Method for treating polyolefin catalyst waste liquid

Abstract

The invention relates to the technical field of organic waste liquid treatment, and particularly discloses a polyolefin catalyst waste liquid treatment method. The treatment method of the polyolefin catalyst waste liquid comprises the following steps: in an inert atmosphere, carrying out redox reaction on a titanium-containing organic waste liquid and an organic metal compound-containing waste liquid, and carrying out solid-liquid separation to obtain a titanium-containing compound and a low-titanium organic waste liquid; the organic metal compound-containing waste liquid comprises at least one of organic aluminum compound-containing waste liquid and organic magnesium compound-containing waste liquid; and rectifying the low-titanium organic waste liquid to obtain an organic solvent and waste. The organo-aluminum compound and the organo-magnesium compound have high reducibility, titanium in the titanium-containing organic waste liquid can be reduced from tetravalent to trivalent and bivalent, the corresponding material state is converted from liquid to solid, and the recovery rate of titanium in the titanium-containing organic waste liquid is increased; after the low-titanium organic waste liquid is rectified to recover the organic solvent, the amount of waste is greatly reduced, and the treatment amount of subsequent three wastes is also greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of organic waste liquid treatment, and in particular to a method for treating polyolefin catalyst waste liquid. Background Art

[0002] High-activity polyolefin catalysts are currently used on a large scale in the polyolefin industry, among which Ziegler-Natta catalysts are the most commonly used high-activity catalysts for polypropylene. Ziegler-Natta catalysts are prepared by the reaction of titanium tetrachloride, organic solvents, magnesium-containing compounds and internal electron donors. The solid particles formed need to be separated from the mother liquor, and the solid particles need to be washed with hydrocarbon solvents to remove unreacted titanium compounds and by-products, and finally the Ziegler-Natta catalyst is prepared. After the above separation and washing, a certain amount of waste liquid will be generated. For cost and environmental considerations, the waste liquid needs to recover organic solvents and titanium tetrachloride. At present, the recycling process of the above waste liquid is to send a mixture containing organic solvents, titanium tetrachloride and high-boiling substances into a distillation tower for separation, separate the light component organic solvent from the top of the tower, and titanium tetrachloride and high-boiling substances from the bottom of the tower, and then distill and separate the materials at the bottom of the tower to obtain titanium tetrachloride and residual liquid; the residual liquid is acidic after hydrolysis, and needs to be neutralized with alkali and discharged as wastewater and waste residue. In this treatment method, the high-boiling-point substance content of the bottom material is high, the material viscosity is high, the fluidity is poor, and the long residence time at high temperature can easily lead to coking of the bottom wall, inability to stir, and even shutdown. Therefore, it is difficult to achieve high-efficiency recovery of titanium tetrachloride. Direct hydrolysis and neutralization not only cause waste of raw materials, but also increase the treatment volume of the three wastes.

[0003] The carrier sources of Ziegler-Natta catalysts include organic magnesium compounds, such as dibutyl magnesium and dioctyl magnesium compounds. The preparation process of these organic magnesium compounds will produce waste liquid containing organic magnesium compounds. Organic magnesium compounds are highly reactive and dangerous. Improper handling will threaten personal safety. Waste treatment generally adopts hydrolysis treatment, which will produce a large amount of alkaline wastewater and waste residue.

[0004] In addition, in order to avoid problems such as high fine powder content in polymer powder caused by polymer agglomeration and catalyst breakage during olefin polymerization, a prepolymerization reaction is introduced before olefin polymerization in industrial applications, so that the activity release of the Ziegler-Natta catalyst is more stable, and more high-value-added polyolefin grades can be produced. Excessive amounts of organoaluminum compounds and organic solvents are added to the prepolymerization catalyst during the preparation process, which will produce a high concentration of waste liquid containing organoaluminum compounds. The current treatment method is hydrolysis treatment, which will produce a large amount of alkaline wastewater and waste residue, which will put great pressure on the environment and the economy. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for treating polyolefin catalyst waste liquid, which carries out oxidation-reduction reaction between titanium-containing organic waste liquid and waste liquid containing organic metal compounds, thereby effectively improving the recovery rate of titanium in the titanium-containing organic waste liquid and significantly reducing the quality of the final waste.

[0006] In order to achieve the above-mentioned object of the invention, the embodiment of the present invention adopts the following technical solution: A method for treating polyolefin catalyst waste liquid comprises the following steps: S1, under an inert atmosphere, subjecting a titanium-containing organic waste liquid to an oxidation-reduction reaction with a waste liquid containing an organic metal compound, and performing solid-liquid separation to obtain a titanium-containing compound and a low-titanium organic waste liquid; The titanium-containing organic waste liquid is a waste liquid containing tetravalent titanium generated during the preparation process of titanium-based polyolefin catalysts; The waste liquid containing organic metal compounds includes at least one of a waste liquid containing organic aluminum compounds or a waste liquid containing organic magnesium compounds; the waste liquid containing organic aluminum compounds includes organic aluminum compounds, and the waste liquid containing organic magnesium compounds includes organic magnesium compounds; S2, distilling the low-titanium organic waste liquid to obtain an organic solvent and waste.

