Production method of high-concentration calcium chloride crystal powder

Abstract

The invention discloses a production method of high-concentration calcium chloride crystal powder, which comprises the following steps: adding a hydrochloric acid solution and a calcium material into a reactor for reaction, continuously introducing hydrogen chloride gas into the hydrochloric acid solution in the reaction process, and continuously adding metered calcium material into the reactor; setting suction filtration conditions, opening a valve at the bottom of the reactor when the reaction reaches the suction filtration conditions, conveying materials at the bottom of the reactor to solid-liquid separation equipment for solid-liquid separation, and returning separated liquid to the reactor to continuously participate in the reaction; and drying the calcium chloride wet material subjected to solid-liquid separation to obtain calcium chloride crystal powder. The hydrogen chloride gas is continuously introduced into the reactor, so that the content of calcium chloride in the reactor is gradually increased along with the reaction time, the concentration of calcium chloride in a system in the prior art is greatly increased, the drying time and energy consumption are greatly reduced during drying, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of calcium chloride production technology, specifically to a method for producing high-concentration calcium chloride crystalline powder. Background Technology

[0002] Calcium chloride (chemical formula: CaCl2) is a white or slightly yellow solid inorganic compound belonging to the salt class. It is a typical ionic halide and is widely used in many fields due to its high solubility, hygroscopicity, and dehydrating properties. Calcium chloride is readily soluble in water, with a solubility of 74 g / 100 g water at 20℃, releasing a large amount of heat in the process.

[0003] Hydrochloric acid is a colorless liquid, an aqueous solution of hydrogen chloride, and has a pungent odor. The mass fraction of industrial hydrochloric acid is generally 10% to 38%. Due to the strong volatility of high-concentration hydrochloric acid, the maximum mass fraction of concentrated hydrochloric acid is about 38%.

[0004] In existing technologies, calcium chloride is mostly produced by reacting hydrochloric acid solution with calcium oxide to remove impurities and generate calcium chloride solution. Then, the calcium chloride solution is dried to remove moisture, and finally, calcium chloride solid is produced. The calcium chloride solid is then pulverized to obtain calcium chloride powder.

[0005] Reference 1: CN109455751A Method for preparing calcium chloride from by-product hydrochloric acid and limestone undersize.

[0006] Reference 1 discloses a method for preparing calcium chloride from by-product hydrochloric acid and limestone undersize. The method includes: (1) adding limestone undersize to a by-product hydrochloric acid solution to prepare hydrochloric acid-lime slurry; (2) adding the hydrochloric acid-lime slurry prepared in step (1) to a jacketed reaction vessel with a stirring device, adding the by-product hydrochloric acid solution while stirring, and detecting the pH value of the reaction. When the pH value of the reactants reaches 8.5-9, the feeding is stopped; (3) pumping the product of the reaction completed in step (2) into a filtration device for filtration and taking the filtrate; (4) decolorizing and removing impurities from the filtrate; (5) directly spraying the decolorized and impurity-removed filtrate to generate dihydrate spherical calcium chloride or anhydrous spherical calcium chloride.

[0007] In Reference 1, lime and hydrochloric acid byproduct were mixed, and then a calcium chloride solution was generated by controlling the pH value. The calcium chloride solution was filtered, decolorized and impurities removed, and then spray-granulated and dried to obtain dihydrate spherical calcium chloride or anhydrous spherical calcium chloride.

[0008] Reference 2: CN109502624 A Method for preparing calcium chloride using by-product hydrochloric acid.

[0009] Reference 2 discloses a method for preparing calcium chloride using by-product hydrochloric acid, comprising the following steps: Step 1, adding an acid-resistant solid adsorbent to the by-product hydrochloric acid, stirring for a period of time, and filtering to remove the solid adsorbent; Step 2, adding quicklime to the by-product hydrochloric acid treated in Step 1 to react, filtering, and obtaining a calcium chloride solution; Step 3, concentrating and drying the calcium chloride solution under reduced pressure to obtain solid calcium chloride. This invention's method for preparing calcium chloride using by-product hydrochloric acid allows for resource reuse of the by-product hydrochloric acid, avoids interference from fluoride ions during the calcium chloride preparation process, and results in a product with high purity and high raw material utilization.

