratio does not reach 4 or more, add a raw material containing silicon dioxide to the bauxite until the silicon-sulfur ratio reaches 4 or more;

[0015] The deammoniation tail liquid is finally introduced into the slurry formed by bauxite grinding;

[0016] performing a pre-desiliconization treatment on the slurry;

[0017] The ore pulp after the pre-desiliconization treatment is subjected to dissolution treatment.

[0018] In some embodiments of the present application, the solid content of the slurry is 180-220 g / L, and the deamination tail liquid is finally introduced into the slurry formed by bauxite grinding, and the amount of the deamination tail liquid entering into each cubic meter of slurry is 2-15 L.

[0019] In some embodiments of the present application, the raw material containing silicon dioxide includes at least one of low-grade bauxite, low-grade bauxite, kaolin, glass, chlorite, diatomaceous earth, and silicon dioxide molecular sieve.

[0020] In some embodiments of the present application, the dissolution temperature is above 200° C.; and / or,

[0021] The dissolution treatment time is more than 5 minutes.

[0022] In some embodiments of the present application, the method for treating sulfate high-salt wastewater further comprises the following steps:

[0023] Absorbing the ammonia gas obtained by deammoniation with dilute sulfuric acid to obtain ammonium sulfate;

[0024] The ammonium sulfate is returned to the vanadium extraction step in the alumina preparation process as a vanadium precipitation agent.

[0025] In some embodiments of the present application, the deamination is implemented as follows:

[0026] Calcium oxide or sodium hydroxide or sodium hydroxide is added to the sulfate high-salt wastewater to allow ammonia to escape.

[0027] In some embodiments of the present application, the deamination is performed at above 50°C.

[0028] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0029] The method for treating sulfate high-salt wastewater provided in the embodiment of the present application is to send the deaminated tail liquid obtained by deammoniation treatment of the sulfate high-salt wastewater to the bauxite grinding process, so that the deaminated tail liquid finally enters the slurry formed by bauxite grinding, and finally the sulfate ions in the slurry will be mixed into the red mud, and the remaining substances in the sulfate high-salt wastewater can be recovered or treated in the alumina preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0032] Figure 1 A schematic flow chart of a method for treating sulfate high-salt wastewater provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0034] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.

[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0036] At present, there are technical problems in the disposal of high-salt sulfate wastewater.

[0037] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0038] The present invention provides a method for treating sulfate high-salt wastewater, and the method for treating sulfate high-salt wastewater comprises the following steps:

[0039] S1: Provide sulfate high-salt wastewater;

[0040] S2: deammoniating the sulfate high-salt wastewater to obtain a deammoniated tail liquid;

[0041] S3: sending the deammoniation tailings to the bauxite grinding process, so that the deammoniation tailings finally enter the slurry formed by the bauxite grinding.

[0042] It is easy to understand that the alumina dissolution process is carried out under strong alkali and high temperature. If the sulfate high-salt wastewater contains a large amount of ammonia, when it participates in the alumina dissolution process, the ammonia will volatilize in large quantities under strong alkali and high temperature, causing poisoning to the production environment. Therefore, by deammoniation treatment of the sulfate high-salt wastewater, after removing the ammonia in the sulfate high-salt wastewater, the sulfate high-salt wastewater can participate in the alumina dissolution process.

[0043] It is easy to understand that after bauxite is ground to form slurry, the slurry is subsequently subjected to dissolution treatment, and a large amount of aluminum compounds in the bauxite will be dissolved in the form of sodium aluminate, and the undissolved substance is red mud. Sodium aluminosilicate will be generated during the dissolution process, and sodium aluminosilicate will enter the red mud, and sulfate will be mixed into the sodium aluminosilicate;.

[0044] In the present application, the deaminated tail liquid obtained by deammoniation treatment of sulfate high-salt wastewater is sent to the bauxite grinding process, so that the deaminated tail liquid finally enters the slurry formed by bauxite grinding. Finally, the sulfate ions in the slurry will be mixed into the red mud, and the remaining substances in the sulfate high-salt wastewater can be recovered or treated in the alumina preparation process.

[0045] In some embodiments of the present application, the sulfate high-salt wastewater is the tail liquid of vanadium extraction in the Bayer process for producing alumina.

