A method of leaching bauxite ore slurry

Abstract

The application relates to a method for leaching bauxite ore slurry, which comprises the following steps: obtaining bauxite raw ore slurry; pre-desiliconizing the bauxite raw ore slurry to obtain pre-desiliconized ore slurry; pre-heating the pre-desiliconized ore slurry to obtain dephosphorized ore slurry; and leaching the dephosphorized ore slurry to obtain bauxite leaching ore slurry. The method can effectively slow down the formation of phosphorus scabs in the leaching pipeline, and can also slow down the formation of silicon and titanium scabs, greatly prolongs the operation cycle, and reduces the cleaning frequency of the scabs. Meanwhile, the method has the advantages of low investment, low cost and easy industrial application.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alumina production, and in particular to a method for leaching bauxite ore slurry. BACKGROUND

[0002] The entire production process of the alumina production process, including the preparation of raw ore slurry, leaching, settling, decomposition and evaporation processes, all have the problem of scabbing, among which the scabbing produced in the high-temperature leaching process is particularly serious. The phosphorus scab produced in the high-temperature leaching process is mainly composed of calcium hydroxyphosphate, which is stable and hard to adhere to the inner wall of the pipeline and tank in the production process, and has a huge impact on the alumina production process.

[0003] Alumina production enterprises usually slow down the formation of scabbing by adding a pre-desiliconization process and adding a scale inhibitor, but the effect of slowing down the phosphorus scab (hydroxyapatite) is not obvious. The phosphorus scab is hard and difficult to clean, which seriously affects the running cycle. The scale inhibitor is generally an organic matter, and the addition of the scale inhibitor may increase the risk of organic matter or impurities in the system. At present, the method of acid leaching and high-pressure water flushing is generally used for scab cleaning, which is high in cost. SUMMARY

[0004] The present application provides a method for leaching bauxite ore slurry to solve the technical problem of easy pipe phosphorus scabbing in the existing bauxite ore slurry leaching process.

[0005] In a first aspect, the present application provides a method for leaching bauxite ore slurry, the method comprising:

[0006] obtaining a bauxite raw ore slurry;

[0007] pre-desiliconizing the bauxite raw ore slurry to obtain a pre-desiliconized ore slurry;

[0008] preheating the pre-desiliconized ore slurry to obtain a desiliconized ore slurry;

[0009] leaching the desiliconized ore slurry to obtain a bauxite leaching ore slurry.

[0010] Optionally, the process parameters of the preheating include a preheating temperature and a preheating time.

[0011] Optionally, the preheating temperature is 220-260℃.

[0012] Optionally, the preheating temperature is 240-260℃.

[0013] Optionally, the preheating time is greater than 30 min.

[0014] Optionally, the obtaining of the bauxite raw ore slurry comprises:

[0015] The bauxite, lime, circulating mother liquor and red mud are ground to obtain the raw bauxite slurry.

[0016] Optionally, the added weight of the red mud is 1% to 10% of the added weight of the bauxite.

[0017] Optionally, the added weight of the lime is 3% to 12% of the added weight of the bauxite.

[0018] Optionally, the process parameters of the pre-desilication include a pre-desilication temperature, a pre-desilication time and a pre-desilication solid content.

[0019] The pre-desilication temperature is 90 to 105 degrees Celsius, the pre-desilication time is 6 to 15 hours, and the pre-desilication solid content is 300 to 1000 g / L.

[0020] Optionally, the dissolution temperature is 260 to 280 degrees Celsius.

[0021] The above technical solution provided by the embodiments of the present application has the following advantages compared with the prior art.

[0022] The method for dissolving bauxite slurry provided by the embodiments of the present application adds a pre-heat desilication step after the steps of obtaining a raw bauxite slurry and pre-desilication of the slurry and before the step of dissolving the slurry, which is beneficial to the reaction of phosphorus minerals in the bauxite to generate calcium hydroxyphosphate into the red mud, reduces the phosphorus content in the solution and slows down the scarring of the dissolution pipe. Compared with the prior art, the method can effectively slow down the generation of phosphorus scarring in the dissolution pipe and also slow down the generation of silicon and titanium scarring, greatly prolongs the operation cycle and reduces the number of scarring cleaning. At the same time, the method also has the advantages of low investment, low cost and easy industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the present application.

