Composite liquid inhibitor and preparation method thereof

Abstract

The invention provides a composite liquid inhibitor and a preparation method thereof, and belongs to the technical field of rare earth hydrometallurgy. The composite liquid inhibitor comprises a hindered phenol compound serving as a main inhibitor, a polyphenol hydroxyl compound serving as an auxiliary inhibitor and an organic solvent serving as a diluent. In the prepared composite liquid inhibitor, the hindered phenol compound and the polyphenol hydroxyl compound have a synergistic effect in the aspect of oxidation resistance of cerium (III). The two inhibitors are difficult to achieve an ideal inhibition effect when being used independently, and complement each other when being used cooperatively, so that an ideal synergistic effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth hydrometallurgy, and in particular to a composite liquid inhibitor and a preparation method thereof. Background Art

[0002] The praseodymium-neodymium series of rare earth elements are the core raw materials of high-performance neodymium-iron-boron magnetic materials. About 40% of the world's rare earth raw materials are used to prepare rare earth magnetic materials. For the separation and purification of rare earth elements, more than 90% of the processes use solvent extraction. In recent years, in order to promote the green and clean development of the rare earth industry, rare earth hydrometallurgical separation enterprises have adopted environmentally friendly diluents such as light white oil, synthetic solvent oil and enhanced hydrogenated kerosene to avoid the defects of traditional diluents, such as the serious pollution of volatile organic compounds (VOCs) caused by traditional sulfonated kerosene as a diluent, the poor operating environment at the production site, and the carcinogens such as benzene, toluene and xylene in the diluent that seriously affect the health of operators. However, a series of production problems have also arisen, such as the problem of excessive rare earth impurity cerium in the praseodymium-neodymium series products in the newly built extraction and separation production line since the start of the trial run, and the original production line has also encountered similar problems as the amount of environmentally friendly diluents added increases.

[0003] Therefore, how to obtain a composite liquid inhibitor to avoid the problem of excessive rare earth impurity cerium in the process of rare earth extraction, separation and purification of praseodymium and neodymium series products is a technical problem that needs to be solved at present. Summary of the invention

[0004] The object of the present invention is to provide a composite liquid inhibitor and a preparation method thereof, which are used to solve the technical problem of excessive rare earth cerium impurities in the process of rare earth extraction, separation and purification of praseodymium and neodymium series products.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a composite liquid inhibitor, which is prepared from raw materials containing the following parts by weight:

[0007] 5-40 parts of main inhibitor;

[0008] 1 to 30 parts of auxiliary inhibitor;

[0009] 80-110 parts of diluent;

[0010] The main inhibitor comprises a hindered phenol compound, and the auxiliary inhibitor comprises a polyphenolic hydroxyl compound.

[0011] Further, the hindered phenol compound comprises one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis-(4-tert-butyl-4-ethylphenol), 2,4,6-tri-tert-butylphenol, 4-hydroxy-3-tert-butyl-anisole, 2,6-di-tert-butyl-4-(dimethylaminomethyl)phenol, 4,4'-thiobis(2-tert-butyl-5-methylphenol), and 4,4'-thiobis(6-tert-butyl-2-methylphenol).

[0012] Furthermore, the polyphenol hydroxy compound includes one or more of propyl gallate, pyrogallol, 1,3-di-tert-butyl-4,6-benzene, 3-butylcatechol, 4-butylcatechol, n-octylresorcinol, 5-pentylresorcinol, 4-propylresorcinol, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2-methyl-5-sec-octadecyl-1,4-benzene, 4,6-di-tert-butylpyrogallol, 4-allylpyrogallol, 2-methyl-4-pentylpyrogallol and phenethylpyrogallol.

[0013] Furthermore, the diluent comprises one or more of kerosene, sulfonated kerosene, aviation kerosene, hydrogenated enhanced kerosene, No. 200 solvent oil, No. 260 solvent oil, synthetic solvent oil, IP80, white oil, light white oil, white wax oil, cyclohexane, cyclohexanone and n-hexane.

[0014] The present invention provides a method for preparing a composite liquid inhibitor, comprising the following steps:

[0015] The main inhibitor, the auxiliary inhibitor and the diluent are mixed and then heated, stirred and cooled in sequence to obtain a composite liquid inhibitor.