[0046] For the vanadium extraction tail liquid, the remaining vanadium, arsenic, fluorine, sodium oxalate and other substances in the vanadium extraction tail liquid will circulate with the alumina production system and return to the alumina vanadium removal process to eventually form alumina process vanadium slag, and the vanadium will be recycled. Finally, sodium sulfate is mixed into the red mud, and the remaining substances in the sulfate high-salt wastewater can be recovered or treated in the alumina preparation process.

[0047] In some embodiments of the present application, the method for treating sulfate high-salt wastewater further comprises the following steps:

[0048] S311: Determine whether the total silicon-sulfur ratio of the deammoniation tail liquid and the bauxite in the grinding process reaches 6 or more. If the silicon-sulfur ratio does not reach 6 or more, add a raw material containing silicon dioxide to the bauxite until the silicon-sulfur ratio reaches 6 or more.

[0049] S312: allowing the deammoniation tail liquid to finally enter the slurry formed by bauxite grinding;

[0050] S313: performing a dissolution treatment on the ore pulp.

[0051] In some embodiments of the present application, the method for treating sulfate high-salt wastewater further comprises the following steps:

[0052] S321: Determine whether the total silicon-sulfur ratio of the deammoniation tail liquid and the bauxite in the grinding process reaches 4 or more. If the silicon-sulfur ratio does not reach 4 or more, add a raw material containing silicon dioxide to the bauxite until the silicon-sulfur ratio reaches 4 or more.

[0053] S322: allowing the deammoniation tail liquid to finally enter the slurry formed by bauxite grinding;

[0054] S323: performing pre-desiliconization treatment on the slurry;

[0055] S324: performing dissolution treatment on the ore pulp after the pre-desiliconization treatment.

[0056] It should be noted that the silicon-sulfur ratio in the present application is defined as the molar ratio of sulfate ions in active silica.

[0057] It should be noted that the production process of some alumina manufacturers does not include a pre-desiliconization step, while some manufacturers include a pre-desiliconization step. Steps S311 to S313 do not include the step of pre-desiliconization treatment of the slurry. Steps S321 to S324 include the step of pre-desiliconization treatment of the slurry. Pre-desiliconization treatment of the slurry will allow more sulfate ions to be included in the sodium aluminosilicate. Therefore, when there is a pre-desiliconization step, a silicon-sulfur ratio of 4 or more can well enrich the sulfate as much as possible in the red mud. When there is no pre-desiliconization step, the silicon-sulfur ratio should preferably be above 6.

[0058] It should be noted that the above-mentioned limitation on the silicon-sulfur ratio is to allow more sulfate to be mixed into the sodium aluminosilicate, so that the sulfate introduced by the deamination tail liquid can be completely mixed into the sodium aluminosilicate. However, the circulating mother liquor of the alumina production process itself contains sodium sulfate. Even if the sulfate introduced by the deamination tail liquid is not completely mixed into the sodium aluminosilicate, a part of it will eventually exist in the sodium aluminate solution obtained by the dissolution treatment, which will not have a great impact on the entire alumina production process. Therefore, the above-mentioned limitation on the silicon-sulfur ratio is not a necessary condition for the implementation of the present invention.

[0059] In some embodiments of the present application, the raw material containing silicon dioxide includes at least one of low-grade bauxite, kaolin, glass, chlorite, diatomaceous earth, and silicon dioxide molecular sieve.

[0060] In some embodiments of the present application, the dissolution temperature is above 200°C.

[0061] It is easy to understand that the aluminum-containing compound can be sufficiently dissolved when the dissolution temperature is 200° C. or higher.

[0062] In some embodiments of the present application, the dissolution treatment time is more than 5 minutes.

[0063] It is easy to understand that the aluminum-containing compound can be fully dissolved when the dissolution treatment time is 5 minutes or longer.

[0064] In some embodiments of the present application, the method for treating sulfate high-salt wastewater further comprises the following steps:

[0065] S4: absorbing the ammonia obtained by deammoniation with dilute sulfuric acid to obtain ammonium sulfate;

[0066] S5: returning the ammonium sulfate to the vanadium extraction step in the alumina preparation process.

[0067] It is easy to understand that bauxite usually contains a certain amount of vanadium, so the alumina preparation process generally includes a vanadium extraction step.

[0068] In some embodiments of the present application, the deamination is implemented as follows:

[0069] Calcium oxide or sodium hydroxide is added to the sulfate high-salt wastewater to allow ammonia to escape.

