A mineralized filter material and preparation method thereof

Abstract

The present invention provides a mineralized filter material, which includes a core layer and a cortex, wherein the core layer includes 0-10 parts by mass of a strontium salt, 30-100 parts by mass of a calcium salt, 4-40 parts by mass of amorphous silica and 3-30 parts by mass of sodium alginate, and the cortex includes polyvinyl alcohol, and the core layer and the cortex are concentric circle structures. Since the mineralized filter material provided by the present invention is selected from specific chemical components, material selection is safe and reliable. In addition, due to the selection of the skin-core structure, the mineral is released basically only at the end face exposed by the particle core layer, and within the entire service life, the area exposed by the core layer end face does not change substantially, thereby making the mineral release rate relatively stable. The mineralized filter material provided by the present invention can supplement beneficial ingredients such as calcium and metasilicic acid, and is suitable for functionalized water quality adjustment of pure water machines.

Description

Technical Field

[0001] The present invention relates to the field of water treatment material preparation, in particular to a pure water mineralization filter material and a preparation method thereof. Background Art

[0002] Water purifiers, such as RO reverse osmosis (RO), have become ubiquitous in millions of households. However, while RO removes pollutants from water, it also removes beneficial minerals such as calcium, strontium, and metasilicic acid. Furthermore, purified water lacks flavor-forming ions, making it inferior to high-quality drinking water. Safely adding minerals to purified water can address these issues and, in the right proportions, improve the water's taste.

[0003] The existing technology generally uses minerals combined with clay to granulate and calcine into porous ceramic balls. The solubility of this material is not controlled in the early stage. In addition, the pH is too high under the soaking conditions, which poses a safety hazard and a bad taste. Subsequent improved solutions, such as application number: 201810416794.8, use natural stone for acid washing, ion exchange and other technologies to produce modified "mineralized materials". Due to the complexity of the composition of natural minerals and the uncontrollable influence of the materials taken from the mineral layers in the mining area, even after the above treatment, there is still a safety risk of excessive harmful substances. In this context, it is very necessary to develop a mineralized filter material with a safe source of raw materials and excellent taste. Summary of the Invention

[0004] In view of the above problems, the present invention discloses a mineralized filter material and a preparation method thereof, so as to overcome the above problems or at least partially solve the above problems.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A mineralized filter material comprising a core layer and a skin layer.

[0007] The core layer comprises 0-10 parts by mass of strontium salt, 30-100 parts by mass of calcium salt, 4-40 parts by mass of amorphous silicon dioxide and 3-30 parts by mass of sodium alginate; the skin layer comprises polyvinyl alcohol; and the core layer and the skin layer are concentric circle structures.

[0008] Preferably, the core layer further comprises 10-30 parts by mass of zinc oxide.

[0009] Preferably, the diameter of the core layer is 30-100 μm, and the outer diameter of the skin layer is 50-140 μm.

[0010] Preferably, the strontium salt is strontium carbonate, and the calcium salt is calcium carbonate.

[0011] A method for preparing a mineralized filter material, characterized in that 0-10 parts by mass of strontium salt and 30-100 parts by mass of calcium salt are wetted and mixed with 40-100 parts by mass of water, and then 20-100 parts by mass of neutral silica sol are poured into the mixture, ground for 4-20 hours, and stirred evenly to obtain a slurry.

[0012] Sodium alginate is added to water and heated, and its pH is adjusted to 6-8 to dissolve to form a viscous sodium alginate solution with a mass concentration of 6-10%, and the temperature is kept at 45-60°C; polyvinyl alcohol is added to water and dissolved to obtain a polyvinyl alcohol aqueous solution with a mass concentration of 8-16%, and the temperature is kept at 60-85°C.

[0013] The slurry and the sodium alginate viscous solution are fed separately through a pump at a mass mixing ratio of 10:3-10:30, and after being fully mixed, a core layer spinning solution is obtained.

[0014] The core layer spinning solution is passed into the core layer of a concentric skin-core spinneret, the polyvinyl alcohol aqueous solution is passed into the skin layer of the concentric skin-core spinneret, and then sprayed into a coagulation bath containing 3-10% calcium chloride with a pH range of 11-13. The primary coagulated fibers are then broken after being allowed to stand for 60-240 seconds to obtain cylindrical strip particles.

[0015] The cylindrical strip particles are dried at 60-80° C. for 4-10 hours to obtain a mineralized filter material.

