A method for recovering niobium from chlorinated waste residue and its application

Abstract

The present invention relates to the technical field of solid waste treatment, and in particular to a method for recovering niobium from chlorinated waste residue and its application. The chlorinated waste residue is mixed with an acid solution and leached, and then solid-liquid separation is performed to obtain a niobium-containing filtrate and leached residue; after the niobium-containing filtrate is mixed with hydrofluoric acid, an extractant is added for extraction to obtain an extract, and then a stripping agent is added for stripping to obtain a stripping solution; the pH of the stripping solution is adjusted to allow the niobium to settle, and then solid-liquid separation is performed to obtain a filter residue; after the filter residue is roasted, a niobium material whose main component includes niobium pentoxide is obtained; after the leached residue is mixed with water and slurried to obtain a slurry, flotation is performed to obtain a flotation tailing and a flotation concentrate whose main component includes coke powder; after the flotation tailing is heated, electrostatic separation is performed to obtain an electrostatic concentrate whose main component includes high-titanium concentrate and an electrostatic tailing whose main component includes silicon dioxide. The method can separate niobium pentoxide, coke powder high-titanium concentrate and silicon powder, and recover the neglected niobium resources in the chlorinated waste residue.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste treatment, and in particular to a method for recovering niobium from chlorinated waste residue and application thereof. Background Art

[0002] At present, there are two main methods for producing titanium dioxide: sulfuric acid method and chlorination method. Compared with sulfuric acid method, chlorination method produces less waste slag and wastewater. As a cleaner and more environmentally friendly large-scale production process, the scale of the industry has been expanding in recent years. The waste slag produced by the chlorination method mainly includes fine coke powder, silicon dioxide and unreacted titanium dioxide blown out with the tail gas, but it should be noted that it contains a large amount of chlorides such as ferrous chloride, sodium chloride, etc., as well as a small amount of niobium, among which niobium comes from the seaside sand ore used for chlorination production. The content of these niobium elements in seaside sand ore is extremely low, generally between 0.05% and 0.5%, but in the process of preparing titanium-rich materials, entering the chlorination furnace and finally being discharged as waste slag, it has been enriched to a certain extent and has the value of recycling.

[0003] Niobium element generally exists in the form of oxide in nature. After entering the chlorination furnace, it undergoes high-temperature chlorination to become chloride. However, in the cooling section after the chlorination furnace, since the boiling point of niobium chloride is much higher than that of titanium tetrachloride, it enters the solid waste during the cooling process. However, it should be noted that niobium chloride has a strong hydrolysis ability and is very easy to hydrolyze in liquid to produce hydrolysis products.

[0004] The currently disclosed high-efficiency comprehensive recovery process of chlorinated waste slag is usually a mineral processing and sorting method. However, in addition to the main phases such as coke powder, titanium dioxide, and silicon dioxide, the chlorinated waste slag also contains a small amount of chlorides and oxides of elements such as iron, niobium, sodium, magnesium, and aluminum. During the sorting process, the chlorides and oxides of elements such as iron, niobium, sodium, magnesium, and aluminum will interfere with the sorting accuracy and sorting yield, thereby reducing the recovery rate of coke powder and titanium dioxide in the chlorinated waste slag.

[0005] Therefore, it is of great significance to comprehensively recover the elements with higher content and higher value (such as carbon, titanium, niobium, and silicon) in chlorinated waste residue and improve the comprehensive recovery efficiency.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The first object of the present invention is to provide a method for recovering niobium from chlorinated waste residue, which can comprehensively recover elements with higher content and higher value (carbon, titanium, niobium, silicon) in chlorinated waste residue, and has high comprehensive recovery efficiency. Specifically, the present invention can gradually extract resources from inert chlorinated waste residue with complex components by subjecting chlorinated waste residue to acid leaching for niobium extraction, flotation for carbon extraction, and electrostatic separation for titanium and silicon separation, thereby obtaining niobium materials whose main components include niobium pentoxide, flotation concentrate whose main components include coke powder, electrostatic separation concentrate whose main components include high-titanium concentrate, and electrostatic separation tailings whose main components include silicon dioxide, and recovering solid waste with maximum resource utilization; and the method can recover the neglected niobium resources in chlorinated waste residue, thereby increasing the added value of the product.

[0008] The second object of the present invention is to provide a method for recovering niobium from chlorinated waste residue and its application in the production of titanium dioxide.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] The present invention first provides a method for recovering niobium from chlorinated waste residue, comprising the following steps:

[0011] After the chlorinated waste residue is mixed with the acid solution and leached, the solid and liquid are separated to obtain a niobium-containing filtrate and leached residue;

[0012] After the niobium-containing filtrate is mixed with hydrofluoric acid, an extractant is added thereto for extraction to obtain an extract; a stripping agent is added to the extract for stripping to obtain a stripping solution; the pH of the stripping solution is adjusted to allow niobium to settle, and then solid-liquid separation is performed to obtain a filter residue; and after the filter residue is roasted, a niobium material whose main component includes niobium pentoxide is obtained;

[0013] The leached residue is mixed with water to obtain a slurry, and then flotation is performed to obtain a flotation tailing and a flotation concentrate whose main component includes coke powder; the flotation tailing is heated and then electrostatically separated to obtain an electrostatic concentrate whose main component includes high-titanium concentrate and an electrostatic tailing whose main component includes silicon dioxide.