[0016] Furthermore, the heating temperature is 25 to 60° C., and the stirring time is 45 to 60 minutes.

[0017] Furthermore, the cooling temperature is 20-45°C.

[0018] Beneficial effects of the present invention:

[0019] (1) In the composite liquid inhibitor prepared by the present invention, the hindered phenol compound and the polyphenol hydroxy compound have a synergistic effect in the anti-oxidation of cerium (III). In the anti-oxidation process, the hindered phenol main inhibitor can quickly and efficiently capture the oxygen free radicals, peroxide free radicals, organic free radicals, cerium (IV) and cerium (IV) complexes and other highly active free radical substances and oxides oxidized by air in the organic extract, inhibiting their further autocatalytic oxidation and the oxidation of a large amount of cerium (III) in the system; while the polyphenol hydroxy compound itself has a certain antioxidant capacity, which can prevent the oxidation of cerium (III), organic matter in the extractant (such as P507, P204, diluent) and rare earth complexes by oxygen in the air, and can protect the main inhibitor from generating excessive free radicals and being accelerated by oxidation. It is difficult to achieve the ideal inhibitory effect when the two inhibitors are used alone, but when used in combination, the effects complement each other and achieve an ideal synergistic effect.

[0020] (2) The composite liquid inhibitor of the present invention is insensitive to changes in the acidity and alkalinity of the rare earth extraction system, and can effectively avoid the problem of oxygen in the air accelerating the oxidation of cerium (III) to cerium (IV) in the high pH environment of the saponification-rare earth soap stage.

[0021] (3) The composite liquid inhibitor of the present invention can effectively avoid the problem of rare earth ions being oxidized during the entire extraction and separation process.

[0022] (4) The easy-reducibility property of the composite liquid inhibitor of the present invention can promote the reduction of the existing cerium (IV) to cerium (III) during the entire extraction and separation process, and can avoid the generation and existence of cerium (IV) during the rare earth extraction and separation process. DETAILED DESCRIPTION

[0023] The present invention provides a composite liquid inhibitor, which is prepared from raw materials containing the following parts by weight:

[0024] 5-40 parts of main inhibitor;

[0025] 1 to 30 parts of auxiliary inhibitor;

[0026] 80-110 parts of diluent;

[0027] The main inhibitor comprises a hindered phenol compound, and the auxiliary inhibitor comprises a polyphenolic hydroxyl compound.

[0028] In the present invention, the content of the main inhibitor is preferably 10 to 35 parts by mass, more preferably 15 to 30 parts, and even more preferably 20 to 25 parts.

[0029] In the present invention, the content of the auxiliary inhibitor is preferably 5 to 25 parts by mass, more preferably 10 to 20 parts, and even more preferably 12 to 18 parts.

[0030] In the present invention, the content of the diluent is preferably 85 to 105 parts by mass, more preferably 90 to 100 parts by mass, and more preferably 90 parts by mass.

[0031] In the present invention, the hindered phenol compound comprises one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-tert-butyl-4-ethylphenol), 2,4,6-tri-tert-butylphenol, 4-hydroxy-3-tert-butyl-anisole, 2,6-di-tert-butyl-4-(dimethylaminomethyl)phenol, 4,4'-thiobis(2-tert-butyl-5-methylphenol), 4,4'-thiobis(6-tert-butyl-2-methylphenol) Several, preferably one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis-(4-tert-butyl-4-ethylphenol) and 2,4,6-tri-tert-butylphenol, further preferably one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester and 2,2'-methylenebis(6-tert-butyl-4-methylphenol).

[0032] In the present invention, the polyphenol hydroxy compound comprises one or more of propyl gallate, pyrogallol, 1,3-di-tert-butyl-4,6-benzene, 3-butylcatechol, 4-butylcatechol, n-octylresorcinol, 5-pentylresorcinol, 4-propylresorcinol, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2-methyl-5-sec-octadecyl-1,4-benzene, 4,6-di-tert-butylpyrogallol, 4-allylpyrogallol, 2-methyl-4-pentylpyrogallol and phenethylresorcinol, preferably propyl gallate, pyrogallol, 1,3-di-tert-butyl-4,6-benzene, 3-butylcatechol, 4-butylcatechol, n-octylresorcinol, 5-pentylresorcinol, 4-propylresorcinol, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2-methyl-5-sec-octadecyl-1,4-benzene, 4,6-di-tert-butylpyrogallol, 4-allylpyrogallol, 2-methyl-4-pentylpyrogallol and phenethylresorcinol. One or more of propyl gallate, pyrogallol, 1,3-di-tert-butyl-4,6-benzene, 3-butylcatechol, 4-butylcatechol, n-octylresorcinol, 5-pentylresorcinol, 4-propylresorcinol, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone and 2-methyl-5-sec-octadecyl-1,4-benzene, and more preferably one or more of propyl gallate, pyrogallol, 1,3-di-tert-butyl-4,6-benzene, 3-butylcatechol, 4-butylcatechol and n-octylresorcinol.

