A preparation method of high-purity attapulgite

Abstract

The present invention discloses a method for preparing high-purity attapulgite, comprising the following steps: (1) crushing attapulgite ore, and performing pre-sorting after crushing to obtain pre-sorted concentrate; (2) sedimenting the pre-sorted concentrate to obtain lower ore pulp; (3) ultrasonically dispersing the lower ore pulp, and performing step centrifugal separation and post-treatment after dispersion to obtain high-purity attapulgite. The present invention provides a method for preparing high-purity attapulgite from attapulgite ore. Compared with the existing wet process, the present invention greatly improves the preparation efficiency, purity, yield and use safety of attapulgite products from multiple aspects such as control of impurity introduction in the preparation process, ore, ore pulp treatment process, and equipment optimization design, and at the same time provides a key foundation for the preparation of high-purity attapulgite required in the biomedical field and the feasibility of large-scale industrial production.

Description

Technical Field

[0001] The invention relates to the field of mineral purification engineering, and in particular to a method for preparing high-purity attapulgite. Background Art

[0002] Attapulgite is a 2:1 layer chain structure of hydrous magnesium-aluminum silicate clay minerals. Due to its unique needle-rod crystal structure, it has a series of excellent physical and chemical properties such as adsorption, colloid, and cation exchange. With these properties, attapulgite is widely used in petrochemical, composite materials, medicine and health care and other fields. Therefore, attapulgite is also known as the "king of thousands of soils, soil of all uses". my country has a large reserve of attapulgite, accounting for about 60% of the world's reserves, and it is mainly distributed in Jiangsu, Anhui, Gansu and the central region.

[0003] Attapulgite has a very broad application prospect in the field of biomedicine. On the one hand, pure attapulgite can be directly used as a medicine, often used to treat gastric diseases; on the other hand, attapulgite can also be used to prepare biomedical composite materials. Although my country has abundant reserves of attapulgite, most of it is only used as low-value-added oil drilling mud, and only a small part of it is used as high-value-added products such as medical and health products and nanocomposites. At present, the main reasons for limiting the high-value utilization of attapulgite include the low purity of purified attapulgite, high purification cost, and the difficulty in removing certain chemical agents introduced during the purification process.

[0004] At present, the commonly used purification methods of attapulgite are dry purification and wet purification. Dry purification mainly uses a grinding machine to grind the raw ore into powder and then uses an air classifier to grade, sort and purify it. The purity of attapulgite purified by dry method is low, and the finished product is mostly used as chemical or construction filler. Wet purification mainly disperses the raw ore in water, and then uses density differences for grading and separation. The products purified by wet method are suitable for industries with high requirements for the purity of attapulgite. For attapulgite used in the field of biomedicine, not only must its purity reach at least 95%, but also the introduction of other chemical impurities should be avoided as much as possible during the purification process. Conventional wet purification will use dispersants, which will reduce the quality of attapulgite products to a certain extent, and will also increase the cost of pharmaceuticals and de-drug costs; at the same time, because attapulgite is fragile and has high viscosity, wet purification also faces the problem of high dehydration costs.

[0005] Therefore, developing a simple, efficient, purely physical method to purify attapulgite ore will have great application prospects and economic value. Summary of the invention

[0006] The invention provides a method for preparing high-purity attapulgite, which is used to solve the technical problems in the existing attapulgite production process that impurities are easily introduced, the product purity cannot meet the application requirements and the production cost is too high.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for preparing high-purity attapulgite comprises the following steps:

[0009] (1) crushing the attapulgite ore, and performing pre-sorting after the crushing to obtain a pre-sorted concentrate;

[0010] (2) sedimenting the pre-separated concentrate to obtain a lower slurry;

[0011] (3) subjecting the lower ore pulp to ultrasonic dispersion, and after dispersion, subjecting it to step centrifugal separation and post-treatment to obtain the high-purity attapulgite.