[0016] Preferably, when 0-10 parts by mass of strontium salt and 30-100 parts by mass of calcium salt are wetted and mixed with 40-100 parts by mass of water, 10-30 parts by mass of zinc oxide are added simultaneously.

[0017] Preferably, the mesh sizes of the strontium salt, the calcium salt and the zinc oxide are all 600-5000 meshes.

[0018] Preferably, the polyvinyl alcohol has a degree of alcoholysis of not less than 98%.

[0019] Preferably, the diameter of the core layer is 30-100 μm, and the outer diameter of the skin layer is 50-140 μm.

[0020] Preferably, the pump is a positive displacement pump and the feeding is forced feeding.

[0021] Because the mineralized filter media provided by the present invention is selected from specific chemical components, the material selection is safe and reliable. Furthermore, due to the selected skin-core structure, mineral release is essentially limited to the exposed end surfaces of the core layer of the particles. The exposed area of ​​the core layer end surfaces remains essentially unchanged throughout the entire use cycle, resulting in a relatively stable mineral release rate. The mineralized filter media provided by the present invention can supplement beneficial ingredients such as calcium and metasilicic acid, making it suitable for functionalizing the output water quality of water purifiers. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0023] Figure 1 is a top view of a mineralized filter material in a specific embodiment of the present invention;

[0024] Figure 2 is a cross-sectional elevation view of a mineralized filter material according to a specific embodiment of the present invention;

[0025] Figure 3 It is a process flow chart of the preparation method of the mineralized filter material in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present invention more clear, the following will provide a clear and complete description of the technical solutions of the present invention in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Mineralized filter media

[0028] The present invention provides a mineralized filter material, comprising Figure 1 and Figure 2 The core layer and the cortex shown, the core layer comprises 0-10 parts by mass of strontium salt, 30-100 parts by mass of calcium salt and 4-40 parts by mass of amorphous silica, the cortex comprises polyvinyl alcohol, and the core layer and the cortex are concentric circle structures. Since the mineralized filter material provided by the present invention is selected from specific chemical components, the material selection is safe and reliable. In addition, due to the selection of the core-skin structure, the mineral is released basically only at the exposed end face of the particle core layer, and during the entire use cycle, the exposed area of ​​the core layer end face does not change basically, so that the mineral release rate is relatively stable. The mineralized filter material provided by the present invention can supplement beneficial ingredients such as calcium and metasilicic acid, and is suitable for functional water quality adjustment of pure water machine outlet.

[0029] Here, the calcium salt and the strontium salt can be selected from one of silicates, carbonates and sulfates. Since bicarbonate ions can improve the taste of drinking water, the calcium salt and the strontium salt are preferably calcium carbonate and strontium carbonate respectively.

[0030] Since zinc oxide has the effect of inhibiting microorganisms, it is preferred that the core layer also includes 10-30 parts by mass of zinc oxide. As the microorganisms, bacteria (for example, Escherichia coli, Staphylococcus aureus, Salmonella), fungi, yeasts, algae and viruses (for example, new coronavirus) can be listed. The core layer diameter and the outer diameter of the cortex vary according to the application scenario of the mineralized filter material. For example, the core layer diameter can be set to 30-100 μm, and the outer diameter of the cortex can be set to 50-140 μm.

[0031] In addition, as mentioned above, in order to ensure the safety and reliability of the selection of the mineralized filter material, the present invention preferably uses a combination of specific chemical components as the raw materials for preparing the mineralized filter material.

[0032] The mineralized filter material provided by the present invention can be added as a functional component to components such as a post-filter element of a water purifier and a water filter pot.

[0033] Preparation method of mineralized filter material

[0034] The mineralized filter material of the present invention is prepared through the following steps.

[0035] Step 1 (slurry preparation): 0-10 parts by mass of strontium salt and 30-100 parts by mass of calcium salt are wetted and mixed with 40-100 parts by mass of water. Then, 20-100 parts by mass of neutral silica sol are added and wet-grinded for 4-20 hours to obtain a slurry.

[0036] Here, the calcium salt and the strontium salt can be one selected from silicate, carbonate, and sulfate. Since bicarbonate ions can improve the taste of drinking water, the calcium salt and the strontium salt are preferably calcium carbonate and strontium carbonate, respectively.