[0014] Furthermore, the acid solution includes at least one of a sulfuric acid solution and a hydrochloric acid solution.

[0015] Furthermore, the mass fraction of the acid solution is 20% to 35%.

[0016] Furthermore, the leaching temperature is 20-45°C.

[0017] Furthermore, the leaching time is 3 to 6 hours.

[0018] Furthermore, the ratio of the mass of the chlorinated waste residue to the volume of the acid solution is 1 kg: 2-4 L.

[0019] Furthermore, the volume ratio of the niobium-containing filtrate to the hydrofluoric acid is 3-6:1, and the mass fraction of the hydrofluoric acid is 30%-50%.

[0020] Furthermore, the extractant includes at least one of tributyl phosphate and N,N-bis(1-methylheptyl)acetamide.

[0021] Furthermore, the ratio of the volume of the extractant to the sum of the volumes of the niobium-containing filtrate and the hydrofluoric acid is 1 to 1.5:1.

[0022] Furthermore, the extraction time is 3 to 8 minutes.

[0023] Furthermore, the stripping agent includes at least one of sodium hydroxide solution and ammonia water.

[0024] Furthermore, the volume ratio of the stripping agent to the extract is 1 to 1.5:1.

[0025] Furthermore, the back extraction time is 3 to 8 minutes.

[0026] Furthermore, the pH of the stripping solution is adjusted to 7-9.

[0027] Furthermore, the sedimentation time of the niobium is 1 to 4 hours.

[0028] Furthermore, the calcination temperature is 750-950°C.

[0029] Furthermore, the calcination time is 2 to 5 hours.

[0030] Furthermore, the mass fraction of the post-immersion residue in the slurry is 20% to 35%.

[0031] Furthermore, the frother used in the flotation comprises pine oil, and the ratio of the mass of the frother to the mass of the leached residue is 400-800g:1t.

[0032] Furthermore, the collector used for flotation includes diesel, and the ratio of the mass of the collector to the mass of the leached residue is 800-1200g:1t.

[0033] Furthermore, the heating temperature is 105-150°C.

[0034] Furthermore, the voltage of the electric selection is 15-25 kV.

[0035] Furthermore, the rotation speed of the roller of the electrostatic separation equipment used in the electrostatic separation is 150 to 250 r / min.

[0036] Furthermore, the mass fraction of the niobium pentoxide in the niobium material is ≥80%.

[0037] Furthermore, the mass fraction of carbon element in the flotation concentrate is ≥75%.

[0038] Furthermore, the titanium content in the electrolytically separated concentrate is ≥85%.

[0039] Furthermore, the mass fraction of the silicon dioxide in the electrolytic separation tailings is ≥75%.

[0040] The present invention further provides application of the method for recovering niobium from chlorinated waste residue in the production of titanium dioxide.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The method for recovering niobium from chlorinated waste slag provided by the present invention can comprehensively recover elements with higher content and higher value (carbon, titanium, niobium, silicon) in the chlorinated waste slag, and the comprehensive recovery efficiency is high; by subjecting the chlorinated waste slag to acid leaching for niobium extraction, flotation for carbon extraction, and electrostatic separation for separation of titanium and silicon, the inert chlorinated waste slag with complex components can be gradually subjected to resource extraction, and niobium pentoxide, coke powder high-titanium concentrate and silicon powder can be separated to obtain, thereby recovering the solid waste with the maximum resource utilization rate.

[0043] (2) The method for recovering niobium from chlorinated waste slag provided by the present invention uses a process of acid leaching niobium-extraction and impurity removal-roasting and oxidation to recover the neglected niobium resources in the chlorinated waste slag, thereby improving the overall value of the chlorinated waste slag and the overall utilization rate of rare metal resources in the titanium ore industry chain.

[0044] (3) The method for recovering niobium from chlorinated waste slag provided by the present invention first performs acid leaching on the chlorinated waste slag to extract niobium. While extracting the niobium element, most of the components in the chlorinated waste slag that are easily leached out by acid, such as iron, calcium, magnesium, and aluminum, are separated from the solid phase, thereby reducing the difficulty of subsequent sorting of coke powder, high-titanium concentrate, and silicon powder.

[0045] (4) The method for recovering niobium from chlorinated waste slag provided by the present invention has high resource utilization rate, simple process and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1The present invention provides a schematic flow diagram of a method for recovering niobium from chlorinated waste residue. DETAILED DESCRIPTION

[0048] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0049] If there is no special explanation, in the present invention, "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "the first", "the second", "the third", "the fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0050] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0051] If there is no special explanation, in the present invention, "one or more" or "at least one" refers to any one, any two or more of the listed items. Among them, "several" refers to any two or more of the listed items.