[0007] Compared with the prior art, the method for treating polyolefin catalyst waste liquid provided by the present invention is to carry out oxidation-reduction reaction on titanium-containing organic waste liquid and waste liquid containing organic metal compounds. The aluminum and magnesium in the organic aluminum compound and the organic magnesium compound are active metals with high reducibility, and can reduce the titanium in the titanium-containing organic waste liquid from tetravalent to trivalent and divalent. The corresponding material state is converted from liquid to solid, and precipitated from the organic waste liquid to obtain low-valent titanium-containing compounds and low-titanium organic waste liquid; the titanium-containing compound can be recycled, such as making titanium dioxide and other materials, thereby improving the recovery rate of titanium in the titanium-containing organic waste liquid; the titanium content in the low-titanium organic waste liquid is greatly reduced, and after the organic solvent is recovered by distillation, the amount of waste can be greatly reduced, and the corresponding subsequent three waste treatment amount is also greatly reduced. In addition, both the organic aluminum compound and the organic magnesium compound are hazardous wastes. After the oxidation-reduction reaction, the chlorine atoms in the titanium-containing organic waste liquid can be taken away, and finally exist in the form of stable aluminum chloride and magnesium chloride, and the danger is greatly reduced.

[0008] Preferably, in S1, the titanium-containing organic waste liquid includes titanium tetrachloride, alkoxytitanium chloride, an internal electron donor, magnesium chloride powder and a first organic solvent.

[0009] Preferably, in S1, the alkoxy titanium chloride includes at least one of methoxy titanium trichloride, ethoxy titanium trichloride, propoxy titanium trichloride, n-butoxy titanium trichloride, dimethoxy titanium dichloride, diethoxy titanium dichloride, dipropoxy titanium dichloride, di-n-butoxy titanium dichloride, trimethoxy titanium chloride, triethoxy titanium chloride, tripropoxy titanium chloride or tri-n-butoxy titanium chloride.

[0010] Preferably, in S1, the internal electron donor includes at least one of a diether compound, an aromatic dicarboxylic acid ester compound, a succinate ester compound, an aromatic diol ester compound, an aliphatic diol ester compound or an amine compound.

[0011] For example, in S1, the internal electron donor includes at least one of di-n-butyl phthalate, 9,9-methoxymethylfluorene, or 2-isopropyl-2-isopentyl-1,3-dimethoxypropane.

[0012] Preferably, in S1, the first organic solvent includes at least one of toluene, benzene, n-hexane, cyclohexane, heptane, dichloromethane or chloroform.

[0013] Further preferably, in S1, the titanium content in the titanium-containing organic waste liquid is 5wt%~15wt%, the chlorine content is 20wt%~35wt%, the content of the internal electron donor is 0.1wt%~3wt%, the content of magnesium chloride powder is ≤5wt%, and the content of the first organic solvent is 50wt%~90wt%.

[0014] Preferably, in S1, the waste liquid containing an organoaluminum compound comprises an organoaluminum compound, an internal electron donor and a second organic solvent.

[0015] Preferably, in S1, the aluminum-containing organic compound includes at least one of alkyl aluminum, chloroalkyl aluminum or aluminoxane.

[0016] Further preferably, in S1, the alkyl aluminum includes at least one of triethyl aluminum, tributyl aluminum, triisobutyl aluminum, tri-n-hexylaluminum, tri-n-octylaluminum or isoprenyl aluminum.

[0017] Further preferably, in S1, the chloroalkylaluminum includes at least one of diethylaluminum monochloride, ethylaluminum dichloride or ethylaluminum sesquichloride.

[0018] More preferably, in S1, the aluminoxane is at least one of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, propylaluminoxane or butylaluminoxane.

[0019] Preferably, in S1, the second organic solvent includes at least one of n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene, ethylbenzene or xylene.

[0020] Further preferably, in S1, the aluminum content in the waste liquid containing the organic aluminum compound is 2wt%~10wt%, the chlorine content is ≤5wt%, the content of the internal electron donor is ≤2wt%, and the content of the second organic solvent is 65wt%~95wt%.

[0021] Preferably, in S1, the waste liquid containing organic magnesium compounds comprises organic magnesium compounds and a third organic solvent.

[0022] Preferably, in S1, the organic magnesium compound includes at least one of alkyl magnesium or alkyl magnesium chloride.

[0023] Further preferably, in S1, the alkyl magnesium includes at least one of dimethyl magnesium, diethyl magnesium, dipropyl magnesium, dibutyl magnesium, dihexyl magnesium, dioctyl magnesium, ethylbutyl magnesium, butylhexyl magnesium, butyloctyl magnesium, methylphenyl magnesium or ethylphenyl magnesium.

[0024] Further preferably, in S1, the alkyl magnesium chloride includes at least one of methyl magnesium chloride, ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride or phenyl magnesium chloride.

[0025] Preferably, in S1, the third organic solvent includes at least one of n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene, ethylbenzene or xylene.

[0026] Further preferably, in S1, the magnesium content in the waste liquid containing the organic magnesium compound is 5wt%~15wt%, the chlorine content is 5wt%~25wt%, and the content of the third organic solvent is 50wt%~90wt%.

[0027] Preferably, in S1, the titanium-containing organic waste liquid includes at least one of a first catalyst mother liquid, a first washing liquid or a first distillation residue generated during the preparation process of a titanium-based polyolefin catalyst.

[0028] Further preferably, in S1, the titanium-based polyolefin catalyst comprises a Ziegler-Natta catalyst.

[0029] Further preferably, in S1, the first distillation residue is the residue after part of the first solvent is removed by distillation of the first catalyst mother liquor and / or the first washing liquid.

[0030] Preferably, in S1, the waste liquid containing the organic aluminum compound includes at least one of a second catalyst mother liquid, a second washing liquid or a second distillation residue generated during the preparation of the prepolymerization catalyst.