[0033] In the present invention, the diluent includes kerosene, sulfonated kerosene, aviation kerosene, hydrogenated enhanced kerosene, No. 200 solvent oil, No. 260 solvent oil, synthetic solvent oil, IP80, white oil, light white oil, white wax oil 、 n-Hexane 、 One or more of cyclohexane, cyclohexanone and n-hexane, preferably one or more of kerosene, sulfonated kerosene, hydrogenated enhanced kerosene, cyclohexane, cyclohexanone and n-hexane, further preferably one or more of kerosene, No. 260 solvent oil, sulfonated kerosene and hydrogenated enhanced kerosene.

[0034] The present invention provides a method for preparing a composite liquid inhibitor, comprising the following steps:

[0035] The main inhibitor, the auxiliary inhibitor and the diluent are mixed and then heated, stirred and cooled in sequence to obtain a composite liquid inhibitor.

[0036] In the present invention, the heating temperature is 25 to 60° C., preferably 30 to 55° C., and more preferably 40 to 50° C.; the stirring time is 45 to 60 min, and preferably 50 to 55 min.

[0037] In the present invention, the cooling temperature is 20-45°C, preferably 25-35°C, and more preferably 30°C.

[0038] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0039] Example 1

[0040] The composite liquid inhibitor is made of the following raw materials in proportion by mass:

[0041] 5 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

[0042] 5 parts of Propyl Gallate

[0043] 90 parts of diluent No. 260 solvent oil

[0044] Preparation method: Mix the main inhibitor, auxiliary inhibitor and solvent oil in a reactor, stir for 0.5h, then heat to 40°C and continue stirring for 50min. After blending, transfer the mixed material to a storage tank through an insulated pipe, cool to 20°C to obtain a composite liquid inhibitor.

[0045] Example 2

[0046] The composite liquid inhibitor is made of the following raw materials in proportion by mass:

[0047] 5 parts of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate

[0048] 1,3-di-tert-butyl-4,6-benzenediol 5 parts

[0049] 90 parts of diluent No. 260 solvent oil

[0050] Preparation method: Mix the main inhibitor, auxiliary inhibitor and solvent oil in a reactor, stir for 0.5h, then heat to 50°C and continue stirring for 50min. After blending, transfer the mixed material to a storage tank through an insulated pipe, cool to 25°C to obtain a composite liquid inhibitor.

[0051] Example 3

[0052] The composite liquid inhibitor is made of the following raw materials in proportion by mass:

[0053] 8 parts of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate

[0054] 2,5-di-tert-butylhydroquinone 12 parts

[0055] Kerosene 100 parts

[0056] Preparation method: Mix the main inhibitor, auxiliary inhibitor and solvent oil in a reactor, stir for 0.5h, then heat to 60°C and continue stirring for 50min. After blending, transfer the mixed material to a storage tank through an insulated pipe, cool to 30°C to obtain a composite liquid inhibitor.

[0057] Example 4

[0058] The composite liquid inhibitor is made of the following raw materials in proportion by mass:

[0059] β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate 20 parts

[0060] 15 parts of phenethyl resorcinol

[0061] Cyclohexane 100 parts

[0062] Preparation method: Mix the main inhibitor, auxiliary inhibitor and solvent oil in a reactor, stir for 0.5h, then heat to 40°C and continue stirring for 50min. After blending, transfer the mixed material to a storage tank through an insulated pipe, cool to 20°C to obtain a composite liquid inhibitor.