[0010] Reference 2 describes a process where byproduct hydrochloric acid is adsorbed to remove impurities, and quicklime is added to obtain a calcium chloride solution. This solution is then concentrated under reduced pressure and dried to obtain solid calcium chloride. The instructions in Reference 2 indicate that the byproduct hydrochloric acid contains 15-35% hydrochloric acid by mass, the mass ratio of byproduct hydrochloric acid to quicklime is 10:4-5, and the reaction time is 3-5 hours.

[0011] Reference 3: CN108862353A A process for preparing and purifying calcium chloride using waste salt mud from chlor-alkali production.

[0012] Reference 3 discloses a process for preparing and purifying calcium chloride using waste salt mud from chlor-alkali plants, including the following steps: (1) Salt mud and excess hydrochloric acid are fed into a reactor to react and obtain a solution containing calcium chloride; (2) Use the calcium chloride-containing solution obtained in step (1) to absorb hydrogen chloride until saturated, and prepare hydrochloric acid. The resulting calcium chloride-containing hydrochloric acid is sent to step (1) to replace the hydrochloric acid in the preparation of calcium chloride. (3) By analyzing the calcium chloride concentration in step (1) and the acid concentration in step (2), salt mud is added quantitatively to the reactor for reaction. The temperature during the reaction is kept above 40℃. If sodium chloride crystals appear in the solution at the end of the reaction, the solution is allowed to stand and the sodium chloride crystals are filtered out. Then, quicklime is added to the filtrate to adjust the pH. If no crystals appear in the solution, quicklime is added directly to adjust the pH. (4) Transfer the pH-adjusted liquid obtained in step (3) to a crystallization tank, cool it to -15 to 15°C, decan the supernatant, collect the crystals, which is the calcium chloride product.

[0013] In Reference 3, salt mud reacts with excess hydrochloric acid in a reactor to obtain a calcium chloride solution. Then, in step (2), the calcium chloride solution absorbs hydrogen chloride gas until saturation, at which point the hydrochloric acid concentration in the calcium chloride increases. Then, a certain amount of salt mud is added according to the hydrochloric acid concentration, the pH value is adjusted, and sodium chloride crystallizes out. Then, the temperature is lowered to -15℃~15℃ to collect the crystals, thus obtaining calcium chloride. Compared with References 1 and 2, Reference 3 adds the step of absorbing hydrogen chloride gas into the calcium chloride until saturation.

[0014] As can be seen from references 1 to 3, the existing methods for producing calcium chloride using hydrochloric acid have the following characteristics: (1) The production process is non-continuous, and the next batch can only be produced after each batch is completed.

[0015] The reason for using a one-pot process in existing technologies is that the reaction process involves mixing hydrochloric acid and a calcium-containing substrate. Even though reference 3 describes a one-time adsorption of hydrogen chloride gas, the adsorption endpoint can only be reached when the solution reaches a concentrated hydrochloric acid level. Therefore, once the hydrochloric acid concentration is determined, the final concentration of the calcium chloride solution is also determined and can be calculated; the concentration of calcium chloride will not change with the amount of hydrochloric acid or calcium-containing substrate added. Therefore, the existing technology uses a one-pot process to account for the situation where the concentration of the calcium chloride solution will not increase with the extension of production time.

[0016] (2) The concentration of the reaction product calcium chloride solution is low.