[0031] Further preferably, in S1, the second distillation residue is the residue after the second catalyst mother liquor and / or the second washing liquid is distilled to remove part of the second solvent.

[0032] Preferably, in S1, the waste liquid containing organic magnesium compounds includes waste liquid containing organic magnesium compounds generated during the preparation process of polyolefin catalysts.

[0033] For example, in S1, the waste liquid containing the organic magnesium compound can be the residual liquid after a part of the organic solvent is removed by distillation.

[0034] The method for treating polyolefin catalyst waste liquid provided by the present invention can simultaneously treat titanium-containing organic waste liquid and waste liquid containing organic aluminum compounds or waste liquid containing organic magnesium compounds generated in the process of preparing polyolefin catalysts. It can not only recover a large amount of titanium in the titanium-containing organic waste liquid and reduce the danger of the waste liquid containing organic aluminum compounds or waste liquid containing organic magnesium compounds, but also greatly improve the recovery rate of organic solvents in the titanium-containing organic waste liquid and waste liquid containing organic aluminum compounds or waste liquid containing organic magnesium compounds. The treatment cost is effectively controlled and the method has good market application value.

[0035] It should be noted that the steps of generating titanium-containing organic waste liquid, organic aluminum compound-containing waste liquid and organic magnesium compound-containing waste liquid can be produced by conventional methods in the art, and the present invention does not impose any special limitation on this.

[0036] Preferably, in S1, the molar ratio of titanium in the titanium-containing organic waste liquid to the metal in the organic metal compound-containing waste liquid is 1:(0.1~30), more preferably 1:(0.1~15), and more preferably 1:(0.1~5).

[0037] For example, in S1, the inert atmosphere may be a nitrogen atmosphere to isolate oxygen in the air.

[0038] Preferably, in S1, the temperature of the redox reaction is 0°C to 100°C, and the reaction time is 1 min to 150 min.

[0039] Further preferably, in S1, the temperature of the redox reaction is 10°C to 90°C, and the reaction time is 10min to 140min.

[0040] Preferably, in S1, the titanium-containing organic matter includes at least three of titanium dichloride, titanium trichloride, low-valent alkoxy titanium chloride or low-valent alkoxy titanium.

[0041] Further preferably, in S1, the low-valent alkoxy titanium chloride includes at least one of methoxy titanium dichloride, ethoxy titanium dichloride, propoxy titanium dichloride, n-butoxy titanium dichloride, dimethoxy titanium monochloride, diethoxy titanium monochloride, dipropoxy titanium monochloride or di-n-butoxy titanium monochloride.

[0042] Further preferably, in S1, the low-valent alkoxy titanium includes at least one of trimethoxy titanium, triethoxy titanium, tripropoxy titanium or tri-n-butoxy titanium.

[0043] Preferably, in S1, the titanium content in the low-titanium organic waste liquid is ≤3.0wt%, more preferably ≤1.8wt%, and more preferably ≤0.9wt%.

[0044] During the oxidation-reduction process, titanium tetrachloride and alkoxytitanium chloride in the titanium-containing organic waste liquid are respectively reduced to titanium dichloride, titanium trichloride, low-valent alkoxytitanium chloride or low-valent alkoxytitanium (the reaction equations can be seen in Formula 1 and Formula 2). At the same time, the organic aluminum compounds in the waste liquid containing organic aluminum compounds and the organic magnesium compounds in the waste liquid containing organic magnesium compounds can take away the chlorine atoms in the titanium-containing organic waste liquid to form stable aluminum chloride and magnesium chloride, which greatly reduces the danger and is conducive to the further treatment of subsequent wastes.

[0045] Formula 1 Formula 2 In Formula 2, R is the corresponding alkyl group in alkoxytitanium chloride.

[0046] Preferably, in S2, the distillation pressure is -0.02MPa~0MPa, and the distillation time is 0.5h~1h.

[0047] It should be noted that the present invention does not impose any particular limitation on the distillation temperature in S2, and the temperature may be within the conventional temperature range in the art according to the recovered organic solvent.

[0048] For example, in S2, the waste may be incinerated. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] Unless otherwise specified, the materials used in the present invention are all commercially available products.

[0051] The testing method for titanium content is spectrophotometry, the testing method for magnesium content and aluminum content is EDTA titration, and the testing method for internal electron donor content is gas chromatography.

[0052] Example 1 This embodiment provides a method for treating polyolefin catalyst waste liquid, comprising the following steps: Sa, Preparation of waste liquid containing organic magnesium compounds: In a four-necked flask equipped with a stirrer, a reflux condenser is installed and a cumulative gas meter is connected to the reflux condenser. After the entire reaction device is fully replaced with nitrogen, 20g (0.823mol) of 250-mesh magnesium powder and 0.3L of n-heptane purified by molecular sieves are added, and then 0.5g of elemental iodine is added as an initiator. After stirring and mixing at room temperature for 30min, the mixture is heated to reflux, and 60.9g (0.658mol) of 1-chlorobutane is slowly added dropwise under reflux. After the addition is completed, the reflux reaction is continued for 60min, and then cooled to room temperature and filtered to obtain a heptane solution of dibutyl magnesium.

[0053] It should be noted that the heptane solution of dibutyl magnesium is one of the raw materials for preparing polyolefin catalysts; the heptane solution of dibutyl magnesium is very active. If floccules or precipitation are found in the heptane solution of dibutyl magnesium, it means that the dibutyl magnesium has deteriorated and failed, and waste liquid treatment (i.e., waste liquid containing organic magnesium compounds) is required. According to measurement, the magnesium content in the waste liquid containing organic magnesium compounds is 7.0wt%, the chlorine content is 8.1wt%, and the n-heptane content is 71.6wt%.