[0052] In a first aspect, the present invention provides a method for recovering niobium from chlorination waste residue, which is also a method for comprehensively improving the resource utilization rate of chlorination waste residue. Figure 1 The process flow diagram of the method for recovering niobium from chlorinated waste slag provided by the present invention is shown in FIG. Figure 1 The method for recovering niobium from chlorinated waste residue comprises the following steps:

[0053] After the chlorinated waste residue is mixed and stirred with the acid solution and leached, the leached system is subjected to solid-liquid separation to obtain a niobium-containing filtrate and leached residue.

[0054] Among them, the chlorinated waste residue is the chlorinated waste residue produced by boiling chlorination of titanium-rich materials.

[0055] The present invention performs leaching before sorting, and leaches chlorides and oxides of elements such as iron, niobium, sodium, magnesium, and aluminum, and separates them from main phases such as coke powder, titanium dioxide, and silicon dioxide, thereby reducing the complexity of the solid phase after leaching, reducing interference factors in the sorting process, and achieving better sorting effects, thereby improving the comprehensive recovery efficiency of chlorination waste slag sorting.

[0056] After the niobium-containing filtrate is mixed with hydrofluoric acid, an extractant is added thereto for extraction to obtain an extract. The hydrofluoric acid has the function of adjusting the pH and promoting the extraction of niobium. The organic phase separated after the extraction is the extract.

[0057] Among them, hydrofluoric acid and niobium ions can produce niobium hydrofluoric acid complexes, such as H2NbH7. The niobium hydrofluoric acid complexes can be better combined with the extractant in the present invention, so that the niobium-related phases have better selectivity.

[0058] It is understandable that niobium chloride has a strong hydrolysis ability, so the present invention performs extraction in an acidic system, otherwise the generated hydrolysis products will combine with other solids, increasing the difficulty of extracting niobium.

[0059] In some specific embodiments, the extraction is followed by standing for at least 2 minutes.

[0060] Adding a stripping agent to the extract to perform stripping to obtain a stripping solution; adjusting the pH of the stripping solution to allow niobium to precipitate, and then performing solid-liquid separation to obtain a filter residue.

[0061] After the filter residue is roasted, a niobium material whose main component includes niobium pentoxide is obtained.

[0062] The leached residue is mixed with water, stirred and slurried to obtain a slurry, and then flotation is performed to obtain a flotation tailing and a flotation concentrate whose main component includes coke powder.

[0063] The equipment used for flotation can be any flotation equipment commonly used in the art, such as a flotation machine or a flotation column, but is not limited thereto.

[0064] After being dried and heated, the flotation tailings are electrostatically separated to obtain electrostatically separated concentrates whose main components include high-titanium concentrates and electrostatically separated tailings whose main components include silicon dioxide (silicon powder).

[0065] In some specific embodiments, the equipment used for the electrostatic separation can be any electrostatic separation equipment commonly used in the art, such as a double-roller electrostatic separator, but is not limited thereto.

[0066] The method for recovering niobium from chlorinated waste residue provided by the present invention can gradually extract resources from inert chlorinated waste residue with complex components and recover solid waste with maximum resource utilization rate by subjecting the chlorinated waste residue to acid leaching for niobium extraction, flotation for carbon extraction, and electrostatic separation for titanium and silicon separation.

[0067] In addition, the present invention uses the process of acid leaching niobium-extraction and impurity removal-roasting and oxidation to recover the neglected niobium resources in the chlorinated waste slag, thereby improving the overall value of the chlorinated waste slag and the overall utilization rate of rare metal resources in the titanium ore industry chain.

[0068] In addition, the present invention first performs acid leaching on chlorinated waste slag to extract niobium, and simultaneously separates most of the easily acid-leached components such as iron, calcium, magnesium, and aluminum in the chlorinated waste slag from the solid phase while extracting the niobium element, thereby reducing the difficulty of subsequent sorting of coke powder, high-titanium concentrate, and silicon powder.

[0069] The method for recovering niobium from chlorinated waste residue provided by the invention has high resource utilization rate, simple process and is easy to implement industrially.

[0070] Specifically, the main components of the chlorinated waste residue produced by boiling chlorination of titanium-rich materials include: coke powder, silicon dioxide, titanium dioxide, a small amount of chlorides or oxides of calcium, magnesium and iron, and a small amount of niobium. This part of niobium is easily leached out by acid after chlorination (niobium is chlorinated during boiling chlorination in the chlorination method) and beating and hydrolysis. In order to better separate the various phases in the chlorinated waste residue, the chlorinated waste residue is first acid-leached to separate the acid-soluble substances from the acid-insoluble substances in the waste residue, reduce the content of elements such as iron, calcium, and magnesium in the acid-leached residue, and make the solid phase particles easier to sort. After acid leaching, the niobium element enters the liquid phase, but it should be noted that the acid leaching solution also contains other elements leached out by acid, so it is necessary to remove impurities through extraction and stripping, and then precipitate the niobium-related phases through pH adjustment (the acidic H2NbH7 is converted into Nb(OH)5 during the pH adjustment process, thereby precipitating), and oxidative roasting can obtain niobium oxide. Compared with silicon dioxide and titanium dioxide, coke powder in acid leaching residue is easier to separate by flotation. Silicon dioxide and titanium dioxide are easy to separate by electrostatic separation due to their different electrical conductivity. The combined flotation-electrostatic separation method can obtain higher-grade coke powder, high-titanium concentrate and silicon powder.

