Method for preparing and rapidly dewatering bentonite gel

Abstract

The application discloses a method for preparing and rapidly dehydrating bentonite gel, which comprises the following steps: adding bentonite raw ore, water and a sodium agent into a sodium tank, mixing and stirring; connecting a hydrocyclone and a horizontal screw centrifuge in series; sequentially feeding the material into the hydrocyclone and the horizontal centrifuge for purification to obtain purified ore slurry; adding CMC into the ore slurry and stirring, and then adopting a plate-frame filter press for pressure filtration and dehydration to obtain filter cake; and crushing and drying the filter cake in a powerful crushing and drying machine to obtain the bentonite gel. The calcium-based bentonite is subjected to sodiumization, the bentonite is purified by using the hydrocyclone and the centrifuge, and the plate-frame filter press is adopted for pressure filtration and dehydration after adding CMC, so that the drying efficiency is improved and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-metallic mineral deep processing, in particular to a bentonite gel preparation and rapid dewatering method. BACKGROUND

[0002] Bentonite is also called bentonite or bentonite, which is a clay mineral with montmorillonite as the main component. The montmorillonite content is generally 85-90%, so some properties of bentonite are determined by montmorillonite. The structural formula of montmorillonite is Na x (H2O)4{(AI 2-x Mg 0.33 )[Si4O 10 ](OH)2}, which consists of two layers of silicon oxygen tetrahedron and one layer of silicon oxygen octahedron. The tetrahedron and octahedron are connected by shared oxygen atoms, the crystal layers are connected by oxygen layers, and the crystal layers are stacked along the c-axis direction, so that it has rigidity, no slip between layers, and the thickness of the crystal layer is about 1nm, and the layer spacing d(001) is 1.2-1.6nm.

[0003] Bentonite is low in price, rich in reserves and wide in application. The mineral has been widely used in many industrial departments due to its good swelling, dispersion, suspension, adsorption, plasticity, high ion exchange capacity, dry bonding strength, high shear and high compressive strength, and good impermeability. However, the product has low solid content during production of the existing bentonite gel, high drying cost, and it is difficult to dry and dewater after modification treatment, and the cost of direct drying of the ore slurry is high.

[0004] Therefore, a bentonite gel preparation and rapid dewatering method is designed, which utilizes a reasonable processing technology to reduce the moisture content of the filter cake and reduce the processing cost, solves the problems in the above background technology, and has a wide application prospect. SUMMARY

[0005] The purpose of the present application is to provide a bentonite gel preparation and rapid dewatering method, which is sodiumized by calcium-based bentonite, purified by a hydrocyclone and a centrifuge, and dewatered by a plate and frame filter press after adding CMC, thereby improving the drying efficiency.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a bentonite gel preparation and rapid dewatering method, comprising the following steps:

[0007] S1, sodiumization of bentonite ore: bentonite ore, water and sodiumizing agent are added into a sodiumizing tank and mixed, and stirring is carried out at a stirring speed of 200-400r / min, and the sodiumization reaction is maintained for 10-60min;

[0008] S2, purification: connecting a hydrocyclone and a horizontal spiral centrifuge in series; the material after sodiumization reaction in step S1 is purified by the hydrocyclone and the horizontal centrifuge in series to obtain purified ore slurry;

[0009] S3, pressure filtration and dewatering: adding CMC (Carboxymethyl Cellulose) into the ore slurry after purification in step S2 and stirring, then using a plate and frame filter press for pressure filtration and dewatering to obtain filter cake;

[0010] S4, crushing and drying: crushing and drying the filter cake obtained in step S3 in a powerful crushing and drying machine to obtain bentonite gel.

[0011] Preferably, the bentonite ore in step S1 is calcium-based bentonite.

[0012] Preferably, in step S1, the mass ratio of water to bentonite ore is 4:1-32:1, and the mass ratio of sodiumizing agent to bentonite ore is 1%-10%.

[0013] In the above, the sodiumizing agent provides Na + The sodiumization reaction refers to replacing other types of cations existing between the layers of the bentonite ore with Na + The sodiumization tank refers to a container for sodiumization of the bentonite ore.

[0014] Preferably, the sodiumizing agent is at least one of sodium carbonate, sodium chloride, sodium fluoride and sodium bicarbonate.

[0015] Preferably, in step S2, the material after sodiumization reaction enters the hydrocyclone from the feed port of the hydrocyclone, sequentially passes through the hydrocyclone and the horizontal centrifuge, and the purified bentonite ore slurry is discharged from the discharge port of the horizontal cyclone.