[0054] Sb, Preparation of titanium-containing organic waste liquid: In a five-necked flask with stirring and fully replaced with nitrogen, add 10g of polyolefin catalyst carrier Mg(OEt) 2 and 80 mL of toluene to prepare a suspension, then 20 mL of titanium tetrachloride was added dropwise at -15 ° C, after the addition was completed, the system was slowly heated to 10 ° C, 60 mL of titanium tetrachloride was added dropwise, and then the temperature was slowly raised to 80 ° C, 3.5 g of di-n-butyl phthalate was added, and then the temperature was continued to rise to 120 ° C and kept warm for 2 hours, and then filtered to obtain a first catalyst mother liquor and a first solid; the first solid was washed with 120 mL of titanium tetrachloride at 125 ° C for 3 times, the solid was washed with 150 mL of n-hexane at 60 ° C for 2 times, and washed at room temperature for 2 times, and the solid-liquid separation was performed to obtain a first washing liquid and a second solid; the second solid was dried to obtain a Ziegler-Natta catalyst (the analyzed titanium content was 2.83 wt% and the di-n-butyl phthalate content was 11.24 wt%).

[0055] The mixed liquid of the first catalyst mother liquid and the first washing liquid is subjected to reduced pressure distillation, and after recovering part of the solvent (a small amount of toluene and all of the n-hexane), the first distillation residue is obtained, which is the titanium-containing organic waste liquid. According to measurement, the titanium content in the titanium-containing organic waste liquid is 9.6wt%, the chlorine content is 26.3wt%, the toluene content is 58.3wt%, and the di-n-butyl phthalate content is 1.3wt%.

[0056] Sc, in a five-necked flask with stirring that has been fully replaced with nitrogen, add 40.0g of titanium-containing organic waste liquid (3.84g titanium, 0.080mol titanium), gradually add 139.2g of organic magnesium compound waste liquid (9.74g magnesium, 0.401mol magnesium) under stirring, carry out redox reaction at 60°C for 2h, cool to room temperature, filter, and obtain 19.3g of titanium compound solid and low-titanium organic waste liquid.

[0057] The titanium content in the low-titanium organic waste liquid was measured to be 0.09wt%. It should be noted that during the redox reaction, the butyl group in dibutyl magnesium is converted into butane and butene and discharged in the form of gas.

[0058] Sd, the low-titanium organic waste liquid was subjected to reduced pressure distillation to obtain an organic solvent (21.3 g toluene, 93.4 g n-heptane) and 38.8 g waste.

[0059] Example 2 This embodiment provides a method for treating polyolefin catalyst waste liquid, comprising the following steps: Sa, preparation of titanium-containing organic waste liquid: the same as Sb in Example 1, no further details are given.

[0060] Preparation of waste liquid containing Sb, organic aluminum compounds: In a five-necked flask fully replaced with nitrogen and equipped with a stirrer, 300 mL of n-hexane, 20 mL of 0.5 mol / L triisobutylaluminum hexane solution and 10 g of the above-mentioned Ziegler-Natta catalyst were added, and the mixture was kept at a constant temperature of 5°C for 5 min; propylene was introduced through a mass flow meter at a rate of 20 g / h, and the reaction lasted for 60 min; the introduction of propylene was stopped, and the mixture was filtered to obtain a second catalyst mother liquid and a third solid; the third solid was washed with n-hexane, and the solid-liquid separation was performed to obtain a second washing liquid and a fourth solid; the fourth solid was taken and dried in vacuo to obtain 26.4 g of a prepolymerized catalyst (the analyzed titanium content was 1.1 wt%, the polymer content was 62.0 wt%, and the prepolymerization multiple of propylene was 1.6).

[0061] The mixed liquid of the second catalyst mother liquid and the second washing liquid is subjected to reduced pressure distillation, and after recovering part of the solvent (normal hexane), the second distillation residue is obtained, which is the waste liquid containing the organic aluminum compound. According to measurement, the aluminum content in the waste liquid containing the organic aluminum compound is 4.1wt%, the chlorine content is 0.5wt%, the internal electron donor content is 0.1wt%, and the normal hexane content is 72.3wt%.

[0062] Sc, in a five-necked flask with stirring that has been fully replaced with nitrogen, add 40.0g of titanium-containing organic waste liquid (3.84g of titanium, 0.080mol of titanium), gradually add 26.4g of waste liquid containing organic aluminum compounds (1.08g of aluminum, 0.040mol of aluminum) under stirring, carry out redox reaction at 40°C for 2h, cool to room temperature, filter, and obtain 13.9g of titanium compound solid and low-titanium organic waste liquid.

[0063] The titanium content in the low-titanium organic waste liquid was measured to be 1.5wt%. It should be noted that during the redox reaction, the isobutyl group in triisobutylaluminum is converted into isobutane and isobutylene, which are discharged in the form of gas.

[0064] Sd, the low-titanium organic waste liquid was subjected to reduced pressure distillation to obtain an organic solvent (18.7 g toluene, 17.2 g n-hexane) and 13.7 g waste.

[0065] Example 3 This embodiment provides a method for treating polyolefin catalyst waste liquid, comprising the following steps: Sa~Sb, preparation of organic magnesium compound-containing waste liquid and titanium-containing organic waste liquid: the same as Example 1, no further details are given.