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without any creative labor.

[0025] Figure 1 A flowchart of a method for dissolving bauxite slurry provided by the embodiments of the present application. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0027] Various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is merely for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the described range has been specifically disclosed all possible sub-ranges and single values in the range. For example, it should be considered that the range description from 1 to 6 has 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 in the range, such as 1, 2, 3, 4, 5 and 6, which applies to any range. In addition, whenever a numerical range is indicated in this document, it refers to any cited number (fraction or integer) in the indicated range.

[0028] In the present application, the orientation words such as "upper" and "lower" are specific to the drawing direction in the drawings. In addition, in the description of the present application, the terms "include", "contain" and the like mean "include but not limited to". In this document, the relationship terms such as "first" and "second" are merely 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 the entities or operations. In this document, "and / or" describes the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B can represent the cases of A alone, A and B together, and B alone. Where A and B can be singular or plural. In this document, "one or more" means one or more, and "multiple" means two or more. "At least one", "at least one of the following" or the like means any combination of the items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0029] Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0030] In a first aspect, the present application provides a method for leaching bauxite ore slurry, which comprises Figure 1

[0031] S1, obtaining a bauxite ore slurry;

[0032] In some embodiments, the obtaining of the bauxite ore slurry comprises:

[0033] Grinding the bauxite, lime, recycled mother liquor and red mud to obtain the bauxite ore slurry.

[0034] In the embodiments of the present application, among the raw materials of the above-mentioned bauxite ore slurry, the bauxite is the core raw material for producing alumina, the lime has the following effects: for diaspore type bauxite, the lime can eliminate the influence of titanium minerals and promote the leaching of alumina, and can also make phosphorus minerals generate calcium hydroxyphosphate to reduce the phosphorus content in the system; for gibbsite, the addition of lime is mainly used to make phosphorus minerals generate calcium hydroxyphosphate to reduce the phosphorus content in the system; the recycled mother liquor has the effect of leaching alumina in the bauxite, and the chemical composition of the recycled mother liquor can be NaOH, NaAl(OH)3, etc.; the red mud has the effect of promoting the generation of calcium hydroxyphosphate as a seed crystal.

[0035] In some embodiments, the added weight of the red mud is 1% to 10% of the added weight of the bauxite.

[0036] In the embodiments of the present application, the added weight of the above-mentioned red mud is controlled, and the red mud promotes the generation of calcium hydroxyphosphate as a seed crystal. If the added amount of the red mud is too large, the solid content of the ore slurry will increase to some extent, and the burden of red mud settlement will increase; if the added amount of the red mud is too small, the above-mentioned beneficial effects will be weakened to some extent. Specifically, the added weight of the red mud can be 1%, 2%, 4%, 6%, 8%, 10% or the like of the added weight of the bauxite.

[0037] In some embodiments, the added weight of the lime is 3% to 12% of the added weight of the bauxite.

[0038] In the embodiments of the present application, the added weight of the above-mentioned lime is controlled, and for diaspore type bauxite, the lime can eliminate the influence of titanium minerals and promote the leaching of alumina, and can also make phosphorus minerals generate calcium hydroxyphosphate to reduce the phosphorus content in the system; for gibbsite, the addition of lime is mainly used to make phosphorus minerals generate calcium hydroxyphosphate to reduce the phosphorus content in the system. If the added amount of the lime is too large, alumina loss will occur to some extent; if the added amount of the lime is too small, the above-mentioned beneficial effects will be weakened to some extent. Specifically, the added weight of the lime can be 3%, 5%, 7%, 9%, 11%, 12% or the like of the added weight of the bauxite.

[0039] ​S2, pre-desilication is performed on the bauxite raw ore slurry to obtain a pre-desilication slurry;

[0040] In some embodiments, the process parameters of the pre-desilication include a pre-desilication temperature, a pre-desilication time, and a pre-desilication solid content; wherein,

[0041] The pre-desilication temperature is 90-105℃, the pre-desilication time is 6-15h, and the pre-desilication solid content is 300-1000g / L.

