A method for resource utilization of acidolysis waste residue of titanium dioxide by sulfuric acid process

Abstract

The present invention provides a method for the resource utilization of acidolysis waste residue of sulfuric acid process titanium dioxide, belonging to the technical field of solid waste resource utilization. The acidolysis waste residue of sulfuric acid process titanium dioxide is subjected to classification to remove the coarse particle charcoal impurities mixed in during the production process. After classification and impurity removal, the acidolysis waste residue of sulfuric acid process titanium dioxide is subjected to strong magnetic rough separation by a high-gradient magnetic separator to recover ilmenite therein, obtaining strong magnetic rough concentrate and strong magnetic rough tailings; the strong magnetic rough concentrate is further subjected to high-gradient strong magnetic cleaning to obtain titanium concentrate and strong magnetic cleaning tailings; the strong magnetic rough tailings are subjected to high-gradient strong magnetic scavenging to obtain strong magnetic scavenging concentrate and magnetic separation tailings; the strong magnetic cleaning tailings and the strong magnetic scavenging concentrate are combined as middlings and returned to the strong magnetic rough separation for re-selection; the magnetic separation tailings are pretreated by roasting and water washing to remove impurities such as organic matter and carbonaceous substances therein; the ore after roasting and water washing pretreatment for impurity removal is subjected to alkali leaching under mild conditions to obtain high-purity water glass and alkali leaching residue respectively; the high-purity water glass solution can be further adjusted by pH to obtain high-purity silica in the form of precipitation method; the alkali leaching residue is separated and purified by flotation or gravity separation to obtain rutile concentrate and silicate tailings, and the obtained silicate tailings have less impurity content and can be used as raw materials for preparing building materials such as cement. The present invention realizes the full resource high-efficiency comprehensive utilization of the acidolysis waste residue of sulfuric acid process titanium dioxide, is beneficial to avoiding waste of resources, and can produce important economic and environmental benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste resource utilization, and particularly to a method for resource utilization of acidolysis waste residue in sulfuric acid process titanium dioxide production. Background Art

[0002] The sulfuric acid process has relatively low requirements for titanium raw materials and can use cheap and easily available ilmenite as raw material, which leads to the generation of a large amount of acidolysis waste residue in the production process of titanium dioxide. It is statistically shown that for every 1t of titanium dioxide produced, 0.3 - 0.6t of acidolysis waste residue of titanium dioxide will be generated. There is still some ilmenite in the acidolysis waste residue that has not participated in the acidolysis reaction and is finally stacked together with the sludge, which not only causes a large waste of valuable resources such as titanium but also has a serious impact on the surrounding ecological environment, resulting in a large loss of titanium and other resources. Effectively maximizing the resource treatment of acidolysis waste residue, reducing solid waste emissions, and improving the recycling rate of resources have important practical significance for the resource utilization and environmental protection of acidolysis waste residue in sulfuric acid process titanium dioxide production.

[0003] Up to now, there is still no good solution to the problem of comprehensive resource utilization of acidolysis waste residue of titanium dioxide. Most enterprises stack it without use or landfill it, resulting in an increasing inventory year by year. This not only causes a large waste of valuable resources, but also because the acidolysis waste residue has strong acidity and may contain some toxic and harmful substances such as heavy metals, and a large amount of stacking will bring certain harm to the surrounding ecological environment. In view of the above situation, it is necessary to carry out research on the comprehensive recovery and utilization of acidolysis waste residue in sulfuric acid process titanium dioxide from the perspectives of economic benefits, titanium resource recovery and utilization, and environmental protection. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for resource utilization of acidolysis waste residue in sulfuric acid process titanium dioxide, so as to solve the technical problem that the stacking of a large amount of acidolysis waste residue causes waste of resources and environmental pollution and cannot be treated.