[0017] In existing technologies, the concentration of hydrochloric acid plays a crucial role in the concentration of the calcium chloride product. Under the same conditions, a higher concentration of hydrochloric acid results in a higher concentration of calcium chloride after adding the same calcium-containing substrate. Since the maximum concentration of hydrochloric acid is 38%, the calcium chloride concentration obtained in existing technologies is generally between 35% and 38%. This lower concentration necessitates drying to obtain solid calcium chloride. For example, as in Reference 1, spray drying is required to remove a large amount of moisture, or as in Reference 3, concentrated hydrochloric acid is used to obtain a higher concentration of calcium chloride, followed by cooling to precipitate crystals. However, crystal precipitation in a crystallization tank results in a mother liquor, which also contains calcium chloride, preventing complete recovery of the calcium chloride within the crystallization tank. To recover the calcium chloride from the cooled mother liquor, concentration is generally required before further cooling to precipitate crystals.

[0018] (3) The final product is related to the drying process. There are several ways to obtain solid calcium chloride powder from calcium chloride solution in the existing technology. One method is to use spray drying to directly dry a low-concentration calcium chloride solution to form calcium chloride powder. Another method is to heat and concentrate the calcium chloride solution until it is dried to obtain block calcium chloride, which is then crushed to obtain calcium chloride powder. A third method is to use a higher-concentration calcium chloride solution to cool and precipitate crystals, and then dry the crystals to obtain calcium chloride crystals.

[0019] Neither spray drying nor pulverization after heat concentration provides the environment and conditions necessary for crystal formation, thus preventing the formation of calcium chloride crystals. However, calcium chloride crystals possess unique porosity and a larger specific surface area, outperforming ordinary calcium chloride powder in many aspects, including adsorption capacity, hygroscopicity, and reaction efficiency. Calcium chloride crystals are also more expensive than calcium chloride powder.

[0020] (4) Concentration and drying consume a lot of energy. Existing technologies are limited by the concentration of hydrochloric acid, resulting in low concentrations of calcium chloride solutions. Subsequent concentration increases and drying require significant heat consumption, leading to high drying costs for anhydrous calcium chloride. This is because the calcium chloride solution has a high water content, and water has a very high specific heat capacity, resulting in extremely high energy consumption during drying or concentration. Traditional processes produce calcium chloride solutions with a concentration of 35%-38%, and the energy consumption for drying one ton of anhydrous calcium chloride is approximately 1200-1500 kWh.

[0021] The industrial production of chlorinated paraffin includes a chlorination process. During chlorination, chlorine reacts with the paraffin oil, where one chlorine atom replaces a hydrogen atom on an alkane, and the hydrogen atom reacts with another chlorine atom to form a hydrogen chloride molecule. Therefore, the production of chlorinated paraffin generates a large amount of hydrogen chloride gas as a byproduct. Hydrogen chloride gas is inconvenient to store and transport directly. It is absorbed by water to form hydrochloric acid. Due to excess hydrochloric acid production capacity, it needs to be treated according to regulations, increasing the operating costs of production enterprises.

[0022] During the alkali recovery process in paper mills, white mud, mainly composed of calcium carbonate, is generated during the causticizing stage. This white mud undergoes cooking, washing, and screening processes to produce black liquor. The black liquor then enters the alkali recovery system for further processing. Summary of the Invention

[0023] The purpose of this invention is to provide a method for producing high-concentration calcium chloride crystalline powder.

[0024] The main technical problems to be solved by this invention include: (1) The concentration of calcium chloride solution is low and cannot exceed 45% by mass. (2) Calcium chloride cannot be produced continuously; (3) After the reaction, calcium chloride is in a solution state and cannot be directly filtered. The drying cost is high and stable calcium chloride crystals cannot be formed after drying.

[0025] To achieve the above objectives, one embodiment of the present invention provides a method for producing high-concentration calcium chloride crystal powder, comprising the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution and calcium material is continuously added into the reactor. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2~2.5:0.8~1; the reaction temperature is 25℃~150℃. Step S2: Set the filtration conditions. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material at the bottom of the reactor to the solid-liquid separation equipment for solid-liquid separation. At the same time, return the separated liquid to the reactor to continue participating in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