[0042] In the embodiments of the present application, a pre-desilication process is provided to slow down the formation of silicon scabs (sodium silicon slag, calcium pyroxene, hydrated garnet, etc.) and titanium scabs (calcium titanate, hydroxy calcium titanate). The pre-desilication temperature is controlled to promote the reaction of silicon minerals in bauxite to generate sodium silicon slag, increase the desilication efficiency, and slow down the formation of silicon scabs. Specifically, the pre-desilication temperature can be 90℃, 95℃, 100℃, 105℃, etc. The pre-desilication time is controlled to promote the reaction of silicon minerals in bauxite to generate sodium silicon slag, increase the desilication efficiency, and slow down the formation of silicon scabs. Specifically, the pre-desilication time can be 6h, 9h, 12h, 15h, etc. If the pre-desilication temperature is too high or the pre-desilication time is too long, the energy consumption will increase to some extent. If the pre-desilication temperature is too low or the pre-desilication time is too short, the reaction of silicon minerals will not be sufficient, and the desilication efficiency will be low. The pre-desilication solid content is controlled. High solid content increases the concentration of SiO2 in the slurry, and more sodium silicon slag is generated by reaction. The sodium silicon slag acts as a seed to further promote the desilication of the solution and has a positive effect on slowing down the scabbing. If the pre-desilication solid content is too high, the viscosity of the slurry will increase to some extent, causing poor flowability of the slurry and poor transportability. If the pre-desilication solid content is too low, the desilication effect will be poor, and the molecular weight of the subsequent leaching solution will be high, resulting in low production efficiency. Specifically, the pre-desilication solid content can be 300g / L, 400g / L, 500g / L, 600g / L, 700g / L, 800g / L, 900g / L, 1000g / L, etc.

[0043] S3, pre-heating is performed on the pre-desilication slurry to obtain a dephosphorization slurry;

[0044] In some embodiments, the process parameters of the pre-heating include a pre-heating temperature and a pre-heating time.

[0045] In some embodiments, the pre-heating temperature is 220-260℃.

[0046] In some embodiments, the pre-heating temperature is 240-260℃.

[0047] In the embodiment of the present application, a preheating process is provided, that is, dephosphorization, to slow down the generation of phosphorus scabs in the dissolution process, slow down the generation of silicon and titanium scabs, effectively prolong the operation cycle, and reduce the number of scab cleaning.

[0048] In the embodiment of the present application, the preheating temperature is controlled, and the reaction rate of phosphorus minerals in the ore is higher in the temperature range, which is more conducive to the generation of calcium hydroxyl phosphate into red mud, and the dephosphorization effect is better. Generally, the dissolution temperature of bauxite at high temperature is 260-280℃, and the preheating temperature does not need to be higher than the dissolution temperature. If the temperature is too high, the requirements for equipment pipes are higher, and the investment cost is higher. If the preheating temperature is too small, the reaction rate of phosphorus minerals will be low to a certain extent, and the dephosphorization will not be sufficient. Specifically, the preheating temperature can be 220℃, 230℃, 240℃, 250℃, 260℃, etc. Preferably, the preheating temperature can be 240-260℃.

[0049] In some embodiments, the preheating time is greater than 30 min.

[0050] In the embodiment of the present application, the preheating time is controlled, which is conducive to the more sufficient reaction of phosphorus minerals and better dephosphorization effect. If the time is too short, the dephosphorization effect will be poor to a certain extent. Specifically, the preheating time can be 40 min, 50 min, 60 min, 70 min, etc.

[0051] S4, dissolving the dephosphorized ore slurry to obtain bauxite dissolution slurry.

[0052] In some embodiments, the dissolution temperature is 260-280℃.

[0053] In the embodiment of the present application, the dissolution temperature is controlled, the alumina dissolution effect is good, and the dissolution rate is high. If the dissolution temperature is too high, the requirements for equipment pipes will be higher to a certain extent, and the investment cost will be greatly increased. If the dissolution temperature is too low, the alumina dissolution rate will be reduced to a certain extent. Specifically, the dissolution temperature can be 260℃, 265℃, 270℃, 275℃, 280℃, etc. After the S4 step, alumina production can be continued.

[0054] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods not specified in the following examples are generally determined according to the national standards. If there is no corresponding national standard, the general international standard, conventional conditions, or the conditions recommended by the manufacturer are used.