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

[0006] The present invention provides a method for resource utilization of acidolysis waste residue in sulfuric acid process titanium dioxide, including the following steps:

[0007] (1) The acidolysis waste residue in sulfuric acid process titanium dioxide is classified to remove the coarse particle impurities mixed in the production process;

[0008] (2) The acidolysis waste residue in sulfuric acid process titanium dioxide after removing coarse particle impurities is subjected to wet high-intensity magnetic rough separation to obtain high-intensity magnetic rough concentrate and high-intensity magnetic rough tailings;

[0009] (3) The high-intensity magnetic rough concentrate is subjected to high-gradient high-intensity magnetic separation to obtain titanium concentrate and high-intensity magnetic separation tailings;

[0010] (4) The tailings from the rough high-intensity magnetic separation are subjected to high-gradient high-intensity magnetic scavenging to obtain high-intensity magnetic scavenging concentrate and magnetic separation tailings;

[0011] (5) The tailings from the high-intensity magnetic cleaning and the high-intensity magnetic scavenging concentrate are combined as middlings and returned to step (2) for re-selection;

[0012] (5) The magnetic separation tailings are sequentially roasted and washed with water to remove the organic matter and carbonaceous impurities therein;

[0013] (6) The magnetic separation tailings after roasting and washing for impurity removal are selectively leached with alkali under mild conditions below the boiling point of the solution to leach out the active silica therein, and after solid-liquid separation, a high-purity water glass solution and alkali leaching residue are obtained;

[0014] (7) The pH of the high-purity water glass solution is adjusted to obtain high-purity silica by precipitation;

[0015] (8) The alkali leaching residue is separated and purified by flotation or gravity separation to obtain rutile concentrate and silicate tailings;

[0016] (9) The alkali leaching residue is separated and purified by flotation or gravity separation to obtain rutile concentrate and silicate tailings.

[0017] Further, in the step (1), the classification size can be controlled to be 0.074 - 8 mm according to the impurities mixed in, and the classification method is screening classification or hydraulic classification.

[0018] Further, the magnetic field intensity of the wet high-intensity magnetic roughing is 0.2 - 1.8 T.

[0019] Further, the magnetic field intensity of the high-gradient high-intensity magnetic cleaning is 0.2 - 1.8 T.

[0020] Further, the magnetic field intensity of the high-gradient high-intensity magnetic scavenging is 0.2 - 1.8 T.

[0021] Further, the roasting temperature is 300 - 800 °C, and the roasting time is 0.5 - 2 h.

[0022] Further, the alkali leaching solution used for alkali leaching is sodium hydroxide solution and / or potassium hydroxide solution, and the concentration of the alkali leaching solution is 1 - 4 mol / L.

[0023] Further, the alkali leaching temperature is 10 - 100 °C, the alkali leaching time is 10 - 180 min, the liquid-solid ratio is 1 - 5, and after alkali leaching is completed, solid-liquid separation can be carried out by filtration or centrifugal separation.

[0024] Further, in the step (8), the pH adjustment is carried out by adding acid or by carbonation with CO2. The addition of acid for adjustment is one or several of sulfuric acid, hydrochloric acid or nitric acid, and the pH of the solution is adjusted to 8 - 12.

[0025] Further, the flotation of the alkali leaching residue is positive flotation or reverse flotation of rutile. The reagents used in the positive flotation are activator, inhibitor, collector and frother; the reagents used in the reverse flotation are inhibitor, collector and frother.

[0026] Further, the gravity separation is table separation, spiral chute separation or centrifugal separation.

[0027] Advantages of the present invention:

[0028] 1. The present invention transforms the traditional waste residue treatment method into a new way of resource utilization. Through the unique treatment of the acid hydrolysis waste residue of sulfuric acid process titanium dioxide, the valuable components contained therein are effectively extracted, realizing the full resource utilization of the waste residue, and avoiding the environmental pollution and resource waste problems caused by the stacking of the acid hydrolysis waste residue of sulfuric acid process titanium dioxide.

[0029] 2. While realizing the resource utilization of the waste residue, the present invention can also effectively reduce the production cost. By effectively utilizing the valuable components in the waste residue, the economic expenditure in the production process is reduced.

[0030] 3. The present invention has a positive significance for environmental protection. The traditional waste residue treatment method may cause environmental pollution and ecological damage, while the present invention transforms the waste residue into utilizable resources, reducing the negative impact on the environment, which conforms to the concept of sustainable development.

[0031] 4. The present invention helps to promote the technological innovation and progress of related industries. By continuously improving and optimizing the waste residue treatment technology, the efficiency and feasibility of waste residue resource utilization can be improved, promoting the related industries to develop towards a cleaner and more efficient direction and promoting the upgrading of the entire industrial chain.

[0032] 5. The present invention effectively comprehensively recovers components such as titanium and silicon in the acid hydrolysis waste residue of sulfuric acid process titanium dioxide, and realizes the high value-added of titanium and silicon based on the applicant's new discovery. No new waste residue is generated during the process, which not only has significant economic benefits, but also has a positive promoting effect on environmental protection and industrial development, and is expected to generate extensive social value and economic benefits in practice.

