A CaCl 2 Purification reagents, materials, apparatus and methods for solutions

Abstract

This invention belongs to the field of materials application and resource recycling, and provides a CaCl₂ 2 Purification agents, materials, apparatus, and methods for solutions. This invention utilizes low-value materials, such as seashells, primarily composed of calcium-based materials, as the main component of the crystallizing agent. Natural organic matter, such as wood flour and straw, is used as the carbon source. After mechanical activation and hydrothermal treatment, the crystallizing agent is obtained by calcination under nitrogen protection. This purification material can be used in various CaCl₂ solutions. 2 Applications in solution purification. The crystallization inducer of this invention has mild preparation conditions, inexpensive materials, and strong targeting, enabling low-cost and efficient removal of CaCl₂. 2 Impurities such as sulfate in the solution.

Description

Purification reagents, apparatus, and method for CaCl2 solution Technical Field

[0001] This invention belongs to the field of materials application and resource recycling, and relates to a purification agent, device and method for CaCl2 solution. Background Technology

[0002] The wastewater generated during the production of titanium dioxide (titanium chloride) is mainly chlorine-containing acidic wastewater. It is typically treated using a neutralization reaction, which is the most common, direct, and effective method. The treatment process is as follows: lime slurry is passed into a wastewater treatment tank, followed by the chlorine-containing acidic wastewater to neutralize it. The direct product is ferric hydroxide, which precipitates as a solid. The solution is then filtered and washed. The filtered solution is a mixture of wastewater containing calcium chloride. Other impurities in this wastewater affect the purity of the calcium chloride, and evaporation alone cannot achieve purification. The main impurities include a certain concentration of sulfate ions and organic matter.

[0003] Industrially, high-salinity wastewater (not primarily composed of calcium chloride) is typically treated by adding calcium chloride to precipitate and remove sulfate ions. However, for high-salinity calcium chloride wastewater, sulfate ion removal is difficult due to the salt effect. Barium salt precipitation introduces barium ions, and barium is expensive and unsuitable for industrial applications. Therefore, no reliable method has been reported for the targeted removal of sulfate ions from high-concentration calcium chloride wastewater.

[0004] This invention prepares an induced crystallization adsorbent and designs a method and matching equipment based on this adsorbent. By adding the induced crystallization adsorbent of this invention into the designed equipment and using the corresponding reaction method, sulfate ions in calcium chloride wastewater can be effectively removed, thereby purifying the calcium chloride solution. Summary of the Invention

[0005] This invention provides a method and equipment for treating impurities such as sulfate in calcium chloride using an inducing crystallizer. This allows for the treatment of low-cost raw materials in specific equipment, effectively processing CaCl2 solutions and ensuring that the products meet standards.

[0006] The technical solution of the present invention:

[0007] A purification agent for CaCl2 solution includes an oxidant, an oxygen scavenger, and an inducing agent, wherein the mass ratio of the inducing agent, oxidant, and oxygen scavenger is 1:0.2 to 1:0.2 to 1; by adding the purification agent, the removal of organic matter, the removal of dissolved oxygen, and the induction of sulfate removal from the CaCl2 solution are achieved.

[0008] The oxidant is a material that does not introduce new elements, such as calcium hypochlorite or hydrogen peroxide. Under the special environmental requirements of the reactor, it can oxidize and remove organic matter in the solution, thereby achieving solution decolorization.

[0009] The oxygen scavenger material mentioned above includes, but is not limited to, iron powder and other reducing materials such as ethanol. Its main function is to remove dissolved oxygen from the water and reduce the corrosion of heating equipment by oxygen.

[0010] The aforementioned inducing agent uses natural calcium-containing substances as the main material, which are mixed with biomass materials and synthesized under specific preparation conditions to form a calcium-based inducing agent with a specific crystal form.

[0011] The inducing agent material includes, but is not limited to, natural calcium-containing substances such as shells, animal bones, and calcium carbonate minerals; and the biomass material includes, but is not limited to, natural plants such as wood, leaves, and fruit peels. The specific preparation conditions refer to mechanical ball milling, hydrothermal reaction at 80-200℃ for 1-3 hours, followed by heating to 600-1000℃ and holding at that temperature for 1-3 hours under nitrogen protection. The mass ratio of natural calcium-containing substances to biomass material is 0.5:1 to 3:1.

[0012] The specific calcium-based inducing agent refers specifically to calcium oxide materials with the dominant crystal face being 111. In its XRD pattern, the main crystal facet peaks are at a 2θ angle of 33.7°, and the 111 crystal facet should be the dominant crystal facet, i.e., the same position as the main peak in Figure 1. Furthermore, its oxide is required to be tightly bonded to carbon elements, and its micro-infrared spectrum should be as shown in Figure 2.

[0013] A purification device for CaCl2 solution, as shown in Figure 3, mainly consists of two parts: a calcium chloride impurity removal induced crystallization tank and a calcium chloride impurity removal induced crystallization precipitation tank.

