A method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Mechanical Vapor Removal and Purification)

Abstract

This invention relates to the field of sponge titanium production technology, specifically a method for refining and cleaning crude brine from waste sponge titanium brine using MVR (Mechanical Vapor Removal and Control) technology. The method includes the following steps: mixing the waste brine with crude brine, allowing it to react fully, and then passing it through a diaphragm filter press to separate calcium carbonate solids and sodium chloride solution. Hydrochloric acid is then added through a pipeline mixer to adjust the pH of the sodium chloride solution to 6.5-7.5. Hydrogen peroxide is added to neutralize excess sodium hypochlorite to obtain refined brine. The refined brine is then concentrated using MVR evaporation to obtain crystalline salt and condensate. This invention utilizes waste brine to remove impurities from crude brine, turning waste into waste, maximizing resource utilization, saving production costs, and improving the quality of crystalline salt and condensate. The use of MVR technology for evaporation and concentration significantly reduces energy consumption and improves production efficiency. This method for refining and cleaning crude brine from waste sponge titanium brine using MVR technology has advantages such as environmental friendliness, energy saving, cost savings, and improved product quality.

Description

Technical Field

[0001] This invention relates to the field of sponge titanium production technology, specifically a method for using waste sponge titanium brine for MVR crude brine purification. Background Technology

[0002] The entire process of sponge titanium production includes chlorination refining, reduction, distillation, electrolysis, and crushing and packaging stages. The tail gas from the chlorination refining and electrolysis processes contains a small amount of chlorine, which needs to be treated to meet emission standards before being released. Sponge titanium plants typically treat this tail gas using a 15%-30% sodium hydroxide solution for multi-stage absorption. When the sodium hydroxide concentration in the absorbent falls below 2%, the absorbent is replaced. This discharged absorbent is collectively referred to as waste brine. The main components of this waste brine are NaClO, NaCl, NaOH, NaCO3, and NaHCO3. The conventional treatment method for this waste brine is to adjust the pH to neutral after sedimentation and filtration, then add hydrogen peroxide or a catalyst to decompose the sodium hypochlorite into sodium chloride, and then use triple-effect evaporation or MVR evaporation to evaporate it into crystalline salt for reuse in the chlorination furnace. This treatment method is lengthy, and apart from NaCl, other components are not effectively utilized, resulting in resource waste and increased production costs.

[0003] The production of sponge titanium also generates a large amount of acidic wastewater. The treatment of this wastewater begins with neutralization using calcium carbide sludge, converting the acidic wastewater into a calcium chloride solution. This calcium chloride solution is then mixed with sodium sulfate solution to remove most of the calcium ions with calcium sulfate precipitation, yielding crude brine. Sodium carbonate solution is added to the crude brine to further precipitate calcium ions, ensuring the calcium ion concentration is less than 5 mg / L, yielding refined brine. This refined brine passes through a ceramic membrane filter and a denitrification system before entering an MVR crystallization evaporator to obtain crystalline salt for reuse in the chlorination furnace. This process requires the purchase and preparation of sodium carbonate solution, increasing production costs and the burden on water treatment. Furthermore, the use of calcium carbide sludge for neutralization introduces some ammonia nitrogen, causing ammonia nitrogen levels in the crystalline salt and condensate to exceed standards, affecting subsequent use. Summary of the Invention

[0004] The purpose of this invention is to provide a method for removing impurities and refining crude brine from waste sponge titanium using MVR (Medium-Vacuum Transformer) salt solution, in order to solve the problems mentioned in the background art, such as the waste of resources and the generation of other wastewater during the production process of sponge titanium.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Medium-Vacuum Transformer Resin) specifically includes the following steps:

[0007] S10: Select the appropriate ratio to mix with crude brine based on the carbonate concentration in the waste brine;

[0008] S11: When the carbonate concentration in the waste brine is higher than 30 g / L, the waste brine and crude brine shall be mixed directly in proportion.

[0009] S12: When the carbonate concentration in the waste brine is below 30 g / L, add sodium carbonate solid to the waste brine to increase the carbonate concentration, and then mix it with crude brine.