[0033] 6. The method for resource utilization of the acid hydrolysis waste residue of ilmenite sulfuric acid process titanium dioxide provided by the present invention has a simple process and is easy to realize batch production in large and medium-sized sulfuric acid process titanium dioxide plants.

[0034] During the research process, the applicant found that the special-structured silica contained in the acidolysis waste residue of sulfuric acid process titanium dioxide has extremely high chemical reaction activity. It can quickly react with strong alkali to form sodium silicate under relatively mild conditions. The mild reaction conditions are conducive to reducing energy consumption during the process. At the same time, the mild reaction conditions can also prevent impurities such as aluminum and titanium from reacting with the alkali and entering the solution. Therefore, high-purity water glass is finally obtained. Based on this, the pH can be further adjusted by adding acid or by carbonation with carbon dioxide, and high-purity silica can be cheaply synthesized by the precipitation method. Based on this new discovery of the applicant, the high-value comprehensive utilization of silica in the acidolysis waste residue of sulfuric acid process titanium dioxide can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is the process flow chart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present invention provides a method for resource utilization of acidolysis waste residue of sulfuric acid process titanium dioxide, which includes the following steps:

[0037] (1) The acidolysis waste residue of sulfuric acid process titanium dioxide is subjected to classification to remove the coarse particle impurities mixed in the production process;

[0038] (2) The acidolysis waste residue of sulfuric acid process titanium dioxide from which the coarse particle impurities have been removed is subjected to wet high-intensity magnetic rough separation to obtain high-intensity magnetic rough separation concentrate and high-intensity magnetic rough separation tailings;

[0039] (3) The high-intensity magnetic rough separation concentrate is subjected to high-gradient high-intensity magnetic separation to obtain titanium concentrate and high-intensity magnetic separation tailings;

[0040] (4) The high-intensity magnetic rough separation tailings are subjected to high-gradient high-intensity magnetic scavenging to obtain high-intensity magnetic scavenging concentrate and magnetic separation tailings;

[0041] (5) The high-intensity magnetic separation tailings and the high-intensity magnetic scavenging concentrate are combined as middlings and returned to step (2) for re-selection;

[0042] (6) The magnetic separation tailings are sequentially roasted and washed with water to remove the organic matter and carbonaceous impurities therein;

[0043] (7) The magnetic separation tailings after roasting and washing for impurity removal are subjected to selective leaching of silica therein under mild conditions below the boiling point of the solution. After the leaching is completed, solid-liquid separation is carried out to obtain high-purity water glass solution and alkali leaching residue;

[0044] (8) The high-purity water glass solution is adjusted to precipitate high-purity silica;

[0045] (9) The alkali leaching residue is separated and purified by flotation or gravity separation to obtain rutile concentrate and silicate tailings.

[0046] In the present invention, in the step (1), the classification size can be controlled to be 0.074 - 8 mm according to the impurities mixed in, and the classification is screening or hydraulic classification. For raw materials without coarse particles mixed in, this classification step can also be omitted.

[0047] In the present invention, the magnetic field intensity of the wet high-intensity magnetic rough separation is 0.2 - 1.8 T, preferably 0.5 - 1.5 T, more preferably 0.8 - 1.2 T, and even more preferably 1.0 T.

[0048] In the present invention, the magnetic field intensity of the high-gradient high-intensity magnetic fine separation is 0.2 - 1.8 T, preferably 0.5 - 1.5 T, more preferably 0.8 - 1.2 T, and even more preferably 1.0 T.

[0049] In the present invention, the magnetic field intensity of the high-gradient high-intensity magnetic scavenging is 0.2 - 1.8 T, preferably 0.5 - 1.5 T, more preferably 0.8 - 1.2 T, and even more preferably 1.0 T.

[0050] In the present invention, the temperature of the roasting is 300 - 800 °C, preferably 300 - 700 °C; the roasting time is 0.5 - 2 h, preferably 1 h.

[0051] In the present invention, the alkali leaching solution used for the alkali leaching is sodium hydroxide solution and / or potassium hydroxide solution, and the concentration of the alkali leaching solution is 1 - 4 mol / L, preferably 2 - 3 mol / L, and more preferably 2.5 mol / L.