[0012] The design idea of ​​the above technical scheme is that, after the attapulgite ore is crushed and preliminarily sorted, the present invention removes large-size and high-density impurities in the ore to achieve efficient pre-sorting, and then dissociates the rod-shaped crystal bundle structure inside the attapulgite through ultrasonic dispersion, which is convenient for subsequent separation and purification, and finally obtains high-purity attapulgite through multiple and step-by-step centrifugal separations; no chemical dispersant is added in the whole preparation process of the present technical scheme, which avoids the introduction of chemical impurities, ensures the purity of the final product, and improves the safety of the product in specific fields; at the same time, the present technical scheme gradually completes the separation of impurities and the purification of attapulgite through multi-stage treatment of the ore, and the separation and purification effects are good. The purity of the attapulgite finally obtained can reach 96%, which meets the purity requirements of attapulgite in the biomedicine field.

[0013] As a further preferred embodiment of the above technical solution, the specific operation of the step centrifugal separation in step (3) is as follows: the ore pulp after ultrasonic dispersion is centrifuged for the first time, the ore pulp is divided into three layers after the first centrifugation, the slurry of the middle layer is taken and added with solvent and stirred to obtain ore pulp A; the ore pulp A is centrifuged for the second time, the ore pulp A is divided into three layers after the second centrifugation, the slurry of the middle layer is taken and added with solvent and stirred to obtain ore pulp B; the ore pulp B is centrifuged for the third time, the ore pulp B is divided into three layers after the third centrifugation, the slurry of the middle layer is taken to obtain ore pulp C, and the ore pulp C is post-processed to obtain the high-purity attapulgite. The inventors have determined after repeated research and multiple experiments that the impurities in the attapulgite can be completely removed after three step centrifugations, and too many centrifugations will lead to separation difficulties, reduced recovery rate and increased energy consumption.

[0014] As a further preferred embodiment of the above technical solution, when the solvent is added and stirred to obtain the slurry A or slurry B, the stirring speed is 1100-1300 r / min and the stirring time is 8-12 min.

[0015] As a further preferred embodiment of the above technical solution, in the step centrifugal separation operation, the speed of the first centrifugation is 5800-6200 r / min, and the centrifugation time is 8-12 min; the speed of the second centrifugation is 7800-8200 r / min, and the centrifugation time is 8-12 min; the speed of the third centrifugation is 9800-10200 r / min, and the centrifugation time is 10 min.

[0016] As a further preferred embodiment of the above technical solution, in the step centrifugal separation operation, the bottom layer of pulp after each centrifugation is collected, and pulp D is obtained after merging. The pulp D is centrifuged three times according to the step centrifugation method, and the middle layer of pulp after the third centrifugation is collected, and the high-purity attapulgite is obtained after post-processing. By collecting, mixing and re-centrifuging the bottom layer of pulp with more impurities, the attapulgite component can be effectively recovered and the recovery rate of attapulgite can be improved. The recovery rate of attapulgite finally obtained can reach 60%.

[0017] In step (1), a countercurrent sorting column is used to pre-sort the crushed attapulgite ore; the countercurrent sorting column comprises a column body, the column body is provided with a feed port, the bottom of the column body is provided with a water inlet and a bottom flow port, the top of the column body is provided with a top flow port and an inclined plate inclined upward, one end of the inclined plate is connected to the top flow port for receiving material overflowing from the top flow port, and the other end is provided with an overflow port. The countercurrent separation column used in the preferred embodiment uses the solid-liquid fluidized bed and inclined plate sedimentation principles to separate the ore pulp. When in use, the ore pulp prepared in advance is fed into the feed bucket. The ore particles in the column area are affected by buoyancy, gravity and rising water drag, and the particles whose interference sedimentation velocity is equal to the rising water flow velocity form a fluidized bed layer in the vertical column area. The particles with a larger sedimentation velocity move downward and are discharged from the bottom flow port, and the particles with a smaller sedimentation velocity enter the inclined plate from the top flow port. The particles on the inclined plate undergo secondary sorting. The particles are washed by water on the inclined plate, so that the particles with high density settle on the inclined plate and slide into the column, thereby enhancing the sorting effect, and the particles with low density are discharged from the overflow port. In the pre-sorting process, the ore pulp first forms a fluidized bed in the column so that the mineral particles are stratified according to density or particle size, and then the upper inclined plate is used to enhance the sedimentation and sorting effect, which is equivalent to performing two sorting processes and enhancing the sorting effect. At the same time, compared with other gravity separation equipment, the equipment also has the advantages of large processing capacity, simple structure, and high separation efficiency.

[0018] As a further preferred embodiment of the above technical solution, a plurality of water inlets are symmetrically arranged at the bottom of the column.

