A sulfuric acid waste acid concentration system for titanium dioxide production

Abstract

This invention relates to the field of titanium dioxide waste acid concentration, and provides a sulfuric acid process titanium dioxide waste acid concentration system. It includes: a primary heater, a primary evaporator, a primary acid hydrometer, a secondary heater, a secondary evaporator, and a secondary acid hydrometer; it also includes a control device, wherein the primary heater, primary evaporator, primary acid hydrometer, secondary heater, secondary evaporator, and secondary acid hydrometer are all communicatively connected to the control device. The control device is used to monitor and control the status of the primary heater, primary evaporator, primary acid hydrometer, secondary heater, and secondary evaporator. This invention solves the technical problem of the inability to monitor and adjust the concentration effect of sulfuric acid process titanium dioxide waste acid in a timely manner by setting up a control device, thereby stabilizing and improving the waste acid concentration efficiency, and reducing the operating cost of waste acid concentration, the amount of waste acid neutralization treatment, and the cost.

Description

Technical Field

[0001] This invention relates to the field of titanium dioxide waste acid concentration, specifically a sulfuric acid process titanium dioxide waste acid concentration system. Background Technology

[0002] Titanium dioxide, the third largest inorganic chemical product after synthetic ammonia and phosphoric acid, is widely used in coatings, plastics, papermaking, and inks due to its stable physicochemical properties and good optical performance. Currently, titanium dioxide production processes are mainly divided into the sulfate process and the chloride process. Compared to the chloride process, the sulfate process has lower requirements for titanium raw materials and technology, and can produce anatase titanium dioxide. Therefore, the sulfate process accounts for a relatively larger share of titanium dioxide production capacity, approximately 57.0% globally and about 90% in my country.

[0003] For every ton of titanium dioxide produced, sulfuric acid titanium dioxide manufacturers generate 4-8 tons of waste acid with a sulfuric acid mass fraction of 18-25%. This waste acid contains a large amount of ferrous sulfate, magnesium sulfate, and small amounts of impurities such as calcium sulfate, manganese sulfate, and titanium oxysulfate. These impurities severely affect the difficulty of comprehensive utilization of the waste acid. Most sulfuric acid titanium dioxide enterprises often use neutralization to treat the waste acid. This method generates a large amount of titanium gypsum, and the neutralization cost is relatively high, accounting for about 5%-10% of the production cost of sulfuric acid titanium dioxide. In economically developed regions, titanium gypsum storage sites are often no longer approved. Therefore, the comprehensive utilization of waste acid is urgent and has become a key factor restricting the survival and development of sulfuric acid titanium dioxide.

[0004] Currently, the most common and effective comprehensive utilization method is to concentrate waste acid to a certain concentration and then reuse it in the acidolysis process as acid for acidolysis of titanium concentrate. The higher the concentration of waste acid, the higher the proportion of waste acid reused. Waste acid concentration mostly adopts the evaporation concentration process, using saturated steam as the heat source, graphite heat exchangers as heating equipment, and vacuum evaporation chambers as evaporation equipment. The higher the concentration efficiency, the greater the concentration or feed rate of waste acid per unit of steam consumption. During the waste acid concentration process, the feed rate of waste acid is often monitored by an online flow meter, while the concentration of waste acid is often monitored by taking the concentrated and matured acid from the tank for solid-liquid separation, neutralization titration, and determination. Because waste acid raw materials are in a liquid state, the feed rate can be easily monitored in real time using a flow meter. However, after the waste acid is concentrated, the acid concentration detection is affected by the presence of solid ferrous sulfate in the solution during the neutralization titration process, which requires separation, and the interference of ferrous sulfate in solution with the determination of the neutralization endpoint. This results in a certain deviation in the waste acid concentration detection results. In addition, the acid concentration after aging in the aging tank is a composite sample and cannot reflect the real-time concentration of the waste acid, thus making it impossible to adjust the waste acid concentration process parameters in a timely manner to ensure that it is at the best concentration efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a sulfuric acid waste acid concentration system for titanium dioxide production to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A waste acid concentration system for sulfuric acid process titanium dioxide production includes: a primary heater, a primary evaporator, a primary acid hydrometer, a secondary heater, a secondary evaporator, and a secondary acid hydrometer; the waste acid outlet of the primary heater is connected to the waste acid inlet of the primary evaporator; the steam outlet of the primary evaporator is connected to the steam inlet of the secondary heater; the waste acid outlet of the secondary heater is connected to the waste acid inlet of the secondary evaporator; the steam outlet of the secondary evaporator is connected to the steam inlet of an atmospheric condenser; a first waste acid solid-liquid separation device is installed at the overflow port of the primary evaporator, the solid separated by the first waste acid solid-liquid separation device enters the primary heater, and the liquid separated by the first waste acid solid-liquid separation device is input to the secondary heater through a pipeline; a primary acid hydrometer is also installed at the secondary heater to monitor the separated liquid; a second waste acid solid-liquid separation device is installed at the overflow port of the secondary evaporator, the solid separated by the second waste acid solid-liquid separation device enters the secondary heater, and a secondary acid hydrometer is also installed at the secondary heater to monitor the separated liquid;