[0066] Sc, preparation of waste liquid containing organic aluminum compounds: the same as Sb in Example 2, no further details are given.

[0067] Sd, in a five-necked flask with stirring that has been fully replaced with nitrogen, add 40.0g of titanium-containing organic waste liquid (3.84g titanium, 0.080mol titanium), gradually add 27.8g of organic magnesium compound waste liquid (1.95g magnesium, 0.080mol magnesium) and 26.4g of organic aluminum compound waste liquid (1.08g aluminum, 0.040mol aluminum) under stirring, carry out redox reaction at 50°C for 2h, cool to room temperature, filter, and obtain 14.2g of titanium compound solid and low-titanium organic waste liquid.

[0068] The titanium content in the low-titanium organic waste liquid was measured to be 0.48wt%. It should be noted that during the redox reaction, the butyl group in dibutyl magnesium is converted into butane and butene, and the isobutyl group in triisobutyl aluminum is converted into isobutane and isobutylene, which are discharged in the form of gas.

[0069] Sd, the low-titanium organic waste liquid was subjected to reduced pressure distillation to obtain an organic solvent (16.3 g toluene, 18.1 g n-hexane, 18.9 g n-heptane) and 23.6 g waste.

[0070] Example 4 This embodiment provides a method for treating polyolefin catalyst waste liquid, comprising the following steps: Sa, Preparation of titanium-containing organic waste liquid: In a five-necked flask with stirring and fully replaced with nitrogen, 10 g of polyolefin catalyst carrier MgClOEt and 80 mL of heptane were added to prepare a suspension, and then 20 mL of titanium tetrachloride was added dropwise at -15°C. After the addition was completed, the system was slowly heated to 10°C, 60 mL of titanium tetrachloride was added dropwise, and then the temperature was slowly raised to 80°C, 3.5 g of 9.9-methoxymethylfluorene was added, and then the temperature was continued to be raised to 120°C and kept warm for 2 hours, and then filtered to obtain a first catalyst mother liquid and a first solid; the first solid was washed 3 times with 120 mL of titanium tetrachloride at 125°C, the solid was washed twice with 150 mL of heptane at 60°C and washed twice at room temperature, and the solid-liquid separation was performed to obtain a first washing liquid and a second solid; the second solid was dried to obtain a Ziegler-Natta catalyst (the analyzed titanium content was 3.68 wt% and the 9.9-methoxymethylfluorene content was 15.08 wt%).

[0071] The mixed liquid of the first catalyst mother liquid and the first washing liquid is subjected to reduced pressure distillation, and after recovering part of the solvent (heptane), the first distillation residue is obtained, which is the titanium-containing organic waste liquid. According to measurement, the titanium content in the titanium-containing organic waste liquid is 9.1wt%, the chlorine content is 24.9wt%, the heptane content is 62.6wt%, and the 9.9-methoxymethylfluorene content is 0.5wt%.

[0072] Preparation of waste liquid containing Sb, organic aluminum compounds: In a five-necked flask fully replaced with nitrogen and equipped with a stirrer, 300 mL of n-pentane, 20 mL of 0.5 mol / L diethylaluminum chloride pentane solution and 10 g of the above-mentioned Ziegler-Natta catalyst were added, and the mixture was kept at a constant temperature of 5°C for 5 min; propylene was introduced through a mass flow meter at a rate of 20 g / h, and the reaction lasted for 60 min; the introduction of propylene was stopped, and the mixture was filtered to obtain a second catalyst mother liquid and a third solid; the third solid was washed with n-pentane, and the solid-liquid separation was performed to obtain a second washing liquid and a fourth solid; the fourth solid was taken and dried in vacuo to obtain 26.0 g of a prepolymerized catalyst.

[0073] The mixed liquid of the second catalyst mother liquid and the second washing liquid is subjected to reduced pressure distillation, and after recovering part of the solvent (normal pentane), the second distillation residue is obtained, which is the waste liquid containing the organic aluminum compound. According to measurement, the aluminum content in the waste liquid containing the organic aluminum compound is 4.2wt%, the chlorine content is 5.6wt%, the internal electron donor content is 0.3wt%, and the normal pentane content is 78.1wt%.

[0074] Sc, in a five-necked flask with stirring that has been fully replaced with nitrogen, add 42.0g of titanium-containing organic waste liquid (3.82g of titanium, 0.080mol of titanium), gradually add 52.8g of waste liquid containing organic aluminum compounds (2.22g of aluminum, 0.082mol of aluminum) under stirring, carry out redox reaction at 10°C for 2.5h, cool to room temperature, filter, and obtain 12.3g of titanium compound solid and low-titanium organic waste liquid.

[0075] The titanium content in the low-titanium organic waste liquid was measured to be 0.8wt%. It should be noted that during the redox reaction, the ethyl group in diethylaluminum monochloride is converted into ethane and ethylene and discharged in the form of gas.

[0076] Sd, the low-titanium organic waste liquid was subjected to reduced pressure distillation to obtain an organic solvent (22.1 g heptane, 39.2 g n-pentane) and 16.9 g waste.

