Method for comprehensively utilizing organic silicon wastewater and waste fused salt of fused salt chlorination

Abstract

The invention discloses a method for comprehensively utilizing organic silicon wastewater and fused salt chlorination waste fused salt, which comprises the following steps: S1, carrying out water leaching on the fused salt chlorination waste fused salt by adopting the organic silicon wastewater, and then carrying out solid-liquid separation to obtain water leaching residues and water leaching liquid; s2, carrying out nanofiltration treatment on the water immersion liquid to obtain nanofiltration concentrated liquid and nanofiltration clear liquid; s3, neutralizing the nanofiltration concentrated liquid by using a calcium-containing alkaline substance, neutralizing the nanofiltration clear liquid by using a sodium-containing alkaline substance, and respectively carrying out solid-liquid separation to obtain a solid-phase product and a liquid-phase product; and S4, concentrating and crystallizing the liquid phase products respectively. The organic silicon wastewater and the chlorination process waste fused salt are comprehensively treated, high-purity ferric hydroxide, calcium chloride and sodium chloride are obtained, and efficient treatment of the organic silicon wastewater and efficient recycling of chlorination process waste fused salt ions are achieved.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment technology, and specifically relates to a method for the comprehensive utilization of organosilicon wastewater and molten salt chlorination waste molten salt. Background Technology

[0002] In the production of titanium dioxide, organic coating wastewater is often generated. For titanium dioxide used in plastics, organosilicon solvents are commonly used as organic coating agents. Therefore, after flash evaporation (organic coating agents are generally added during the flash evaporation stage), a large amount of organosilicon-containing wastewater is produced. This organosilicon wastewater has a high COD (chemical oxygen demand) content, posing a potential risk of organic fouling when it enters membrane systems for treatment. Therefore, advanced oxidation treatment is commonly used for this organosilicon wastewater; however, this method is costly, has poor treatment efficiency, and negatively impacts water treatment systems.

[0003] Molten salt chlorination is a chlorination process conducted in a high-temperature molten salt medium, primarily used to process refractory metal ores or intermediate products, achieving the generation and separation of metal chlorides. This technology is widely applied in the extraction and refining of rare metals such as titanium, zirconium, and rare earth elements. However, due to problems such as byproduct deposition and incomplete reaction during the reaction, a large amount of waste molten salt is generated. Currently, the primary method for disposing of this waste molten salt is stockpiling. This method not only wastes resources but also increases the salinity of groundwater. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the comprehensive utilization of organosilicon wastewater and molten salt chlorination waste to overcome the shortcomings of the prior art.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for the comprehensive utilization of organosilicon wastewater and molten salt chlorination waste includes the following steps:

[0007] S1. The molten salt chlorination waste is leached with organosilicon wastewater, and then solid-liquid separation is performed to obtain leached residue and leached liquid;

[0008] S2. Perform nanofiltration on the aqueous extract to obtain nanofiltration concentrate and nanofiltration clear liquid;

[0009] S3. The nanofiltration concentrate is neutralized with a calcium-containing alkaline substance, and the nanofiltration clear liquid is neutralized with a sodium-containing alkaline substance, and solid-liquid separation is performed separately to obtain solid-phase product and liquid-phase product.

[0010] S4. The liquid products are concentrated and crystallized separately.

[0011] Preferably, the silicon ion content of the organic silicon wastewater in step S1 is 300-800 mg / L, the TOC content is 300-800 ppm, and the COD content is 500-1500 ppm.

[0012] Preferably, the sodium chloride content of the waste molten salt in step S1 is 15-45%, the magnesium chloride content is 5-20%, the aluminum chloride content is 0-5%, the silicon chloride content is 0-10%, the calcium chloride content is 0-10%, the manganese chloride content is 0-10%, and the iron chloride content is 0-20%.