[0026] This invention also discloses a method for producing high-concentration calcium chloride crystalline powder, which is carried out using a reactor and a solid-liquid separation device. The reactor includes a tank with a feed port, a gas inlet, and an exhaust pipe. The feed port is connected to a calcium feed device, and the gas inlet is connected to a hydrogen chloride gas source. The gas inlet is connected to an inlet pipe that extends into the tank. The exhaust pipe has a detection branch connected to a gas detection device and an exhaust pipe connected to a waste gas treatment device. The outlet at the bottom of the reactor is connected to the inlet of the solid-liquid separation device through a valve, and the liquid outlet of the solid-liquid separation device is piped to the reactor. The method for producing calcium chloride using the above-mentioned reactor and solid-liquid separation equipment includes the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor as substrates for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution through the gas inlet, and calcium material is continuously added into the reactor through the feed inlet. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2~2.5:0.8~1; the reaction temperature is 25℃~150℃; the exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection treatment, and the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate the absorption of hydrogen chloride gas by the solution. Step S2: Set the filtration conditions. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material at the bottom of the reactor to the solid-liquid separation equipment for solid-liquid separation. At the same time, return the separated liquid to the reactor to continue participating in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

[0027] As a further optimization of the present invention, the calcium material in step S1 is a material containing calcium carbonate or calcium oxide, and the calcium carbonate material includes caustic soda mud and calcium carbonate ore.

[0028] As a further optimization of the present invention, in step S1, the concentration of hydrochloric acid solution in the reactor and the content of hydrogen chloride gas in the gas discharged from the reactor are monitored during the reaction process; when the concentration of hydrochloric acid solution is lower than the lower limit of concentration, the molar ratio of hydrogen chloride gas is increased; when the content of hydrogen chloride in the gas in the reactor is higher than the preset upper limit of hydrogen chloride gas content, the molar ratio of hydrogen chloride gas is decreased.

[0029] As a further optimization of the present invention, in step S1, the molar ratio of hydrogen chloride gas to calcium material fed per unit time is 2~2.2:0.9~1; the reaction temperature is 80℃~100℃.

[0030] As a further optimization of the present invention, in step S1, the volume of hydrochloric acid solution added is 20% to 35% of the total capacity of the reactor, and the flow rate of hydrogen chloride gas per hour is 400L to 800L.

[0031] As a further optimization of the present invention, the filtration conditions in step S2 are as follows: the final concentration of calcium chloride is calculated based on the volume of hydrochloric acid solution added in step S1 and the mass of calcium material added, and filtration is performed when the concentration of calcium chloride reaches 60%~70%.

[0032] As a further optimization of the present invention, the drying temperature in step S3 is 90℃~160℃.

[0033] This invention also discloses a method for producing high-concentration calcium chloride crystalline powder, comprising the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution to ensure that the calcium material is completely reacted. The reaction temperature is 25℃~150℃. Step S2: After the reaction is complete, the material at the bottom of the reactor is transported to a solid-liquid separation device for solid-liquid separation, and the separated liquid is returned to the reactor to continue to participate in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

[0034] In summary, the present invention has the following advantages: 1. This invention uses a continuous production method to continuously introduce hydrogen chloride gas and calcium material into the reactor, so that the calcium chloride content in the reactor gradually increases with the reaction time, reaching a maximum of about 70%, which greatly improves the concentration of calcium chloride in the system in the prior art.

[0035] 2. This invention enables continuous production. The calcium chloride solution obtained after production has a very high mass fraction and is in a slurry state, which can be directly filtered. After filtration, the water content is further reduced, which greatly reduces drying time and energy consumption, thus reducing production costs.

[0036] 3. The calcium chloride powder obtained by this invention is obtained by natural precipitation without spray drying and pulverization. It does not require pulverization after drying, thus preserving the crystal structure of calcium chloride. The resulting product is calcium chloride crystal powder, which has better porosity and reactivity. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the production method of the present invention; Figure 2 This is a schematic diagram of the production equipment used in the production method of the present invention.