[0077] Example 5 This embodiment provides a method for treating polyolefin catalyst waste liquid, comprising the following steps: Sa, Preparation of titanium-containing organic waste liquid: In a five-necked flask with stirring and fully replaced with nitrogen, 10g of polyolefin catalyst carrier MgClEt and 80mL of dichloromethane were added to prepare a suspension, and then 20mL of titanium tetrachloride was added dropwise at -15°C. After the addition was completed, the system was slowly heated to 10°C, and 60mL of titanium tetrachloride was added dropwise. Then, the temperature was slowly raised to 80°C, and 3.5g of 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, then continue to heat to 120°C and keep warm for 2h, filter press to obtain the first catalyst mother liquor and the first solid; take the first solid and wash it with 120mL titanium tetrachloride at 125°C for 3 times, take the solid and wash it with 150mL dichloromethane at 60°C for 2 times, wash it at room temperature for 2 times, separate the solid and the liquid to obtain the first washing liquid and the second solid; take the second solid and dry it to obtain a Ziegler-Natta catalyst (the analyzed titanium content is 3.15wt%, and the content of 2-isopropyl-2-isopentyl-1,3-dimethoxypropane is 16.52wt%).

[0078] The mixed liquid of the first catalyst mother liquid and the first washing liquid is subjected to reduced pressure distillation, and after recovering part of the solvent (dichloromethane), the first distillation residue is obtained, which is the titanium-containing organic waste liquid. According to measurement, the titanium content in the titanium-containing organic waste liquid is 10.3wt%, the chlorine content is 28.1wt%, the dichloromethane content is 53.6wt%, and the 2-isopropyl-2-isopentyl-1,3-dimethoxypropane content is 0.7wt%.

[0079] Preparation of waste liquid containing Sb, organic aluminum compounds: In a five-necked flask fully replaced with nitrogen and equipped with a stirrer, 300 mL of toluene, 20 mL of a 0.5 mol / L propylaluminoxane toluene solution and 10 g of the above-mentioned Ziegler-Natta catalyst were added, and the mixture was kept at a constant temperature of 5°C for 5 min; propylene was introduced through a mass flow meter at a rate of 20 g / h, and the reaction lasted for 60 min; the introduction of propylene was stopped, and the mixture was filtered to obtain a second catalyst mother liquid and a third solid; the third solid was washed with toluene, and the solid-liquid separation was performed to obtain a second washing liquid and a fourth solid; the fourth solid was taken and vacuum dried to obtain 25.9 g of a prepolymerized catalyst.

[0080] The mixed liquid of the second catalyst mother liquid and the second washing liquid is subjected to reduced pressure distillation, and after recovering part of the solvent (toluene), the second distillation residue is obtained, which is the waste liquid containing the organic aluminum compound. According to measurement, the aluminum content in the waste liquid containing the organic aluminum compound is 3.9wt%, the chlorine content is 0.7wt%, the internal electron donor content is 0.6wt%, and the toluene content is 82.5wt%.

[0081] Sc, in a five-necked flask with stirring that has been fully replaced with nitrogen, add 37.2g of titanium-containing organic waste liquid (3.83g titanium, 0.080mol titanium), gradually add 79.2g of waste liquid containing organic aluminum compounds (3.09g aluminum, 0.114mol aluminum) under stirring, carry out redox reaction at 95°C for 10min, cool to room temperature, filter, and obtain 15.5g of titanium-containing compound and low-titanium organic waste liquid.

[0082] The titanium content in the low-titanium organic waste liquid was measured to be 0.22 wt%. It should be noted that during the redox reaction, the propyl group in propylaluminoxane is converted into propane and propylene and discharged in the form of gas.

[0083] Sd, the low-titanium organic waste liquid was distilled under reduced pressure to obtain an organic solvent (59.7 g toluene, 18.8 g dichloromethane) and 19.3 g waste.

[0084] Example 6 This embodiment provides a method for treating polyolefin catalyst waste liquid, comprising the following steps: Sa, Preparation of titanium-containing organic waste liquid: In a five-necked flask with stirring and fully replaced with nitrogen, add 10g of polyolefin catalyst carrier Mg(Et) 2and 80 mL of cyclohexane to prepare a suspension, then 20 mL of titanium tetrachloride was added dropwise at -15 ° C, after the addition was completed, the system was slowly heated to 10 ° C, 60 mL of titanium tetrachloride was added dropwise, and then the temperature was slowly raised to 80 ° C, 3.5 g of di-n-butyl phthalate was added, and then the temperature was continued to rise to 120 ° C and kept warm for 2 hours, and then filtered to obtain a first catalyst mother liquor and a first solid; the first solid was washed with 120 mL of titanium tetrachloride at 125 ° C for 3 times, the solid was washed with 150 mL of cyclohexane at 60 ° C for 2 times, and washed at room temperature for 2 times, and the solid-liquid separation was performed to obtain a first washing liquid and a second solid; the second solid was dried to obtain a Ziegler-Natta catalyst (the analyzed titanium content was 3.31 wt% and the di-n-butyl phthalate content was 12.07 wt%).

[0085] The mixed liquid of the first catalyst mother liquid and the first washing liquid is used as titanium-containing organic waste liquid. According to measurement, the titanium content in the titanium-containing organic waste liquid is 8.9wt%, the chlorine content is 25.4wt%, the cyclohexane content is 62.3wt%, and the di-n-butyl phthalate content is 0.5wt%.

[0086] Preparation of waste liquid containing Sb, organic aluminum compounds: In a five-necked flask fully replaced with nitrogen and equipped with a stirrer, 300 mL of cyclohexane, 20 mL of a 0.5 mol / L tri-n-butylaluminum cyclohexane solution and 10 g of the above-mentioned Ziegler-Natta catalyst were added, and the mixture was kept at a constant temperature of 5°C for 5 min; propylene was introduced through a mass flow meter at a rate of 20 g / h, and the reaction lasted for 60 min; the introduction of propylene was stopped, and the mixture was filtered to obtain a second catalyst mother liquid and a third solid; the third solid was washed with cyclohexane, and solid-liquid separation was performed to obtain a second washing liquid and a fourth solid; the fourth solid was taken and vacuum dried to obtain 26.2 g of a prepolymerized catalyst.