[0070] In some embodiments of the present application, the deamination is performed at above 50°C.

[0071] It is easy to understand that after adding calcium oxide or sodium hydroxide to the sulfate high-salt wastewater, ammonia can easily escape, so there is no need to carry out deamination at too high a temperature, and deamination can be fully carried out at above 50°C.

[0072] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.

[0073] Example 1

[0074] A vanadium extraction tail liquid is obtained from an alumina production line, wherein the sodium concentration of the vanadium extraction tail liquid is 88 g / L, the ammonium ion concentration is 28 g / L, the vanadium concentration is 0.4 g / L, and the arsenic concentration is 0.5 g / L. Sodium hydroxide is added to the vanadium extraction tail liquid, and a deammoniation tail liquid is obtained after deammoniation treatment at 60°C. The ammonium ion concentration of the deammoniation tail liquid is less than 2 mg / L, and the sodium ion concentration in the solution is 122 g / L. The bauxite used in the alumina production line has an active silicon dioxide content of 2%, the solid content of the bauxite grinding slurry is 200g / L, and the amount of deamination tail liquid added per cubic meter of bauxite grinding slurry is 2.7L; the sodium sulfate content in the circulating mother liquor is 3.8g / L; the bauxite grinding slurry is dissolved at 200°C for 5min, and the sodium sulfate concentration in the dissolution liquid is 3.8g / L, which is not higher than the sodium sulfate concentration in the circulating mother liquor. It can be seen that the sodium sulfate in the bauxite and the deamination tail liquid has all entered the red mud.

[0075] Example 2

[0076] A vanadium extraction tail liquid is obtained from an alumina production line, wherein the sodium concentration of the vanadium extraction tail liquid is 88 g / L, the ammonium ion concentration is 28 g / L, the vanadium concentration is 0.4 g / L, and the arsenic concentration is 0.5 g / L. Sodium hydroxide is added to the vanadium extraction tail liquid, and a deammoniation tail liquid is obtained after deammoniation treatment at 60°C. The ammonium ion concentration of the deammoniation tail liquid is less than 2 mg / L, and the sodium ion concentration in the solution is 122 g / L. The bauxite used in the alumina production line has an active silicon dioxide content of 1%, the solid content of the bauxite grinding slurry is 200g / L, the amount of deamination tail liquid added to each cubic meter of bauxite grinding slurry is 2.7L, and 4.9kg of kaolin is additionally added to the bauxite grinding slurry, and the silicon dioxide content in the kaolin is 45%; the sodium sulfate content in the circulating mother liquor is 3.8g / L; the bauxite grinding slurry is dissolved at 260°C for 30min, and the sodium sulfate concentration in the dissolving liquid is 3.3g / L, which is not higher than that in the circulating mother liquor. It can be seen that the sodium sulfate in the bauxite and the deamination tail liquid has all entered the red mud.

[0077] Example 3

[0078] A vanadium extraction tail liquid is obtained from an alumina production line, wherein the sodium concentration of the vanadium extraction tail liquid is 88 g / L, the ammonium ion concentration is 28 g / L, the vanadium concentration is 0.4 g / L, and the arsenic concentration is 0.5 g / L. Sodium hydroxide is added to the vanadium extraction tail liquid, and a deammoniation tail liquid is obtained after deammoniation treatment at 60°C. The ammonium ion concentration of the deammoniation tail liquid is less than 2 mg / L, and the sodium ion concentration in the solution is 122 g / L. The active silicon dioxide content in the bauxite used in the alumina production line is 3%, the solid content of the bauxite grinding slurry is 200g / L, and the amount of deamination tail liquid added per cubic meter of bauxite grinding slurry is 5.4L; the sodium sulfate content in the circulating mother liquor is 3.8g / L; the bauxite grinding slurry is pre-desiliconized at 90°C for 6h and then dissolved at 260°C. The sodium sulfate concentration in the dissolving liquid is 2.2g / L, and the sodium sulfate concentration in the dissolving liquid is not higher than that in the circulating mother liquor. It can be seen that the sodium sulfate in the bauxite and the deamination tail liquid has all entered the red mud.