[0052] In the present invention, the purposes of roasting and water washing are to remove impurities such as organic matter and carbonaceous matter therein.

[0053] In the present invention, the temperature of the alkali leaching is 10 - 100 °C, preferably 20 - 90 °C, more preferably 30 - 80 °C, and even more preferably 40 - 60 °C; the alkali leaching time is 10 - 180 min, preferably 20 - 150 min, more preferably 40 - 120 min, and even more preferably 50 - 100 min; the liquid-solid ratio is 1 - 5, preferably 3 - 4, and more preferably 4. After the alkali leaching is completed, solid-liquid separation can be carried out by filtration or centrifugation.

[0054] In the present invention, in the step (8), the pH adjustment is carried out by adding acid or by introducing CO2 carbonation adjustment. The acid addition adjustment is one or several of sulfuric acid, hydrochloric acid or nitric acid, and the pH of the solution is adjusted to 8 - 12, preferably 12.

[0055] In the present invention, the flotation of the alkali leaching residue is either positive flotation or reverse flotation of rutile. The reagents used in the positive flotation are an activator, an inhibitor, a collector, and a frother. The activator is lead nitrate, and the addition amount is 50 - 2000 g / t, preferably 50 - 200 g / t. The inhibitor is sodium hexametaphosphate, and the addition amount is 50 - 2000 g / t, preferably 50 - 200 g / t. The collector is salicylhydroxamic acid or dodecylamine dimethyl phosphonic acid, and the addition amount is 50 - 2000 g / t, preferably 50 - 100 g / t. The frother is terpineol or MIBC frother, and the addition amount is 10 - 500 g / t, preferably 50 - 400 g / t, and more preferably 100 - 200 g / t.

[0056] In the present invention, the reagents used in the reverse flotation are an inhibitor, a collector, and a frother. The inhibitor is aluminum sulfate and dextrin, and the addition amounts are 50 - 2000 g / t respectively, preferably 50 - 200 g / t. The collector is dimethyl phosphonic acid, and the addition amount is 50 - 2000 g / t, preferably 50 - 200 g / t. The frother is terpineol, and the addition amount is 10 - 500 g / t, preferably 50 - 400 g / t, and more preferably 100 - 200 g / t.

[0057] In the present invention, the gravity separation is shaking table separation, spiral chute separation or centrifugal separation, preferably inner shaking table separation.

[0058] In the present invention, the obtained silicate tailings have less impurity content and can be used as raw materials for preparing building materials such as cement.

[0059] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0060] Example 1

[0061] As Figure 1 shown, a method for resource utilization of acidolysis waste residue of sulfuric acid process titanium dioxide is as follows:

[0062] (1) Sampling an acidolysis waste residue of sulfuric acid process titanium dioxide from a certain place in Panzhihua, Sichuan. The content of Si element in this acidolysis waste residue is the highest, which is 24.39%, followed by the content of metal element Ti, which is 10.87%. The contents of Fe, Ca, Mg, Al, and Mn are relatively low, which are 7.74%, 2.66%, 1.34%, 1.20%, and 0.17% respectively. The content of heavy metal elements in this acidolysis residue is relatively low, but the content of As is relatively high, which is 0.18%. Screen the acidolysis waste residue of ilmenite sulfuric acid process titanium dioxide, the screen hole size is 0.074 mm, the product on the screen is mainly charcoal, and it is discarded. The product under the screen is slurried, and the slurry concentration is controlled at 20%.

[0063] (2) The undersize product obtained in step (1) is subjected to wet high-intensity magnetic rough separation using a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.5 T to obtain a high-intensity magnetic roughing concentrate and a high-intensity magnetic roughing tailing.

[0064] (3) The high-intensity magnetic roughing concentrate product obtained in step (2) is subjected to cleaning using a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.3 T to obtain titanium concentrate with a yield of 37.31%, a TiO2 grade of 50.39%, and a recovery rate of 87.64% and a high-intensity magnetic cleaning tailing.

