Method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid

Abstract

The invention provides a method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid, and belongs to the technical field of clean energy and environment-friendly recovery. The titanium element and the high-purity hydrochloric acid in the waste acid are extracted and recycled through the composite extraction agent, the extraction effect is greatly improved by optimizing the types of the extraction agent and the stabilizer in the composite extraction agent, and the number of stages of extraction is reduced; after raffinate obtained after single-stage extraction is subjected to reverse extraction through a soluble alkali solution and / or a soluble salt solution, a water phase is subjected to simple filter pressing, a carbon dioxide recycled material and high-quality hydrochloric acid can be obtained, and the extraction rate of Ti in the titanium-containing waste hydrochloric acid is gt; the HCl recovery rate is gt; and 98%. According to the technology, comprehensive resource utilization of the titanium-containing waste acid generated in the process of producing titanium dioxide through a chlorination method is achieved, the comprehensive recovery value of the titanium-containing waste hydrochloric acid is increased through high-yield recovery of the titanium element and hydrogen chloride, environmental pollution and resource waste are effectively reduced, and remarkable economic and ecological environment benefits are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of clean energy and environmental protection recycling, and particularly to a method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid. Background Art

[0002] Titanium-containing waste hydrochloric acid mainly comes from the waste acid generated in the process of producing titanium dioxide by the chlorination method, mainly from the following aspects: (1) Chlorination reaction: In the chlorination process, rutile or high-titanium slag and other titanium-rich raw materials react with chlorine at high temperature to generate titanium tetrachloride. In this process, although titanium tetrachloride is mainly generated, a small amount of unreacted hydrogen chloride gas will also be generated, and these gases dissolve in the subsequent treatment medium to form waste acid.

[0003] (2) By-product treatment: In the refining process of titanium tetrachloride, in order to remove impurities, acidic solutions are usually used for washing, and the wastewater generated in these washing processes contains a high acidity and is also regarded as waste acid.

[0004] (3) Equipment cleaning: During the daily maintenance and cleaning of production equipment, acidic solutions are used for cleaning, and these cleaning waste liquids also constitute a part of the waste acid.

[0005] In summary, the waste acid generated in the process of producing titanium dioxide by the chlorination method mainly comes from the by-products of the chlorination reaction, the washing wastewater in the by-product treatment process, and the equipment cleaning waste liquid. There is currently no mature treatment process for these waste acids. Most of them are simply neutralized and discharged or sold at a low price. The titanium resources in the waste liquid become waste residues, and the hydrochloric acid cannot reflect its value, wasting a large amount of resources, being unfavorable for sustainable development, and at the same time being prone to causing land pollution and generating environmental burdens.

[0006] How to effectively separate and recover waste acid and valuable metal titanium, explore new, more efficient, environmentally friendly and economical separation technologies, so as to improve production efficiency and product quality, while reducing costs and environmental impacts, and realizing resource recycling has important resource value significance and environmental significance. The existing technology CN103773962B discloses a method for recovering titanium from waste hydrochloric acid generated in the production of titanium dioxide by the chlorination method. However, this method not only has many extraction and back-extraction stages, a cumbersome process, and high recovery requirements, but also can only recover a small part of the titanium in the waste acid, still causing relatively large waste. Therefore, there is an urgent need to provide a method with a simple recovery process and high recovery rates of titanium and hydrochloric acid. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid. The recovery process provided by the present invention is simple and has high recovery rates of titanium and hydrochloric acid.

[0008] To achieve the above-mentioned invention object, the present invention provides the following technical solutions: The present invention provides a method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid, comprising the following steps: (1) Mix a composite extractant with the titanium-containing waste hydrochloric acid for single-stage extraction, and then separate to obtain high-quality hydrochloric acid and an organic phase loaded with titanium; (2) Mix the organic phase loaded with titanium obtained in step (1) with a stripping agent for single-stage stripping, and then separate to obtain an organic phase and an aqueous phase loaded with titanium. Finally, perform solid-liquid separation on the aqueous phase loaded with titanium to obtain a carbon dioxide recovery product; In step (1), the composite extractant includes an extractant, an improver, and a diluent; the extractant includes any one or more of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902; the improver includes any one or more of TBP, sec-octanol, and isoamyl alcohol; In step (2), the stripping agent is a soluble alkali solution and / or a soluble salt solution.