[0013] Preferably, the amount of the organic silicon wastewater in step S1 is 1-5 times the mass of the waste molten salt for molten salt chlorination; and the pH of the system after water immersion is 0-3.

[0014] Preferably, the nanofiltration treatment in step S2 uses an acidic nanofiltration membrane.

[0015] Preferably, in step S2, the Fe ion content in the nanofiltration clear liquid is controlled to be 0-5 g / L, the Ca ion content is 0-1 g / L, the Mg ion content is 0-5 g / L, the manganese ion content is 0-1 g / L, the sodium ion content is 10-60 g / L, the silicon content is 1-40 mg / L, and the pH is 0-3; and the Fe ion content in the nanofiltration concentrated liquid is 50-160 g / L, the Ca ion content is 0-50 g / L, the Mg ion content is 10-70 g / L, the manganese ion content is 0-40 g / L, the sodium ion content is 10-50 g / L, the silicon content is 20-60 mg / L, and the pH is 0-3.

[0016] Preferably, in step S3, the pH of the nanofiltration concentrated liquid is first adjusted to 4.0-7.5, and after solid-liquid separation, a solid-phase product containing iron hydroxide is obtained; and then the pH is further adjusted to 10-12, and after solid-liquid separation again, a solid-phase product is obtained.

[0017] Preferably, in step S3, the pH of the nanofiltration clear liquid is 10-11.

[0018] The present application comprehensively treats organic silicon wastewater and waste molten salt for molten salt chlorination, and obtains high-purity iron hydroxide, calcium chloride, and sodium chloride, thereby achieving efficient treatment of organic silicon wastewater and efficient recovery and utilization of ions in waste molten salt for molten salt chlorination. DETAILED DESCRIPTION

[0019] The present application provides a method for comprehensive utilization of organic silicon wastewater and waste molten salt for molten salt chlorination, comprising the following steps:

[0020] S1. Water immersion of waste molten salt for molten salt chlorination is performed using organic silicon wastewater, and then solid-liquid separation is performed to obtain water immersion residues and water immersion liquid;

[0021] S2. The aqueous extract is subjected to nanofiltration to obtain nanofiltration concentrate and nanofiltration clear liquid;

[0022] S3. Neutralize the nanofiltration concentrate and nanofiltration solution with calcium-containing alkaline substances and sodium-containing alkaline substances, respectively, and then perform solid-liquid separation to obtain solid-phase products and liquid-phase products.

[0023] S4. Concentrate and crystallize the liquid phase products separately to obtain salts.

[0024] The organosilicon wastewater used in this embodiment is the organosilicon wastewater generated during the titanium dioxide production process, with a silicon ion content of 300-800 mg / L, a TOC (total organic carbon) content of 300-800 ppm, and a COD (chemical oxygen demand) content of 500-1500 ppm. The molten salt used in the molten salt chlorination process is the waste molten salt produced by the molten salt chlorination reaction, containing 15-45% sodium chloride, 5-20% magnesium chloride, 0-5% aluminum chloride, 0-10% silicon chloride, 0-10% calcium chloride, 0-10% manganese chloride, and 0-20% ferric chloride.

[0025] This application utilizes organosilicon wastewater to quench molten salt from chlorination wastewater. During this process, the organosilicon in the wastewater can gelatinize and form partial precipitates, thus separating from the wastewater and achieving the purpose of removing organosilicon from the wastewater. The applicant hypothesizes that the organosilicon gelation precipitation principle is as follows: ions in the waste molten salt can cause the organosilicon monomers in the organosilicon wastewater to react, thereby causing gelation.

[0026] After water quenching, most of the organosilicon in the wastewater is removed, thus significantly reducing the COD content (COD is mainly caused by organosilicon additives in the water, so COD and organosilicon content are correlated; tests show that COD is approximately 2-3 times higher than organosilicon content). A small amount of unprecipitated silicon remains in the wastewater. Simultaneously, a large number of water-soluble ions from the molten salt dissolve in the wastewater during quenching. Therefore, the sodium and magnesium ion content in the water-leached residue after solid-liquid separation is significantly reduced, while the silicon ion content is significantly increased. The silicon ion and COD content in the water-leached solution is significantly reduced, while the sodium, iron, and magnesium ion content is significantly increased.