[0065] (4) The high-intensity magnetic roughing tailing product obtained in step (2) is subjected to scavenging using a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.6 T to obtain a high-intensity magnetic scavenging concentrate and a scavenging tailing. And further increase the magnetic induction intensity to 1.4 T to remove magnetic and weakly magnetic impurities for subsequent processes and obtain a magnetic separation tailing; the high-intensity magnetic cleaning tailing and the high-intensity magnetic scavenging concentrate are combined as middlings and returned to the wet high-intensity magnetic roughing step;

[0066] (5) The magnetic separation tailing obtained in step (4) is calcined at 350 °C, washed with water, and then added to a reaction kettle, and a 2.5 mol / L NaOH solution is added for alkali leaching reaction. Control the liquid-solid ratio of the leaching system to 3:1, the reaction temperature to 90 °C, the reaction time to 60 min, and the stirring speed to 200 r / min. After the reaction is completed, the slag and liquid are separated to obtain a water glass solution with an Fe content of 0.008% and a water glass modulus of 2.21 and an alkali leaching residue.

[0067] (6) The water glass solution obtained in step (5) is adjusted to a pH of 12 by adding dilute sulfuric acid, and high-purity silica with a purity of 99.95% is precipitated.

[0068] (7) The alkali leaching residue obtained in step (5) is subjected to pulp flotation. First, 80 g / t lead nitrate is added as an activator, 100 g / t sodium hexametaphosphate is added as an inhibitor, then 100 g / t salicylhydroxamic acid is added as a collector, and 50 g / t MIBC is added as a foaming agent. Rutile is recovered by positive flotation to obtain a concentrate with a TiO2 grade of 46%. The flotation tailings are mainly silicate minerals and can be added to cement as building materials.

[0069] Example 2

[0070] As Figure 1 shown, a method for resource utilization of acidolysis waste residue of sulfuric acid process titanium dioxide, the specific steps are as follows:

[0071] (1) The acid hydrolysis residue of sulfuric acid process titanium dioxide sampled from Panzhihua, Sichuan. In this acid hydrolysis residue, the content of Si element is the highest, being 24.39%, followed by the content of metal element Ti which is 10.87%. The contents of Fe, Ca, Mg, Al, and Mn are relatively low, being 7.74%, 2.66%, 1.34%, 1.20%, and 0.17% respectively. The content of heavy metal elements in this acid hydrolysis residue is relatively low, but the content of As is relatively high, being 0.18%. The acid hydrolysis residue of ilmenite sulfuric acid process titanium dioxide is screened with a sieve pore size of 0.074 mm. The product on the sieve is mainly charcoal and is subjected to tailing rejection treatment. The product under the sieve is slurried, and the slurry concentration is controlled at 20%.

[0072] (2) The product under the sieve obtained in step (1) is subjected to wet high-intensity magnetic rough separation by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.5 T to obtain a strong magnetic rough separation concentrate and a strong magnetic rough separation tailing.

[0073] (3) The strong magnetic rough separation concentrate product obtained in step (2) is subjected to cleaning by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.3 T to obtain a titanium concentrate with a yield of 37.31%, a TiO2 grade of 50.39%, and a recovery rate of 87.64% and a strong magnetic cleaning tailing.

[0074] (4) The strong magnetic rough separation tailing product obtained in step (2) is subjected to scavenging by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.6 T to obtain a strong magnetic scavenging concentrate and a scavenging tailing. And the magnetic induction intensity is further increased to 1.4 T to remove the magnetic and weakly magnetic impurities therein for the subsequent process and obtain a magnetic separation tailing; the strong magnetic cleaning tailing and the strong magnetic scavenging concentrate are combined as middlings and returned to the wet high-intensity magnetic rough separation step;

[0075] (5) The magnetic separation tailing obtained in step (4) is calcined at 350 °C, washed with water, and then added to a reaction kettle. A 2.5 mol / L NaOH solution is added for alkali dissolution reaction, controlling the liquid-solid ratio of the leaching system at 3:1, the reaction temperature at 90 °C, the reaction time at 60 min, and the stirring speed at 200 r / min. After the reaction is completed, the slag-liquid separation is carried out to obtain a water glass solution with an Fe content of 0.008% and a water glass modulus of 2.21 and an alkali leaching residue.

[0076] (6) The pH of the water glass solution obtained in step (5) is adjusted to 11 by adding dilute sulfuric acid, and high-purity silica with a purity of 99.95% is precipitated.

[0077] (7) Pulp the alkali leaching residue obtained in step (5) and perform reverse flotation. First, add 50 g / t of aluminum sulfate and 50 g / t of dextrin as inhibitors for rutile, then add 150 g / t of dimethylphosphonic acid as a collector, and add 30 g / t of terpineol as a foaming agent. Recover the rutile therein by reverse flotation to obtain a concentrate with a titanium dioxide grade of 46%. The flotation tailings are mainly silicate minerals and can be added to cement as building materials.