[0009] Preferably, in step (1), the concentration of hydrogen chloride in the titanium-containing waste hydrochloric acid is ≤ 38 wt.%, and the titanium content in the titanium-containing waste hydrochloric acid is 5 ppm to 15 wt.%.

[0010] Preferably, in step (1), the extractant is any two of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902, and the mass ratio of any two extractants is (1 to 3):(1 to 3).

[0011] Preferably, in step (1), the diluent includes any one or more of 206# kerosene, 260# kerosene, and solvent white oil.

[0012] Preferably, in step (1), the volume ratio of the extractant to the improver is (1 to 5):1; the volume ratio of the extractant to the diluent is 1:(3 to 10).

[0013] Preferably, in step (1), the volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid is 1:(2 to 5).

[0014] Preferably, in step (2), the soluble alkali solution includes any one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water; the mass concentration of the soluble alkali solution is 5 to 20%.

[0015] Preferably, in step (2), the soluble salt solution includes any one or more of sodium carbonate solution, potassium carbonate solution, sodium chloride solution, and potassium chloride solution; the concentration of the soluble salt solution is 5 to 20%.

[0016] Preferably, in the step (2), the volume ratio of the titanium-loaded organic phase to the stripping agent is (1-5):1.

[0017] Preferably, the solid-liquid separation in the step (2) is carried out in a filter press.

[0018] The present invention provides a method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid, comprising the following steps: (1) mixing a composite extractant and titanium-containing waste hydrochloric acid, performing single-stage extraction, and then separating to obtain high-quality hydrochloric acid and a titanium-loaded organic phase; (2) mixing the titanium-loaded organic phase obtained in the step (1) with a stripping agent, performing single-stage stripping, and then separating to obtain an organic phase and a titanium-loaded aqueous phase, and finally performing solid-liquid separation on the titanium-loaded aqueous phase to obtain a carbon dioxide recovery product; the composite extractant in the step (1) comprises an extractant, an improver, and a diluent; the extractant comprises any one or more of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902; the improver comprises any one or more of TBP, sec-octanol, and isoamyl alcohol; the stripping agent in the step (2) is a soluble alkali solution and / or a soluble salt solution. The present invention uses a composite extractant to extract and recover titanium elements and high-purity hydrochloric acid from waste acid. By optimizing the types of the extractant and stabilizer in the composite extractant, not only can the extraction effect be greatly improved, but also the number of extraction stages can be reduced; after the raffinate after single-stage extraction is stripped with a soluble alkali solution and / or a soluble salt solution, the aqueous phase can obtain a carbon dioxide recovery product through simple pressure filtration, which can greatly improve the recovery rate of titanium elements, and the stripping stage is only single-stage stripping, simplifying the stripping process, and the titanium-loaded aqueous phase after stripping can obtain a carbon dioxide recovery product through simple pressure filtration, which is beneficial to the subsequent recovery of titanium elements. The impurity content in the wastewater after pressure filtration is low, which is beneficial to post-treatment, reduces environmental pollution and resource waste, and is beneficial to the sustainable development strategy. The results of the examples show that the method provided by the present invention has a Ti extraction rate of more than 99% and an HCl recovery rate of more than 98% for titanium-containing waste hydrochloric acid. Description of the Drawings

[0019] Figure 1 It is a flow chart of the method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid provided by the present invention. Detailed Embodiments

[0020] The present invention provides a method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid, comprising the following steps: (1) Mixing a composite extractant and titanium-containing waste hydrochloric acid, performing single-stage extraction, and then separating to obtain high-quality hydrochloric acid and a titanium-loaded organic phase; (2) Mix the titanium-loaded organic phase obtained in step (1) with the stripping agent for single-stage stripping, then separate to obtain the organic phase and the titanium-loaded aqueous phase, and finally perform solid-liquid separation on the titanium-loaded aqueous phase to obtain the carbon dioxide recovery product; In step (1), the composite extractant includes an extractant, an improver, and a diluent; the extractant includes any one or more of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902; the improver includes any one or more of TBP, sec-octanol, and isoamyl alcohol; In step (2), the stripping agent is a soluble alkali solution and / or a soluble salt solution.