[0014] The calcium chloride impurity removal and induced crystallization tank is a circular reactor with a coarser top and a finer bottom. It is equipped with a constant temperature protection device. A local heating device is installed in the mixing zone of the fine tube area at the bottom of the tank, occupying 30% of the mixing zone area. This local heating device, used in conjunction with an inducing agent, improves the induced crystallization efficiency. The tank is equipped with a stirring motor, with an inlet in the lower fine tube mixing zone and a pipe connecting the upper coarse tube area to the outer ring of the calcium chloride impurity removal and induced crystallization sedimentation tank.

[0015] The calcium chloride impurity removal induced crystallization sedimentation tank is a cylindrical annular reactor with a coarser outer ring and a finer inner ring. The ratio of the inner diameter of the outer ring to the inner ring is 10:1, and the outer and inner rings are connected at the bottom. A water inlet is connected to the calcium chloride impurity removal induced crystallization sedimentation tank through a pipe on the outer ring, and a sludge discharge port is opened at the bottom of the outer ring. A water outlet is opened on the inner ring, and multiple inclined planes are arranged between the outer and inner rings. The inclined planes may or may not be perforated, and the angle between the inclined planes and the horizontal plane is 30-60°, which facilitates the crystallization and precipitation separation of the inducing agent and impurities.

[0016] A method for purifying CaCl2 solution involves introducing a calcium chloride solution (containing sulfate impurities) with a mass concentration of 20%–35% and a temperature of 10–85°C into a calcium chloride impurity removal induced crystallization tank via a pipeline. The amount of inducing agent (protective agent) added is 0.5 g / L–10 g / L. The stirring motor and local heating device in the calcium chloride impurity removal induced crystallization tank are started to raise the liquid temperature to above 65°C. The solution temperature is maintained and the reaction is continued for 2–4 hours. The liquid is then discharged from the outlet of the calcium chloride impurity removal induced crystallization tank to a calcium chloride impurity removal induced crystallization precipitation tank. The residence time in the calcium chloride impurity removal induced crystallization precipitation tank is 2 hours. The effluent can achieve the removal of impurities such as sulfate.

[0017] First, the natural calcium-containing material is washed and dried, then crushed. After being crushed by a crusher, it is subjected to mechanochemical reaction with the crushed biomass material. It is then ball-milled for 40 minutes in a ball mill, and then calcined in a tube furnace under nitrogen protection for 3 hours. After washing with deionized water, a powdered inducer is obtained.

[0018] The beneficial effects of this invention are as follows: This invention utilizes materials such as seashells and waste biomass as the main materials, and employs certain pretreatment and calcination processes to prepare a calcium-based inducing crystallizer material with a specific crystal form. Based on the characteristics of this material in treating calcium chloride solution, a special locally heated calcium chloride impurity removal inducing crystallization pool and a calcium chloride impurity removal inducing crystallization precipitation pool were designed and invented. The CaCl2 solution treated by the reagent material and treatment method proposed in this invention can effectively reduce the concentration of sulfate ions in the solution. After subsequent evaporation and pelletizing, qualified calcium chloride products can be obtained.

[0019] The crystallizing agent and equipment prepared by this invention can be specifically used to remove organic matter such as sulfate from CaCl2 wastewater, achieving zero discharge of calcium chloride wastewater for various enterprises, and has broad market prospects.

[0020] The preparation process of this invention is simple, environmentally friendly, and low in cost, and it plays a positive role in the treatment of CaCl2 solution wastewater. Attached Figure Description

[0021] Figure 1 is the XRD reference spectrum of the crystallization inducer of the present invention.

[0022] Figure 2 is a micro-infrared spectrum of the crystallization inducer of the present invention, wherein (a) is a microscopic image of the sample, (b) is a mass density distribution map of the sample in the microscopic image, and (c) is the infrared spectrum of 9 sample points corresponding to a and b.

[0023] Figure 3 is a simplified diagram of the calcium chloride impurity removal induced crystallization tank and sedimentation tank of the present invention.

[0024] Figure 4 is a cross-sectional schematic diagram of the calcium chloride impurity removal induced crystallization precipitation tank of the present invention.

[0025] In the diagram: 1. Stirring motor; 2. Induction crystallization zone; 3. Inlet of induction crystallization tank; 4. Heating zone; 5. Inlet of sedimentation tank; 6. Inner pipe of sedimentation tank; 7. Outlet of sedimentation tank; 8. Inclined surface (sloping plate) between inner and outer rings; 9. Sludge discharge port. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0027] Example 1:

[0028] After cleaning and crushing the seashells, 5g of the powder was added to 3g of wood flour in a ball mill jar and ball-milled at 400 rpm for 40 minutes for activation. The powder was then placed in a tube furnace and heated to 850℃ under nitrogen protection, held for 2 hours, and cooled to obtain crystallization inducer 1-1. 1L of calcium chloride wastewater from a certain enterprise, containing 30% calcium chloride and 0.7% sulfate, was taken. At a controlled room temperature of approximately 25℃, 1g of crystallization inducer 1-1 was added and stirred for 2 hours. Then, 3mg of polyaluminum chloride was added, and the mixture was coagulated for 25 minutes and allowed to settle for 1 hour. The supernatant was tested and found to contain approximately 0.07% sulfate.