[0027] Tests showed that the Fe ion content in the water extract was 20–50 g / L, the Ca ion content was 0–15 g / L, the Mg ion content was 5–20 g / L, the manganese ion content was 0–10 g / L, the sodium ion content was 10–50 g / L, the pH was 0–3, and the silicon content was 9–40 mg / L.

[0028] The water-leached residue contains 2-20% sodium chloride, 0-5% magnesium chloride, 2-15% aluminum chloride, 8-40% silicon chloride, 2-5% calcium chloride, 1-3% manganese chloride, and 4-8% ferric chloride.

[0029] Then, the aqueous leaching solution is passed through a nanofiltration membrane to separate high-valence ions from monovalent ions (mainly sodium ions). Since the COD content in the wastewater is already low, it will not easily cause clogging of the nanofiltration membrane.

[0030] Then, different alkaline substances are used for neutralization. Specifically, calcium-containing alkaline substances are used to neutralize high-valence ions, and sodium-containing alkaline substances are used to neutralize monovalent ions. High-valence ions and monovalent ions are treated in a targeted manner, and after concentration, a salt with high purity is obtained. This salt can be recycled for molten salt chlorination, thereby achieving the purpose of recycling waste molten salt.

[0031] Therefore, this application integrates the treatment of organosilicon wastewater and molten salt from the chlorination process. The molten salt is quenched with organosilicon wastewater, followed by nanofiltration membrane separation of high-valence and monovalent ions. Subsequently, calcium-containing alkaline substances are used to neutralize the high-valence ions, and sodium-containing alkaline substances are used to neutralize the monovalent ions. This achieves both the reduction of organosilicon wastewater and the efficient recovery and utilization of the molten salt. Furthermore, the above treatment method only involves nanofiltration membranes and concentration treatment, without involving advanced oxidation or other special treatments, resulting in relatively low cost and suitability for large-scale application.

[0032] When molten salt chlorination waste is discharged from the molten salt furnace, the temperature is relatively high, about 600-800℃. If it is directly soaked in water, it can promote the gelation and precipitation of organosilicification. However, soaking in water at high temperature has certain risks. Therefore, it is also possible to soak in water after cooling.

[0033] Preferably, the amount of organosilicon wastewater used in step S1 is 1 to 5 times the mass of the molten salt chlorination waste salt, and the pH of the system after water leaching is 0 to 3. Within this range, the organosilicon in the wastewater can precipitate as much as possible, while the water-soluble ions in the waste molten salt can dissolve in the wastewater as much as possible. If a large amount of organosilicon wastewater is used, the pH of the system will increase after water leaching, causing some ferric hydroxide to settle prematurely, affecting the subsequent nanofiltration membrane separation.

[0034] Preferably, the nanofiltration process in step S2 uses an acidic nanofiltration membrane, which is resistant to acid corrosion from water immersion and extends the service life of the nanofiltration membrane.

[0035] More preferably, the nanofiltration pressure is 0–2 MPa. The nanofiltration clarified solution is controlled to have the following ion contents: Fe ion content 0–5 g / L, Ca ion content 0–1 g / L, Mg ion content 0–5 g / L, Manganese ion content 0–1 g / L, Sodium ion content 10–60 g / L, Silicon content 1–40 mg / L, pH 0–1, and Chloride ion content 80–195 g / L; the nanofiltration concentrate is controlled to have the following ion contents: Fe ion content 50–160 g / L, Ca ion content 0–50 g / L, Mg ion content 10–70 g / L, Manganese ion content 0–40 g / L, Sodium ion content 10–50 g / L, Silicon content 9–60 mg / L, pH 0–1, and Chloride ion content 80–195 g / L.