[0071] In some specific embodiments, the acid solution includes at least one of a sulfuric acid solution and a hydrochloric acid solution. The acid solution is used for acid leaching reaction.

[0072] In some specific embodiments, the mass fraction of the acid solution is 20% to 35%, including but not limited to any point value of 22%, 23%, 25%, 28%, 30%, 32%, 33% or a range between any two of them.

[0073] In some specific embodiments, the leaching reaction temperature is 20-45°C, including but not limited to any point value of 28°C, 30°C, 32°C, 35°C, 37°C, 40°C, 43°C or a range value between any two of them.

[0074] In some specific embodiments, the leaching reaction time is 3 to 6 hours, including but not limited to any one of 4 hours, 4.5 hours, 5 hours, and 5.5 hours, or a range between any two of them.

[0075] In some specific embodiments, during the mixing and leaching process, the ratio of the mass (in kg) of the chlorinated waste residue to the volume (in L) of the acid solution is 1 kg:2-4 L, for example, 1 kg:3 L.

[0076] In some specific embodiments, during the mixing of the niobium-containing filtrate and the hydrofluoric acid, the volume ratio of the niobium-containing filtrate to the hydrofluoric acid is 3 to 6:1, such as 4:1 or 5:1.

[0077] In some specific embodiments, the mass fraction of the hydrofluoric acid is 30% to 50%, including but not limited to 32%, 35%, 37%, 40%, 43%, 45%, 48%, any one of the points or any range between two of them.

[0078] In some specific embodiments, during the extraction process, the extractant includes at least one of tributyl phosphate and N,N-bis(1-methylheptyl)acetamide.

[0079] In some specific embodiments, during the extraction process, the ratio of the volume of the extractant to the sum of the volumes of the niobium-containing filtrate and the hydrofluoric acid is 1 to 1.5:1, for example, 1.1:1, 1.2:1, 1.3:1 or 1.4:1.

[0080] In some specific implementations, the extraction time is 3 to 8 minutes, including but not limited to any one of 4 minutes, 5 minutes, 6 minutes, and 7 minutes, or a range between any two of them.

[0081] In some specific embodiments, during the stripping process, the stripping agent includes at least one of a sodium hydroxide solution and an ammonia solution.

[0082] In some specific embodiments, during the stripping process, the volume ratio of the stripping agent to the extract is 1 to 1.5:1, for example, 1.1:1, 1.2:1, 1.3:1 or 1.4:1.

[0083] In some specific embodiments, during the back extraction process, the back extraction time is 3 to 8 minutes, including but not limited to any one of 4 minutes, 5 minutes, 6 minutes, and 7 minutes, or a range between any two of them.

[0084] In some specific embodiments, during the precipitation of niobium, the pH of the stripping solution is adjusted to 7-9, including but not limited to any one of 7.3, 7.5, 7.7, 8, 8.2, 8.5, 8.8 or a range between any two of them.

[0085] In some specific embodiments, the sedimentation time (ie, reaction time) for niobium sedimentation is 1 to 4 hours, including but not limited to any one of 2 hours, 2.5 hours, and 3 hours, or a range between any two of them.

[0086] In some specific embodiments, the calcination temperature is 750-950°C, including but not limited to any point value of 780°C, 800°C, 830°C, 850°C, 880°C, 900°C, 920°C or a range between any two of them.

[0087] In some specific embodiments, the calcination holding time is 2 to 5 hours, including but not limited to any one of 3 hours, 3.5 hours, and 4 hours, or a range between any two of them.

[0088] In some specific embodiments, in the process of mixing the post-immersion residue with water to obtain a slurry, the mass fraction of the post-immersion residue in the obtained slurry is 20% to 35%, that is, the concentration of the slurry is 20% to 35%, including but not limited to any one of 23%, 25%, 28%, 30%, 32% or a range between any two of them.

[0089] In some specific embodiments, the reagents used for flotation include frothers and collectors.

[0090] In some specific embodiments, the frother used in the flotation comprises pine oil.

[0091] In some specific embodiments, the ratio of the mass of the foaming agent (in g) to the mass of the leached residue (in t, i.e., ton) is 400-800 g:1 t, for example, 500 g:1 t, 600 g:1 t or 700 g:1 t.

[0092] In some specific embodiments, the collector used for flotation includes diesel.

[0093] In some specific embodiments, the ratio of the mass of the collector (in g) to the mass of the leached residue (in t) is 800-1200 g:1 t, for example, 900 g:1 t, 1000 g:1 t or 1100 g:1 t.

[0094] In some specific embodiments, before the electroselection, the heating temperature is 105-150°C, including but not limited to any point value of 110°C, 120°C, 130°C, 140°C or a range between any two of them.