[0078] Example 3

[0079] As Figure 1 shown, a method for resource utilization of acidolysis waste residue of sulfuric acid process titanium dioxide is as follows:

[0080] (1) Sample the acidolysis residue of sulfuric acid process titanium dioxide from a certain place in Yunnan. The content of Si element in this acidolysis waste residue is the highest, which is 23.68%. Followed by the content of metal element Ti, which is 14.66%. The contents of Fe, Ca, Mg, Al, and Mn are 9.65%, 3.21%, 2.12%, 1.37%, and 0.11% respectively. Pulp the acidolysis waste residue of ilmenite sulfuric acid process titanium dioxide directly and control the slurry concentration at 20%.

[0081] (2) Subject the undersize product obtained in step (1) to wet high-intensity magnetic roughing by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.5 T to obtain a high-intensity magnetic roughing concentrate and a high-intensity magnetic roughing tailing.

[0082] (3) Subject the high-intensity magnetic roughing concentrate product obtained in step (2) to cleaning by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.3 T to obtain a titanium concentrate with a yield of 38.85%, a TiO2 grade of 49.98%, and a recovery rate of 89.21% and a high-intensity magnetic cleaning tailing.

[0083] (4) Subject the high-intensity magnetic roughing tailing product obtained in step (2) to scavenging by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.6 T to obtain a high-intensity magnetic scavenging concentrate and a scavenging tailing. Further increase the magnetic induction intensity to 1.4 T to remove the magnetic and weakly magnetic impurities therein for the subsequent process and obtain a magnetic separation tailing; Combine the high-intensity magnetic cleaning tailing and the high-intensity magnetic scavenging concentrate as middlings and return them to the wet high-intensity magnetic roughing step;

[0084] (5) Calcinate the magnetic separation tailings obtained in step (4) at 350 °C, wash them with water, add them to a reaction kettle, add a 2.5 mol / L NaOH solution for alkali dissolution reaction, and control the liquid-solid ratio of the leaching system to be 3:1, the reaction temperature to be 90 °C, the reaction time to be 60 min, and the stirring speed to be 200 r / min. After the reaction is completed, separate the slag from the liquid to obtain a water glass solution with an Fe content of 0.002% and a water glass modulus of 2.20 and alkali leaching slag.

[0085] (6) Pass the water glass solution obtained in step (5) into CO2 gas for carbon precipitation to obtain high-purity silica with a purity of 99.97%.

[0086] (7) Perform shaking table gravity separation on the alkali leaching slag obtained in step (5) to obtain a concentrate with a titanium dioxide grade of 40%. The flotation tailings are mainly silicate minerals and can be added to cement as building materials.

[0087] Example 4

[0088] As Figure 1 shown, a method for resource utilization of acidolysis waste residue of sulfuric acid process titanium dioxide, the specific steps are as follows:

[0089] (1) Take a sample of acidolysis waste residue of sulfuric acid process titanium dioxide from Yunnan. The content of Si element in this acidolysis waste residue is the highest, which is 23.68%. Followed by the content of metal element Ti, which is 14.66%. The contents of Fe, Ca, Mg, Al, and Mn are 9.65%, 3.21%, 2.12%, 1.37%, and 0.11% respectively. Directly adjust the pulp of this ilmenite sulfuric acid process titanium dioxide acidolysis waste residue and control the pulp concentration to be 20%.

[0090] (2) Subject the undersize product obtained in step (1) to wet high-intensity magnetic rough separation by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.5 T to obtain a high-intensity magnetic rough separation concentrate and a high-intensity magnetic rough separation tailings.

[0091] (3) Subject the high-intensity magnetic rough separation concentrate product obtained in step (2) to cleaning by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.3 T to obtain a titanium concentrate with a yield of 38.85%, a TiO2 grade of 49.98%, and a recovery rate of 89.21% and a high-intensity magnetic cleaning tailings.