[0010] S20: The waste brine and crude brine are mixed evenly and reacted fully. The mixture is then passed through a diaphragm filter press to separate calcium carbonate solid and sodium chloride solution.

[0011] S30: Sodium chloride solution is added to hydrochloric acid via a pipe mixer to adjust the pH to neutral;

[0012] S40: The sodium chloride solution after pH adjustment enters the neutralization tank, and hydrogen peroxide is added in proportion to neutralize the excess hypochlorite. The neutralized sodium chloride solution is then further passed through a membrane filter and denitrification equipment to obtain refined brine.

[0013] S50: The refined brine is concentrated by evaporation using MVR to obtain crystalline salt and condensate.

[0014] Preferably, the waste salt solution is an alkaline waste liquid generated during the tail gas absorption process of sponge titanium production, and its main components are NaClO, NaCl, NaOH, NaCO3 and NaHCO3.

[0015] Preferably, when the carbonate concentration in the waste brine is below 30 g / L, the sodium carbonate replenishment amount is 50 kg / m³. 3 .

[0016] Preferably, the crude brine is obtained by pressure filtration after reacting calcium chloride wastewater with sodium sulfate solution, wherein the sodium chloride concentration is 8%-15%, and the sulfate and calcium ion concentrations are each less than 5g / L.

[0017] Preferably, the ratio of waste brine to crude brine is CO3. 2- Ca 2+ Molar ratio 1:1.

[0018] Preferably, a 1% hydrochloric acid solution is added to the pipe mixer to adjust the solution pH to 6.5-7.5.

[0019] Preferably, excess sodium hypochlorite is neutralized by adding hydrogen peroxide, wherein the hydrogen peroxide is added in a ratio of ClO₂. - The molar ratio of H2O2 is 1:1, and the concentration of hydrogen peroxide is 25-30%.

[0020] Preferably, the reaction time of the mixture in the impurity removal reaction tank is 1-2 hours.

[0021] Preferably, the evaporation crystallization method is MVR.

[0022] Preferably, the crystallized salt is dried and reused in the chlorination furnace, and the condensate is reused in the circulating water system.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. The method of using waste sponge titanium waste salt solution for the purification of crude brine in MVR uses waste salt solution to remove impurities from crude brine, turning waste into waste, maximizing resource utilization, saving production costs, and improving the quality of crystallized salt and condensate.

[0025] 2. The method of using waste sponge titanium salt solution for MVR crude brine purification and refining of the present invention treats the waste salt solution as a resource for treating crude brine, thereby improving the utilization rate of the waste salt solution and reducing environmental pollution. When the carbonate concentration in the waste salt solution is below 30 g / L, the carbonate concentration can be increased by adding solid sodium carbonate, which can reduce the amount of new materials used and save processing costs. Through a series of processing steps, such as mixing, reaction, pressure filtration, pH adjustment, and neutralization, a refined sodium chloride solution and crystalline salt can be obtained, improving product quality. This method can recover valuable elements in the waste salt solution, such as calcium carbonate and sodium chloride, realizing resource recycling. This method generates less waste during the treatment process, and the final product can be reused, which is environmentally friendly. Using MVR technology for evaporation and concentration can greatly reduce energy consumption and improve production efficiency. In summary, this method of using waste sponge titanium salt solution for MVR crude brine purification and refining of the present invention has the advantages of being environmentally friendly, energy-saving, cost-saving, and improving product quality. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are explained in detail together with the embodiments of the invention, but do not constitute a limitation thereof.

[0027] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] A method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Medium-Vacuum Transformer Resin) processes, such as... Figure 1 As shown, when the carbonate concentration in the waste brine is greater than 30 g / L, the treatment method includes the following steps: the waste brine is discharged into a sodium carbonate solution tank; the waste brine and crude brine are added to a purification reaction tank in a certain proportion; the crude brine is obtained by reacting calcium chloride wastewater with sodium sulfate solution and then filtering it.

[0031] Furthermore, the concentration of sodium chloride in the crude brine is 8%-15%, and the sulfate and calcium ions are less than 5g / L respectively; the ratio of waste brine to crude brine is 1:1 (CO32-:Ca2+ molar ratio). After the waste brine and crude brine are fully mixed, they enter the impurity removal and settling tank for further reaction.