[0095] In some specific embodiments, the heating holding time is 2 to 6 hours, including but not limited to any one of 3 hours, 4 hours, and 5 hours or any range between the two. After the heating is completed, the electroselection is started.

[0096] In some specific embodiments, the voltage of the electroselection is 15-25 kV, including but not limited to any point value of 18 kV, 20 kV, 23 kV or a range of values ​​between any two of them.

[0097] In some specific embodiments, the rotation speed of the rollers of the electrostatic separation equipment used for the electrostatic separation (i.e., the rotation speed of the upper and lower rollers) is 150-250 r / min, including but not limited to any point value of 180 r / min, 200 r / min, 230 r / min or a range value between any two of them.

[0098] In some specific embodiments, the mass fraction of the niobium pentoxide in the niobium material is ≥80%, including but not limited to any point value of 83%, 85%, 88%, 90%, 92%, 95%, 98%, 99% or a range value between any two of them.

[0099] In some specific embodiments, the mass fraction of carbon in the flotation concentrate is ≥75%, including but not limited to any point value of 78%, 80%, 83%, 85%, 88%, 90%, 92%, 95%, 98% or a range value between any two of them.

[0100] In some specific embodiments, the titanium grade in the electrolytic concentrate is ≥85%, including but not limited to any one of 87%, 90%, 93%, 95%, 98%, 99% or a range between any two of them.

[0101] In some specific embodiments, the mass fraction of the silicon dioxide in the electrolytic separation tailings is ≥75%, including but not limited to any point value of 78%, 80%, 83%, 85%, 88%, 90%, 92%, 95%, 98% or a range value between any two of them.

[0102] In a second aspect, the present invention provides application of the method for recovering niobium from chlorinated waste residue in the production of titanium dioxide.

[0103] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0104] The main components of the chlorinated waste residue used in the following embodiments and comparative examples of the present invention include: in terms of mass percentage, 29.59% C element content, 34.78% TiO2 content, 15.14% SiO2 content, 9.22% Fe2O3 content, 1.58% Nb2O3 content, and the remaining components are small amounts of S, Cl, Na, Mg, Al and Mn elements.

[0105] Example 1

[0106] The method for recovering niobium from chlorinated waste residue provided in this embodiment comprises the following steps:

[0107] (1) adding the chlorinated waste residue into a sulfuric acid solution and stirring and leaching at room temperature (25° C.), wherein the mass fraction of the sulfuric acid solution is 25%, the mass ratio of the chlorinated waste residue to the volume of the sulfuric acid solution is 1 kg:3 L, and the leaching time is 6 h. After the leaching is completed, filtering and washing are performed to obtain a niobium-containing filtrate and leached residue.

[0108] (2) adding hydrofluoric acid to the niobium-containing filtrate to adjust the pH of the system, wherein the volume ratio of the niobium-containing filtrate to the hydrofluoric acid is 4:1, and the mass fraction of the hydrofluoric acid is 40%, and then adding an extractant thereto, wherein the extractant is tributyl phosphate, and the ratio of the volume of the extractant to the sum of the volumes of the niobium-containing filtrate and the hydrofluoric acid is 1:1, extracting and separating the organic phase to obtain an extract, wherein the extraction time is 5 minutes and the standing time is 2 minutes.

[0109] A stripping agent is added to the above-mentioned extract for stripping, wherein dilute ammonia water (mass fraction is 20%) is selected as the stripping agent, the volume ratio of the stripping agent to the extract is 1:1, the stripping time is 5 minutes, and the standing time is 2 minutes to obtain a stripping solution.

[0110] The pH of the stripping solution was adjusted to 8, and then aged for 2 hours to allow the niobium to precipitate. The niobium was then filtered, the filter cake was washed and dried, and the dried filter cake was oxidatively roasted at 800°C for 3 hours to obtain a niobium material with a mass fraction of Nb2O5 of 95.31%.

[0111] (3) The leached residue is slurried with water, and the slurry concentration (mass fraction) is controlled to be 30%, and then flotation is carried out, wherein the frother is selected as pine oil and the collector is selected as diesel in the flotation reagent, the frother is added in an amount of 600g:1t, and the collector is added in an amount of 1000g:1t (that is, the mass of the frother and the collector added per ton of leached residue are 600g and 1000g respectively), and flotation tailings and flotation concentrate whose main component is coke powder are obtained. After washing, filter pressing and drying, the mass fraction of carbon in the flotation concentrate is measured to be 82.27%.

[0112] The flotation tailings are washed, filtered, and dried, and then heated to 120°C and kept warm for 4 hours before being electrostatically separated. The electrostatic separation equipment is a double-roller electrostatic separator with a voltage of 20 kV and a roller speed of 200 r / min to obtain electrostatically separated concentrate and electrostatically separated tailings. The electrostatically separated concentrate is a high-titanium concentrate with a titanium grade of 92.93%. The main component of the electrostatically separated tailings is silicon powder, in which the mass fraction of silicon dioxide is 86.81%.