[0092] (4) The strong magnetic roughing tailings product obtained in step (2) is subjected to scavenging by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.6 T to obtain strong magnetic scavenging concentrate and scavenging tailings. Further increase the magnetic induction intensity to 1.4 T to remove magnetic and weakly magnetic impurities therein for preparation of subsequent processes, and obtain magnetic separation tailings; The strong magnetic cleaning tailings and the strong magnetic scavenging concentrate are combined as middlings and returned to the wet high-intensity magnetic roughing step;

[0093] (5) The magnetic separation tailings obtained in step (4) are calcined at 350 °C, washed with water, and then added to a reaction kettle. A 2.5 mol / L NaOH solution is added for alkali leaching reaction, and the liquid-solid ratio of the leaching system is controlled at 3:1, the reaction temperature is 90 °C, the reaction time is 60 min, and the stirring speed is 200 r / min. After the reaction is completed, the slag and liquid are separated to obtain a water glass solution with an Fe content of 0.002% and a water glass modulus of 2.20 and alkali leaching slag.

[0094] (6) The water glass solution obtained in step (5) is passed through CO2 gas for carbon precipitation to obtain high-purity silica with a purity of 99.97%.

[0095] (7) The alkali leaching slag obtained in step (5) is subjected to pulp flotation. First, 50 g / t of aluminum sulfate and 50 g / t of dextrin are added as inhibitors for rutile, then 150 g / t of dimethylphosphonic acid is added as a collector, and 30 g / t of terpineol is added as a foaming agent. Rutile therein is recovered by reverse flotation to obtain a concentrate with a titanium dioxide grade of 43%. The flotation tailings are mainly silicate minerals and can be added to cement as building materials.

[0096] Example 5

[0097] As Figure 1 shown, a method for resource utilization of acidolysis waste residue of sulfuric acid process titanium dioxide, the specific steps are as follows:

[0098] (1) Sampling an acidolysis residue of sulfuric acid process titanium dioxide from a certain place in Sichuan. The content of Si element in this acidolysis waste residue is 28.37% at most, and the content of metal element Ti is 12.23% secondly. First, the acidolysis residue is passed through a sieve with a sieve hole of 0.074 mm to remove coarse-grained impurities therein, and the sample under the sieve is slurried, and the slurry concentration is controlled at 20%.

[0099] (2) The product under the sieve obtained in step (1) is subjected to wet high-intensity magnetic roughing by a SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.6 T to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings.

[0100] (3) The strong magnetic roughing concentrate product obtained in step (2) is beneficiated by an SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.5 T to obtain titanium concentrate with a yield of 35.26%, a TiO2 grade of 50.37%, and a recovery rate of 85.21%, and strong magnetic beneficiation tailings.

[0101] (4) The strong magnetic roughing tailings product obtained in step (2) is scavenged by an SLon-100 high-gradient magnetic separator under the condition of a magnetic induction intensity of 0.8 T to obtain strong magnetic scavenging concentrate and scavenging tailings; and the magnetic induction intensity is further increased to 1.4 T to remove magnetic and weakly magnetic impurities therein for preparation of subsequent processes, and magnetic separation tailings are obtained; the strong magnetic beneficiation tailings and the strong magnetic scavenging concentrate are combined as middlings and returned to the wet strong magnetic roughing step;

[0102] (5) The magnetic separation tailings obtained in step (4) are calcined at 350 °C, washed with water, and then added to a reaction kettle, and a 2.5 mol / L NaOH solution is added for alkali leaching reaction, controlling the liquid-solid ratio of the leaching system to be 3:1, the reaction temperature to be 25 °C, the reaction time to be 120 min, and the stirring speed to be 200 r / min. After the reaction is completed, slag-liquid separation is carried out to obtain a water glass solution with an Fe content of 0.001% and a water glass modulus of 2.25 and alkali leaching slag.

[0103] (6) The water glass solution obtained in step (5) is passed through CO2 gas for carbon precipitation to obtain high-purity silica with a purity of 99.98%.

[0104] (7) The alkali leaching slag obtained in step (5) is slurried and floated. First, 80 g / t lead nitrate is added as an activator, 100 g / t sodium hexametaphosphate is added as an inhibitor, then 100 g / t dodecylamine dimethyl phosphonic acid is added as a collector, and 30 g / t terpineol is added as a foaming agent. Rutile therein is recovered by positive flotation to obtain concentrate with a TiO2 grade of 41%, and the flotation tailings are mainly silicate minerals and can be added to cement as building materials.

[0105] As can be seen from the above embodiments, the present invention provides a method for resource utilization of acid hydrolysis waste residue of sulfuric acid process titanium dioxide. The present invention transforms the traditional waste residue treatment method into a new way of resource utilization. Through the unique treatment of the acid hydrolysis waste residue of sulfuric acid process titanium dioxide, the valuable components contained therein are effectively extracted, realizing the full resource utilization of the waste residue and avoiding the environmental pollution and resource waste problems caused by the stacking of acid hydrolysis waste residue of sulfuric acid process titanium dioxide.