[0038] Explanation of possession markings: 1. Tank body; 2. Feed port; 3. Gas inlet; 4. Exhaust pipe; 5. Solid-liquid separation equipment Detailed Implementation

[0039] refer to Figure 1 This invention provides a method for producing high-concentration calcium chloride crystalline powder, comprising the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution and calcium material is continuously added into the reactor. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2~2.5:0.8~1; the reaction temperature is 25℃~150℃. Step S2: Set the filtration conditions. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material at the bottom of the reactor to the solid-liquid separation equipment for solid-liquid separation. At the same time, return the separated liquid to the reactor to continue participating in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

[0040] refer to Figure 2 This invention discloses a method for producing high-concentration calcium chloride crystalline powder, which is carried out using a reactor and a solid-liquid separation device. The reactor includes a tank with a feed port, a gas inlet, and an exhaust pipe. The feed port is connected to a calcium feed device, and the gas inlet is connected to a hydrogen chloride gas source. The gas inlet is connected to an inlet pipe that extends into the tank. The exhaust pipe has a detection branch connected to a gas detection device and an exhaust pipe connected to a waste gas treatment device. The outlet at the bottom of the reactor is connected to the inlet of the solid-liquid separation device through a valve, and the liquid outlet of the solid-liquid separation device is piped to the reactor. The method for producing calcium chloride using the above-mentioned reactor and solid-liquid separation equipment includes the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor as substrates for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution through the gas inlet, and calcium material is continuously added into the reactor through the feed inlet. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2~2.5:0.8~1; the reaction temperature is 25℃~150℃; the exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection treatment, and the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate the absorption of hydrogen chloride gas by the solution. Step S2: Set the filtration conditions. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material at the bottom of the reactor to the solid-liquid separation equipment for solid-liquid separation. At the same time, return the separated liquid to the reactor to continue participating in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder. Example

[0041] The continuous production method of the present invention requires optimization of the reaction equipment of the prior art. The overall reaction system of the present invention includes a reactor, a solid-liquid separation device and a waste gas treatment device.

[0042] The reactor includes a tank with a feed port, a gas inlet, and an exhaust pipe. The feed port is connected to a calcium feed addition device, and the gas inlet is connected to a hydrogen chloride gas source. The calcium feed is a solid material, and the calcium feed addition device can control the addition rate. The gas inlet can be connected to a hydrogen chloride gas source via a pipeline. The hydrogen chloride gas source is a byproduct of the factory and can be directly introduced through the factory's pipeline. An intermediate storage tank and valves, common chemical control equipment, can also be installed on the pipeline. The waste gas treatment equipment can absorb the hydrogen chloride gas overflowing during the production process, preventing excessive hydrogen chloride gas from being released into the air with carbon dioxide. The waste gas treatment equipment of this invention can be a hydrogen chloride absorption tank, which uses water to absorb the overflowing hydrogen chloride gas.

[0043] The gas filling port is connected to an inlet pipe that extends deep into the tank, allowing hydrogen chloride gas to be directly introduced into the water for absorption. The exhaust pipe's detection branch connects to a gas detection device, which can be equipped with a valve. This valve can be opened when needed to allow the gas detection device to detect the hydrogen chloride gas content in the exhaust gas, thus providing a reference for controlling the amount of hydrogen chloride gas introduced. The exhaust pipe also connects to waste gas treatment equipment, allowing the hydrogen chloride gas to be directly absorbed and treated.

[0044] The outlet at the bottom of the reactor is connected to the inlet of the solid-liquid separation equipment via a valve, and the drain of the solid-liquid separation equipment is piped into the reactor. The solid-liquid separation equipment can be a plate and frame filter, capable of handling large quantities of precipitate filtration. The separated liquid is pumped into the reactor, while the solid calcium chloride wet material remains in the plate and frame. After filtration, the valve at the bottom of the reactor is closed, and the wet material in the plate and frame is removed for transfer and drying. This process does not affect the continuous production of calcium chloride in the reactor. Example

[0045] Step S1: Select a 5000L reactor as the reactor. Add 1200L of 30% hydrochloric acid solution and calcium material as the substrate to the reactor. After starting the reaction for 5 minutes, continuously introduce hydrogen chloride gas into the hydrochloric acid solution through the gas inlet, and continuously add calcium material into the reactor through the feed inlet. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2:1. The hourly hydrogen chloride gas flow rate is 400L~800L. Since the calcium material is a calcium oxide, the molar amount of calcium can be calculated based on the type of calcium material, and the amount of calcium material used can be calculated based on the hydrogen chloride flow rate. This chemical reaction process is existing technology. For example, in this embodiment, the calcium material selected is caustic soda mud, whose composition is calcium carbonate.