[0036] As described above, the nanofiltration concentrate in step S3 contains high levels of iron, calcium, and magnesium ions. Therefore, a calcium-containing alkaline substance, such as calcium carbide sludge, is used for staged precipitation. First, the pH is adjusted to 4.0–7.5. At this pH, ferric hydroxide precipitates first, and after solid-liquid separation, a solid product containing ferric hydroxide is obtained. Aluminum ions can also precipitate simultaneously under these pH conditions; however, the aluminum ion content in the entire system is relatively low, thus having little impact on the purity of the ferric hydroxide. Testing revealed that the total iron content (calculated as iron) in this solid product is ≥45% by mass.

[0037] Then, a calcium-containing alkaline substance is added to the separated liquid phase to adjust the pH to 10-12, causing other ions such as Mg ions to precipitate and separate from the calcium ions. After solid-liquid separation, the liquid phase product is concentrated and crystallized by MVR to obtain calcium chloride solid. The calcium chloride content in the solid is 95-99%.

[0038] The nanofiltration solution in step S3 has a high sodium ion content and also contains small amounts of Fe, Ca, Mg, and other ions. Therefore, a sodium-containing alkaline substance, such as sodium hydroxide, is used to adjust the pH to 10-11 for neutralization. At this pH, most of the metal ions precipitate and are separated from the water. Then, MVR concentration is performed to obtain sodium chloride solid with high purity. The sodium chloride content in this part of the sodium chloride is 99%-99.5%, which meets the salt requirements of molten salt chlorination and is returned to molten salt chlorination for reuse.

[0039] When neutralizing the nanofiltration concentrate with calcium carbide sludge, the calcium carbide sludge needs to be slurried before being added. The slurry water used can be the concentrated mother liquor from the MVR (Medium-Vacuum Reduction) process, thus achieving the recycling of organosilicon wastewater. (During the evaporation and concentration process, a small amount of organosilicon in the water is also concentrated and retained in the MVR mother liquor. During the recycling of the mother liquor for slurrying of calcium carbide sludge and neutralization of the nanofiltration concentrate, the organosilicon in the mother liquor re-enters the system. Because the ferric hydroxide produced by the nanofiltration concentrate has a certain adsorption capacity, it can further adsorb the organosilicon, thereby removing the silicon content from the mother liquor. This ensures that the silicon content remains stable at the equilibrium value during subsequent cycles, without significantly impacting the evaporation and concentration system.) The evaporation condensate has a low ion content and is returned to other processes for reuse.

[0040] The condensate from the nanofiltration clarified liquid has a chloride ion content ≤50ppm, a sodium ion content ≤30ppm, a pH of 5-7, a COD ≤30ppm, and an ammonia nitrogen content ≤10ppm. It can be used as wash water in the titanium dioxide chlorination production system. The condensate from the nanofiltration concentrated liquid can be used to replenish the cooling tower water in the titanium dioxide chlorination production system. It has a chloride ion content ≤50ppm, a calcium ion content ≤50ppm, a pH of 5-7, a COD ≤50ppm, and an ammonia nitrogen content ≤10ppm.

[0041] After leaching, the molten salt waste is about 1 / 15 to 1 / 10 the mass of the leached residue, and the volume of the leached residue is greatly reduced, making it convenient for further processing.

[0042] Therefore, this application integrates the treatment of organosilicon wastewater with molten salt from the chlorination process to obtain high-purity ferric hydroxide, calcium chloride, and sodium chloride, achieving efficient treatment of organosilicon wastewater and efficient recovery and utilization of ions from molten salt from the chlorination process.