[0106] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for resource utilization of waste residues from acid hydrolysis of titanium dioxide produced by sulfuric acid process, characterized in that: The following steps are involved: (1) The waste residue from the acid hydrolysis of titanium dioxide produced by the sulfuric acid process is graded to remove the coarse particle impurities mixed in during the production process; (2) wet strong magnetic roughing of the waste residue of sulfuric acid process titanium dioxide acid hydrolysis from which coarse particle impurities have been removed to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings; (3) subjecting the strong magnetic roughing concentrate to high gradient strong magnetic concentration to obtain titanium concentrate and strong magnetic concentration tailings; (4) subjecting the strong magnetic rougher tailings to high gradient strong magnetic sweeping to obtain strong magnetic sweeping concentrate and magnetic separation tailings; (5) The tailings from the high-intensity magnetic separation and the concentrate from the high-intensity magnetic separation are combined as the middlings and returned to step (2) for re-selection; (6) roasting and washing the magnetic separation tailings to remove organic and carbonaceous impurities; (7) The magnetic tailings after roasting, washing and impurity removal are subjected to alkaline leaching under mild conditions below the boiling point of the solution to selectively leach the active silica therein, and after solid-liquid separation, a high-purity water glass solution and alkaline leaching residue are obtained; (8) adjusting the pH of the high-purity water glass solution to obtain high-purity silicon dioxide by precipitation; (9) Separating and purifying the alkali leaching residue by flotation or gravity separation to obtain rutile concentrate and silicate tailings; The magnetic field strength of the high gradient strong magnetic separation is 1.0~1.8T; The magnetic field strength of the high gradient strong magnetic sweep is 1.0~1.8T.

2. The method for resource utilization of waste residues from acid hydrolysis of titanium dioxide produced by sulfuric acid process according to claim 1, characterized in that: In the step (1), the classification size can be controlled to be 0.074-8 mm depending on the impurities mixed in, and the classification method is screening classification or hydraulic classification.

3. The method for resource utilization of waste residues from acid hydrolysis of titanium dioxide produced by sulfuric acid process according to claim 1, characterized in that: The magnetic field strength of the wet strong magnetic roughing is 0.2~1.8T.

4. The method for resource utilization of waste residues from acid decomposition of titanium dioxide produced by sulfuric acid process according to any one of claims 1 to 3, characterized in that: The calcination temperature is 300-800° C., and the calcination time is 0.5-2 hours.

5. The method for resource utilization of waste residues from acid hydrolysis of titanium dioxide produced by sulfuric acid process according to claim 4, characterized in that: The alkaline leaching solution used in the alkaline leaching is a sodium hydroxide solution and / or a potassium hydroxide solution, and the concentration of the alkaline leaching solution is 1-4 mol / L.

6. The method for resource utilization of waste residues from acid decomposition of titanium dioxide produced by sulfuric acid process according to claim 1, 3 or 5, characterized in that: The alkali leaching temperature is 10-100° C., the alkali leaching time is 10-180 min, the liquid-to-solid ratio is 1-5, and after the alkali leaching is completed, the solid-liquid separation can be carried out by filtering or centrifugal separation.

7. The method for resource utilization of waste residues from acid hydrolysis of titanium dioxide produced by sulfuric acid process according to claim 6, characterized in that: In the step (8), the pH is adjusted by adding acid or by introducing CO2, and the acid is one or more of sulfuric acid, hydrochloric acid or nitric acid to adjust the solution pH to 8-12.

8. The method for resource utilization of waste residues from acid decomposition of titanium dioxide produced by sulfuric acid process according to claim 1, 2, 3 or 5, characterized in that: The flotation of the alkaline leaching residue is rutile direct flotation or rutile reverse flotation, the reagents used in the direct flotation are activator, inhibitor, collector and frother; the reagents used in the reverse flotation are inhibitor, collector and frother.

9. The method for resource utilization of waste residues from acid decomposition of titanium dioxide produced by sulfuric acid process according to claim 1, 2, 3, 5 or 7, characterized in that: The gravity separation is shaking table gravity separation, spiral chute gravity separation or centrifugal gravity separation.

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