[0037] Since zinc oxide has the effect of inhibiting microorganisms, it is preferred that 10-30 parts by mass of zinc oxide be further added in step 1 for moistening and mixing with water.

[0038] When performing wet grinding, a grinding mill is preferably used. The grinding mill can be any of a ball mill, a sand mill, and a vertical mill. Ball mills are preferred in the present invention because they can adapt to a variety of materials, meet the needs of large-scale production, have a large grinding ratio of up to 300, and can easily adjust the fineness of the product.

[0039] Sodium alginate solution is spinnable and can also bind calcium carbonate and strontium carbonate powders, preventing them from disintegrating. Sodium alginate undergoes ionic crosslinking with calcium and strontium ions, increasing viscosity and ultimately gelling. However, due to the low solubility of calcium carbonate and strontium carbonate, and the low levels of free calcium and strontium, crosslinking proceeds slowly and requires considerable time. Therefore, it is preferable to add sodium alginate later.

[0040] The neutral silica sol preferably has a solids concentration of 20%-40%, more preferably 25%-35%. High-concentration silica sols generally have larger particle sizes, and the subsequently formed amorphous silica has larger pores, facilitating mass transfer and accelerating ion release within the neutral silica sol. However, excessively high concentrations can easily clog the spinneret, so amorphous silica with a solids concentration of 25-35% is selected, as it has larger particle sizes and is more convenient for production.

[0041] Step 1 (pulping process) is a step of manufacturing a mineralized material release body, wherein the mineralized material contains calcium and metasilicic acid, and preferably also contains components such as strontium and bicarbonate. In order to remove water as quickly as possible in the subsequent drying process and to avoid excessive addition of water and resulting in too low viscosity of the resulting solution without causing the material to agglomerate, the amount of water used should be as little as possible. The amount of water used is preferably 40-80 parts by mass, more preferably 40-50 parts by mass. It should be noted that, in the present invention, the specific meanings of minerals such as "calcium" and "metasilic acid" can be reasonably interpreted according to specific scenarios, as long as such interpretation does not exceed the common understanding of those skilled in the art. For example, "calcium" can sometimes be understood as calcium ions, and "metasilic acid" can sometimes be understood as metasilicate ions.

[0042] Step 2 (spinning solution dissolution process): Sodium alginate is put into water and heated, and its pH is adjusted to 6-8 to dissolve, forming a viscous sodium alginate solution with a mass concentration of 6-10%. The sodium alginate solution configured in this process provides suitable viscosity and lubricity, which can improve the spinnability of the core material. Separately, polyvinyl alcohol is dissolved in water to obtain a polyvinyl alcohol aqueous solution with a mass concentration of 8-16%, and the temperature is kept at 60-85°C. Polyvinyl alcohol has good spinning characteristics, high spinnability, and good performance as a coating material. Here, water can be any one of tap water, distilled water, deionized water, reverse osmosis water, purified water, high-purity water, and ultrapure water, preferably reverse osmosis water.

[0043] Step 3 (spinning process): The slurry is heated to 40-60°C, and then the slurry and sodium alginate solution are fed separately through a pump at a mass mixing ratio of 10:3-10:30, and mixed in a high viscosity mixer to obtain a core layer spinning solution, which is passed into the core layer of the concentric skin-core spinneret. A polyvinyl alcohol aqueous solution is passed into the skin layer of the concentric skin-core spinneret. It is sprayed into a coagulation bath containing 3-10% calcium chloride with a pH range of 11-13, and left for 60-240 seconds to obtain cylindrical particles. The spinnability of the core layer liquid can be adjusted by adjusting the mixing ratio of the slurry and the sodium alginate solution. Here, the mass mixing ratio of the slurry and the sodium alginate solution is preferably 10:6-10:20, and more preferably 10:8-10:15. If the mass mixing ratio of the slurry to the sodium alginate solution is less than 10:30, the material dissolves slowly, the mineralized filter material fails to sufficiently increase the mineral ions in the water, and the mineralization lifespan is short. If the mass mixing ratio of the slurry to the sodium alginate solution is greater than 10:3, the material dissolves rapidly and cannot be effectively controlled. The mineralized filter material excessively increases the mineral ions in the water, resulting in a safety hazard and unpleasant taste in the resulting mineral water. Adjusting the temperature of the polyvinyl alcohol aqueous solution can adjust the spinnability of the cortical liquid. Polyvinyl alcohol will coagulate when exposed to a strong alkaline liquid. The coagulation rate is related to the pH, with higher pH increasing the coagulation rate. The pH of the calcium chloride coagulation bath is preferably 10.5-12.5, preferably 11-12, to achieve a particularly suitable coagulation rate. Sodium alginate coagulates when exposed to calcium chloride, and the coagulation rate is controlled by the calcium chloride concentration. The calcium chloride concentration in the calcium chloride coagulation bath is preferably 4-8%, more preferably 5-6%, to achieve a particularly suitable coagulation rate. Since polyvinyl alcohol relies on alkalinity for coagulation and sodium alginate relies on free calcium ions for coagulation, in order to ensure that the cortex and core layer coagulate basically synchronously, the selected pH and calcium chloride concentration must be appropriate. If the cortex coagulates too quickly, stress concentration in the cortex is likely to occur, resulting in cortical cracking. If the core layer coagulates too quickly, the cortex and core layer are likely to separate, which is not conducive to ion controlled release. By setting the pH and calcium chloride concentration of the calcium chloride coagulation bath within the above-mentioned preferred range, the cortex and core layer can also be coagulated basically synchronously. The manufacture of this material uses a technology similar to dry-wet spinning, but the goal is not to stretch to form continuous fibers, but only to form strip-shaped particles.