[0029] Example 2:

[0030] Take 1L of calcium chloride wastewater from a certain enterprise, containing 30% calcium chloride and 0.7% sulfate. Control the reaction temperature at 85℃, add 1g of crystallization inducer 1-1, stir for 2h, add 3mg of polyaluminum chloride, coagulate for 25min, precipitate for 1h, and take the supernatant to test the sulfate content, which is about 0.06%.

[0031] Example 3:

[0032] Take 3L of calcium chloride wastewater from a certain enterprise, containing 30% calcium chloride and 0.7% sulfate, and put it into a locally heated reactor. The reactor is heated locally periodically to control the solution temperature to be above 65℃. Add 1g of crystallization inducer 1-1, stir for 2h, add 3mg of polyaluminum chloride, coagulate for 25min, and precipitate for 1h (without raising the temperature during precipitation). Take the supernatant and test the sulfate content to be approximately 0.04%.

Claims

1. A purification agent for CaCl2 solution, characterized in that, The purification agent for this CaCl2 solution includes an oxidant, an oxygen scavenger, and an inducing agent, wherein the mass ratio of the inducing agent, oxidant, and oxygen scavenger is 1:0.2~1:0.2~1. By adding the purification agent, organic matter, dissolved oxygen, and sulfate ions are removed from the CaCl2 solution. The inducing agent is mainly composed of natural calcium-containing substances, prepared by mixing with biomass materials. The natural calcium-containing substances include shells, animal bones, and calcium carbonate minerals, while the biomass materials include wood, leaves, and fruit peels. The preparation conditions involve mechanical ball milling, hydrothermal reaction at 80-200℃ for 1-3 hours, followed by heating to 600-1000℃ and holding at that temperature for 1-3 hours under nitrogen protection. The mass ratio of natural calcium-containing substances to biomass materials is 0.5:1~3:

1.

2. The purification agent material for CaCl2 solution according to claim 1, characterized in that, The oxidant is calcium hypochlorite or hydrogen peroxide.

3. A method for purifying CaCl2 solution, characterized in that, A calcium chloride solution with a mass concentration of 20%~35% and a temperature of 10~85℃ is piped into a calcium chloride impurity removal induced crystallization tank. The inducing agent described in claim 1 is added at a concentration of 0.5g / L~10g / L. The stirring motor and local heating device in the calcium chloride impurity removal induced crystallization tank are started to raise the liquid temperature to above 65℃. The solution temperature is maintained, and the reaction continues for 2~4 hours. The liquid is then discharged from the outlet of the calcium chloride impurity removal induced crystallization tank to a calcium chloride impurity removal induced crystallization sedimentation tank. The residence time in the calcium chloride impurity removal induced crystallization sedimentation tank is 2 hours, and sulfate removal is achieved in the effluent. The calcium chloride impurity removal induced crystallization tank is a circular reaction vessel with a coarser top and a thinner bottom. The design of the calcium chloride impurity removal induced crystallization tank... The system is equipped with a constant temperature protection device. A local heating device is installed in the mixing zone of the thin tube area at the bottom of the calcium chloride impurity removal induced crystallization tank, which is used in conjunction with the inducing agent to improve the induced crystallization efficiency. The calcium chloride impurity removal induced crystallization tank is equipped with a stirring motor. The mixing zone of the thin tube area at the bottom of the tank has a water inlet, and the coarse tube area at the top has a pipe connected to the outer ring of the calcium chloride impurity removal induced crystallization sedimentation tank. The calcium chloride impurity removal induced crystallization sedimentation tank is a cylindrical annular reactor with a coarse outer ring and a fine inner ring, which are connected at the bottom. Water is introduced through the pipe on the outer ring that connects to the calcium chloride impurity removal induced crystallization sedimentation tank. A sludge discharge port is opened at the bottom of the outer ring. A water outlet is opened on the inner ring, and multiple inclined surfaces are arranged between the outer and inner rings to facilitate the separation of the inducing agent and impurities through crystallization and precipitation.

4. The purification method for CaCl2 solution according to claim 3, characterized in that, The inclined plane may or may not have a hole, and the angle between the inclined plane and the horizontal plane is 30~60°.

5. The method for purifying CaCl2 solution according to claim 3, characterized in that, The local heating device occupies 30% of the mixing area in the thin tube region.

6. The method for purifying CaCl2 solution according to claim 3, characterized in that, The ratio of the outer ring inner diameter to the inner ring inner diameter of the reactor is 10:1.

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