[0008] It also includes a control device, wherein the primary heater, primary evaporator, primary acid hydrometer, secondary heater, secondary evaporator and secondary acid hydrometer are all communicatively connected to the control device; the control device is used to monitor and control the status of the primary heater, primary evaporator, primary acid hydrometer, secondary heater and secondary evaporator; and is used to receive monitoring data sent by the primary acid hydrometer and secondary acid hydrometer.

[0009] As a further aspect of the present invention: the control device is used to acquire waste acid concentration feed rate, waste acid concentration vacuum degree, waste acid concentration temperature, waste acid concentration, and waste acid concentration condensate status data of the primary evaporator and the secondary evaporator respectively.

[0010] As a further aspect of the present invention: the control device determines whether to adjust the corresponding process parameters of the primary evaporator based on whether the concentration of waste acid concentration or the first ratio of the primary evaporator meets the first preset threshold. If the concentration exceeds the first preset threshold, the corresponding process parameters of the primary evaporator are adjusted.

[0011] As a further aspect of the present invention: if the first preset threshold is exceeded, the process parameters corresponding to the first-stage evaporator are adjusted, including:

[0012] Adjust the vacuum level of the first-stage evaporator according to the preset rules, and after running for a set time, determine whether the concentration meets the first preset threshold.

[0013] If it does not meet the requirements, the steam input of the primary heater will be adjusted according to the preset rules to complete the adjustment of the process parameters corresponding to the primary evaporator.

[0014] As a further aspect of the present invention: the control device determines whether to adjust the corresponding process parameters of the secondary evaporator based on whether the concentration of waste acid in the secondary evaporator or the second ratio meets the second preset threshold. If the second preset threshold is exceeded, the corresponding process parameters of the secondary evaporator are adjusted.

[0015] As a further aspect of the present invention: if the second preset threshold is exceeded, the process parameters corresponding to the secondary evaporator are adjusted, including:

[0016] Adjust the vacuum level of the secondary evaporator according to the preset rules, and after running for a set time, determine whether the concentration meets the first preset threshold.

[0017] If it does not meet the requirements, the steam input of the secondary heater will be adjusted according to the preset rules to complete the adjustment of the process parameters corresponding to the secondary evaporator.

[0018] As a further aspect of the present invention: the process parameters include the vacuum degree of the evaporation chamber and the temperature of the heat exchanger; wherein the ratio is the ratio between the condensate flow rate and the waste acid feed rate.

[0019] As a further aspect of the present invention: the control device determines whether to adjust the process parameters of the primary and secondary evaporators based on whether the concentration or ratio of the waste acid concentration of the primary evaporator and the secondary evaporator meets the preset threshold, wherein the adjustment range of the process parameters is % to % of the maximum allowable value of the process parameters.

[0020] As a further embodiment of the present invention: the output end of the primary acid hydrometer is connected to the input end of the secondary heater via a first vacuum pump; the output end of the secondary acid hydrometer is connected to the input end of the aging tank via a second vacuum pump.

[0021] As a further aspect of the present invention: the liquid separated by the second waste acid solid-liquid separation device enters the maturation tank.