[0019] As a further preferred embodiment of the above technical solution, before pre-sorting the crushed attapulgite ore in step (1), the crushed attapulgite ore is prepared into a slurry with a concentration of 20% with clean water and stirred evenly.

[0020] As a further preferred embodiment of the above technical solution, in step (1), a double-roll crusher is used to crush the attapulgite ore; the particle size of the attapulgite ore after crushing is 0.425 to 1 mm.

[0021] As a further preferred embodiment of the above technical solution, the sedimentation time of the pre-separated slurry in step (2) is 10 hours to 24 hours.

[0022] As a further preferred embodiment of the above technical solution, the ultrasonic frequency of the ultrasonic dispersion operation in step (3) is 40 to 100 kHz, and the ultrasonic time is 25 to 35 minutes. The inventors have found through multiple experiments and repeated studies that the ultrasonic operation within the parameter range of this preferred solution can achieve the dissociation of the rod-shaped crystal bundle structure inside the attapulgite powder to the greatest extent, and effectively improve the purification efficiency and effect of the subsequent step centrifugal separation, thereby improving the purity and yield of the final attapulgite product.

[0023] As a further preferred embodiment of the above technical solution, before the step centrifugal separation in step (3), the ore pulp after ultrasonic dispersion is stirred at a stirring speed of 1000-1400 r / min and a stirring time of 40-80 min. This preferred solution uses mechanical stirring force to separate the attapulgite particles from the main impurities such as quartz before the step centrifugal separation, which is convenient for the separation of impurities in the subsequent centrifugal process, the purification efficiency and effect of the step centrifugal separation, and the purity and yield of the final attapulgite product.

[0024] As a further preferred embodiment of the above technical solution, the post-treatment operation of the product obtained by step centrifugation in step (3) is dehydration, pre-freezing and vacuum freeze drying, the pre-freezing temperature is -20°C to -80°C, the pre-freezing time is 10 to 24 hours; the vacuum freeze drying time is 24 hours. The purpose of post-treatment in this preferred solution is, on the one hand, to fully dissociate the rod crystal bundles of attapulgite, and on the other hand, to prevent secondary agglomeration caused by ordinary drying. After the secondary agglomeration, the product needs to be subjected to a grinding process to avoid the cumbersome process and the increase of production cost.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] The present invention provides a method for preparing high-purity attapulgite from attapulgite ore. Compared with the existing wet process, the present invention greatly improves the preparation efficiency, purity, yield and use safety of attapulgite products from multiple aspects such as control of impurity introduction in the preparation process and optimization design of ore and slurry treatment process, while avoiding the cost increase problem caused by the dehydration process in the existing process, providing theoretical and practical feasibility of large-scale industrial production for the preparation of high-purity attapulgite required in the medical field, and adopts a countercurrent sorting column to pre-sort the ore before cascade centrifugation, thereby improving the sorting effect and providing effective guarantee for the efficiency and effect of subsequent cascade centrifugation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a SEM comparison of the raw ore and high-purity attapulgite in Example 1;

[0028] Figure 2 This is a TEM image of the high-purity attapulgite of Example 1;

[0029] Figure 3 Schematic diagram of the structure of the countercurrent separation column used in each embodiment.

[0030] Legend:

[0031] 1. Column; 2. Stirring assembly; 3. Feed inlet; 4. Bottom flow outlet; 5. Water inlet; 6. Countercurrent cavity; 7. Top flow outlet; 8. Inclined plate; 9. Cavity; 10. Overflow outlet; 11. Inclined plate area. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with specific embodiments.

[0033] Embodiment 1:

[0034] like Figure 1 As shown, the preparation method of high-purity attapulgite in this embodiment comprises the following steps:

[0035] (1) Crushing of the ore: The dried attapulgite ore is crushed by a double-roll crusher; the particle size of the crushed attapulgite ore is 1 mm; the ore comes from Duliang Mining Group in Xuyi County, Jiangsu Province, and the particle size of the ore is less than 6 mm. The attapulgite content in the ore is 78%, and the main impurity is quartz, which has a content of 18%, and also contains very small amounts of montmorillonite and dolomite;