[0016] In the above, the hydrocyclone can remove the sandy material of relatively coarse particle size, which protects the horizontal spiral centrifugal separator. In the horizontal spiral centrifugal separator, the ore slurry is in dynamic motion under the action of centrifugal force due to the high-speed movement of the separator drum, which can eliminate the adverse effects of thixotropy of the ore slurry itself on mineral separation. It can achieve stable performance and excellent quality of sodiumization purification products at a relatively high concentration.

[0017] Preferably, the hydrocyclone includes a Φ75 hydrocyclone, the horizontal centrifuge includes a WLB-350 horizontal centrifuge, and the Φ75 hydrocyclone and the WLB-350 horizontal centrifuge are connected in series.

[0018] Preferably, the Φ75 hydrocyclone overflow port diameter is 10-30 mm, the underflow port diameter is 2-12 mm, the feed pressure is 0.3 MPa, the processing capacity is 100-160 kg / h, and the feed concentration is 3-6%. 3 Preferably, the WLB-350 horizontal spiral centrifuge separation factor is 1500-1800, the processing capacity is 2-5 m

[0019] Preferably, the separation factor refers to the separation factor of the horizontal spiral centrifuge, and the calculation formula is separation factor = n 2 r / 894, wherein n is the rotation speed of the centrifuge, and r is the radius of the centrifuge.

[0020] Preferably, in step S3, the mass ratio of CMC to bentonite is 1‰-10‰, the molecular weight of CMC is 1-5 million, and the moisture content of the filter cake is 30%-40%.

[0021] In the above, in step S4, a powerful crushing dryer is used for crushing and drying, and the crushing and drying are simultaneously performed, so that the water wrapped in the particles is exposed on the surface in time, and is rapidly evaporated, which not only improves the drying efficiency, but also timely discharges under negative pressure to avoid excessive drying and reduce the product quality.

[0022] Preferably, the gel product prepared in step S4 is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0023] Compared with the prior art, the present application has the following advantages due to the use of the above technical scheme:

[0024] 1. The present application uses the method of adding CMC, and the plate and frame filter press is used for dewatering and pressure filtration, which improves the drying efficiency and reduces the production cost.

[0025] 2. The dynamic centrifugal purification process of the present application can eliminate the adverse effects of the thixotropy of the ore slurry on mineral separation, and can realize the separation of montmorillonite and impurity minerals under a high concentration condition, and has the advantages of continuous operation, good stability, easy automation operation, and stable quality of sodium purification products.

[0026] 3. The method of the present application is simple, can automatically realize effective separation, purification and drying of minerals, has good purification and drying effects, and is suitable for popularization and use. BRIEF DESCRIPTION OF DRAWINGS

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Fig. 1 This is a schematic diagram of the process flow for preparing and rapidly dehydrating bentonite gel according to the present invention.

[0029] Fig. 2 This is a schematic diagram of the bentonite gel prepared according to the present invention. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figs. 1-2 As shown, this embodiment relates to a method for preparing and rapidly dehydrating bentonite gel, including the following steps:

[0033] S1. Sodiumization of bentonite ore: Add bentonite ore, water and sodiumizing agent to a sodiumization tank and mix them. Stir at a speed of 200-400 r / min and maintain the sodiumization reaction for 10-60 min.

[0034] S2. Purification: Connect the hydrocyclone and the horizontal screw centrifuge in series; pass the material that has completed the sodium reaction in step S1 through the hydrocyclone and the horizontal centrifuge in sequence for purification to obtain the purified slurry.

[0035] S3. Filtration and dewatering: CMC is added to the slurry purified in step S2 and stirred. After stirring, a plate and frame filter press is used for filtration and dewatering to obtain filter cake.

[0036] S4. Crushing and drying: The filter cake obtained in step S3 is crushed and dried in a high-power crusher and dryer to obtain bentonite gel.

[0037] Preferably, the bentonite ore in step S1 is calcium-based bentonite.

[0038] Preferably, in step S1, the mass ratio of water to bentonite ore is 4:1 to 32:1, and the mass ratio of sodium-modifying agent to bentonite ore is 1% to 10%.

[0039] In the above, the sodium agent provides Na+, and the sodium reaction refers to replacing other types of cations existing in the interlayer of the bentonite ore with Na+, thereby facilitating ion exchange of the organic cation; the sodium tank refers to a container for sodium of the bentonite ore.

[0040] Preferably, the sodium agent is at least one of sodium carbonate, sodium chloride, sodium fluoride and sodium bicarbonate.

[0041] Preferably, in step S2, the material after the sodium reaction is fed into the hydrocyclone from the feed inlet, sequentially passes through the hydrocyclone and the horizontal centrifuge, and the purified bentonite ore slurry is discharged from the discharge outlet of the horizontal cyclone.