[0044] Here, as the pump, it can be any one of a volumetric pump, a vane pump, and a jet pump. In the present invention, a volumetric pump is preferred, and a screw pump is particularly preferred. The reason for preferring a screw pump is that the screw pump has a simple structure, is easy to manufacture, has a large flow rate, a small head loss, a high efficiency, is easy to repair and maintain, and has a low head and a low speed, which is particularly suitable for the purpose of forming strip-shaped particles rather than stretching to form continuous fibers in the present invention. As the feeding, it can be any one of forced feeding and manual feeding. Compared with manual feeding, forced feeding is that after the raw materials are conveyed to the storage hopper of the granulator main machine in the forced feeding machine, they are bitten by the spiral of the feeding device and are evenly supplied to the main machine at a uniform speed. The speed control system can adjust and control the amount of feeding, thereby avoiding the situation of uneven manual feeding and prone to safety accidents, and achieving the purpose of saving, safety, and efficiency. Therefore, forced feeding is preferred in the present invention.

[0045] If the spinneret is immersed in the coagulation bath, it is easy to get clogged. If the spinneret is too far away from the coagulation bath, the mechanical properties of the cortex and core layers formed by the uncoagulated spinning liquid will be different, and the cortex and core layers will be easy to peel off. Therefore, the air distance for air injection is preferably 5mm-15mm, and more preferably 7mm-12mm.

[0046] Step 4 (drying process): drying the particles obtained in step 3 (spinning process) at 60-80° C. for 4-10 hours to obtain a mineralized filter material.

[0047] In the preparation steps of the mineralized filter media described above, calcium carbonate, strontium carbonate, zinc oxide, and other materials are present as fine solid powders, dispersed in a viscous sodium alginate solution. After the sodium alginate is gelled in a coagulation bath, the fine solid powders are fixed within the alginate gel. In other words, the core layer has a structure in which the fine solid powders are suspended in the sodium alginate solution.

[0048] Because the dissolution of calcium carbonate, strontium carbonate, and other ions raises the pH of the surrounding environment, the highly alcoholyzed polyvinyl alcohol (PVA) coating the core layer is extremely difficult to dissolve at high pH, ​​significantly increasing viscosity and hindering ion migration within the PVA. Furthermore, the mineralized powder components release calcium and strontium ions. Therefore, even after the sodium alginate gels, it is cross-linked by the continuously released calcium, strontium, and zinc ions. Furthermore, because calcium carbonate, strontium carbonate, and zinc oxide are poorly soluble and have low saturation solubility, the concentrations of these ions in the sodium alginate layer are relatively stable, resulting in a more stable gel structure and a relatively consistent ion migration rate. Therefore, mineral release occurs primarily at the exposed end faces of the core layer, and the exposed area of ​​the core layer remains essentially unchanged throughout the entire lifecycle, achieving a relatively stable mineral release rate. The PVA preferably has a PVA degree of alcoholyzation of no less than 98%, and more preferably no less than 99%. Polyvinyl alcohol with a high PVA degree of alcoholyzation solidifies more quickly, has a lower solubility after drying, and exhibits high water resistance.