[0043] Example 1

[0044] 1. The waste molten salt is leached in organosilicon wastewater. The organosilicon wastewater contains 350 ppm silicon, 400 ppm TOC, and 900 mg / L COD. The molten salt contains 32% sodium chloride, 8.2% magnesium chloride, 1.4% aluminum chloride, 3.1% silicon chloride, 3.3% calcium chloride, 3.1% manganese chloride, and 8.2% ferric chloride. The amount of organosilicon wastewater used is three times the mass of the waste molten salt.

[0045] 2. After water immersion, solid-liquid separation is performed to obtain water-immersion residue and water-immersion liquid. The water-immersion residue contains 2.0% sodium chloride, 3.7% magnesium chloride, 8.1% aluminum chloride, 32.6% silicon chloride, 3.6% calcium chloride, 1.7% manganese chloride, and 6.0% ferric chloride. The water-immersion liquid contains 23.3 g / L Fe ions, 4.6 g / L Ca ions, 10.1 g / L Mg ions, 4.04 g / L manganese ions, 39.3 g / L sodium ions, has a pH of 0.5, and contains 9.9 mg / L silicon.

[0046] 3. The aqueous extract is passed through a nanofiltration membrane for salt separation to obtain a concentrated nanofiltration solution and a clear nanofiltration solution. The concentrated nanofiltration solution contains 70 g / L iron, 14 g / L calcium ions, 30 g / L magnesium ions, 12 g / L manganese ions, and 30 mg / L silicon ions. The clear nanofiltration solution contains 3.5 g / L iron, 0.69 g / L calcium ions, 1.5 g / L magnesium ions, 0.6 g / L manganese ions, and 1.5 mg / L silicon ions.

[0047] 4. The nanofiltration concentrate is neutralized using calcium carbide slurry. First, the pH is adjusted to 6.0, and after solid-liquid separation, solid ferric hydroxide with a purity of 47.5% (calculated as iron) is obtained. The pH is then adjusted to 11.5, and solid-liquid separation is performed again. The clarified liquid is sent to MVR for concentration and crystallization to obtain calcium chloride crystals. The calcium chloride content in the crystals is 96.8%. The concentrated mother liquor can be recycled to pulverize the calcium carbide sludge. The chloride ion content in the evaporation condensate is 35 ppm, the calcium ion content is 38 ppm, the pH is 6.5, the COD is 32 ppm, and the ammonia nitrogen is 0.7 ppm. This condensate is returned to other processes for reuse.

[0048] 5. The nanofiltration solution is neutralized with sodium hydroxide to a pH of 10.2, followed by solid-liquid separation. The solution contains 0 g / L Fe, 0 g / L Ca, 0 g / L Mg, 0 g / L Manganese, 3.6 mg / L Silicon, and 135 g / L Sodium. The solution is then concentrated and crystallized using an MVR (Medium-Vacuum Retention Machine) to obtain solid sodium chloride. The solid contains 97.5% sodium chloride and is returned for molten salt chlorination. The concentrated mother liquor can be recycled for pulping calcium carbide sludge. The evaporation condensate contains 35 ppm chloride, 20 ppm sodium, has a pH of 6.5, 20 ppm COD, and 0.3 ppm ammonia nitrogen, and is returned for use in other processes.

[0049] Example 2

[0050] 1. The waste molten salt is leached with organosilicon wastewater; the amount of organosilicon wastewater used is twice the mass of the waste molten salt; the organosilicon wastewater used has a silicon content of 485 ppm, a TOC content of 510 ppm, and a COD content of 950 mg / L; the molten salt used contains 32% sodium chloride, 8.2% magnesium chloride, 1.4% aluminum chloride, 3.1% silicon chloride, 3.3% calcium chloride, 3.1% manganese chloride, and 8.2% ferric chloride.