[0042] In the above, the hydrocyclone can remove the sandy material of a relatively coarse particle size, and protects the horizontal spiral centrifuge; in the horizontal spiral centrifuge, the slurry is in dynamic motion under the action of the centrifugal force caused by the high-speed rotation of the drum, and the thixotropy of the slurry itself does not adversely affect the separation of the minerals; and the sodium purification product with stable performance and excellent quality can be obtained at a high concentration.

[0043] Preferably, the hydrocyclone includes a Φ75 hydrocyclone, and the horizontal centrifuge includes a WLB-350 horizontal centrifuge, and the Φ75 hydrocyclone and the WLB-350 horizontal centrifuge are connected in series.

[0044] Preferably, the Φ75 hydrocyclone has an overflow port with a diameter of 10-30 mm, an underflow port with a diameter of 2-12 mm, a feed pressure of 0.3 MPa, a processing capacity of 100-160 kg / h, and a feed concentration of 3-6%; the WLB-350 horizontal spiral centrifuge has a separation factor of 1500-1800, a processing capacity of 2-5 m3 / h, and a feed concentration of 2-5%.

[0045] Preferably, the separation factor refers to the separation factor of the horizontal spiral centrifuge, and the calculation formula is separation factor = n2r / 894, where n is the rotation speed of the centrifuge, and r is the radius of the centrifuge.

[0046] Preferably, in step S3, the mass ratio of CMC to bentonite is 1‰-10‰, the molecular weight of CMC is 1 million-5 million, and the moisture content of the filter cake is 30%-40%.

[0047] In the above, in step S4, a powerful crushing dryer is used for crushing and drying, and the crushing and drying are simultaneously performed, so that the water wrapped in the particles is exposed on the surface in time, and is rapidly evaporated, thereby improving the drying efficiency, and the product is discharged in time under negative pressure, and the product quality is not reduced due to excessive drying.

[0048] Preferably, the gel product prepared in step S4 is detected, and the product viscosity is >1000 mPa-s at 5% solid content.

[0049] Example Two

[0050] This example is based on the above-mentioned example one, and the same parts as the above-mentioned example one are not described.

[0051] In this example, in step S1, the stirring speed is 200 r / min, and the sodium reaction is maintained for 10 min; wherein the mass ratio of water to bentonite raw ore is 4:1, and the mass ratio of sodium agent to bentonite raw ore is 2%.

[0052] In step S2, the overflow port diameter of the Φ75 hydrocyclone is 30 mm, the underflow port diameter is 6 mm, the feed pressure is 0.3 MPa, the processing capacity is 143.7 kg / h, and the feed concentration is 4.2%. The separation factor of the WLB-350 horizontal screw centrifuge is 1700, the processing capacity is 3.6 m 3 / h, and the feed concentration is 3.87%.

[0053] In this example, the yield of the concentrate product obtained in the sodium purification test is 71.0%, the concentration is 13.26%, the montmorillonite content is 90.0%, and the d(001) value is also changed from 1.5768 nm to 1.1872 nm, indicating that the sodium purification effect is good.

[0054] In step S3, the mass ratio of CMC to bentonite is 2‰, the molecular weight of CMC is 1 million, and the moisture content of the filter cake is 32%.

[0055] The gel product prepared in this example is detected, and the product viscosity is >1000 mPa-s at 5% solid content.

[0056] Example Three

[0057] This example is based on the above-mentioned example two, and the same parts as the above-mentioned example two are not described.

[0058] In this example, in step S1, the stirring speed is 200 r / min, and the sodium reaction is maintained for 10 min; wherein the mass ratio of water to bentonite raw ore is 10:1, and the mass ratio of sodium agent to bentonite raw ore is 2%.

[0059] In this example, the yield of the concentrate product obtained in the sodium purification test is 75.0%, the concentration is 4.21%, the montmorillonite content is 91.0%, and the d(001) value is also changed from 1.5768 nm to 1.1872 nm, indicating that the sodium purification effect is good.

[0060] The gel product prepared in this embodiment is detected, and the product viscosity is >1000 mPa s at 5% solid content.

[0061] Example Four

[0062] This embodiment is based on the above-mentioned embodiment two, and the same as the above-mentioned embodiment two will not be described.

[0063] In this embodiment, in step S1, the stirring speed is 200 r / min, and the sodium reaction is maintained for 10 min; wherein the mass ratio of water to bentonite raw ore is 35:1, and the mass ratio of sodium agent to bentonite raw ore is 2%.