[0087] The mixed liquid of the second catalyst mother liquid and the second washing liquid is used as the waste liquid containing the organic aluminum compound. After measurement, the aluminum content in the waste liquid containing the organic aluminum compound is 5.3wt%, the chlorine content is 0.9wt%, the internal electron donor content is 0.4wt%, and the cyclohexane content is 70.1wt%.

[0088] Sc, in a five-necked flask with stirring that has been fully replaced with nitrogen, add 43.0g of titanium-containing organic waste liquid (3.83g of titanium, 0.080mol of titanium), gradually add 326.1g of waste liquid containing organic aluminum compounds (17.28g of aluminum, 0.64mol of aluminum) under stirring, carry out redox reaction at 80°C for 30min, cool to room temperature, filter, and obtain 15.3g of titanium-containing compound and low-titanium organic waste liquid.

[0089] The titanium content in the low-titanium organic waste liquid was measured to be 0.03wt%. It should be noted that during the redox reaction, the n-butyl in tri-n-butylaluminum is converted into butane and butene and discharged in the form of gas.

[0090] Sd, the low-titanium organic waste liquid was subjected to reduced pressure distillation to obtain an organic solvent (77.8 g cyclohexane) and 202.4 g waste.

[0091] Comparative Example 1 This comparative example provides a method for treating titanium-containing organic waste liquid, comprising the following steps: Sa, preparation of titanium-containing organic waste liquid: the same as Sb in Example 1, no further details are given.

[0092] Sb, slowly pour 40g of titanium-containing organic waste liquid (3.84g titanium, 0.080mol titanium) into 500mL of water at room temperature, stir rapidly until hydrolysis is complete, add 9.17g of calcium oxide in batches under stirring conditions, react at 60°C for 2h, cool to room temperature, and filter to obtain 27.6g of paste, 485g of aqueous phase and 33g of organic phase.

[0093] Comparative Example 2 This comparative example provides a method for treating titanium-containing organic waste liquid, comprising the following steps: Sa, preparation of titanium-containing organic waste liquid: the same as Sb in Example 1, no further details are given.

[0094] Sb, slowly pour 40g of titanium-containing organic waste liquid (3.84g titanium, 0.080mol titanium) into 500mL of water at room temperature, stir rapidly until hydrolysis is complete, add 13.0g of sodium hydroxide in batches under stirring conditions, react at 60°C for 2h (the reaction equation can be seen in Formula 3 and Formula 4), cool to room temperature, filter, and obtain 25.5g of paste, 490g of aqueous phase and 28g of organic phase.

[0095] Formula 3 Formula 4 In formula 4, R is the corresponding alkyl group in alkoxytitanium chloride.

[0096] It can be seen from the test data of the above embodiments and comparative examples that the titanium in the titanium-containing organic waste liquid exists in the form of titanium tetrachloride, alkoxy titanium chloride, etc. The hydrolyzate of the titanium-containing organic waste liquid is treated by neutralization with an inorganic alkali to obtain three products: a paste, an aqueous phase, and an organic phase. The paste is mainly a hydrolyzate of titanium tetrachloride (titanium dioxide), and also contains impurities such as inorganic salts and excess alkali, which can be further recycled; the organic phase is an organic solvent containing high boiling points; the aqueous phase is mainly an aqueous solution containing inorganic salts and excess alkali, such as an aqueous solution containing a small amount of sodium hydroxide, sodium chloride, and magnesium chloride. The aqueous phase and the organic phase need to be further processed, and the above measures increase the cost, and the effect of the present invention using waste liquid containing organic metal compounds for treatment cannot be achieved. The recovery rate of titanium in the titanium-containing organic waste liquid and the recovery rate of the organic solvent are greatly improved.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating polyolefin catalyst waste liquid, characterized in that: The following steps are involved: S1, under an inert atmosphere, subjecting a titanium-containing organic waste liquid to an oxidation-reduction reaction with a waste liquid containing an organic metal compound, and performing solid-liquid separation to obtain a titanium-containing compound and a low-titanium organic waste liquid; The titanium-containing organic waste liquid is a waste liquid containing tetravalent titanium generated during the preparation process of titanium-based polyolefin catalysts; The waste liquid containing organic metal compounds includes at least one of a waste liquid containing organic aluminum compounds or a waste liquid containing organic magnesium compounds; the waste liquid containing organic aluminum compounds includes organic aluminum compounds, and the waste liquid containing organic magnesium compounds includes organic magnesium compounds; S2, distilling the low-titanium organic waste liquid to obtain an organic solvent and waste.

2. The method for treating polyolefin catalyst waste liquid as claimed in claim 1, characterized in that: In S1, the titanium-containing organic waste liquid includes titanium tetrachloride, alkoxy titanium chloride, an internal electron donor, magnesium chloride powder and a first organic solvent; In S1, the waste liquid containing organic aluminum compounds includes organic aluminum compounds, internal electron donors and a second organic solvent; the waste liquid containing organic magnesium compounds includes organic magnesium compounds and a third organic solvent.