[0036] (2) Pre-separation of raw ore: Prepare the raw ore into a slurry with a concentration of 20%, stir it evenly, and then use a countercurrent separation column for pre-separation. The countercurrent separation column is as follows: Figure 3As shown, it includes a column 1, a feed port 3 is arranged on the column 1, a stirring assembly 2 is arranged inside the column 1, the bottom of the column 1 is a countercurrent chamber 6, a water inlet 5 and a bottom flow port 4 are arranged therein, and two water inlets 5 are arranged, which are located at symmetrical positions at the bottom of the column 1; an inclined plate area 11 is arranged on the top of the column 1, and the inclined plate area 11 includes an inclined plate 8 arranged obliquely upward, one end of the inclined plate 8 is connected to the column 1 through a top flow port 7 arranged at the top of the column 1, and the other end is connected to a cavity 9, and an overflow port 10 is opened in the cavity 9; the bottom liquid flowing out of the bottom flow port 4 during the pre-sorting process is used for tailings treatment, and the slurry flowing out of the overflow port 10 is the pre-sorted concentrate;

[0037] (3) Sedimentation of pre-sorted concentrate: The pre-sorted concentrate is subjected to sedimentation for 10 hours, and the supernatant is removed after sedimentation, leaving the sedimented coarse concentrate slurry for standby use;

[0038] (4) Dispersion after ore pre-sorting: Collect the settled coarse concentrate slurry produced in step (3), take 1 L of the slurry and treat it with ultrasound for 25 min at an ultrasound frequency of 100 kHz, and then use a magnetic stirrer to stir the slurry after ultrasound for 60 min at a stirring speed of 1200 r / min;

[0039] (5) Stepwise centrifugal separation of the dispersed slurry: The slurry stirred in step (4) is centrifuged for the first time using a high-speed centrifuge at a centrifugal speed of 6200 r / min for 8 min. After centrifugation, the slurry has an obvious three-layer structure, the top layer is a water layer, the middle layer is a milky white slurry layer, i.e., purified attapulgite, and the bottom layer is an off-white slurry layer, i.e., an impurity layer; the centrifugal liquid is removed, the milky white slurry in the middle layer is collected, an appropriate amount of distilled water is added, and mechanical stirring is performed at a stirring speed of 1200 r / min for 10 min to obtain slurry A; the off-white slurry in the bottom layer is taken out for later use; and slurry A is centrifuged for the second time. The centrifugal speed is 7800 r / min, and the centrifugal time is 12 min. After centrifugation, the slurry still has a three-layer structure. The centrifugal liquid is removed in the same way, and the milky white slurry in the middle layer is collected again. An appropriate amount of distilled water is added for mechanical stirring at a stirring speed of 1200 r / min and a stirring time of 10 min to obtain slurry B. The gray-white slurry at the bottom is taken out for later use. Slurry B is centrifuged for the third time at a centrifugal speed of 9800 r / min and a centrifugal time of 10 min. After centrifugation, the slurry still has a three-layer structure. The centrifugal liquid is removed in the same way, and the milky white slurry in the middle layer is collected again to obtain slurry C, and the gray-white slurry at the bottom is collected for later use. The gray-white slurry at the bottom collected by three centrifugations was mixed, and an appropriate amount of water was added. After mechanical stirring, the same three centrifugations were performed as above. The middle layer slurry after the third centrifugation was taken, and it was combined with the ore pulp C and then dehydrated, pre-frozen and vacuum freeze-dried. The pre-freezing temperature was -20°C, the pre-freezing time was 24h, and the vacuum freeze-drying time was 24h; finally, it was ground into powder to obtain high-purity attapulgite. The SEM comparison of the original ore and the final high-purity attapulgite in this embodiment is shown in FIG. Figure 1 As shown ( Figure 1 a and b are SEM display results of raw ore at different scales, c and d are SEM display results of high-purity attapulgite at different scales); TEM image of high-purity attapulgite prepared in this embodiment is as shown in Figure 2 As shown ( Figure 2 Figures ad in the figure are TEM display results of high-purity attapulgite at different scales, and the specific scales are shown in the figure).

[0040] The attapulgite prepared in this example was tested, and the results showed that the purity of the purified attapulgite was 97%, and the recovery rate was 70%.