[0049] Adding neutral silica sol increases structural strength, making it easier for inorganic powders to agglomerate into larger aggregates. Upon drying, the neutral silica sol forms amorphous silica, also known as silicic acid gel. This irreversible reaction occurs when the amorphous silica dissolves in water, primarily in the form of metasilicic acid. Therefore, the silicic acid gel produced after the neutral silica sol solidifies serves as the source of metasilicic acid in the mineralized filter media, while also acting as a binder.

[0050] In addition to its antibacterial effect, the addition of zinc oxide can also assist in the gelation of sodium alginate, delaying the degradation of polyvinyl alcohol and sodium alginate under the action of microorganisms, so that the filter material maintains relatively stable performance over a longer period of time.

[0051] Polyvinyl alcohol is used in the cortex because it has excellent Newtonian rheological properties, good spinnability, low cost, pH-responsive properties (viscous to solidify at high pH), and reduced solubility at high pH. Other ingredients can also be appropriately selected, such as pH-responsive materials (flow at low pH; viscous to solidify at high pH) and calcium ion-responsive materials (gelling in the presence of calcium ions), but polyvinyl alcohol is preferred.

[0052] Sodium alginate is composed of two monomers: mannuronic acid (M) and guluronic acid (G). Sodium alginate with a high G ratio forms a hard and brittle gel, while a high M ratio forms a soft and elastic gel. If the G / M ratio is too high, the calcium alginate gel formed by the core layer of sodium alginate after contact with the coagulation bath will easily break during drying. The broken calcium alginate gel forms new end faces at the rupture sites, resulting in rapid mineral release. If the G / M ratio is too low, ion mass transfer in the calcium alginate gel formed after contact with the coagulation bath is rapid. At an appropriate G / M ratio, the calcium alginate gel has greater strength and viscosity, is less prone to breaking, and has the slowest ion mass transfer rate. Therefore, adjusting the sodium alginate grade can control the rate of mineral ion release.

[0053] As described above, the present invention provides a mineralized filter material and a preparation method thereof. The mineralized filter material can supplement the calcium and metasilicic acid filtered out by the reverse osmosis water purifier, and preferably also supplement components such as strontium and bicarbonate. The beneficial effects of the technical solution provided by the present invention are: the material selection is safe and reliable, and the material dissolution rate can be controlled by the ratio of the slurry to the sodium alginate used as the spinning solution and the model of the sodium alginate. Due to the selection of the skin-core structure, the mineral is released basically only on the exposed end face of the particle core layer, and during the entire use cycle, the exposed area of ​​the core layer end face basically does not change, so that the mineral release rate is relatively stable. Its sanitary safety meets the requirements of the "Sanitary Safety Evaluation Standard for Drinking Water Transmission and Distribution Equipment and Protective Materials" (2001). The mineralized filter material provided by the present invention can supplement the calcium and metasilicic acid filtered out by the reverse osmosis water purifier, and preferably also supplement beneficial components such as strontium. The preferred added bicarbonate can improve the taste of drinking water. It is suitable for functional water quality adjustment of pure water machine output.

[0054] The following combination Figure 2 , the preparation method of the mineralized filter material in the embodiment of the present invention is described in detail. It should be noted that, without hindering the purpose of the present invention, the Figure 2 It should be noted that the room temperature in all the following embodiments refers to 20-25°C.

[0055] Example 1

[0056] Step 1 (slurry preparation process): 10 parts by mass of 1000-mesh strontium carbonate, 30 parts by mass of 2500-mesh calcium carbonate, 10 parts by mass of 1000-mesh zinc oxide, and 40 parts by mass of water are mixed uniformly, 40 parts by mass of 30% neutral silica sol is poured therein, and wet-grinded for 10 hours using a ball mill. Grind and stir uniformly to obtain a slurry.

[0057] Step 2 (Spinning Dope Dissolution): Sodium alginate (trade name: KIMICA I-3) is placed in room temperature water and heated to approximately 60°C. The pH is adjusted to 6-7 to dissolve the sodium alginate, forming an 8% viscous solution. A mixture of polyvinyl alcohol 1799 and room temperature water is heated to obtain a 16% aqueous solution of polyvinyl alcohol, which is then maintained at 70±2°C.