[0063] Example 5

[0064] The composite liquid inhibitor is made of the following raw materials in proportion by mass:

[0065] 2,2'-Methylenebis(6-tert-butyl-4-methylphenol) 18 parts

[0066] 2-Methyl-4-pentyl phloroglucinol 22 parts

[0067] Cyclohexanone 100 parts

[0068] Preparation method: Mix the main inhibitor, auxiliary inhibitor and solvent oil in a reactor, stir for 0.5h, then heat to 40°C and continue stirring for 50min. After blending, transfer the mixed material to a storage tank through an insulated pipe, cool to 20°C to obtain a composite liquid inhibitor.

[0069] Example 6

[0070] The composite liquid inhibitor is made of the following raw materials in proportion by mass:

[0071] 2,6-di-tert-butyl-p-cresol 15 parts

[0072] 20 parts of 4-allyl pyrogallol

[0073] 90 parts of No. 200 solvent oil

[0074] Preparation method: Mix the main inhibitor, auxiliary inhibitor and solvent oil in a reactor, stir for 0.5h, then heat to 50°C and continue stirring for 50min. After blending, transfer the mixed material to a storage tank through an insulated pipe, cool to 20°C to obtain a composite liquid inhibitor.

[0075] Application Example 1

[0076] It is implemented in the industrial production line of cerium and praseodymium extraction and separation, and the operating conditions are as follows:

[0077] The flow ratio condition is:

[0078] Organic phase: alkali solution: rare earth soap material: mixed rare earth chloride material solution: praseodymium, neodymium and samarium washing solution: back acid: washing water = 450:45:35:40:30:45:5

[0079] Feed solution: concentration 1.5M, wherein the rare earth distribution La:Ce:PNS=27:52:21 (i.e. the distribution of cerium in the rare earth solution system is 52% of the total rare earth content)

[0080] Organic phase: concentrated 1.5M P507, diluent is environmentally friendly hydrogenated kerosene

[0081] Liquid caustic soda: concentration 6.0M

[0082] Stripping solution: 5.6M hydrochloric acid

[0083] Number of tank levels in each section:

[0084] Saponification stage: 2 levels

[0085] Rare earth saponification stage: 4 levels

[0086] Extraction stage: 56 levels

[0087] Washing section: 47 levels

[0088] Stripping stage: 12 levels

[0089] The specific implementation content is as follows: the composite liquid inhibitor and P507-environmentally friendly diluent are prepared in a volume ratio of 1:9 to form an organic phase with a composite liquid inhibitor concentration of 10%, which is added to the first level of the saponification section for extraction and separation of cerium and praseodymium elements to obtain a series of praseodymium and neodymium products with rare earth impurity cerium meeting the standards.

[0090] Application Example 2

[0091] The raw material for extraction is a mixed rare earth sulfate solution (water leaching solution), and the current mainstream transformation and separation integrated linkage advanced process in the rare earth industry is adopted. During the transformation process, the saponified organic and rare earth sulfate liquid composed of P507-diluent undergo countercurrent extraction, and the magnesium sulfate wastewater produced is treated by the water treatment system and then reused in the water leaching system. The loaded organic enters the chlorination system separation section, and the hydrochloric acid enters each section of the tank directly after automatic acid preparation. The transformation organic extraction volume is used to achieve partial or complete separation and purification of rare earth elements, and high-purity lanthanum chloride, high-purity cerium chloride, high-purity lanthanum cerium chloride, high-purity praseodymium chloride, high-purity neodymium chloride, high-purity praseodymium-neodymium chloride and samarium-europium-gadolinium enriched solution are produced according to market demand.

[0092] The specific implementation contents are as follows: the composite liquid inhibitor and P507-environmentally friendly diluent are prepared in a volume ratio of 0.5:9.5 to form an organic phase with a composite liquid inhibitor concentration of 5%, which is added to the last stage of the stripping section. The blank organic phase is saponified and used for the extraction and separation of rare earth elements to obtain a series of praseodymium chloride and neodymium chloride products with rare earth impurity cerium meeting the standards.