[0032] The reaction time of the mixture in the impurity removal reaction tank is about 2 hours; after the mixture has fully reacted, it is converted into a sodium chloride solution containing calcium carbonate solid.

[0033] Specifically, the mixture is passed through a diaphragm filter press to obtain sodium chloride solution and calcium carbonate solid; the sodium chloride solution enters the oxidation tank through a pipeline mixer, and the calcium carbonate solid is collected and sold.

[0034] It is worth noting that a 1% hydrochloric acid solution was added to the pipe mixer to adjust the pH of the solution to 6.5-7.5;

[0035] It is worth noting that the purpose of adding hydrochloric acid is twofold: firstly, to enhance the oxidizing power of sodium hypochlorite and remove ammonia nitrogen from the solution, and secondly, to neutralize excess OH-. - and CO3 2- This improves the quality of crystallized salts and condensate.

[0036] In addition, excess sodium hypochlorite is neutralized by adding hydrogen peroxide, which is a 25-30% hydrogen peroxide solution; the ratio of hydrogen peroxide added is 1:1 molar ratio of ClO- to H2O2.

[0037] Furthermore, the sodium chloride solution after neutralization of ClO- passes through a ceramic membrane filter and a denitrification device before entering the refined brine storage tank; the refined brine is then evaporated and crystallized to obtain crystalline salt and condensate.

[0038] In this embodiment, the evaporation crystallization method is MVR; the crystallized salt is dried and reused in the chlorination furnace, and the condensate is reused in the circulating water system.

[0039] Example 2

[0040] A method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Medium-Vacuum Transformer Resin) processes, such as... Figure 1 As shown, when the carbonate concentration in the waste brine is less than 30 g / L, the treatment method includes the following steps: the waste brine is introduced into a sodium carbonate preparation tank, stirring is started, and solid sodium carbonate is added at a rate of 50 kg / m³. 3The prepared sodium carbonate solution and crude brine were added to the impurity removal reaction tank in proportion; the crude brine was obtained by pressure filtration after reacting calcium chloride wastewater with sodium sulfate solution.

[0041] Furthermore, the sodium chloride concentration in the crude brine is 8%-15%, and the sulfate and calcium ion concentrations are both less than 5 g / L; the ratio of waste brine to crude brine is [missing information - likely CO3]. 2- Ca 2+ Molar ratio 1:1.

[0042] Specifically, the waste brine and crude brine are thoroughly mixed and then introduced into a sedimentation tank for further reaction; the reaction time of the mixture in the sedimentation tank is about 2 hours; after the mixture has fully reacted, it is converted into a sodium chloride solution containing calcium carbonate solids.

[0043] In addition, the mixture is passed through a diaphragm filter press to obtain sodium chloride solution and calcium carbonate solid; the sodium chloride solution enters the oxidation tank through a pipeline mixer, and the calcium carbonate solid is collected and sold.

[0044] It is worth noting that a 1% hydrochloric acid solution is added to the pipeline mixer to adjust the solution pH to 6.5-7.5. The purpose of adding hydrochloric acid is twofold: firstly, to enhance the oxidizing power of sodium hypochlorite and remove ammonia nitrogen from the solution; and secondly, to neutralize excess OH- and CO32-, thereby improving the quality of the crystallized salt and condensate.

[0045] It is worth noting that excess sodium hypochlorite is neutralized by adding hydrogen peroxide, which is a 25-30% hydrogen peroxide solution; the ratio of hydrogen peroxide added is 1:1 molar ratio of ClO- to H2O2.

[0046] In this embodiment, neutralizing ClO - The sodium chloride solution then passes through a ceramic membrane filter and a denitrification device before entering the refined brine storage tank; the refined brine is then evaporated and crystallized to obtain crystalline salt and condensate.

[0047] It is worth noting that the evaporation crystallization method is MVR; the crystallized salt is dried and reused in the chlorination furnace, and the condensate is reused in the circulating water system.