[0022] Compared with the prior art, the beneficial effects of the present invention are: by setting up a control device, the technical problem of the inability to monitor and adjust the concentration effect of waste acid in sulfuric acid process titanium dioxide in a timely manner is solved, thereby stabilizing and improving the waste acid concentration efficiency, reducing the operating cost of waste acid concentration, the amount and cost of waste acid neutralization treatment, realizing intelligent control of waste acid concentration in sulfuric acid process titanium dioxide, and improving the green manufacturing level of sulfuric acid process titanium dioxide. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a sulfuric acid waste acid concentration system for titanium dioxide production according to an embodiment of the present invention.

[0024] In the diagram: 1-First stage heater, 2-First stage evaporator, 3-First stage acid hydrometer, 4-First vacuum pump, 5-Second stage heater, 6-First stage condensate flow meter, 7-Second stage evaporator, 8-Second stage acid hydrometer, 9-Second stage vacuum pump, 10-Atmospheric condenser, 11-Third stage vacuum pump, 12-Plate heat exchanger, 13-Second stage condensate flow meter, 14-Curing tank, 15-Control device. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please see Figure 1 This invention provides a structural diagram of a waste acid concentration system for the sulfuric acid process in titanium dioxide production. The system includes: a primary heater 1, a primary evaporator 2, a primary acid hydrometer 3, a secondary heater 5, a secondary evaporator 7, a secondary acid hydrometer 8, and a second vacuum pump 9. The waste acid outlet of the primary heater 1 is connected to the waste acid inlet of the primary evaporator 2. The steam outlet of the primary evaporator 2 is connected to the steam inlet of the secondary heater 5. The waste acid outlet of the secondary heater 5 is connected to the waste acid inlet of the secondary evaporator 7, and the steam outlet of the secondary evaporator 7 is connected to the steam inlet of the atmospheric condenser 10. A first waste acid solid-liquid separation device is installed at the overflow port of the primary evaporator 2. The solid separated by the first waste acid solid-liquid separation device enters the primary heater 1, and the liquid separated by the first waste acid solid-liquid separation device is input to the secondary heater 5 through a pipeline. A primary acid hydrometer 3 is also installed on the primary heater 2 to monitor the separated liquid.

[0027] A second waste acid solid-liquid separation device is installed at the overflow port of the secondary evaporator 7. The solid separated by the second waste acid solid-liquid separation device enters the secondary heater 5. A secondary acid hydrometer 8 is also installed on the 7 to monitor the separated liquid.

[0028] It also includes a control device 15, wherein the primary heater 1, primary evaporator 2, primary acid hydrometer 3, secondary heater 5, secondary evaporator 7 and secondary acid hydrometer 8 are all communicatively connected to the control device 15; the control device 15 is used to monitor and control the status of the primary heater 1, primary evaporator 2, primary acid hydrometer 3, secondary heater 5 and secondary evaporator 7; and to receive monitoring data sent by the primary acid hydrometer 3 and secondary acid hydrometer 8.

[0029] This invention solves the technical problem of the inability to monitor and adjust the concentration effect of waste acid in sulfuric acid process titanium dioxide in a timely manner by setting up a control device 15, thereby stabilizing and improving the waste acid concentration efficiency, reducing the operating cost of waste acid concentration, the amount and cost of waste acid neutralization treatment, realizing intelligent control of waste acid concentration in sulfuric acid process titanium dioxide, and improving the green manufacturing level of sulfuric acid process titanium dioxide.

[0030] In a preferred embodiment of the present invention, the control device 15 is used to acquire the waste acid concentration feed rate, waste acid concentration vacuum degree, waste acid concentration temperature, waste acid concentration, and waste acid concentration condensate status data of the primary evaporator 2 and the secondary evaporator 7, respectively.

[0031] In a preferred embodiment of the present invention, the control device 15 determines whether to adjust the corresponding process parameters of the first-stage evaporator 2 based on whether the concentration or first ratio of the waste acid concentration of the first-stage evaporator 2 meets the first preset threshold. If the first preset threshold is exceeded, the corresponding process parameters of the first-stage evaporator 2 are adjusted.

[0032] In a preferred embodiment of the present invention, if the first preset threshold is exceeded, the process parameters corresponding to the primary evaporator 2 are adjusted, including:

[0033] Adjust the vacuum level of the first-stage evaporator 2 according to the preset rules, and after running for a set time, determine whether the concentration meets the first preset threshold.

[0034] If it does not meet the requirements, the steam input of the first-stage heater 1 will be adjusted according to the preset rules to complete the adjustment of the process parameters corresponding to the first-stage evaporator 2.