[0021] In the present invention, the composite extractant is mixed with the titanium-containing waste hydrochloric acid for single-stage extraction, and then separated to obtain high-quality hydrochloric acid and the titanium-loaded organic phase.

[0022] In the present invention, the extractant includes any one or more of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902, and more preferably any two of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902. In the present invention, when the extractant is any two of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902, the mass ratio of the any two extractants is preferably (1-3):(1-3). As an embodiment of the present invention, the extractant is P204 and P507, and the mass ratio of P204 and P507 can be 1:1; the extractant is P204 and N235, and the mass ratio of P204 and N235 can be 1:1. By using the above extractant for subsequent extraction in the present invention, the extraction efficiency can be improved, and other components in the titanium-containing waste hydrochloric acid can be extracted as much as possible, so as to obtain high-quality hydrochloric acid.

[0023] In the present invention, the improver includes any one or more of TBP, sec-octanol, and isoamyl alcohol. In the present invention, the improver can improve the extraction effect of the extractant, thereby further improving the quality of hydrochloric acid.

[0024] In the present invention, the diluent preferably includes any one or more of 206# kerosene, 260# kerosene, and solvent white oil. In the present invention, the diluent is used to provide the organic phase, so that the extractant loaded with titanium elements after extraction is dispersed in the organic phase, which is convenient for subsequent separation from high-quality hydrochloric acid.

[0025] The present invention does not have special limitations on the specific sources of the extractant, improver, and diluent, and commercially available products well-known to those skilled in the art can be used.

[0026] In the present invention, the volume ratio of the extractant to the improver is preferably (1 - 5):1. As an embodiment of the present invention, the volume ratio of the extractant to the improver can be 1:1, 2:1, 3:1, 4:1, or 5:1. By controlling the volume ratio of the extractant to the improver, the extraction effect can be further improved.

[0027] In the present invention, the volume ratio of the extractant to the diluent is preferably 1:(3 - 10). As an embodiment of the present invention, the volume ratio of the extractant to the diluent can be 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10. By controlling the volume ratio of the extractant to the diluent, it can be ensured that the extractant and titanium-containing components are distributed in the diluent, and the extraction efficiency can be further improved.

[0028] In the present invention, the preparation method of the composite extractant is preferably: first mix the extractant and the improver, and then add the diluent and stir to mix to obtain the composite extractant. The present invention does not have special limitations on the stirring and mixing rate, which is determined according to the common technical knowledge of those skilled in the art, as long as splashing of the solution is avoided. The present invention does not have special limitations on the stirring and mixing time, and it is sufficient to make each component mix evenly. As an embodiment of the present invention, the stirring and mixing time can be 20 - 60 min, and can also be 30 - 40 min.

[0029] In the present invention, the mixing of the extractant, improver, and diluent is preferably carried out in an extraction tank. The present invention does not have special limitations on the specific model and source of the extraction tank, and commercially available extraction tanks well-known to those skilled in the art can be used. By carrying out the mixing in the extraction tank, subsequent single-stage extraction is facilitated.

[0030] In the present invention, the titanium-containing waste hydrochloric acid preferably includes any one or more of the waste hydrochloric acid collected during the production process of chloride process titanium dioxide, the titanium-containing waste hydrochloric acid in the metallurgical process, and the titanium-containing waste hydrochloric acid in the disposal of solid hazardous waste. In the present invention, the concentration of hydrogen chloride in the titanium-containing waste hydrochloric acid is preferably ≤ 38 wt.%; the titanium content in the titanium-containing waste hydrochloric acid is preferably 5 ppm - 15 wt.%.