[0048] Specific Implementation Case 1

[0049] Waste brine indicators:

[0050]

[0051] Waste brine enters the sodium carbonate solution tank, where it mixes with crude brine according to CO32-. 2- Ca 2+ Add the mixture to the impurity removal reaction tank at a molar ratio of 1:1; after mixing evenly, pump the mixture into the conversion settling tank via a mortar pump and allow it to react fully for 2 hours.

[0052] After the reaction is complete, calcium carbonate solid and sodium chloride solution are obtained by separating them using a diaphragm filter press.

[0053] The calcium carbonate solid obtained from pressure filtration is collected and sold. Sodium chloride solution enters the oxidation tank through a pipeline mixer. A 1% hydrochloric acid solution is added to the pipeline mixer to adjust the pH of the sodium chloride solution. The oxidation tank is equipped with a pH meter, which is interlocked with the hydrochloric acid flow control valve. The hydrochloric acid flow rate is controlled by the pH value in the oxidation tank to ensure the pH is maintained between 6.5 and 7.5. The solution remains in the oxidation tank for approximately 2 hours to ensure complete decomposition of ammonia nitrogen in the solution by sodium hypochlorite.

[0054] A buffer tank is installed before the ceramic membrane filter and the membrane denitrification equipment. 27% hydrogen peroxide is added to the buffer tank to neutralize excess sodium hypochlorite. An ORP potentiometer is installed after the buffer tank to provide feedback on the redox properties of the solution and further characterize the sodium hypochlorite and hydrogen peroxide content in the solution. The theoretical amount of hydrogen peroxide added is ClO₂. - The molar ratio of H2O2 is 1:1.

[0055] The sodium chloride solution, after neutralizing excess hypochlorite, is passed sequentially through a ceramic membrane filter and a membrane denitrification unit to obtain refined brine.

[0056] The refined brine is then evaporated and concentrated in an MVR system to obtain crystalline salt and condensate. The crystalline salt is dried and reused in the chlorination furnace, while the condensate is reused in the circulating water system.

[0057] Specific Implementation Case 2

[0058] Waste brine indicators:

[0059]

[0060] Waste brine is introduced into a sodium carbonate preparation tank, stirring is started, and solid sodium carbonate is added at a rate of 50 kg / m³. 3 ;

[0061] The prepared sodium carbonate solution and crude brine were mixed according to CO3. 2- Ca 2+ Add the mixture to the impurity removal reaction tank at a molar ratio of 1:1; after mixing evenly, pump the mixture into the conversion settling tank via a mortar pump and allow it to react fully for 2 hours.

[0062] After the reaction is complete, calcium carbonate solid and sodium chloride solution are obtained by separating them using a diaphragm filter press.

[0063] The calcium carbonate solid obtained from pressure filtration is collected and sold. Sodium chloride solution enters the oxidation tank through a pipeline mixer. A 1% hydrochloric acid solution is added to the pipeline mixer to adjust the pH of the sodium chloride solution. The oxidation tank is equipped with a pH meter, which is interlocked with the hydrochloric acid flow control valve. The hydrochloric acid flow rate is controlled by the pH value in the oxidation tank to ensure the pH is maintained between 6.5 and 7.5. The solution remains in the oxidation tank for approximately 2 hours to ensure complete decomposition of ammonia nitrogen in the solution by sodium hypochlorite.

[0064] A buffer tank is installed before the ceramic membrane filter and the membrane denitrification equipment. 27% hydrogen peroxide is added to the buffer tank to neutralize excess sodium hypochlorite. An ORP potentiometer is installed after the buffer tank to provide feedback on the redox properties of the solution and further characterize the sodium hypochlorite and hydrogen peroxide content in the solution. The theoretical amount of hydrogen peroxide added is ClO₂. - The molar ratio of H2O2 is 1:1.

[0065] The sodium chloride solution, after neutralizing excess hypochlorite, is passed sequentially through a ceramic membrane filter and a membrane denitrification unit to obtain refined brine.

[0066] The refined brine is then evaporated and concentrated in an MVR system to obtain crystalline salt and condensate. The crystalline salt is dried and reused in the chlorination furnace, while the condensate is reused in the circulating water system.