[0051] 2. After water immersion, solid-liquid separation is performed to obtain water-immersion residue and water-immersion liquid. The water-immersion residue contains 2.0% sodium chloride, 4.2% magnesium chloride, 7.4% aluminum chloride, 29.4% silicon chloride, 3.8% calcium chloride, 1.8% manganese chloride, and 6.8% ferric chloride. The water-immersion liquid contains 28.9 g / L Fe ions, 5.9 g / L Ca ions, 11.8 g / L Mg ions, 4.8 g / L manganese ions, 51.7 g / L sodium ions, has a pH of 0.6, and contains 9.9 mg / L silicon.

[0052] 3. The aqueous extract is passed through a nanofiltration membrane for salt separation to obtain a concentrated nanofiltration solution and a clear nanofiltration solution. The concentrated nanofiltration solution contains 86 g / L of iron, 18 g / L of calcium ions, 35 g / L of magnesium ions, 14 g / L of manganese ions, and 59 mg / L of silicon ions. The clear nanofiltration solution contains 4.3 g / L of iron, 0.9 g / L of calcium ions, 1.8 g / L of magnesium ions, 0.7 g / L of manganese ions, and 3 mg / L of silicon ions.

[0053] 4. The nanofiltration concentrate is neutralized using calcium carbide slurry. First, the pH is adjusted to 6.5, and after solid-liquid separation, solid ferric hydroxide with a purity of 48.3% (calculated as iron) is obtained. The pH is then adjusted to 11.3, and solid-liquid separation is performed again. The clarified liquid is sent to MVR for concentration and crystallization to obtain calcium chloride crystals. The calcium chloride content in the crystals is 97.5%. The chloride ion content in the evaporation condensate is 22 ppm, the calcium ion content is 23 ppm, the pH is 6.7, the COD is 22 ppm, and the ammonia nitrogen is 1.0 ppm. This condensate is returned to other processes for reuse.

[0054] 5. The nanofiltration solution is neutralized with sodium hydroxide to a pH of 10.2, followed by solid-liquid separation. The solution contains 0 g / L Fe, 0 g / L Ca, 0 g / L Mg, 0 g / L Manganese, 0.4 mg / L Silicon, and 172 g / L Sodium. The solution is then subjected to MVR concentration and crystallization to obtain solid sodium chloride. Analysis shows a sodium chloride content of 98.3%, which is returned for molten salt chlorination. The evaporation condensate contains 15 ppm chloride, 11 ppm sodium, has a pH of 6.2, 10 ppm COD, and 0.15 ppm ammonia nitrogen, and is returned for use in other processes.

[0055] Comparative Example 1

[0056] 1. The waste molten salt is leached with organosilicon wastewater; the amount of organosilicon wastewater used is 0.5 times the mass of the waste molten salt; the organosilicon wastewater has a silicon content of 485 ppm, a TOC content of 510 ppm, and a COD content of 950 mg / L; the molten salt contains 32% sodium chloride, 8.2% magnesium chloride, 1.4% aluminum chloride, 3.1% silicon chloride, 3.3% calcium chloride, 3.1% manganese chloride, and 8.2% ferric chloride.

[0057] 2. Due to the small amount of water used for leaching, the overall system viscosity is high, making it impossible to stir and resulting in poor leaching effect, which leads to the inability to operate subsequently.

[0058] Comparative Example 2

[0059] 1. The waste molten salt is leached with organosilicon wastewater; the amount of organosilicon wastewater used is 10 times the mass of the waste molten salt; the organosilicon wastewater has a silicon content of 485 ppm, a TOC content of 510 ppm, and a COD content of 950 mg / L; the molten salt contains 32% sodium chloride, 8.2% magnesium chloride, 1.4% aluminum chloride, 3.1% silicon chloride, 3.3% calcium chloride, 3.1% manganese chloride, and 8.2% ferric chloride.