[0031] In the present invention, the volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid is preferably 1:(2 - 5). As an embodiment of the present invention, the volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid can be 1:(3 - 4). By controlling the volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid, the present invention can ensure that the composite extractant extracts the titanium element and other impurities in the titanium-containing waste hydrochloric acid, thereby improving the quality of hydrochloric acid.

[0032] In the present invention, the single-stage extraction is preferably carried out under stirring conditions; the stirring time is preferably 5 - 30 min; the temperature of the single-stage extraction is preferably room temperature. As an embodiment of the present invention, the stirring time can be 5 min, 10 min, 15 min, 20 min, 25 min or 30 min. The present invention has no special limitation on the stirring rate, which is determined according to the common technical knowledge of those skilled in the art as long as it can avoid splashing of the solution. By stirring during the extraction process, the present invention can ensure sufficient mixing of the composite extractant and the titanium-containing waste hydrochloric acid, further improving the extraction efficiency.

[0033] The present invention preferably further includes allowing the product of the single-stage extraction to stand still and then separating.

[0034] In the present invention, the standing time is preferably 20 - 50 min. As an embodiment of the present invention, the standing time can be 20 min, 25 min, 30 min, 35 min, 40 min, 45 min or 50 min. By standing still, the present invention can separate the organic phase and the aqueous phase into upper and lower layers, facilitating subsequent separation.

[0035] The present invention has no special limitation on the specific separation method as long as it can separate the organic phase and the aqueous phase. As an embodiment of the present invention, the separation preferably involves discharging the high-quality hydrochloric acid through the bottom of the extraction tank into the hydrochloric acid tank, and pumping the titanium-loaded organic phase into the stripping tank.

[0036] After obtaining the high-quality hydrochloric acid and the titanium-loaded organic phase, the present invention mixes the titanium-loaded organic phase and the stripping agent for stripping, then separates to obtain the organic phase and the titanium-loaded aqueous phase, and finally performs solid-liquid separation on the titanium-loaded aqueous phase to obtain the carbon dioxide recovery product.

[0037] In the present invention, the stripping agent is a soluble alkali solution and / or a soluble salt solution. In the present invention, the soluble alkali solution preferably includes any one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia solution; the mass concentration of the soluble alkali solution is preferably 5-20%. In the present invention, the soluble salt solution preferably includes any one or more of sodium carbonate solution, potassium carbonate solution, sodium chloride solution, and potassium chloride solution; the concentration of the soluble salt solution is preferably 5-20%. In the present invention, when the stripping agent is a soluble alkali solution and a soluble salt solution, the soluble alkali solution and the soluble salt solution are preferably mixed in any proportion; the total mass concentration of the soluble alkali and soluble salt in the soluble alkali solution and the soluble salt solution is preferably 5-20%. As one embodiment of the present invention, the mass concentration of the soluble alkali solution can be 5%, 8%, 10%, 12%, 15%, 18%, or 20%; the mass concentration of the soluble salt solution can be 5%, 8%, 10%, 12%, 15%, 18%, or 20%; and the total mass concentration of the soluble alkali and soluble salt in the soluble alkali solution and the soluble salt solution can be 5%, 8%, 10%, 12%, 15%, 18%, or 20%. By using the above-mentioned stripping agent, the present invention can improve the stripping effect and thereby increase the recovery rate of titanium.

[0038] The present invention has no particular limitation on the specific source of the stripping agent, and commercially available products well known to those skilled in the art may be used.

[0039] In the present invention, the volume ratio of the titanium-loaded organic phase to the stripping agent is preferably (1-5):1. As one embodiment of the present invention, the volume ratio of the titanium-loaded organic phase to the stripping agent can be 1:1, 2:1, 3:1, 4:1, or 5:1. By controlling the dosage of the stripping agent, the present invention ensures that the stripping agent strips titanium-containing components and the like from the organic phase, facilitating subsequent titanium recovery. Furthermore, the stripped organic phase can be reused for the extraction of titanium-containing waste hydrochloric acid, avoiding the generation of waste liquid and improving the environmental friendliness of the process.