[0079] Example 4

[0080] A vanadium extraction tail liquid is obtained from an alumina production line, wherein the sodium concentration of the vanadium extraction tail liquid is 88 g / L, the ammonium ion concentration is 28 g / L, the vanadium concentration is 0.4 g / L, and the arsenic concentration is 0.5 g / L. Sodium hydroxide is added to the vanadium extraction tail liquid, and a deammoniation tail liquid is obtained after deammoniation treatment at 60°C. The ammonium ion concentration of the deammoniation tail liquid is less than 2 mg / L, and the sodium ion concentration in the solution is 122 g / L. The active silicon dioxide content in the bauxite used in the alumina production line is 3%, the solid content of the bauxite grinding slurry is 200g / L, the amount of deamination tail liquid added to each cubic meter of bauxite grinding slurry is 10.8L, and 2.2kg of silicon dioxide is added; the sodium sulfate content in the circulating mother liquor is 3.8g / L; the bauxite grinding slurry is dissolved at 260°C, and the sodium sulfate concentration in the dissolving liquid is 3.2 / L, and the concentration of sodium sulfate in the dissolving liquid is not higher than that in the circulating mother liquor. It can be seen that the sodium sulfate in the bauxite and the deamination tail liquid has all entered the red mud.

[0081] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0082] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. 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 that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, and c can be single or multiple, respectively.

[0083] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for treating sulfate high-salt wastewater, characterized in that: The method for treating sulfate high-salt wastewater comprises the following steps: Provide sulfate high-salinity wastewater; Deammoniation treatment is performed on the sulfate high-salt wastewater to obtain a deammoniation tail liquid; The deammoniation tail liquid is sent to the bauxite grinding process, so that the deammoniation tail liquid finally enters the slurry formed by the bauxite grinding.

2. The method for treating sulfate high-salt wastewater according to claim 1, characterized in that: The sulfate high-salt wastewater is the tail liquid of vanadium extraction in the Bayer process of producing alumina.

3. The method for treating sulfate high-salt wastewater according to claim 2, characterized in that: The method for treating sulfate high-salt wastewater also includes the following steps: Determine whether the total silicon-sulfur ratio of the deammoniation tail liquid and the bauxite in the grinding process reaches 6 or more, and if the silicon-sulfur ratio does not reach 6 or more, add a raw material containing silicon dioxide to the bauxite until the silicon-sulfur ratio reaches 6 or more; The deammoniation tail liquid is finally introduced into the slurry formed by bauxite grinding; The ore pulp is subjected to a dissolution treatment.

4. The method for treating sulfate high-salt wastewater according to claim 3, characterized in that: The method for treating sulfate high-salt wastewater also includes the following steps: Determine whether the total silicon-sulfur ratio of the deammoniation tail liquid and the bauxite in the grinding process reaches 4 or more, if the silicon-sulfur ratio does not reach 4 or more, add a raw material containing silicon dioxide to the bauxite until the silicon-sulfur ratio reaches 4 or more; The deammoniation tail liquid is finally introduced into the slurry formed by bauxite grinding; performing a pre-desiliconization treatment on the slurry; The ore pulp after the pre-desiliconization treatment is subjected to dissolution treatment.

5. The method for treating sulfate high-salt wastewater according to any one of claims 1 to 4, characterized in that: The solid content of the slurry is 180-220 g / L. The deammoniation tail liquid is finally introduced into the slurry formed by bauxite grinding, and the amount of the deammoniation tail liquid introduced into each cubic meter of slurry is 2-15 L.

6. The method for treating sulfate high-salt wastewater according to claim 3 or 4, characterized in that: The raw material containing silicon dioxide includes at least one of low-grade bauxite, kaolin, glass, chlorite, diatomaceous earth and silicon dioxide molecular sieve.

7. The method for treating sulfate high-salt wastewater according to claim 1, characterized in that: The dissolution temperature is above 200°C; and / or, The dissolution treatment time is more than 5 minutes.

8. The method for treating sulfate high-salt wastewater according to claim 1, characterized in that: The method for treating sulfate high-salt wastewater also includes the following steps: Absorbing the ammonia gas obtained by deammoniation with dilute sulfuric acid to obtain ammonium sulfate; The ammonium sulfate is returned to the vanadium extraction step in the alumina production process.

9. The method for treating sulfate high-salt wastewater according to claim 1, characterized in that: The implementation method of the deamination is: Calcium oxide or sodium hydroxide is added to the sulfate high-salt wastewater to allow ammonia to escape.

10. The method for treating sulfate high-salt wastewater according to claim 8, characterized in that: The deamination is carried out at a temperature above 50°C.

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