[0058] Step 3 (spinning process): The slurry is heated to 40-60°C, and then the slurry and sodium alginate solution are force-fed through different screw pumps with a feed volume ratio of 1:1. The core layer spinning solution is obtained through a mixing tube, and then the core layer spinning solution enters the spinneret flow channel with a core layer diameter of about 40μm. The polyvinyl alcohol aqueous solution is pumped into the skin spinneret flow channel with an outer diameter of about 60μm. The spinneret temperature is controlled at about 70°C. It is sprayed into a 10% calcium chloride coagulation bath with a pH of 11.5. The air distance is about 10mm. The material stays for about 60s and then is fished out by a conveyor net. The appearance is cylindrical small strip particles.

[0059] Step 4 (drying process): After the material is fished out, it is dried at 80° C. for 4 hours to obtain the mineralized filter material of Example 1.

[0060] Example 2

[0061] Step 1 (slurrying process): 5 parts by mass of 2000 mesh strontium carbonate, 100 parts by mass of 800 mesh calcium carbonate, 30 parts by mass of 1000 mesh zinc oxide, and 100 parts by mass of water are mixed uniformly, 100 parts by mass of 30% neutral silica sol is introduced therein, and wet-grinded using a ball mill for 10 hours to obtain a slurry.

[0062] Step 2 (Spinning solution dissolution process): Sodium alginate (KIMICA I-3G) is placed in water at room temperature (20-25°C) and heated to about 60°C. The pH is adjusted to 7-8 to dissolve the sodium alginate to form a 10% viscous solution. A mixture of polyvinyl alcohol 2699 and room temperature water is heated to obtain an 8% polyvinyl alcohol aqueous solution and kept warm to 80±2°C.

[0063] Step 3 (spinning process): The slurry is heated to 40-60°C, and then the slurry and sodium alginate solution are force-fed through different screw pumps at a feed volume ratio of 1:7. The slurry enters the spinneret flow channel with a core layer diameter of about 40μm through a mixing tube. The polyvinyl alcohol aqueous solution is pumped into the spinneret flow channel with an outer diameter of about 70μm in the skin layer. The spinneret temperature is controlled at about 85°C. The slurry is sprayed into a 5% calcium chloride coagulation bath with a pH of 11.5. The distance between the spinnerets is about 10mm. The material stays for about 60 seconds and then is fished out by a conveyor net. The appearance is cylindrical small strip particles.

[0064] Step 4 (drying process): After the material is fished out, it is dried at 60 degrees Celsius for 10 hours to obtain the mineralized filter material of Example 2.

[0065] Example 3

[0066] Step 1 (slurry preparation process): 0 parts by mass of 2000 mesh strontium carbonate, 60 parts by mass of 5000 mesh calcium carbonate, 20 parts by mass of 800 mesh zinc oxide, and 20 parts by mass of water are mixed uniformly, 300 parts by mass of 30% neutral silica sol is introduced therein, and wet-grinded using a ball mill for 10 hours to obtain a slurry.

[0067] Step 2 (Spinning Dope Dissolution): Sodium alginate (KIMICA I-3G) was placed in room temperature water and heated to approximately 60°C. The pH was adjusted to 7-8 to dissolve the sodium alginate, forming a 10% viscous solution. A mixture of polyvinyl alcohol 2699 and room temperature water was heated to obtain an 8% aqueous solution of polyvinyl alcohol, which was then maintained at 80±2°C.

[0068] Step 3 (spinning process): The slurry is heated to 40-60°C, and then the slurry and sodium alginate solution are force-fed through different screw pumps at a feed volume ratio of 1:1. The slurry enters the spinneret flow channel with a core layer diameter of about 60μm through a mixing tube. The polyvinyl alcohol aqueous solution is pumped into the spinneret flow channel with an outer diameter of about 70μm in the skin layer. The spinneret temperature is controlled at about 85°C. The slurry is sprayed into a 5% calcium chloride coagulation bath with a pH of 11.5. The distance between the spinnerets is about 10mm. The material stays for about 60 seconds and then is fished out by a conveyor net. The appearance is cylindrical small strip particles.

[0069] Step 4 (drying process): After the material is fished out, it is dried at 60 degrees Celsius for 10 hours to obtain the mineralized filter material of Example 3.

[0070] Comparative Example 1

[0071] 10 parts by mass of strontium carbonate, 30 parts by mass of calcium carbonate, 10 parts by mass of zinc oxide, 40 parts by mass of kaolin, 40 parts by mass of silica sol, and 100 parts of 2% carboxymethyl cellulose (CMC) are mixed, granulated and dried, mixed and sintered at 780-830°C for 6 hours, and the product is washed with water and dried.