[0040] In the present invention, the single-stage stripping is preferably carried out under stirring; the stirring time is preferably 5 to 30 minutes; and the temperature of the single-stage stripping is preferably room temperature. As an embodiment of the present invention, the stirring time can be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes. The present invention does not have any particular limitation on the stirring rate, and it can be determined according to the technical common sense of those skilled in the art as long as it can avoid splashing of the solution. By stirring during the stripping process, the present invention can ensure that the titanium-loaded organic phase and the stripping agent are fully mixed, thereby further improving the stripping efficiency.

[0041] In the present invention, the single-stage stripping is preferably carried out in a stripping tank. The present invention has no special limitation on the specific model and source of the stripping tank, and a commercially available stripping tank well-known to those skilled in the art can be used.

[0042] The present invention preferably further includes allowing the product of the single-stage stripping to stand, and then separating to obtain an organic phase and a titanium-loaded aqueous phase.

[0043] In the present invention, the standing time is preferably 20 to 50 min. As an embodiment of the present invention, the standing time can be 20 min, 25 min, 30 min, 35 min, 40 min, 45 min or 50 min. By standing in the present invention, the organic phase and the titanium-loaded aqueous phase can be separated into upper and lower layers, facilitating subsequent separation.

[0044] The present invention has no special limitation on the specific separation method, as long as the organic phase and the titanium-loaded aqueous phase can be separated. As an embodiment of the present invention, the separation is preferably pumping the organic phase to the extraction tank for recycling as a composite extractant, and pumping the titanium-loaded aqueous phase to a filter press.

[0045] In the present invention, the solid-liquid separation is preferably carried out in a filter press. The present invention has no special limitation on the specific model and source of the filter press, and a commercially available filter press well-known to those skilled in the art can be used. The present invention has no special limitation on the specific operation of the solid-liquid separation, and filter press separation can be carried out according to the common technical knowledge of those skilled in the art.

[0046] The flow chart of the method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid provided by the present invention is as Figure 1 shown. It can be Figure 1 seen that in the present invention, a composite extractant is used to extract and recover titanium elements and high-purity hydrochloric acid from waste acid. By optimizing the types of extractants and stabilizers in the composite extractant, not only can the extraction effect be greatly improved, but also the number of extraction stages can be reduced; after the raffinate after single-stage extraction is stripped with a soluble alkali solution and / or a soluble salt solution, the carbon dioxide recovery can be obtained by simple filter pressing of the aqueous phase, which can greatly improve the recovery rate of titanium elements. At the same time, the stripping stage is only single-stage stripping, which simplifies the stripping process, and the titanium-loaded aqueous phase after stripping can obtain the carbon dioxide recovery by simple filter pressing, which is beneficial to the subsequent recovery of titanium elements. The impurities in the wastewater after filter pressing are low in content, which is beneficial to post-treatment, reduces environmental pollution and resource waste, and is beneficial to the sustainable development strategy.

[0047] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Example 1 A method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid comprises the following steps: (1) First, put the extractant into the extraction tank, then add the improver, and then add the diluent and stir for 30 min to obtain a composite extractant; the extractant is a mixture of P204 and P507, the mass ratio of P204 to P507 is 1:1, the improver is sec-octanol, the diluent is 260# kerosene, the volume ratio of the extractant to the improver is 2:1, and the volume ratio of the extractant to the diluent is 1:5; (2) Mix the composite extractant obtained in step (1) with the titanium-containing waste hydrochloric acid and perform single-stage extraction at room temperature, stir for 15 min, then let it stand for 30 min, and then discharge the high-quality hydrochloric acid to the hydrochloric acid tank through the bottom of the extraction tank, and pump the titanium-loaded organic phase to the stripping tank to obtain high-quality hydrochloric acid and the titanium-loaded organic phase; the titanium-containing waste hydrochloric acid is the waste hydrochloric acid collected during the production of titanium dioxide by the chlorination method, the concentration of hydrogen chloride in the titanium-containing waste hydrochloric acid is 29.57 wt.%, and the titanium content is 0.44 wt.%; the volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid is 1:3; (3) Mix the titanium-loaded organic phase obtained in step (2) with the stripping agent in the stripping tank and perform single-stage stripping at room temperature, stir for 15 min, then let it stand for 30 min to obtain the organic phase and the titanium-loaded aqueous phase, then pump the organic phase to the extraction tank for recycling as the composite extractant, pump the titanium-loaded aqueous phase to the filter press, and finally perform solid-liquid separation on the titanium-loaded aqueous phase to obtain the carbon dioxide recovery; the stripping agent is a sodium hydroxide solution, and the mass concentration of the sodium hydroxide solution is 10%; the volume ratio of the titanium-loaded organic phase to the stripping agent is 2:1.

