Optimization process of sedimentation flocculant for acidolysis titanium liquid

Abstract

The invention discloses an optimization process of a settling flocculant for titaniferous solution acidolysis, belongs to the technical field of titanium dioxide preparation, and aims to solve the problem that the cost consumed in the flocculant settling and purifying process needs to be further reduced at present. By accurately controlling the concentration of the flocculating agent and matching the flocculating agent with the clarification temperature of the titaniferous solution to be clarified, the concentration of the flocculating agent can be increased as much as possible under the condition that the use effect of the flocculating agent is not influenced, so that the dosage of water when the flocculating agent and the titaniferous solution are mixed is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium dioxide preparation, and in particular relates to an optimization process of a sedimentation flocculant for acid hydrolysis of titanium liquid. Background Art

[0002] In the titanium dioxide production process, ilmenite is acid-decomposed in sulfuric acid, and titanium liquid is obtained after decomposition through leaching. The titanium liquid is turbid and must be subjected to precipitation purification treatment for the next step of production. If it is not handled properly, it will not only cause the filter cloth of the filter press used for filtration to be blocked, but will also greatly affect the output and quality of titanium dioxide. For a long time, various production units have adopted the method of filtration to separate the mud in the black liquor, and charcoal powder or diatomaceous earth is used as a filter aid in the process, but the effect is not ideal. Flocculants are used in the existing titanium liquid purification process. The existing flocculants are currently added to the titanium liquid after acid hydrolysis after configuration to dilute the concentration of the titanium liquid and increase the steam consumed by concentrating the titanium liquid. Therefore, it is currently necessary to further reduce the cost consumed in the flocculant precipitation purification process. Summary of the invention

[0003] In view of the problems in the prior art, the present invention provides an optimized process for a sedimentation flocculant for acid hydrolysis of titanium liquid. By increasing the flocculant concentration, the amount of flocculant added when mixed with the titanium liquid can be reduced, ensuring that the molecular weight of the flocculant in the flocculant solution at the previous and later concentrations is fixed, thereby reducing the amount of water entering the titanium liquid, thereby increasing the concentration, which helps to save steam consumed in subsequent concentration; when the concentration of the flocculant is too high, the concentration of polymers in the solution is very high, and the surface of the particles is completely covered by the adsorbed polymers. The particles will no longer flocculate by bridging. At this time, the polymer plays a protective role and inhibits the flocculation and sedimentation effect; the flocculation effect will increase as the water temperature increases. Under low temperature conditions, the amount of flocculant must be increased. On the other hand, if the water temperature is too high, the floccules formed will be small, the water content of the sludge will increase, and it will be difficult to handle; therefore, water temperature that is too high or too low is not good for flocculation; therefore, the present application finds an optimal flocculant concentration, accurately controls the concentration of the flocculant, and matches the clarification temperature of the titanium liquid to be clarified, so as to increase the concentration of the flocculant as much as possible without affecting the effect of the flocculant, thereby reducing the amount of water added when the flocculant and the titanium liquid are mixed.

[0004] The technical solution adopted by the present invention is as follows:

[0005] An optimization process for a sedimentation flocculant for acid hydrolysis of titanium liquid comprises the following steps:

[0006] Step 1: Prepare flocculant solution according to the proportion;

[0007] Step 2: Add the flocculant solution prepared in step 1 once or several times into the titanium liquid to be clarified, mix evenly to obtain solution A, and the addition ratio of the flocculant solution to the titanium liquid to be clarified is 0.04-0.03:1;

[0008] Step 3: Pass solution A into a thickener for solid-liquid separation and continuous sedimentation.

[0009] Preferably, the method for preparing the flocculant solution in step 1 is: adding desalted water and flocculant into a preparation tank, stirring for 25 to 30 minutes to obtain a flocculant solution without large agglomerated particles in the preparation tank.

[0010] Preferably, the concentration of the flocculant solution prepared in step 1 is 650-850 ppm.

[0011] Preferably, the temperature range for preparing the flocculant in step 1 is 20 to 30°C.

[0012] Preferably, the pH value of the flocculant prepared in step 1 is in the range of 4.0 to 8.0.

[0013] Preferably, the clarification temperature in step 2 is in the range of 60 to 75°C.

[0014] Preferably, the output flow rate of the supernatant of solution A continuously settling in step 3 is 30 to 40 m 3 / h.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0016] 1. This application increases the concentration of flocculant, thereby reducing the amount of flocculant added when mixing with titanium liquid, ensuring that the molecular weight of the flocculant in the flocculant solution is fixed at the previous and next concentrations, thereby reducing the amount of water entering the titanium liquid, thereby increasing the concentration;

[0017] 2. However, when the concentration of the flocculant is too high, the concentration of polymers in the solution is very high, the surface of the particles is completely covered by the adsorbed polymers, and the particles will no longer flocculate by bridging. At this time, the polymers play a protective role and inhibit the flocculation and sedimentation effect; the flocculation effect will increase with the increase of water temperature. Under low temperature conditions, the amount of flocculant must be increased; on the other hand, if the water temperature is too high, the formed floccules will be small, the sludge water content will increase, and it will be difficult to handle; therefore, too high or too low water temperature is not conducive to flocculation; therefore, the present application finds an optimal flocculant concentration, accurately controls the concentration of the flocculant, and matches the clarification temperature of the titanium liquid to be clarified, so as to increase the concentration of the flocculant as much as possible without affecting the use effect of the flocculant, thereby reducing the amount of water added when the flocculant and the titanium liquid are mixed. DETAILED DESCRIPTION

[0018] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Usually, the components of the embodiments of the present application shown can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0019] An optimization process for a sedimentation flocculant for acid hydrolysis of titanium liquid comprises the following steps:

[0020] Step 1: Prepare flocculant solution according to the proportion;

[0021] Step 2: Add the flocculant solution prepared in step 1 into the titanium liquid to be clarified once or several times, mix evenly to obtain solution A, and the addition ratio of the flocculant solution to the titanium liquid to be clarified is 0.04-0.03:1;

[0022] Step 3: Pass solution A into a thickener for solid-liquid separation and continuous sedimentation.