[0113] Example 2

[0114] The method for recovering niobium from chlorinated waste residue provided in this embodiment comprises the following steps:

[0115] (1) adding the chlorinated waste residue into a sulfuric acid solution and stirring and leaching at a temperature of 40° C., wherein the mass fraction of the sulfuric acid solution is 25%, the mass ratio of the chlorinated waste residue to the volume of the sulfuric acid solution is 1 kg:2 L, and the leaching time is 3 h. After the leaching is completed, filtering and washing are performed to obtain a niobium-containing filtrate and leached residue.

[0116] (2) adding hydrofluoric acid to the niobium-containing filtrate to adjust the pH of the system, wherein the volume ratio of the niobium-containing filtrate to the hydrofluoric acid is 3:1, and the mass fraction of the hydrofluoric acid is 40%, and then adding an extractant thereto, wherein the extractant is tributyl phosphate, and the ratio of the volume of the extractant to the sum of the volumes of the niobium-containing filtrate and the hydrofluoric acid is 1:1, extracting and separating the organic phase to obtain an extract, wherein the extraction time is 5 minutes and the standing time is 2 minutes.

[0117] A stripping agent is added to the above extract for stripping, wherein dilute ammonia water is selected as the stripping agent, the volume ratio of the stripping agent to the extract is 1:1, the stripping time is 5 minutes, and the standing time is 2 minutes, to obtain a stripping solution.

[0118] The pH of the stripping solution was adjusted to 8, and then aged for 2 hours to allow the niobium to precipitate. The niobium was then filtered, the filter cake was washed and dried, and the dried filter cake was oxidatively roasted at 800°C for 3 hours to obtain a niobium material with a mass fraction of Nb2O5 of 93.56%.

[0119] (3) The leached residue is slurried with water, and the slurry concentration (mass fraction) is controlled to be 35%, and then flotation is carried out, wherein the frother is selected as pine oil and the collector is selected as diesel, the frother is added in an amount of 500g:1t, and the collector is added in an amount of 900:1t, and flotation tailings and flotation concentrate whose main component is coke powder are obtained. After washing, filter pressing and drying, the mass fraction of carbon in the flotation concentrate is measured to be 79.81%.

[0120] The flotation tailings are washed, filtered, and dried, and then heated to 120°C for electrostatic separation. The electrostatic separation equipment is a double-roller electrostatic separator with an electrostatic separation voltage of 16kV and a roller speed of 225r / min to obtain electrostatically separated concentrate and electrostatically separated tailings. The electrostatically separated concentrate is a high-titanium concentrate with a titanium grade of 93.05%. The main component of the electrostatically separated tailings is silicon powder, in which the mass fraction of silicon dioxide is 84.76%.

[0121] Example 3

[0122] The method for recovering niobium from chlorinated waste residue provided in this embodiment comprises the following steps:

[0123] (1) adding the chlorinated waste residue into a sulfuric acid solution and stirring and leaching at a temperature of 40° C., wherein the mass fraction of the sulfuric acid solution is 30%, the mass ratio of the chlorinated waste residue to the volume of the sulfuric acid solution is 1 kg:4 L, and the leaching time is 5 h. After the leaching is completed, filtering and washing are performed to obtain a niobium-containing filtrate and leached residue.

[0124] (2) adding hydrofluoric acid to the niobium-containing filtrate to adjust the pH of the system, wherein the volume ratio of the niobium-containing filtrate to the hydrofluoric acid is 4:1, and the mass fraction of the hydrofluoric acid is 40%, and then adding an extractant thereto, wherein the extractant is tributyl phosphate, and the ratio of the volume of the extractant to the sum of the volumes of the niobium-containing filtrate and the hydrofluoric acid is 1:1, extracting and separating the organic phase to obtain an extract, wherein the extraction time is 5 minutes and the standing time is 2 minutes.

[0125] A stripping agent is added to the above extract for stripping, wherein dilute ammonia water is selected as the stripping agent, the volume ratio of the stripping agent to the extract is 1:1, the stripping time is 5 minutes, and the standing time is 2 minutes, to obtain a stripping solution.

[0126] The pH of the stripping solution was adjusted to 8, and then aged for 2 hours to allow the niobium to precipitate. The niobium was then filtered, the filter cake was washed and dried, and the dried filter cake was oxidatively roasted at 800°C for 3 hours to obtain a niobium material with a mass fraction of Nb2O5 of 91.24%.

[0127] (3) The leached residue is slurried with water, and the slurry concentration (mass fraction) is controlled to be 30%, and then flotation is carried out, wherein the frother in the flotation reagent is pine oil, and the collector is diesel, the frother amount is 700g:1t, and the collector amount is 1100g:1t, and flotation tailings and flotation concentrate whose main component is coke powder are obtained. After washing, filter pressing and drying, the mass fraction of carbon in the flotation concentrate is measured to be 80.41%.

[0128] The flotation tailings are washed, filtered, and dried, and then heated to 120°C for electrostatic separation. The electrostatic separation equipment is a double-roller electrostatic separator with an electrostatic separation voltage of 22kV and a roller speed of 175r / min to obtain electrostatic concentrate and electrostatic tailings. The electrostatic concentrate is a high-titanium concentrate with a titanium grade of 89.52%. The main component of the electrostatic tailings is silicon powder, in which the mass fraction of silicon dioxide is 86.43%.