[0046] The initial reaction temperature of this invention is room temperature. Since the reaction is exothermic, the reaction temperature gradually increases, and it needs to be controlled below 120°C. In this embodiment, after reaching stability, the reaction temperature is controlled at 100°C. The exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection treatment, and the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate the absorption of hydrogen chloride gas by the solution.

[0047] Step S2: Set the filtration conditions. Calculate the final calcium chloride concentration based on the volume of hydrochloric acid solution added in Step S1 and the mass of calcium material added. Perform filtration when the calcium chloride concentration reaches 60%. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material to a solid-liquid separation device for solid-liquid separation. Simultaneously, return the separated liquid to the reactor to continue participating in the reaction.

[0048] Step S3: The solid-liquid separated wet calcium chloride material is dried at 90℃ to obtain calcium chloride crystalline powder. During the drying process, the moisture content of the wet material is greatly reduced, and the energy consumption required for drying each ton of product is approximately 700 kWh. Example

[0049] Step S1: Select a 5000L reactor as the reactor. Add 1650L of 32% hydrochloric acid solution and calcium material as the substrate to the reactor for reaction. After starting the reaction for 8 minutes, continuously introduce hydrogen chloride gas into the hydrochloric acid solution through the gas inlet. In this invention, calcium material is continuously added to the reactor through the feed inlet, and the molar ratio of hydrogen chloride gas to calcium material per unit time is 2.2:1. The hourly hydrogen chloride gas flow rate is 500L. In this embodiment, calcium carbonate ore is selected as the calcium material. Since the purity of the ore is lower than that of white mud, the amount added can be appropriately increased. The ore also needs to be pre-crushed before addition.

[0050] In this embodiment, after stabilization, the reaction temperature is controlled at around 80°C. The exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection, while the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate absorption of hydrogen chloride gas by the solution.

[0051] Step S2: Set the filtration conditions. Calculate the final calcium chloride concentration based on the volume of hydrochloric acid solution added in Step S1 and the mass of calcium material added. Perform filtration when the calcium chloride concentration reaches 70%. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material to a solid-liquid separation device for solid-liquid separation. Simultaneously, return the separated liquid to the reactor to continue participating in the reaction.

[0052] Step S3: Dry the solid-liquid separated wet calcium chloride material at a temperature of 130°C to obtain calcium chloride crystalline powder. Example

[0053] Step S1: Select a 5000L reactor as the reactor. Add 1200L of 25% hydrochloric acid solution and calcium material as the substrate to the reactor for reaction. After starting the reaction for 10 minutes, continuously introduce hydrogen chloride gas into the hydrochloric acid solution through the gas inlet. In this invention, calcium material is continuously added to the reactor through the feed inlet. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2.3:0.9. The hourly hydrogen chloride gas flow rate is 400L. In this embodiment, calcium carbonate ore is selected as the calcium material, and its composition is calcium carbonate.

[0054] In this embodiment, after stabilization, the reaction temperature is controlled at around 100°C. The exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection, while the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate absorption of hydrogen chloride gas by the solution.

[0055] Step S2: Set the filtration conditions. Calculate the final calcium chloride concentration based on the volume of hydrochloric acid solution added in Step S1 and the mass of calcium material added. Perform filtration when the calcium chloride concentration reaches 65%. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material to a solid-liquid separation device for solid-liquid separation. Simultaneously, return the separated liquid to the reactor to continue participating in the reaction.