[0041] Embodiment 2:

[0042] The preparation method of high-purity attapulgite in this embodiment comprises the following steps:

[0043] (1) Crushing of the ore: The dried attapulgite ore is crushed by a jaw crusher; the particle size of the crushed attapulgite ore is 0.5 mm; the ore comes from Huaiyuan Mining Group in Xuyi County, Jiangsu Province, and the particle size is less than 6 mm. The attapulgite content in the ore is 50% after testing, and the main impurities in the ore are quartz and a small amount of montmorillonite;

[0044] (2) Pre-separation of raw ore: Prepare the raw ore into a slurry with a concentration of 20%, stir it evenly, and then use a countercurrent separation column for pre-separation. The countercurrent separation column is as follows: Figure 3 As shown, it includes a column 1, a feed port 3 is arranged on the column 1, a stirring assembly 2 is arranged inside the column 1, the bottom of the column 1 is a countercurrent chamber 6, a water inlet 5 and a bottom flow port 4 are arranged therein, and two water inlets 5 are arranged, which are located at symmetrical positions at the bottom of the column 1; an inclined plate area 11 is arranged on the top of the column 1, and the inclined plate area 11 includes an inclined plate 8 arranged obliquely upward, one end of the inclined plate 8 is connected to the column 1 through a top flow port 7 arranged at the top of the column 1, and the other end is connected to a cavity 9, and an overflow port 10 is opened in the cavity 9; the bottom liquid flowing out of the bottom flow port 4 during the pre-sorting process is used for tailings treatment, and the slurry flowing out of the overflow port 10 is the pre-sorted concentrate;

[0045] (3) Sedimentation of pre-sorted concentrate: The pre-sorted concentrate is subjected to sedimentation for 10 hours, and the supernatant is removed after sedimentation, leaving the sedimented coarse concentrate slurry for standby use;

[0046] (4) Dispersion after ore pre-sorting: Collect the settled coarse concentrate slurry produced in step (3), take 1 L of the slurry and perform ultrasonic treatment for 35 min at an ultrasonic frequency of 40 kHz, and then use a magnetic stirrer to stir the ultrasonic slurry for 80 min at a stirring speed of 1000 r / min;

[0047] (5) Stepwise centrifugal separation of the dispersed slurry: The slurry stirred in step (4) is centrifuged for the first time using a high-speed centrifuge at a centrifugal speed of 5800 r / min for a centrifugal time of 12 min. After centrifugation, the slurry has an obvious three-layer structure, the top layer is a water layer, the middle layer is a milky white slurry layer, i.e., purified attapulgite, and the bottom layer is an off-white slurry layer, i.e., an impurity layer; the centrifugal liquid is removed, the milky white slurry in the middle layer is collected, an appropriate amount of distilled water is added, and mechanical stirring is performed at a stirring speed of 1200 r / min for a stirring time of 10 min to obtain slurry A; the off-white slurry in the bottom layer is taken out for later use; and slurry A is centrifuged for a second time. The centrifugal speed is 8200 r / min, and the centrifugal time is 8 min. After centrifugation, the slurry still has a three-layer structure. The centrifugal liquid is removed in the same way, and the milky white slurry in the middle layer is collected again. An appropriate amount of distilled water is added for mechanical stirring at a stirring speed of 1200 r / min and a stirring time of 10 min to obtain slurry B. The gray-white slurry at the bottom is taken out for later use. Slurry B is centrifuged for the third time at a centrifugal speed of 10200 r / min and a centrifugal time of 10 min. After centrifugation, the slurry still has a three-layer structure. The centrifugal liquid is removed in the same way, and the milky white slurry in the middle layer is collected again to obtain slurry C, and the gray-white slurry at the bottom is collected for later use. The gray-white slurry at the bottom layer collected by three centrifugations was mixed, an appropriate amount of water was added, and the same three centrifugations were performed after mechanical stirring. The middle layer slurry after the third centrifugation was taken, and it was combined with the ore pulp C and then dehydrated, pre-frozen and vacuum freeze-dried. The pre-freezing temperature was -80°C, the pre-freezing time was 10 hours, the vacuum freeze-drying time was 24 hours, and it was ground into powder to obtain high-purity attapulgite. The attapulgite prepared in this example was tested, and the results showed that the purity of the purified attapulgite was 95.7%, and the recovery rate was 65%.