[0055] The embodiment of the present application provides a method for dissolving bauxite ore slurry, which comprises:

[0056] S11, obtaining a bauxite raw ore slurry;

[0057] S21, pre-desiliconizing the bauxite raw ore slurry to obtain a pre-desiliconized ore slurry;

[0058] S31, pre-heating the pre-desiliconized ore slurry to obtain a dephosphorized ore slurry;

[0059] S41, leaching the dephosphorized ore slurry to obtain a bauxite leaching ore slurry. The specific implementation process parameters can be seen in Examples 1-8 and Comparative Examples 1-2 below.

[0060] Comparative Example 1

[0061] 1# The content of P2O5 in the bauxite is 0.15%, and the bauxite is used for producing alumina. First, the bauxite, lime and recycled mother liquor are ball milled according to a certain proportion to prepare a raw ore slurry, and the lime is added in an amount of 5% of the weight of the bauxite. The pre-desiliconization is carried out under the conditions of a pre-desiliconization temperature of 90°C, a pre-desiliconization time of 8h and a pre-desiliconization solid content of 400g / L, and the pre-desiliconized ore slurry is pre-heated to 265°C for leaching for 60min.

[0062] Comparative Example 2

[0063] 2# The content of P2O5 in the bauxite is 0.25%, and the bauxite is used for producing alumina. First, the bauxite, lime and recycled mother liquor are ball milled according to a certain proportion to prepare a raw ore slurry, and the lime is added in an amount of 9% of the weight of the bauxite. The pre-desiliconization is carried out under the conditions of a pre-desiliconization temperature of 90°C, a pre-desiliconization time of 8h and a pre-desiliconization solid content of 400g / L, and the pre-desiliconized ore slurry is pre-heated to 265°C for leaching for 60min.

[0064] Example 1

[0065] 1# The bauxite is used in the technical solution, and the bauxite, lime, recycled mother liquor and a small amount of red mud are ball milled according to a certain proportion to prepare a raw ore slurry, and the lime is added in an amount of 5% of the weight of the bauxite, and the red mud is added in an amount of 2% of the weight of the bauxite. The pre-desiliconization is carried out under the conditions of a pre-desiliconization temperature of 95°C, a pre-desiliconization time of 8h and a pre-desiliconization solid content of 400g / L, and the pre-desiliconized ore slurry is pre-heated to 230°C and then kept in a pressure digester for 60min, and then heated to 265°C for leaching for 60min.

[0066] Example 2

[0067] 1# bauxite adopts the technical scheme, the bauxite, lime, circulating mother liquor and a small amount of red mud are ball milled according to certain proportion to prepare raw ore slurry, the lime addition amount is 5% of the weight of bauxite, the red mud addition amount is 5% of the weight of bauxite;Under the conditions of pre-desiliconization temperature 105℃, pre-desiliconization time 10h, pre-desiliconization solid content 600g / L, pre-desiliconization is carried out, the pre-desiliconization slurry is preheated to 240℃, then kept in the pressure digester for 60min, then heated to 265℃ and dissolved for 60min.

[0068] Example 3

[0069] 1# bauxite adopts the technical scheme, the bauxite, lime, circulating mother liquor and a small amount of red mud are ball milled according to certain proportion to prepare raw ore slurry, the lime addition amount is 5% of the weight of bauxite, the red mud addition amount is 8% of the weight of bauxite;Under the conditions of pre-desiliconization temperature 105℃, pre-desiliconization time 10h, pre-desiliconization solid content 600g / L, pre-desiliconization is carried out, the pre-desiliconization slurry is preheated to 250℃, then kept in the pressure digester for 60min, then heated to 270℃ and dissolved for 60min.

[0070] Example 4

[0071] 1# bauxite adopts the technical scheme, the bauxite, lime, circulating mother liquor and a small amount of red mud are ball milled according to certain proportion to prepare raw ore slurry, the lime addition amount is 5% of the weight of bauxite, the red mud addition amount is 10% of the weight of bauxite;Under the conditions of pre-desiliconization temperature 105℃, pre-desiliconization time 10h, pre-desiliconization solid content 600g / L, pre-desiliconization is carried out, the pre-desiliconization slurry is preheated to 260℃, then kept in the pressure digester for 40min, then heated to 270℃ and dissolved for 60min.