[0056] Step S3: Dry the solid-liquid separated wet calcium chloride material at 100℃ to obtain calcium chloride crystalline powder. Example

[0057] Step S1: Select a 5000L reactor as the reactor. Add 1200L of 25% hydrochloric acid solution and calcium material as the substrate to the reactor for reaction. After starting the reaction for 10 minutes, continuously introduce hydrogen chloride gas into the hydrochloric acid solution through the gas inlet. In this invention, calcium material is continuously added to the reactor through the feed inlet. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2.3:0.9. The hourly hydrogen chloride gas flow rate is 800L. In this embodiment, calcium oxide ore is selected as the calcium material, and its composition is calcium oxide.

[0058] In this embodiment, after stabilization, the reaction temperature is controlled at around 100°C. The exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection, while the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate absorption of hydrogen chloride gas by the solution.

[0059] Step S2: Set the filtration conditions. Calculate the final calcium chloride concentration based on the volume of hydrochloric acid solution added in Step S1 and the mass of calcium material added. Perform filtration when the calcium chloride concentration reaches 65%. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material to a solid-liquid separation device for solid-liquid separation. Simultaneously, return the separated liquid to the reactor to continue participating in the reaction.

[0060] Step S3: Dry the solid-liquid separated wet calcium chloride material at 100℃ to obtain calcium chloride crystalline powder. Example

[0061] Step S1: Select a 5000L reactor as the reactor. Add 1200L of 25% hydrochloric acid solution and calcium material as the substrate to the reactor for reaction. After starting the reaction for 10 minutes, continuously introduce hydrogen chloride gas into the hydrochloric acid solution through the gas inlet. In this invention, calcium material is continuously added to the reactor through the feed inlet, and the molar ratio of hydrogen chloride gas to calcium material per unit time is 2.3:0.9. The hourly hydrogen chloride gas flow rate is 550L. In this embodiment, calcium oxide ore is selected as the calcium material, and its composition is calcium oxide.

[0062] In this embodiment, after stabilization, the reaction temperature is controlled at around 100°C. The exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection, while the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate absorption of hydrogen chloride gas by the solution.

[0063] During the reaction, the concentration of hydrochloric acid solution in the reactor and the content of hydrogen chloride gas in the reactor exhaust gas are monitored. When the concentration of hydrochloric acid solution is lower than the lower limit of 20%, the molar ratio of hydrogen chloride gas is increased. When the content of hydrogen chloride in the gas in the reactor is higher than the preset upper limit of hydrogen chloride gas content of 10%, the molar ratio of hydrogen chloride gas is decreased.

[0064] Step S2: Set the filtration conditions. Calculate the final calcium chloride concentration based on the volume of hydrochloric acid solution added in Step S1 and the mass of calcium material added. Perform filtration when the calcium chloride concentration reaches 65%. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material to a solid-liquid separation device for solid-liquid separation. Simultaneously, return the separated liquid to the reactor to continue participating in the reaction.

[0065] Step S3: Dry the solid-liquid separated wet calcium chloride material at 100℃ to obtain calcium chloride crystalline powder. Example

[0066] This invention also discloses a method for producing high-concentration calcium chloride crystalline powder, comprising the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution to ensure that the calcium material is completely reacted. The reaction temperature is 25℃~150℃. Step S2: After the reaction is complete, the material at the bottom of the reactor is transported to a solid-liquid separation device for solid-liquid separation, and the separated liquid is returned to the reactor to continue to participate in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

Claims

1. A method for producing high-concentration calcium chloride crystalline powder, characterized in that, Includes the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution to ensure that the calcium material is completely reacted. The reaction temperature is 25℃~150℃. Step S2: After the reaction is complete, the material at the bottom of the reactor is transported to a solid-liquid separation device for solid-liquid separation, and the separated liquid is returned to the reactor to continue to participate in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