[0048] Embodiment 3:

[0049] The preparation method of high-purity attapulgite in this embodiment comprises the following steps:

[0050] (1) Crushing of the ore: The dried attapulgite ore is crushed by a jaw crusher; the particle size of the crushed attapulgite ore is 1 mm; the ore comes from Zhangye, Gansu, and the particle size is less than 6 mm. The attapulgite content in the ore is only 30% after testing, and the main impurities in the ore are quartz and dolomite, containing a small amount of bentonite;

[0051] (2) Pre-sorting of raw ore: The raw ore is prepared into a slurry with a concentration of 20%, stirred evenly, and then pre-sorted using a countercurrent sorting column. The countercurrent sorting column includes a column 1, a feed port 3 is provided on the column 1, a stirring assembly 2 is provided inside the column 1, and a countercurrent chamber 6 is provided at the bottom of the column 1, in which a water inlet 5 and an underflow port 4 are provided. There are two water inlets 5, which are located at symmetrical positions at the bottom of the column 1; an inclined plate area 11 is provided at the top of the column 1, and the inclined plate area 11 includes an inclined plate 8 arranged obliquely upward. One end of the inclined plate 8 is connected to the column 1 through a topflow port 7 provided at the top of the column 1, and the other end is connected to a cavity 9, and an overflow port 10 is provided in the cavity 9; during the pre-sorting process, the bottom liquid flowing out of the underflow port 4 is used for tailings treatment, and the slurry flowing out of the overflow port 10 is the pre-sorted concentrate;

[0052] (3) Sedimentation of pre-sorted concentrate: The pre-sorted concentrate is subjected to sedimentation for 10 hours, and the supernatant is removed after sedimentation, leaving the sedimented coarse concentrate slurry for standby use;

[0053] (4) Dispersion after ore pre-sorting: Collect the settled coarse concentrate slurry produced in step (3), take 1 L of the slurry and perform ultrasonic treatment for 30 min at an ultrasonic frequency of 70 kHz, and then use a magnetic stirrer to stir the ultrasonic slurry for 40 min at a stirring speed of 1400 r / min;

[0054] (5) Stepwise centrifugal separation of the dispersed slurry: The slurry stirred in step (4) is centrifuged for the first time using a high-speed centrifuge at a centrifugal speed of 6000 r / min for 10 min. After centrifugation, the slurry has an obvious three-layer structure, the top layer is a water layer, the middle layer is a milky white slurry layer, i.e., purified attapulgite, and the bottom layer is an off-white slurry layer, i.e., an impurity layer; the centrifugal liquid is removed, the milky white slurry in the middle layer is collected, an appropriate amount of distilled water is added, and mechanical stirring is performed at a stirring speed of 1200 r / min for 10 min to obtain slurry A; the off-white slurry in the bottom layer is taken out for later use; slurry A is centrifuged for the second time at a centrifugal speed of 8000 r / min. in, the centrifugal force is 6791×g, and the centrifugal time is 10min; after centrifugation, the slurry still has a three-layer structure, and the centrifugal liquid is removed in the same way, and the milky white slurry in the middle layer is collected again, and an appropriate amount of distilled water is added for mechanical stirring, the stirring speed is 1200r / min, and the stirring time is 10min to obtain slurry B; the gray-white slurry at the bottom is taken out for later use; slurry B is centrifuged for the third time, the centrifugal speed is 10000r / min, the centrifugal force is 10611×g, and the centrifugal time is 10min; after centrifugation, the slurry still has a three-layer structure, and the centrifugal liquid is removed in the same way, and the milky white slurry in the middle layer is collected again to obtain slurry C, and the gray-white slurry at the bottom is collected for later use. The gray-white slurry at the bottom layer collected by three centrifugations is mixed, an appropriate amount of water is added, and the same three centrifugations are performed after mechanical stirring. The middle layer slurry after the third centrifugation is taken, combined with the pulp C, and then dehydrated, pre-frozen and vacuum freeze-dried. The pre-freezing temperature is -50°C, the pre-freezing time is 18 hours, and the vacuum freeze-drying time is 24 hours. Finally, it is ground into powder to obtain high-purity attapulgite.

[0055] The attapulgite prepared in this example was tested, and the results showed that the purity of the purified attapulgite was 95.7%, and the recovery rate was 58%.