[0072] Example 5

[0073] 2# bauxite adopts the technical scheme, the bauxite, lime, circulating mother liquor and a small amount of red mud are ball milled according to certain proportion to prepare raw ore slurry, the lime addition amount is 8% of the weight of bauxite, the red mud addition amount is 2% of the weight of bauxite;Under the conditions of pre-desiliconization temperature 95℃, pre-desiliconization time 8h, pre-desiliconization solid content 400g / L, pre-desiliconization is carried out, the pre-desiliconization slurry is preheated to 230℃, then kept in the pressure digester for 60min, then heated to 265℃ and dissolved for 60min.

[0074] Example 6

[0075] 2#bauxite ore, the bauxite ore, lime, circulating mother liquor and a small amount of red mud are ball milled to prepare an original ore slurry according to a certain proportion, the lime addition amount is 8% of the weight of the bauxite ore, and the red mud addition amount is 8% of the weight of the bauxite ore; pre-desilication is carried out under the conditions of a pre-desilication temperature of 105℃, a pre-desilication time of 10h, and a pre-desilication solid content of 600g / L, the pre-desilication ore slurry is preheated to 250℃, then is kept in a pressure digester for 60min, and then is heated to 270℃ for dissolution for 60min.

[0076] Example 7

[0077] 2#bauxite ore, the bauxite ore, lime, circulating mother liquor and a small amount of red mud are ball milled to prepare an original ore slurry according to a certain proportion, the lime addition amount is 8% of the weight of the bauxite ore, and the red mud addition amount is 8% of the weight of the bauxite ore; pre-desilication is carried out under the conditions of a pre-desilication temperature of 105℃, a pre-desilication time of 10h, and a pre-desilication solid content of 600g / L, the pre-desilication ore slurry is preheated to 250℃, then is kept in a pressure digester for 60min, and then is heated to 270℃ for dissolution for 60min.

[0078] Example 8

[0079] 2#bauxite ore, the bauxite ore, lime, circulating mother liquor and a small amount of red mud are ball milled to prepare an original ore slurry according to a certain proportion, the lime addition amount is 8% of the weight of the bauxite ore, and the red mud addition amount is 8% of the weight of the bauxite ore; pre-desilication is carried out under the conditions of a pre-desilication temperature of 105℃, a pre-desilication time of 10h, and a pre-desilication solid content of 600g / L, the pre-desilication ore slurry is preheated to 250℃, then is kept in a pressure digester for 60min, and then is heated to 270℃ for dissolution for 60min.

[0080] The running cycle of the dissolution pipeline through the dissolution bauxite ore slurry method in the above examples 1-8 and comparative examples 1-2 is shown in Table 1.

[0081] Table 1: Running cycle of dissolution pipeline

[0082] Serial number Operation cycle of the dissolution conduit / day Comparative Example 1 35 Comparative Example 2 25 Example 1 50 Example 2 59 Example 3 63 Example 4 65 Example 5 40 Example 6 50 Example 7 52 Example 8 55

[0083] Through the dissolution bauxite ore slurry method of the examples of the present application, the generation of phosphorus scabs in the dissolution pipeline is effectively slowed down, and the generation of silicon and titanium scabs is also slowed down, greatly prolonging the running cycle (as shown in Table 1) and reducing the number of scab cleaning. At the same time, the technology also has the advantages of low investment, low cost, and easy industrialization application.

[0084] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A method of leaching bauxite ore slurry, characterized by, The method comprises: Grinding bauxite, lime, circulating mother liquor and red mud to obtain bauxite raw ore slurry; Pre-desilication is performed on the bauxite raw ore slurry to obtain pre-desilication slurry; The pre-desilication slurry is preheated to obtain dephosphorization slurry; The dephosphorization slurry is dissolved to obtain bauxite dissolution slurry; The preheating temperature is 240-260 DEG C, and the preheating time is greater than 30 min; The added weight of the red mud is 1-10% of the added weight of the bauxite.

2. The method of claim 1, wherein, The added weight of the lime is 3-12% of the added weight of the bauxite. The process parameters of the pre-desilication include pre-desilication temperature, pre-desilication time and pre-desilication solid content; wherein 3. The method of claim 1, wherein, The pre-desilication temperature is 90-105 DEG C, the pre-desilication time is 6-15 h, and the pre-desilication solid content is 300-1000 g / L. The dissolution temperature is 260-280 DEG C. ​ ​ 4. The method of claim 1, wherein, ​

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