[0035] In a preferred embodiment of the present invention, the process parameters include the vacuum degree of the evaporation chamber and the temperature of the heat exchanger; wherein the ratio is the ratio between the condensate flow rate and the waste acid feed rate.

[0036] In a preferred embodiment of the present invention, the control device 15 determines whether to adjust the corresponding process parameters of the secondary evaporator 7 based on whether the waste acid concentration or the second ratio of the secondary evaporator 7 meets the second preset threshold. If the second preset threshold is exceeded, the corresponding process parameters of the secondary evaporator 7 are adjusted.

[0037] In a preferred embodiment of the present invention, if the second preset threshold is exceeded, the process parameters corresponding to the secondary evaporator 7 are adjusted, including:

[0038] Adjust the vacuum level of the secondary evaporator 7 according to the preset rules, and after running for a set time, determine whether the concentration meets the first preset threshold.

[0039] If it does not meet the requirements, the steam input of the secondary heater 5 will be adjusted according to the preset rules to complete the adjustment of the process parameters corresponding to the secondary evaporator 7.

[0040] In a preferred embodiment of the present invention, the control device 15 determines whether to adjust the process parameters of the first-stage evaporator 2 and the second-stage evaporator 7 based on whether the concentration or ratio of the waste acid concentration of the first-stage evaporator 2 and the second-stage evaporator 7 meets the preset threshold. The adjustment range of the process parameters is 5% to 10% of the maximum allowable value of the process parameters.

[0041] In a preferred embodiment of the present invention, the output end of the primary acid hydrometer 3 is connected to the input end of the secondary heater 5 via the first vacuum pump 4; the output end of the secondary acid hydrometer 8 is connected to the input end of the aging tank 14 via the second vacuum pump 9.

[0042] In a preferred embodiment of the present invention, the liquid separated by the second waste acid solid-liquid separation device enters the maturation tank 14.

[0043] In a preferred embodiment of the present invention, a primary condensate flow meter 6 is provided at the condensate outlet of the secondary heater 5; a secondary condensate flow meter 13 is provided at the condensate outlet of the atmospheric condenser 10; and the heat exchange inlet and outlet of the atmospheric condenser 10 are connected to the plate heat exchanger 12.

[0044] Operating principle of this invention:

[0045] This invention installs flow meters on the outlet pipes of the condensate from the evaporated water in each stage of the waste acid concentration evaporation chamber to monitor the mass flow rate of the condensed water. A concentration monitoring device is installed at the overflow outlet of each stage of the evaporation chamber. This device includes a waste acid solid-liquid separation unit and a hydrometer to monitor the specific gravity of the waste acid. The waste acid solid-liquid separation uses a quartz sand filtration device, specifically a Buchner funnel filter element installed on the pipeline. The filtration power is provided by a separate peristaltic vacuum pump for solid-liquid separation. A chain relationship is established between the feed rate of each stage of waste acid concentration, the vacuum degree of each stage of waste acid concentration, the concentration of each stage of waste acid concentration, and the condensate from the waste acid concentration, with an automatic control function. The ratio of condensate flow rate to waste acid feed rate serves as a secondary indicator of concentration, preventing misjudgments in waste acid concentration monitoring. This system serves as a supplementary measure when monitoring is inaccurate and fails to reflect the concentration effect of waste acid, acting as a double insurance. After changes in the concentration at each stage, adjustments are made sequentially within the control range of each process parameter, following the evaporator vacuum degree and heat exchanger temperature. Only when the concentration still does not meet the requirements after adjusting the vacuum degree should the steam flow rate be adjusted, followed by the concentration temperature, until the required concentration efficiency is achieved. Adjustments to process parameters should follow the principle of small-scale adjustments, with each adjustment ranging from 5% to 10% of the maximum allowable value of the process parameter. After each adjustment, stable operation for 2 to 10 hours is allowed until the concentration effect stabilizes. Then, an evaluation is conducted based on the changes in the concentration effect to determine whether further adjustments to the concentration process are necessary.