[0093] Application Example 3

[0094] It is implemented in the industrial production line of praseodymium-neodymium extraction and separation, and the operating conditions are as follows:

[0095] The flow ratio condition is:

[0096] Organic phase: alkali solution: rare earth soap material: praseodymium-neodymium material solution: neodymium washing solution: back acid: washing water = 130:13:8:13:8:9:3

[0097] Feed solution: concentration 1.5M, rare earth distribution Pr:Nd = 25:75, impurity cerium = 300ppm

[0098] Organic phase: concentrated 1.5M P507, diluent is environmentally friendly hydrogenated kerosene

[0099] Liquid caustic soda: concentration 6.0M

[0100] Stripping solution: 5.6M hydrochloric acid

[0101] Number of tank levels in each section:

[0102] Saponification stage: 2 levels

[0103] Rare earth saponification stage: 4 levels

[0104] Extraction stage: 52 levels

[0105] Washing section: 48 levels

[0106] Stripping stage: 12 levels

[0107] The specific implementation contents are as follows: the composite liquid inhibitor and P507-environmentally friendly diluent are mixed into an organic phase of a certain concentration and added to the last stage of the stripping section. The blank organic phase is saponified and used for the extraction and separation of rare earth elements to obtain a series of praseodymium chloride and neodymium chloride products with rare earth impurity cerium meeting the standards.

[0108] The extraction separation wastewater added with composite liquid inhibitor which has been running for more than 30 days was tested. The test results are shown in Table 1:

[0109] Table 1 Test results

[0110] Cerium content in praseodymium-neodymium series rare earth chloride products Application Example 1 ≤300ppm Application Example 2 ≤300ppm Application Example 3 ≤300ppm

[0111] The composite liquid inhibitor described in any one of Examples 1 to 3 is added to the organic phase composed of P507-environmentally friendly diluent in a one-time or gradual manner in a certain proportion, so that the final volume ratio of the composite liquid inhibitor in the environmentally friendly diluent is 0.1-30%. The extraction organic phase to which the composite liquid inhibitor is added is added from the trough head of the extraction production line, and completes a cycle through the saponification-rare earth soap section, the extraction section, the washing section, and the stripping section. During the reciprocating cycle of the organic phase to which the inhibitor is added, it can significantly inhibit and eliminate cerium (IV) in the extraction system. It can be seen from Table 1 that the content of cerium (IV) is less than 300 ppm, ensuring the qualification of cerium in the praseodymium-neodymium series products.

[0112] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A composite liquid inhibitor, characterized in that: Prepared from the following raw materials in parts by weight: 5-40 parts of main inhibitor; 1 to 30 parts of auxiliary inhibitor; 80-110 parts of diluent; The main inhibitor comprises a hindered phenol compound, and the auxiliary inhibitor comprises a polyphenolic hydroxyl compound.

2. The composite liquid inhibitor according to claim 1, characterized in that: The hindered phenol compound comprises one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis-(4-tert-butyl-4-ethylphenol), 2,4,6-tri-tert-butylphenol, 4-hydroxy-3-tert-butyl-anisole, 2,6-di-tert-butyl-4-(dimethylaminomethyl)phenol, 4,4'-thiobis(2-tert-butyl-5-methylphenol), and 4,4'-thiobis(6-tert-butyl-2-methylphenol).

3. The composite liquid inhibitor according to claim 1 or 2, characterized in that: The polyphenol hydroxy compound comprises one or more of propyl gallate, pyrogallol, 1,3-di-tert-butyl-4,6-benzene, 3-butylcatechol, 4-butylcatechol, n-octylresorcinol, 5-pentylresorcinol, 4-propylresorcinol, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2-methyl-5-sec-octadecyl-1,4-benzene, 4,6-di-tert-butylpyrogallol, 4-allylpyrogallol, 2-methyl-4-pentylpyrogallol and phenethylpyrogallol.

4. The composite liquid inhibitor according to claim 1, characterized in that: The diluent comprises one or more of kerosene, sulfonated kerosene, aviation kerosene, hydrogenated enhanced kerosene, No. 200 solvent oil, No. 260 solvent oil, synthetic solvent oil, IP80, white oil, light white oil, white wax oil, cyclohexane, cyclohexanone and n-hexane.

5. The method for preparing the composite liquid inhibitor according to any one of claims 1 to 4, characterized in that: The following steps are involved: The main inhibitor, the auxiliary inhibitor and the diluent are mixed and then heated, stirred and cooled in sequence to obtain a composite liquid inhibitor.

6. The method for preparing the composite liquid inhibitor according to claim 5, characterized in that: The heating temperature is 25-60° C., and the stirring time is 45-60 min.

7. The method for preparing the composite liquid inhibitor according to claim 5 or 6, characterized in that: The cooling temperature is 20-45°C.