[0072] Hygiene and safety test: Take 20g of each of the above filter materials and conduct an immersion test to evaluate safety according to GBT17219-2001 standard. The immersion liquid is 200ml. The results are as follows:

[0073] Table 1

[0074]

[0075]

[0076] As can be seen from Table 1 above, all evaluation results of Examples 1-3 meet the requirements specified in the rightmost column, while at least pH, total dissolved solids and lead of Comparative Example 1 do not meet the requirements specified in the rightmost column.

[0077] Take 50g of each of the above filter materials, fill them into a fillable filter housing, pass R0 water at a flow rate of 1L / min, flush with 30L of water and then test.

[0078] Table 2

[0079] Water mineral status (initial)

[0080]

[0081] Table 3

[0082] Mineral content of the effluent (after 30L)

[0083]

[0084] As shown in Tables 2 and 3, compared with Comparative Example 1, the mineral ions in Examples 1-3 always maintain a relatively stable release amount, while in Comparative Document 1, the release amount of calcium ions, in particular, changes greatly at the initial stage and after flushing 30L of water.

[0085] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A mineralized filter material, characterized in that: Including core layer and skin layer, The core layer comprises 0-10 parts by mass of strontium salt, 30-100 parts by mass of calcium salt, 4-40 parts by mass of amorphous silicon dioxide and 3-30 parts by mass of sodium alginate; the skin layer comprises polyvinyl alcohol; and the core layer and the skin layer are concentric circle structures.

2. The mineralized filter material according to claim 1, wherein The core layer further comprises 10-30 parts by mass of zinc oxide.

3. The mineralized filter material according to claim 1 or 2, wherein: The diameter of the core layer is 30-100 μm, and the outer diameter of the skin layer is 50-140 μm.

4. The mineralized filter material according to claim 1 or 2, wherein: The strontium salt is strontium carbonate, and the calcium salt is calcium carbonate.

5. A method for preparing a mineralized filter material, characterized in that: 0-10 parts by mass of strontium salt and 30-100 parts by mass of calcium salt are wetted and mixed with 40-100 parts by mass of water, and then 20-100 parts by mass of neutral silica sol are poured in, ground for 4-20 hours, and stirred evenly to obtain a slurry. Sodium alginate is added to water and heated, and its pH is adjusted to 6-8 to dissolve to form a viscous sodium alginate solution with a mass concentration of 6-10%, and the temperature is kept at 45-60°C; polyvinyl alcohol is added to water and dissolved to obtain a polyvinyl alcohol aqueous solution with a mass concentration of 8-16%, and the temperature is kept at 60-85°C. The slurry and the sodium alginate viscous solution are fed separately through a pump at a mass mixing ratio of 10:3-10:30, and after being fully mixed, a core layer spinning solution is obtained. The core layer spinning solution is passed into the core layer of a concentric skin-core spinneret, the polyvinyl alcohol aqueous solution is passed into the skin layer of the concentric skin-core spinneret, and then sprayed into a coagulation bath containing 3-10% calcium chloride with a pH range of 11-13. The primary coagulated fibers are then broken after being allowed to stand for 60-240 seconds to obtain cylindrical strip particles. The cylindrical strip particles are dried at 60-80° C. for 4-10 hours to obtain a mineralized filter material.

6. The method for preparing the mineralized filter material according to claim 5, wherein: When 0-10 parts by mass of strontium salt and 30-100 parts by mass of calcium salt are wetted and mixed with 40-100 parts by mass of water, 10-30 parts by mass of zinc oxide are added simultaneously.

7. The method for preparing the mineralized filter material according to claim 6, wherein: The mesh sizes of the strontium salt, the calcium salt and the zinc oxide are all 600-5000 meshes.

8. The method for preparing the mineralized filter material according to claim 5 or 6, wherein: The polyvinyl alcohol has an alcoholysis degree of not less than 98%.

9. The method for preparing the mineralized filter material according to claim 5 or 6, wherein: The diameter of the core layer is 30-100 μm, and the outer diameter of the skin layer is 50-140 μm.

10. The method for preparing the mineralized filter material according to claim 5 or 6, wherein: The pump is a positive displacement pump, and the feeding is forced feeding.

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