[0046] Example 1

[0047] Waste acid was concentrated using a traditional two-stage waste acid concentration process, with a concentration of 22.0% (mass fraction). The concentration process parameters were: feed rate 11m³ / h. 3 / h, the concentration temperature of the primary waste acid concentration is 108℃ and the concentration vacuum degree is -70kpa, the concentration temperature of the secondary waste acid concentration is 80℃ and the concentration vacuum degree is -89kpa. After the operation is stable, the concentration of concentrated acid in the maturation tank is monitored every 8 hours. After 12 days of continuous operation, the saturated steam consumption of concentrated acid (mass fraction converted to 100%) is calculated.

[0048] Example 2

[0049] The waste acid concentration process and equipment described in this application are used for two-stage waste acid concentration, with a waste acid concentration of 22.0% (mass fraction). The concentration process parameters are as follows: feed rate is 11m³ / min. 3 / h, the concentration temperature of the first-stage waste acid concentration is 108℃ and the concentration vacuum degree is -70kpa, the concentration temperature of the second-stage waste acid concentration is 80℃ and the concentration vacuum degree is -89kpa. After the operation is stable, the acid concentration and feed rate of each stage of waste acid concentration and the flow rate ratio of each stage of condensate are monitored in real time. When the concentration of each stage of concentration changes, the waste acid concentration process parameters of each stage of concentration are automatically adjusted by the system. The concentration of concentrated acid in the maturation tank is monitored every 8 hours. After 12 days of continuous operation, the saturated steam consumption of concentrated acid (mass fraction converted to 100%) is calculated.

[0050] Example 3

[0051] The waste acid is concentrated in two stages according to the waste acid process and equipment described in this application. The waste acid concentration is 22.0% (mass fraction), and the concentration process parameters are: feed rate 11m³ / h. 3 / h, the concentration temperature of the first-stage waste acid concentration is 118℃ and the concentration vacuum degree is -70kpa, the concentration temperature of the second-stage concentration is 80℃ and the concentration vacuum degree is 89kpa. After the operation is stable, the acid concentration and feed rate of each stage of waste acid concentration and the flow rate ratio of each stage of condensate are monitored in real time. When the concentration of each stage of concentration changes, the waste acid concentration process parameters of each stage of concentration are automatically adjusted by the system. The concentration of concentrated acid in the maturation tank is monitored every 8 hours. After 12 days of continuous operation, the saturated steam consumption of concentrated acid (mass fraction converted to 100%) is calculated.

[0052] Example 4

[0053] The waste acid is concentrated in two stages according to the waste acid process and equipment described in this application, with a waste acid concentration of 22.0% (mass fraction). The waste acid concentration process parameters are: feed rate 11m³ / h. 3 / h, the concentration temperature of the first-stage waste acid concentration is 108℃ and the concentration vacuum degree is -89kpa, the concentration temperature of the second-stage waste acid concentration is 80℃ and the concentration vacuum degree is 89kpa. After the operation is stable, the acid concentration and feed rate of each stage of waste acid concentration and the flow rate ratio of each stage of condensate are monitored in real time. When the concentration of each stage of concentration changes, the waste acid concentration process parameters of each stage of concentration are automatically adjusted by the system. The concentration of concentrated acid in the maturation tank is monitored every 8 hours. After 12 days of continuous operation, the saturated steam consumption of concentrated acid (mass fraction converted to 100%) is calculated.

[0054] The results of the embodiments are shown in Table 1.

[0055] Table 1 Results of the Examples

[0056]

[0057] Steam here refers to saturated steam with a temperature of 160℃.