[0060] 2. Due to the large volume of water used in the leaching process, the pH of the leaching solution after leaching was 2.2. After solid-liquid separation, the leaching residue contained 0.3% sodium chloride, 0.9% magnesium chloride, 1.7% aluminum chloride, 6.6% silicon chloride, 0.75% calcium chloride, 0.29% manganese chloride, 1.37% ferric chloride, and 3.4% ferric chloride. The leaching solution contained 3.2 g / L Fe ions, 1.17 g / L Ca ions, 2.25 g / L Mg ions, 1.0 g / L manganese ions, 11.2 g / L sodium ions, with a pH of 2.2 and a silicon content of 2.3 mg / L.

[0061] 3. After soaking in water for 24 hours, due to the high pH, ​​ferric hydroxide precipitates continue to form, causing further loss of iron ions. The overall system is unstable, and the risk of membrane blockage during membrane treatment is high, making membrane treatment impossible.

[0062] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.

Claims

1. A method for the comprehensive utilization of organosilicon wastewater and molten salt chlorination waste, characterized in that, Includes the following steps: S1. The molten salt chlorination waste is leached with organosilicon wastewater, and then solid-liquid separation is performed to obtain leached residue and leached liquid; S2. Perform nanofiltration on the aqueous extract to obtain nanofiltration concentrate and nanofiltration clear liquid; S3. The nanofiltration concentrate is neutralized with a calcium-containing alkaline substance, and the nanofiltration clear liquid is neutralized with a sodium-containing alkaline substance, and solid-liquid separation is performed separately to obtain solid-phase product and liquid-phase product. S4. The liquid products are concentrated and crystallized separately.

2. The method for comprehensive utilization of organosilicon wastewater and molten salt chlorination waste as described in claim 1, characterized in that, The organosilicon wastewater in step S1 has a silicon ion content of 300-800 mg / L, a TOC content of 300-800 ppm, and a COD content of 500-1500 ppm.

3. The method for comprehensive utilization of organosilicon wastewater and molten salt chlorination waste as described in claim 1, characterized in that, The molten salt chlorination waste salt mentioned in step S1 contains 15-45% sodium chloride, 5-20% magnesium chloride, 0-5% aluminum chloride, 0-10% silicon chloride, 0-10% calcium chloride, 0-10% manganese chloride, and 0-20% ferric chloride.

4. The method for comprehensive utilization of organosilicon wastewater and molten salt chlorination waste as described in claim 1, characterized in that, The amount of organosilicon wastewater used in step S1 is 1 to 5 times the mass of the molten salt chlorination waste salt; the pH of the system after water leaching is 0 to 3.

5. The method for comprehensive utilization of organosilicon wastewater and molten salt chlorination waste as described in claim 1, characterized in that, The nanofiltration process described in step S2 uses an acidic nanofiltration membrane.

6. The method for comprehensive utilization of organosilicon wastewater and molten salt chlorination waste as described in claim 1, characterized in that, Step S2 controls the content of Fe ions in the nanofiltration solution to be 0-5 g / L, Ca ions to be 0-1 g / L, Mg ions to be 0-5 g / L, Manganese ions to be 0-1 g / L, Sodium ions to be 10-60 g / L, Silicon to be 1-40 mg / L, and pH to be 0-3; the content of Fe ions in the nanofiltration concentrate is 50-160 g / L, Ca ions to be 0-50 g / L, Mg ions to be 10-70 g / L, Manganese ions to be 0-40 g / L, Sodium ions to be 10-50 g / L, Silicon to be 20-60 mg / L, and pH to be 0-3.

7. The method for comprehensive utilization of organosilicon wastewater and molten salt chlorination waste as described in claim 1, characterized in that, In step S3, the concentration of nanofiltration solution is first adjusted to pH 4.0–7.5, and after solid-liquid separation, a solid product containing ferric hydroxide is obtained. The pH is then adjusted to 10–12, and solid-liquid separation is performed again to obtain the solid product.

8. The method for comprehensive utilization of organosilicon wastewater and molten salt chlorination waste as described in claim 1, characterized in that, The pH of the nanofiltration solution in step S3 is neutralized to 10-11.