[0064] In this embodiment, the concentrate product yield obtained by the sodium purification test is 70.0%, the concentration is 2.10%, the montmorillonite content is 91.0%, and the d(001) value is also changed from 1.5768 nm to 1.1872 nm, indicating that the sodium purification effect is good.

[0065] The gel product prepared in this embodiment is detected, and the product viscosity is >1000 mPa s at 5% solid content.

[0066] Example Five

[0067] This embodiment is based on the above-mentioned embodiment two, and the same as the above-mentioned embodiment two will not be described.

[0068] In this embodiment, in step S1, the stirring speed is 200 r / min, and the sodium reaction is maintained for 10 min; wherein the mass ratio of water to bentonite raw ore is 10:1, and the mass ratio of sodium agent to bentonite raw ore is 5%.

[0069] In this embodiment, the concentrate product yield obtained by the sodium purification test is 75.39%, the concentration is 4.20%, the montmorillonite content is 92.0%, and the d(001) value is also changed from 1.5768 nm to 1.1872 nm, indicating that the sodium purification effect is good.

[0070] The gel product prepared in this embodiment is detected, and the product viscosity is >1000 mPa s at 5% solid content.

[0071] Example Six

[0072] This embodiment is based on the above-mentioned embodiment two, and the same as the above-mentioned embodiment two will not be described.

[0073] In this embodiment, in step S1, the stirring speed is 200 r / min, and the sodium reaction is maintained for 10 min; wherein the mass ratio of water to bentonite raw ore is 10:1, and the mass ratio of sodium agent to bentonite raw ore is 15%.

[0074] In this embodiment, the concentrate product yield obtained by the sodiumization purification test is 74.0%, the concentration is 4.21%, the montmorillonite content is 91.0%, and the d(001) value is changed from 1.5768 nm to 1.1872 nm, indicating that the sodiumization purification effect is good.

[0075] The gel product prepared in this embodiment is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0076] Example Seven

[0077] This embodiment is based on the above-mentioned embodiment two, and the same parts as the above-mentioned embodiment two will not be repeated.

[0078] In this embodiment, in step S3, the mass ratio of CMC to bentonite is 1‰, the molecular weight of CMC is 5 million, and the filter cake moisture is 35%.

[0079] The gel product prepared in this embodiment is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0080] Example Eight

[0081] This embodiment is based on the above-mentioned embodiment two, and the same parts as the above-mentioned embodiment two will not be repeated.

[0082] In step S3, the mass ratio of CMC to bentonite is 3‰, the molecular weight of CMC is 1 million, and the filter cake moisture is 33%.

[0083] The gel product prepared in this embodiment is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0084] Example Nine

[0085] This embodiment is based on the above-mentioned embodiment two, and the same parts as the above-mentioned embodiment two will not be repeated.

[0086] In step S3, the mass ratio of CMC to bentonite is 15‰, the molecular weight of CMC is 1 million, and the filter cake moisture is 42%.

[0087] The gel product prepared in this embodiment is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0088] Comparative Example One

[0089] This comparative example is based on the above-mentioned embodiment two, and the same parts as the above-mentioned embodiment two will not be repeated.

[0090] In the present comparative example, the stirring speed in step S1 is 200 r / min, and the sodium reaction is maintained for 10 min; wherein the mass ratio of water to bentonite raw ore is 3:1, and the mass ratio of sodium agent to bentonite raw ore is 5%.

[0091] In the present example, the yield of the concentrate product obtained in the sodium purification test is 71.66%, the concentration is 14.77%, the montmorillonite content is 75.0%, and the d(001) value is also changed from 1.5768 nm to 1.1872 nm, indicating that the sodium purification effect is good.

[0092] The gel product prepared in the present example is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0093] Comparative Example Two

[0094] The present comparative example is based on the above-mentioned Example Two, and the same parts as the above-mentioned Example Two will not be repeated.

[0095] In the present comparative example, the stirring speed in step S1 is 200 r / min, and the sodium reaction is maintained for 10 min; wherein the mass ratio of water to bentonite raw ore is 39:1, and the mass ratio of sodium agent to bentonite raw ore is 2%.

[0096] In the present example, the yield of the concentrate product obtained in the sodium purification test is 61.21%, the concentration is 1.13%, the montmorillonite content is 91.0%, and the d(001) value is also changed from 1.5768 nm to 1.1872 nm, indicating that the sodium purification effect is good.

[0097] The gel product prepared in the present example is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0098] Comparative Example Three

[0099] The present comparative example is based on the above-mentioned Example Two, and the same parts as the above-mentioned Example Two will not be repeated.