[0058] As can be seen from the results of the examples, compared with Examples 1, 2, 3 and 4, the new method improves the mean, minimum and maximum acid concentrations in the aging tank after waste acid concentration, while reducing the standard deviation. This indicates that the concentration stability and concentration of waste acid are improved under the new method. In addition, the steam consumption per unit volume decreases under the premise of increased acid concentration in the aging tank.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0062] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for concentrating waste acid from the sulfuric acid process in titanium dioxide production, characterized in that, A waste acid concentration device for titanium dioxide production using the sulfuric acid process is employed. The device comprises: a primary heater (1), a primary evaporator (2), a primary acid hydrometer (3), a secondary heater (5), a secondary evaporator (7), and a secondary acid hydrometer (8). The waste acid outlet of the primary heater (1) is connected to the waste acid inlet of the primary evaporator (2). The steam outlet of the primary evaporator (2) is connected to the steam inlet of the secondary heater (5). The waste acid outlet of the secondary heater (5) is connected to the waste acid inlet of the secondary evaporator (7), and the steam outlet of the secondary evaporator (7) is connected to the steam inlet of an atmospheric condenser (10). A first waste acid solid-liquid separation device is installed at the overflow port of (2). The solid separated by the first waste acid solid-liquid separation device enters the first-stage heater (1), and the liquid separated by the first waste acid solid-liquid separation device is input into the second-stage heater (5) through a pipeline. A first-stage acid hydrometer (3) for monitoring the separated liquid is also installed on the first-stage evaporator (2). A second waste acid solid-liquid separation device is installed at the overflow port of the second-stage evaporator (7). The solid separated by the second waste acid solid-liquid separation device enters the second-stage heater (5), and a second-stage acid hydrometer (8) for monitoring the separated liquid is also installed on the second-stage evaporator (7). It also includes a control device (15), wherein the primary heater (1), primary evaporator (2), primary acid hydrometer (3), secondary heater (5), secondary evaporator (7) and secondary acid hydrometer (8) are all communicatively connected to the control device (15); the control device (15) is used to monitor and control the status of the primary heater (1), primary evaporator (2), primary acid hydrometer (3), secondary heater (5) and secondary evaporator (7); and to receive monitoring data sent by the primary acid hydrometer (3) and secondary acid hydrometer (8); The control device (15) is used to acquire the waste acid concentration feed rate, waste acid concentration vacuum degree, waste acid concentration temperature, waste acid concentration and waste acid concentration condensate status data of the primary evaporator (2) and the secondary evaporator (7). The method includes the control device (15) determining whether to adjust the corresponding process parameters of the primary evaporator (2) based on whether the concentration of the waste acid concentrate or the first ratio of the primary evaporator (2) meets the first preset threshold. If the first preset threshold is exceeded, the process parameters corresponding to the first-stage evaporator (2) will be adjusted, including: Adjust the vacuum degree of the first-stage evaporator (2) according to the preset rules, and after running for a set time, determine whether the concentration meets the first preset threshold. If it does not meet the requirements, the steam input of the primary heater (1) will be adjusted according to the preset rules to complete the adjustment of the process parameters corresponding to the primary evaporator (2). The first ratio is the ratio between the condensate flow rate of the first-stage evaporator (2) and the waste acid feed rate.

2. The method for concentrating waste acid from the sulfuric acid process for titanium dioxide production according to claim 1, characterized in that, The control device (15) determines whether to adjust the corresponding process parameters of the secondary evaporator (7) based on whether the concentration of the waste acid concentrate or the second ratio of the secondary evaporator (7) meets the second preset threshold. If the second preset threshold is exceeded, the corresponding process parameters of the secondary evaporator (7) are adjusted. The second ratio is the ratio between the condensate flow rate of the secondary evaporator (7) and the waste acid feed rate.

3. The method for concentrating waste acid from the sulfuric acid process for titanium dioxide production according to claim 2, characterized in that, If the second preset threshold is exceeded, the process parameters corresponding to the secondary evaporator (7) will be adjusted, including: Adjust the vacuum degree of the secondary evaporator (7) according to the preset rules, and after running for a set time, determine whether the concentration meets the second preset threshold. If it does not meet the requirements, the steam input of the secondary heater (5) will be adjusted according to the preset rules to complete the adjustment of the process parameters corresponding to the secondary evaporator (7).

4. A method for concentrating waste acid from the sulfuric acid process for titanium dioxide production according to any one of claims 1-3, characterized in that, The process parameters include the vacuum degree of the evaporation chamber and the temperature of the heat exchanger; wherein, the ratio is the ratio between the condensate flow rate and the waste acid feed rate.

5. The method for concentrating waste acid from the sulfuric acid process for titanium dioxide production according to claim 1, characterized in that, The output end of the primary acid hydrometer (3) is connected to the input end of the secondary heater (5) via the first vacuum pump (4); the output end of the secondary acid hydrometer (8) is connected to the input end of the ripening tank (14) via the second vacuum pump (9).

6. The method for concentrating waste acid from the sulfuric acid process for titanium dioxide production according to claim 1, characterized in that, The liquid separated by the second waste acid solid-liquid separation device enters the maturation tank (14).

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