[0049] Example 2 A method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid comprises the following steps: (1) First, put the extractant into the extraction tank, then add the improver, and then add the diluent and stir for 30 min to obtain a composite extractant; the extractant is a mixture of P204 and N235, the mass ratio of P204 to N235 is 1:1, the improver is TBP, the diluent is 260# kerosene, the volume ratio of the extractant to the improver is 2:1, and the volume ratio of the extractant to the diluent is 1:5; (2) Mix the composite extractant obtained in step (1) with the titanium-containing waste hydrochloric acid, and perform single-stage extraction at room temperature. Stir for 15 min, then let it stand for 30 min. Then, discharge the high-quality hydrochloric acid through the bottom of the extraction tank into the hydrochloric acid tank, and pump the organic phase loaded with titanium into the stripping tank to obtain high-quality hydrochloric acid and the organic phase loaded with titanium. The titanium-containing waste hydrochloric acid is the waste hydrochloric acid collected during the production process of chloride process titanium dioxide. The concentration of hydrogen chloride in the titanium-containing waste hydrochloric acid is 25.57 wt.%, and the titanium content is 0.94 wt.%. The volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid is 1:3. (3) Mix the organic phase loaded with titanium obtained in step (2) with the stripping agent in the stripping tank, and perform single-stage stripping at room temperature. Stir for 15 min, then let it stand for 30 min to obtain the organic phase and the aqueous phase loaded with titanium. Then, pump the organic phase into the extraction tank for recycling as the composite extractant, pump the aqueous phase loaded with titanium into the filter press, and finally perform solid-liquid separation on the aqueous phase loaded with titanium to obtain the carbon dioxide recovery product. The stripping agent is a potassium hydroxide solution, and the mass concentration of the potassium hydroxide solution is 15%. The volume ratio of the organic phase loaded with titanium to the stripping agent is 2:1.

[0050] Example 3 A method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid, comprising the following steps: (1) First, put the extractant into the extraction tank, then add the improver, and then add the diluent and stir for 30 min to obtain the composite extractant. The extractant is a mixture of P204 and P507, the mass ratio of P204 to N235 is 1:1, the improver is TBP, the diluent is 206# kerosene, the volume ratio of the extractant to the improver is 2:1, and the volume ratio of the extractant to the diluent is 1:5. (2) Mix the composite extractant obtained in step (1) with the titanium-containing waste hydrochloric acid, and perform single-stage extraction at room temperature. Stir for 15 min, then let it stand for 30 min. Then, discharge the high-quality hydrochloric acid through the bottom of the extraction tank into the hydrochloric acid tank, and pump the organic phase loaded with titanium into the stripping tank to obtain high-quality hydrochloric acid and the organic phase loaded with titanium. The titanium-containing waste hydrochloric acid is the waste hydrochloric acid collected during the production process of chloride process titanium dioxide. The concentration of hydrogen chloride in the titanium-containing waste hydrochloric acid is 22.57 wt.%, and the titanium content is 0.74 wt.%. The volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid is 1:3. (3) Mix the titanium-loaded organic phase obtained in the step (2) with the stripping agent in a stripping tank and perform single-stage stripping at room temperature. Stir for 15 min, then let it stand for 30 min to obtain an organic phase and a titanium-loaded aqueous phase. Then pump the organic phase to the extraction tank for recycling as a composite extractant, pump the titanium-loaded aqueous phase to a filter press, and finally perform solid-liquid separation on the titanium-loaded aqueous phase to obtain a carbon dioxide recovery product; the stripping agent is ammonia water, and the mass concentration of ammonia water is 12%; the volume ratio of the titanium-loaded organic phase to the stripping agent is 2:1.