3. The method for treating polyolefin catalyst waste liquid as claimed in claim 2, characterized in that: In S1, the alkoxy titanium chloride includes at least one of methoxy titanium trichloride, ethoxy titanium trichloride, propoxy titanium trichloride, n-butoxy titanium trichloride, dimethoxy titanium dichloride, diethoxy titanium dichloride, dipropoxy titanium dichloride, di-n-butoxy titanium dichloride, trimethoxy titanium chloride, triethoxy titanium chloride, tripropoxy titanium chloride or tri-n-butoxy titanium chloride; In S1, the internal electron donor includes at least one of a diether compound, an aromatic dicarboxylic acid ester compound, a succinate ester compound, an aromatic diol ester compound, an aliphatic diol ester compound or an amine compound; In S1, the first organic solvent includes at least one of toluene, benzene, n-hexane, cyclohexane, heptane, dichloromethane or chloroform.

4. The method for treating polyolefin catalyst waste liquid as claimed in claim 2, characterized in that: In S1, the organoaluminum compound includes at least one of alkylaluminum, chloroalkylaluminum or aluminoxane; In S1, the second organic solvent includes at least one of n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene, ethylbenzene or xylene; In S1, the organomagnesium compound comprises at least one of alkylmagnesium or alkylmagnesium chloride; In S1, the third organic solvent includes at least one of n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene, ethylbenzene or xylene.

5. The method for treating polyolefin catalyst waste liquid as claimed in claim 4, characterized in that: In S1, the alkyl aluminum includes at least one of triethyl aluminum, tributyl aluminum, triisobutyl aluminum, tri-n-hexyl aluminum, tri-n-octylaluminum or isoprenyl aluminum; In S1, the chloroalkylaluminum includes at least one of diethylaluminum monochloride, ethylaluminum dichloride or ethylaluminum sesquichloride; In S1, the aluminoxane is at least one of methyl aluminoxane, modified methyl aluminoxane, ethyl aluminoxane, propyl aluminoxane or butyl aluminoxane; In S1, the alkyl magnesium includes at least one of dimethyl magnesium, diethyl magnesium, dipropyl magnesium, dibutyl magnesium, dihexyl magnesium, dioctyl magnesium, ethylbutyl magnesium, butylhexyl magnesium, butyloctyl magnesium, methylphenyl magnesium or ethylphenyl magnesium; In S1, the alkyl magnesium chloride includes at least one of methyl magnesium chloride, ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride or phenyl magnesium chloride.

6. The method for treating polyolefin catalyst waste liquid as claimed in claim 2, characterized in that: In S1, the titanium-containing organic waste liquid includes at least one of a first catalyst mother liquid, a first washing liquid or a first distillation residue generated during the preparation of a titanium-based polyolefin catalyst; In S1, the waste liquid containing the organoaluminum compound includes at least one of the second catalyst mother liquid, the second washing liquid or the second distillation residue generated in the process of preparing the prepolymerization catalyst; In S1, the waste liquid containing organic magnesium compounds includes waste liquid containing organic magnesium compounds generated in the process of preparing polyolefin catalysts.

7. The method for treating polyolefin catalyst waste liquid as claimed in claim 6, characterized in that: In S1, the first distillation residue is the residue after the first catalyst mother liquid and / or the first washing liquid is distilled to remove part of the first solvent; In S1, the second distillation residue is the residue after the second catalyst mother liquid and / or the second washing liquid is distilled to remove part of the second solvent; In S1, the third distillation residue is the residue after part of the third solvent is removed from the third catalyst mother liquor and / or the third washing liquid by distillation.

8. The method for treating polyolefin catalyst waste liquid according to any one of claims 2 to 7, characterized in that: In S1, the titanium content of the titanium-containing organic waste liquid is 5wt%-15wt%, the chlorine content is 20wt%-35wt%, the content of the internal electron donor is 0.1wt%-3wt%, the content of magnesium chloride powder is ≤5wt%, and the content of the first organic solvent is 50wt%-90wt%; In S1, the aluminum content in the waste liquid containing the organic aluminum compound is 2wt%~10wt%, the chlorine content is ≤5wt%, the content of the internal electron donor is ≤2wt%, and the content of the second organic solvent is 65wt%~95wt%; In S1, the magnesium content in the waste liquid containing the organic magnesium compound is 5wt%~15wt%, the chlorine content is 5wt%~25wt%, and the content of the third organic solvent is 50wt%~90wt%.

9. The method for treating polyolefin catalyst waste liquid according to any one of claims 1 to 7, characterized in that: In S1, the molar ratio of titanium in the titanium-containing organic waste liquid to the metal in the organic metal compound-containing waste liquid is 1:(0.1-30); In S1, the temperature of the redox reaction is 0°C to 100°C, and the reaction time is 1 min to 150 min.

10. The method for treating polyolefin catalyst waste liquid according to any one of claims 1 to 7, characterized in that: In S1, the titanium-containing organic matter includes at least three of titanium dichloride, titanium trichloride, low-valent alkoxy titanium chloride or low-valent alkoxy titanium; The low-valent alkoxy titanium chloride includes at least one of methoxy titanium dichloride, ethoxy titanium dichloride, propoxy titanium dichloride, n-butoxy titanium dichloride, dimethoxy titanium monochloride, diethoxy titanium monochloride, dipropoxy titanium monochloride or di-n-butoxy titanium monochloride; The low-valent alkoxy titanium includes at least one of trimethoxy titanium, triethoxy titanium, tripropoxy titanium or tri-n-butoxy titanium; In S1, the titanium content in the low-titanium organic waste liquid is ≤3.0wt%.