[0129] Example 4

[0130] The method for recovering niobium from chlorinated waste residue provided in this embodiment comprises the following steps:

[0131] (1) adding the chlorinated waste residue into a sulfuric acid solution and stirring and leaching at room temperature (25° C.), wherein the mass fraction of the sulfuric acid solution is 20%, the mass ratio of the chlorinated waste residue to the volume of the sulfuric acid solution is 1 kg:2 L, and the leaching time is 3 h. After the leaching is completed, filtering and washing are performed to obtain a niobium-containing filtrate and leached residue.

[0132] (2) adding hydrofluoric acid to the niobium-containing filtrate to adjust the pH of the system, wherein the volume ratio of the niobium-containing filtrate to the hydrofluoric acid is 4:1, and the mass fraction of the hydrofluoric acid is 40%, and then adding an extractant thereto, wherein the extractant is tributyl phosphate, and the ratio of the volume of the extractant to the sum of the volumes of the niobium-containing filtrate and the hydrofluoric acid is 1:1, extracting and separating the organic phase to obtain an extract, wherein the extraction time is 5 minutes and the standing time is 2 minutes.

[0133] A stripping agent is added to the above-mentioned extract for stripping, wherein sodium hydroxide solution (molar concentration is 2 mol / L) is selected as the stripping agent, the volume ratio of the stripping agent to the extract is 1:1, the stripping time is 5 min, and the standing time is 2 min, to obtain a stripping solution.

[0134] The pH of the stripping solution was adjusted to 8, and then aged for 2 hours to allow the niobium to precipitate. The niobium was then filtered, the filter cake was washed and dried, and the dried filter cake was oxidatively roasted at 800°C for 3 hours to obtain a niobium material with a mass fraction of Nb2O5 of 87.19%.

[0135] (3) The leached residue is slurried with water, and the slurry concentration (mass fraction) is controlled to be 30%, and then flotation is carried out, wherein the frother in the flotation reagent is pine oil, and the collector is diesel, the frother amount is 600g:1t, and the collector amount is 1000g:1t, to obtain flotation tailings and flotation concentrate whose main component is coke powder. After washing, filter pressing and drying, the mass fraction of carbon in the flotation concentrate is measured to be 77.64%.

[0136] The flotation tailings are washed, filtered, and dried, and then heated to 120°C for electrostatic separation. The electrostatic separation equipment is a double-roller electrostatic separator with an electrostatic separation voltage of 20 kV and a roller speed of 200 r / min to obtain electrostatic concentrate and electrostatic tailings. The electrostatic concentrate is a high-titanium concentrate with a titanium grade of 89.16%. The main component of the electrostatic tailings is silicon powder, in which the mass fraction of silicon dioxide is 81.34%.

[0137] Example 5

[0138] The method for recovering niobium from chlorinated waste residue provided in this embodiment is basically the same as that in embodiment 1, except that in step (2), the extractant tributyl phosphate is replaced by an equal mass of N,N-bis(1-methylheptyl)acetamide.

[0139] The mass fraction of Nb2O5 in the niobium material obtained in this embodiment is 87.63%; the mass fraction of carbon in the flotation concentrate obtained in this embodiment is 78.19% after washing, filter pressing and drying; the titanium grade of the electrostatic concentrate obtained in this embodiment is 89.35%; the mass fraction of silicon dioxide in the electrostatic tailings obtained in this embodiment is 81.91%.

[0140] Comparative Example 1

[0141] The method for recovering niobium from chlorinated waste residue provided in this comparative example comprises the following steps:

[0142] The chlorinated waste residue is slurried with water, and the slurry concentration (mass fraction) is controlled to be 30%, and then flotation is carried out, wherein the frother in the flotation reagent is pine oil, and the collector is diesel, the frother addition amount is 600g:1t, and the collector addition amount is 1000g:1t, and flotation tailings and flotation concentrate whose main component is coke powder are obtained. After washing, filter pressing and drying, the mass fraction of carbon element in the flotation concentrate is measured to be 65.62%.

[0143] The flotation tailings are washed, filtered, and dried, and then heated to 120°C for electrostatic separation. The electrostatic separation equipment is a double-roller electrostatic separator with an electrostatic separation voltage of 20 kV and a roller speed of 200 r / min to obtain electrostatic concentrate and electrostatic tailings. The electrostatic concentrate is a high-titanium concentrate with a titanium grade of 85.17%. The main component of the electrostatic tailings is silicon powder, in which the mass fraction of silicon dioxide is 67.55%.

[0144] In this comparative example, acid leaching, extraction and stripping were not performed, and the niobium material whose main component was niobium pentoxide was not separated. In addition, the products obtained in this comparative example had low carbon content, low titanium grade and low silicon powder content.