[0067] The present invention describes a method for removing impurities from crude brine in MVR using waste sponge titanium salt solution. This method utilizes waste salt solution to remove impurities from crude brine, turning waste into waste, thereby maximizing resource utilization, saving production costs, and improving the quality of crystalline salt and condensate.

[0068] The present invention discloses a method for refining and cleaning crude brine from waste titanium sponge solution using MVR (Medium-Vacuum Resinerting) technology. This method utilizes the waste brine as a resource to treat crude brine, improving the utilization rate of the waste brine and reducing environmental pollution. When the carbonate concentration in the waste brine is below 30 g / L, adding solid sodium carbonate increases the carbonate concentration, reducing the amount of new material used and saving processing costs. Through a series of processing steps, such as mixing, reaction, pressure filtration, pH adjustment, and neutralization, a refined sodium chloride solution and crystalline salt can be obtained, improving product quality. This method also allows for the recovery and reuse of valuable elements in the waste brine, such as calcium carbonate and sodium chloride, achieving resource recycling. The method generates less waste during processing, and the final product can be reused, making it environmentally friendly. Using MVR technology for evaporation and concentration significantly reduces energy consumption and improves production efficiency. In summary, this method for refining and cleaning crude brine from waste titanium sponge solution using MVR technology offers advantages such as environmental friendliness, energy saving, cost savings, and improved product quality.

[0069] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Medium-Vacuum Transformer Resinator) processes, characterized in that: Specifically, the following steps are included: S10: Select the appropriate ratio to mix with crude brine based on the carbonate concentration in the waste brine; S11: When the carbonate concentration in the waste brine is higher than 30 g / L, the waste brine and crude brine shall be mixed directly in proportion. S12: When the carbonate concentration in the waste brine is below 30 g / L, add sodium carbonate solid to the waste brine to increase the carbonate concentration, and then mix it with crude brine. S20: The waste brine and crude brine are mixed evenly and reacted fully. The mixture is then passed through a diaphragm filter press to separate calcium carbonate solid and sodium chloride solution. S30: Sodium chloride solution is added to hydrochloric acid via a pipe mixer to adjust the pH to neutral; S40: The sodium chloride solution after pH adjustment enters the neutralization tank, and hydrogen peroxide is added in proportion to neutralize the excess hypochlorite. The neutralized sodium chloride solution is then further passed through a membrane filter and denitrification equipment to obtain refined brine. S50: The refined brine is concentrated by evaporation using MVR to obtain crystalline salt and condensate; The waste salt solution is an alkaline waste liquid generated during the tail gas absorption process of sponge titanium production, and its main components are NaClO, NaCl, NaOH, Na2CO3 and NaHCO3. When the carbonate concentration in the waste brine is below 30 g / L, the sodium carbonate replenishment amount is 50 kg / m³. 3 ; The crude brine is obtained by pressure filtration after reacting calcium chloride wastewater with sodium sulfate solution, wherein the sodium chloride concentration is 8%-15%, and the sulfate and calcium ions are less than 5g / L respectively. The ratio of waste brine to crude brine is CO3. 2- Ca 2+ Molar ratio 1:1; Excess sodium hypochlorite is neutralized by adding hydrogen peroxide, wherein the hydrogen peroxide is added in a ratio of ClO. - The molar ratio of H2O2 is 1:1, and the concentration of hydrogen peroxide is 25-30%.

2. The method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Medium-Vacuum Transformer) according to claim 1, characterized in that: Add 1% hydrochloric acid solution to the pipeline mixer to adjust the pH of the solution to 6.5-7.

5.

3. The method for removing impurities and refining crude brine from sponge titanium waste brine according to claim 1, characterized in that: The reaction time of the mixture in the impurity removal reaction tank is 1-2 hours.

4. The method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Medium-Vacuum Transformer) according to claim 1, characterized in that: The evaporation crystallization method is MVR.

5. The method for removing impurities and refining crude brine from waste titanium sponge solution used in MVR (Medium-Vacuum Transformer) according to claim 1, characterized in that: After the crystallized salt is dried, it is reused in the chlorination furnace, and the condensate is reused in the circulating water system.

Images