[0051] Detect the extraction rate of titanium and the recovery rate of hydrochloric acid in Examples 1 to 3, and the results are shown in Table 1: Table 1 Extraction rate of titanium and recovery rate of hydrochloric acid in Examples 1 to 3

[0052] In Table 1, ∑Ti before extraction is the titanium content in the titanium-containing waste hydrochloric acid; ∑Ti after extraction is the titanium content in the high-quality hydrochloric acid; HCl before extraction is the HCl content in the titanium-containing waste hydrochloric acid; HCl after extraction is the HCl content in the high-quality hydrochloric acid.

[0053] It can be seen from Table 1 that by using the method provided by the present invention to treat the titanium-containing waste hydrochloric acid, the recovery rates of hydrochloric acid and titanium elements in the titanium-containing waste hydrochloric acid can be greatly improved. Among them, the Ti extraction rate reaches more than 99%, and the HCl recovery rate reaches more than 98%.

[0054] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for recovering titanium and high-quality hydrochloric acid from titanium-containing waste hydrochloric acid, characterized in that, It includes the following steps: (1) Mix the composite extractant with the titanium-containing waste hydrochloric acid and perform single-stage extraction, and then separate to obtain high-quality hydrochloric acid and the organic phase loaded with titanium; (2) Mix the organic phase loaded with titanium obtained in the step (1) with the stripping agent and perform single-stage stripping, and then separate to obtain the organic phase and the aqueous phase loaded with titanium. Finally, perform solid-liquid separation on the aqueous phase loaded with titanium to obtain the carbon dioxide recovery product; In the step (1), the composite extractant includes an extractant, an improver, and a diluent; the extractant includes any one or more of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902; the improver includes any one or more of TBP, sec-octanol, and isoamyl alcohol; In the step (2), the stripping agent is a soluble alkali solution and / or a soluble salt solution.

2. The method according to claim 1, wherein In the step (1), the concentration of hydrogen chloride in the titanium-containing waste hydrochloric acid is ≤ 38 wt.%, and the titanium content in the titanium-containing waste hydrochloric acid is 5 ppm to 15 wt.%.

3. The method according to claim 1, characterized in that In the step (1), the extractant is any two of P204, P507, N1923, N263, N235, LK-N21, MIBK, and C902, and the mass ratio of any two extractants is (1~3):(1~3).

4. The method according to claim 1, characterized in that, In the step (1), the diluent includes any one or more of 206# kerosene, 260# kerosene, and solvent white oil.

5. The method according to claim 1, characterized in that In the step (1), the volume ratio of the extractant to the improver is (1~5):1; the volume ratio of the extractant to the diluent is 1:(3~10).

6. The method according to claim 1, wherein In the step (1), the volume ratio of the composite extractant to the titanium-containing waste hydrochloric acid is 1:(2~5).

7. The method according to claim 1, characterized in that In the step (2), the soluble alkali solution includes any one or more of sodium hydroxide solution, potassium hydroxide solution, and ammonia water; the mass concentration of the soluble alkali solution is 5~20%.

8. The method according to claim 1, wherein In the step (2), the soluble salt solution includes any one or more of sodium carbonate solution, potassium carbonate solution, sodium chloride solution, and potassium chloride solution; the concentration of the soluble salt solution is 5~20%.

9. The method according to claim 1, wherein In the step (2), the volume ratio of the organic phase loaded with titanium to the stripping agent is (1~5):

1.

10. The method according to claim 1, characterized in that, In the step (2), the solid-liquid separation is carried out in a filter press.

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