[0145] Comparative Example 2

[0146] The method for recovering niobium from chlorinated waste slag provided in this comparative example is basically the same as that in Example 1, except that: the leaching time in step (1) is 1 hour, the volume ratio of the niobium-containing filtrate to the hydrofluoric acid in step (2) is 1:1, the slurry concentration (mass fraction) is controlled to be 60% in step (3), and no heating is performed before electroselection.

[0147] The mass fraction of Nb2O5 in the niobium material obtained in this comparative example is 62.39%; the mass fraction of carbon in the flotation concentrate obtained in this embodiment is 73.22% after washing, filter pressing and drying; the titanium grade of the electrostatic concentrate obtained in this embodiment is 57.48%; the mass fraction of silicon dioxide in the electrostatic tailings obtained in this embodiment is 59.30%.

[0148] The products obtained in this comparative example have low carbon content, low titanium grade and low silicon powder content.

[0149] Comparative Example 3

[0150] The method for recovering niobium from chlorinated waste slag provided in this comparative example is basically the same as that in Example 1, except that hydrofluoric acid is not added in step (2).

[0151] The mass fraction of Nb2O5 in the niobium material obtained in this comparative example is 45.16%; the mass fraction of carbon in the flotation concentrate obtained in this embodiment is 71.37% after washing, filter pressing and drying; the titanium grade of the electrostatic concentrate obtained in this embodiment is 84.23%; the mass fraction of silicon dioxide in the electrostatic tailings obtained in this embodiment is 75.54%.

[0152] The products obtained in this comparative example have low carbon content, low titanium grade and low silicon powder content.

[0153] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for recovering niobium from chlorinated waste residue, characterized in that: The steps include: After the chlorinated waste residue is mixed with the acid solution and leached, the solid and liquid are separated to obtain a niobium-containing filtrate and leached residue; After the niobium-containing filtrate is mixed with hydrofluoric acid, an extractant is added thereto for extraction to obtain an extract; a stripping agent is added to the extract for stripping to obtain a stripping solution; the pH of the stripping solution is adjusted to allow niobium to precipitate, and then solid-liquid separation is performed to obtain a filter residue; After the filter residue is roasted, a niobium material whose main component includes niobium pentoxide is obtained; The leached residue is mixed with water to obtain a slurry, and then flotation is performed to obtain a flotation tailing and a flotation concentrate whose main component includes coke powder; the flotation tailing is heated and then electrostatically separated to obtain an electrostatic concentrate whose main component includes high-titanium concentrate and an electrostatic tailing whose main component includes silicon dioxide.

2. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: At least one of the following conditions is met: (1) The acid solution includes at least one of a sulfuric acid solution and a hydrochloric acid solution; (2) The mass fraction of the acid solution is 20% to 35%; (3) The leaching temperature is 20 to 45° C.; (4) The leaching time is 3 to 6 hours; (5) The ratio of the mass of the chlorinated waste residue to the volume of the acid solution is 1 kg: 2 to 4 L.

3. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: At least one of the following conditions is met: (1) The volume ratio of the niobium-containing filtrate to the hydrofluoric acid is 3 to 6:1, and the mass fraction of the hydrofluoric acid is 30% to 50%; (2) the extractant comprises at least one of tributyl phosphate and N,N-bis(1-methylheptyl)acetamide; (3) the ratio of the volume of the extractant to the sum of the volumes of the niobium-containing filtrate and the hydrofluoric acid is 1 to 1.5:1; (4) The extraction time is 3 to 8 minutes.

4. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: At least one of the following conditions is met: (1) The stripping agent includes at least one of sodium hydroxide solution and ammonia water; (2) the volume ratio of the stripping agent to the extract is 1 to 1.5:1; (3) The stripping time is 3 to 8 minutes.

5. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: The step of adjusting the pH of the stripping solution to 7 to 9; And / or, the sedimentation time of the niobium is 1 to 4 hours.

6. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: The calcination temperature is 750-950° C., and / or the calcination time is 2-5 hours.

7. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: At least one of the following conditions is met: (1) The mass fraction of the leached residue in the slurry is 20% to 35%; (2) The frother used in the flotation comprises pine oil, and the ratio of the mass of the frother to the mass of the leached residue is 400-800 g:1 t; (3) The collector used for flotation includes diesel, and the ratio of the mass of the collector to the mass of the leached residue is 800-1200 g:1 t.

8. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: At least one of the following conditions is met: (1) The heating temperature is 105 to 150° C.; (2) The voltage of the electric separation is 15 to 25 kV; (3) The rotation speed of the roller of the electrostatic separation equipment used in the electrostatic separation is 150 to 250 r / min.

9. The method for recovering niobium from chlorinated waste residue according to claim 1, characterized in that: At least one of the following conditions is met: (1) The mass fraction of niobium pentoxide in the niobium material is ≥ 80%; (2) the mass fraction of carbon in the flotation concentrate is ≥ 75%; (3) The titanium content of the electrolytically separated ore is ≥ 85%; (4) The mass fraction of the silicon dioxide in the electrolytic separation tailings is ≥75%.

10. Use of the method for recovering niobium from chlorinated waste residue according to any one of claims 1 to 9 in the production of titanium dioxide.

Images