2. A method for producing high-concentration calcium chloride crystalline powder, characterized in that, Includes the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution and calcium material is continuously added into the reactor. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2~2.5:0.8~1; the reaction temperature is 25℃~150℃. Step S2: Set the filtration conditions. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material at the bottom of the reactor to the solid-liquid separation equipment for solid-liquid separation. At the same time, return the separated liquid to the reactor to continue participating in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

3. A method for producing high-concentration calcium chloride crystalline powder, characterized in that: The production process is completed using a reactor and a solid-liquid separation device. The reactor includes a tank with a feed port, a gas inlet, and an exhaust pipe. The feed port is connected to the calcium feed equipment, and the gas inlet is connected to a hydrogen chloride gas source. The gas inlet is connected to an inlet pipe that extends into the tank. The exhaust pipe's detection branch is connected to a gas detection device, and the exhaust pipe is connected to a waste gas treatment device. The outlet at the bottom of the reactor is connected to the inlet of the solid-liquid separation device via a valve, and the liquid outlet of the solid-liquid separation device is piped to the reactor. The method for producing calcium chloride using the above-mentioned reactor and solid-liquid separation equipment includes the following steps: Step S1: Add hydrochloric acid solution and calcium material to the reactor as substrates for reaction. During the reaction, hydrogen chloride gas is continuously introduced into the hydrochloric acid solution through the gas inlet, and calcium material is continuously added into the reactor through the feed inlet. The molar ratio of hydrogen chloride gas to calcium material per unit time is 2~2.5:0.8~1; the reaction temperature is 25℃~150℃; the exhaust pipe discharges the gas generated in the reactor to the waste gas treatment equipment for environmental protection treatment, and the inlet pipe introduces hydrogen chloride gas into the bottom of the reactor tank to facilitate the absorption of hydrogen chloride gas by the solution. Step S2: Set the filtration conditions. When the reaction reaches the filtration conditions, open the valve at the bottom of the reactor to transport the material at the bottom of the reactor to the solid-liquid separation equipment for solid-liquid separation. At the same time, return the separated liquid to the reactor to continue participating in the reaction. Step S3: Dry the solid-liquid separated wet calcium chloride material to obtain calcium chloride crystalline powder.

4. The method for producing high-concentration calcium chloride crystalline powder as described in any one of claims 1 to 3, characterized in that: In step S1, the calcium material is a material containing calcium carbonate or calcium oxide. The calcium carbonate material includes caustic soda mud and calcium carbonate ore.

5. The method for producing high-concentration calcium chloride crystal powder as described in any one of claims 2 or 3, characterized in that: In step S1, the concentration of hydrochloric acid solution in the reactor and the content of hydrogen chloride gas in the reactor exhaust gas are monitored during the reaction process; when the concentration of hydrochloric acid solution is lower than the lower limit, the molar ratio of hydrogen chloride gas is increased; when the content of hydrogen chloride in the gas in the reactor is higher than the preset upper limit of hydrogen chloride gas content, the molar ratio of hydrogen chloride gas is decreased.

6. The method for producing high-concentration calcium chloride crystal powder as described in any one of claims 2 or 3, characterized in that: In step S1, the molar ratio of hydrogen chloride gas to calcium feed per unit time is 2~2.2:0.9~1; the reaction temperature is 80℃~100℃.

7. The method for producing high-concentration calcium chloride crystalline powder as described in any one of claims 1 to 3, characterized in that: In step S1, the volume of hydrochloric acid solution added is 20% to 35% of the total reactor capacity, and the hourly flow rate of hydrogen chloride gas is 400L to 800L.

8. The method for producing high-concentration calcium chloride crystalline powder as described in any one of claims 2 or 3, characterized in that: The filtration conditions for step S2 are as follows: calculate the final concentration of calcium chloride based on the volume of hydrochloric acid solution added in step S1 and the mass of calcium material added, and perform filtration when the calcium chloride concentration reaches 60%~70%.

9. The method for producing high-concentration calcium chloride crystalline powder as described in any one of claims 1 to 3, characterized in that: The drying temperature in step S3 is 90℃~160℃.

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