[0100] In step S3, the mass ratio of CMC to bentonite is 15‰, the molecular weight of CMC is 1 million, and the moisture content of the filter cake is 52%.

[0101] The gel product prepared in the present example is detected, and the product viscosity is >1000 mPa·s at 5% solid content.

[0102] From the above examples 2 to 6 and comparative examples 1 to 2, it can be obviously seen that under the same conditions, when the mass ratio of water to bentonite raw ore is 10:1 and the mass ratio of sodium agent to bentonite raw ore is 5%, the yield, montmorillonite content and concentration of the concentrate product are higher, and the sodium purification effect is good; when the mass ratio of water to bentonite raw ore exceeds the range of the present application, the yield, montmorillonite content or concentration of the concentrate product is lower.

[0103] From the above examples 2, 7 to 9 and comparative example 3, it can be obviously seen that under the same conditions, when the mass ratio of CMC to bentonite is 3‰ and the molecular weight of CMC is 1 million, the filter cake moisture is lower and the dewatering effect is better; when the mass ratio of CMC to bentonite exceeds the range of the present application, the filter cake moisture is higher and the dewatering effect is poorer.

[0104] The above description of disclosed examples enables one skilled in the art to make or use the application. Numerous modifications to these examples will be apparent to those skilled in the art, and the general principles defined herein can be applied to other examples without departing from the spirit or scope of the application. Therefore, the present application is not to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing and rapidly dehydrating bentonite gel, characterized in that, Includes the following steps: S1. Sodiumization of bentonite ore: Add bentonite ore, water and sodiumizing agent to a sodiumization tank and mix them. Stir at a speed of 200-400 r / min and maintain the sodiumization reaction for 10-60 min. S2. Purification: Connect the hydrocyclone and the horizontal screw centrifuge in series; pass the material that has completed the sodium reaction in step S1 through the hydrocyclone and the horizontal centrifuge in sequence for purification to obtain the purified slurry. S3. Filtration and dewatering: CMC is added to the slurry purified in step S2 and stirred. After stirring, a plate and frame filter press is used for filtration and dewatering to obtain filter cake. S4. Crushing and drying: The filter cake obtained in step S3 is crushed and dried in a high-power crusher and dryer to obtain bentonite gel. In step S1, the mass ratio of water to bentonite ore is 4:1 to 32:1, and the mass ratio of sodium-modifying agent to bentonite ore is 1% to 10%. In step S3, the mass ratio of CMC to bentonite is 1‰ to 10‰, the molecular weight of CMC is 1 million to 5 million, and the moisture content of the filter cake is 30% to 40%.

2. The method for preparing and rapidly dehydrating bentonite gel according to claim 1, characterized in that, The bentonite ore mentioned in step S1 is calcium-based bentonite.

3. The method for preparing and rapidly dehydrating bentonite gel according to claim 1, characterized in that, The sodium-containing agent is selected from at least one of sodium carbonate, sodium chloride, sodium fluoride, and sodium bicarbonate.

4. The method for preparing and rapidly dehydrating bentonite gel according to claim 1, characterized in that, In step S2, the material that has completed the sodium reaction enters the hydrocyclone from the feed port of the hydrocyclone, passes through the hydrocyclone and the horizontal centrifuge in sequence, and the purified bentonite slurry is discharged from the discharge port of the horizontal hydrocyclone.

5. The method for preparing and rapidly dehydrating bentonite gel according to claim 4, characterized in that, The hydrocyclone includes a Φ75 hydrocyclone, and the horizontal centrifuge includes a WLB-350 horizontal centrifuge. The Φ75 hydrocyclone and the WLB-350 horizontal centrifuge are connected in series.

6. The method for preparing and rapidly dehydrating bentonite gel according to claim 5, characterized in that, The Φ75 hydrocyclone has an overflow port diameter of 10~30mm, an underflow port diameter of 2~12mm, a feed pressure of 0.3MPa, a throughput of 100~160kg / h, and a feed concentration of 3~6%; the WLB-350 horizontal screw centrifuge has a separation factor of 1500~1800 and a throughput of 2~5m³. 3 / h, with a feed concentration of 2~5%.

7. The method for preparing and rapidly dehydrating bentonite gel according to claim 6, characterized in that, Separation factor refers to the separation factor of a horizontal screw centrifuge, and the calculation formula is separation factor = n 2 r / 894, where n is the centrifuge speed and r is the centrifuge radius.

8. The method for preparing and rapidly dehydrating bentonite gel according to claim 1, characterized in that, The gel product prepared in step S4 was tested, and the viscosity of the product with a solid content of 5% was >1000mPa·s.

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