[0056] Comparative Example 1:

[0057] The preparation method of the attapulgite in this comparative example is different from that in Example 3 in that in step (4), the ore pulp is separated by centrifugation once, the centrifugal speed is 8000 r / m, and the centrifugal time is 10 min, which is consistent with each step in Example 3. The attapulgite prepared in this comparative example was tested, and the results showed that the purity of the attapulgite prepared in this comparative example was 65%, and the recovery rate was 85%.

[0058] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and changes obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing high-purity attapulgite, characterized in that: The process includes the following steps: Step 1: crushing the attapulgite ore, and then pre-sorting it to obtain a pre-sorted concentrate; Step 2: sedimenting the pre-separated concentrate to obtain a lower ore pulp; Step 3: subjecting the lower slurry to ultrasonic dispersion, and after dispersion, subjecting it to step centrifugal separation and post-treatment to obtain the high-purity attapulgite; The ultrasonic dispersion operation has an ultrasonic frequency of 40 to 100 kHz and an ultrasonic time of 25 to 35 minutes; The specific operation of the step centrifugal separation is as follows: the ore pulp after ultrasonic dispersion is subjected to the first centrifugation, the ore pulp is divided into three layers after the first centrifugation, the ore pulp is taken from the middle layer and added with solvent and stirred to obtain ore pulp A; the ore pulp A is subjected to the second centrifugation, the ore pulp A is divided into three layers after the second centrifugation, the ore pulp B is taken from the middle layer and added with solvent and stirred to obtain ore pulp B; the ore pulp B is subjected to the third centrifugation, the ore pulp B is divided into three layers after the third centrifugation, the ore pulp C is taken from the middle layer, and the ore pulp C is post-processed to obtain the high-purity attapulgite; in the step centrifugal separation operation, the speed of the first centrifugation is 5800-6200 r / min, and the centrifugation time is 8-12 min; the speed of the second centrifugation is 7800-8200 r / min, and the centrifugation time is 8-12 min; the speed of the third centrifugation is 9800-10200 r / min, and the centrifugation time is 10 min; No chemical dispersant is added in the preparation method.

2. The method for preparing high-purity attapulgite according to claim 1, characterized in that: In the step centrifugal separation operation, the bottom layer of pulp after each centrifugation is collected and combined to obtain pulp D. The pulp D is centrifuged three times according to the step centrifugal separation operation, and the middle layer of pulp after the third centrifugation is collected. After post-processing, the high-purity attapulgite is obtained.

3. The method for preparing high-purity attapulgite according to claim 1, characterized in that: In step one, a countercurrent sorting column is used to pre-sort the crushed attapulgite ore; the countercurrent sorting column comprises a column (1), the column (1) is provided with a feed port (3), the bottom of the column (1) is provided with a water inlet (5) and a bottom flow port (4), the top of the column (1) is provided with a top flow port (7) and an inclined plate (8) inclined upward, one end of the inclined plate (8) is connected to the top flow port (7) for receiving material overflowing from the top flow port (7), and the other end is provided with an overflow port (10).

4. The method for preparing high-purity attapulgite according to claim 3, characterized in that: Before pre-sorting the crushed attapulgite ore in step 1, the crushed attapulgite ore is prepared into a slurry with a concentration of 20% with clean water and stirred evenly.

5. The method for preparing high-purity attapulgite according to any one of claims 1 to 4, characterized in that: In step 1, a double-roll crusher is used to crush the attapulgite ore; the particle size of the attapulgite ore after crushing is 0.425-1 mm.

6. The method for preparing high-purity attapulgite according to any one of claims 1 to 4, characterized in that: In step 2, the sedimentation time of the pre-separated concentrate is 10 hours to 24 hours.

7. The method for preparing high-purity attapulgite according to any one of claims 1 to 4, characterized in that: Before the step centrifugal separation in step 3, the ore pulp after ultrasonic dispersion is stirred at a stirring speed of 1000 to 1400 r / min and a stirring time of 40 to 80 min.

8. The method for preparing high-purity attapulgite according to any one of claims 1 to 4, characterized in that: In step 3, the post-processing operations performed on the product obtained by step centrifugation are dehydration, pre-freezing and vacuum freeze-drying. The pre-freezing temperature is -20°C to -80°C, and the pre-freezing time is 10 to 24 hours; the vacuum freeze-drying time is 24 hours.

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