[0023] In this embodiment, the method for preparing the flocculant solution in step 1 is: add desalted water and modified aminomethyl polyacrylamide (AMPAM) into the preparation tank, stir for 25 to 30 minutes, and the preparation is completed when no large agglomerated particles can be seen in the preparation tank through the observation hole, and then stop stirring.

[0024] In this embodiment, the concentration of the flocculant solution prepared in step 1 is 650-850 ppm.

[0025] In this embodiment, the temperature range of preparing the flocculant in step 1 is 25°C.

[0026] In this embodiment, the pH range of the flocculant prepared in step 1 is 7.0.

[0027] In this embodiment, the temperature range of clarification in step 2 is 60-75°C.

[0028] In this embodiment, the output flow rate of the supernatant of solution A continuously settling in step 3 is 30-40 m 3 / h.

[0029] Among them, some data of Examples 1 to 4 and Comparative Examples 1 to 5 are recorded in Table 1 below

[0030]

[0031] The flocculant sedimentation processes of Examples 1 to 4 and Comparative Examples 1 to 5 were used to conduct experiments respectively. A certain amount of acid hydrolysis slurry and a flocculant in equal proportion were added to a stoppered measuring cylinder, mixed evenly and allowed to stand. After a period of sedimentation, the bottom sedimentation corresponded to the scale of the measuring cylinder. The smaller the scale, the better the sedimentation effect.

[0032] After experiments, the characterization data of the flocculation effect in Examples 1 to 4 and Comparative Examples 1 to 5 were obtained.

[0033]

[0034] The above embodiments and comparative examples show that the present invention adopts 650-850ppm of flocculant, and controls the addition ratio of flocculant solution to the titanium liquid to be clarified to 0.04-0.03:1, and performs the clarification reaction at 60-75°C. Compared with the concentration of the traditional flocculant, the present application can reduce the amount of flocculant added when mixing with the titanium liquid by increasing the flocculant concentration, thereby ensuring that the flocculant molecular weight in the flocculant solution at the previous and next concentrations is fixed, thereby reducing the amount of water entering the titanium liquid, thereby increasing the concentration, which helps to save steam consumed in subsequent concentration; when the concentration of the flocculant is too high, the concentration of the polymer in the solution is very high, the surface of the particle is completely covered by the adsorbed polymer, and the particle will no longer flocculate by bridging. At this time, the polymer plays a protective role and inhibits the flocculation and sedimentation effect; the flocculation effect will increase as the water temperature increases. Under low temperature conditions, the amount of flocculant must be increased. On the other hand, if the water temperature is too high, the formed floccules will be small, the moisture content of the sludge will increase, and it will be difficult to handle. Therefore, water temperature that is too high or too low is not conducive to flocculation. Therefore, the present application finds an optimal flocculant concentration, accurately controls the concentration of the flocculant, and matches the flocculant with the clarification temperature of the titanium liquid to be clarified, so as to increase the concentration of the flocculant as much as possible without affecting the effectiveness of the flocculant, thereby reducing the amount of water added when the flocculant and the titanium liquid are mixed.

[0035] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. An optimization process for a sedimentation flocculant for acid hydrolysis of titanium liquid, characterized in that: The following steps are involved: Step 1: Prepare flocculant solution according to the proportion; Step 2: Add the flocculant solution prepared in step 1 once or several times into the titanium liquid to be clarified, mix evenly to obtain solution A, and the addition ratio of the flocculant solution to the titanium liquid to be clarified is 0.04-0.03:1; Step 3: Pass solution A into a thickener for solid-liquid separation and continuous sedimentation.

2. The optimization process of a sedimentation flocculant for acid hydrolysis of titanium liquid according to claim 1, characterized in that: The method for preparing the flocculant solution in step 1 is: adding desalted water and flocculant into the preparation tank, stirring for 25 to 30 minutes, and obtaining the flocculant solution without large agglomerated particles in the preparation tank.

3. The optimization process of a sedimentation flocculant for acid hydrolysis of titanium liquid according to claim 2, characterized in that The concentration of the flocculant solution prepared in step 1 is 650-850 ppm.

4. The optimization process of a sedimentation flocculant for acid hydrolysis of titanium liquid according to claim 1, characterized in that: The temperature range for preparing the flocculant in step 1 is 20 to 30°C.

5. The optimization process of a sedimentation flocculant for acid hydrolysis of titanium liquid according to claim 1, characterized in that: The pH range of the flocculant prepared in step 1 is 4.0 to 8.

0.

6. The optimization process of a sedimentation flocculant for acid hydrolysis of titanium liquid according to claim 1, characterized in that: The temperature range for clarification in step 2 is 60 to 75°C.

7. The optimization process of a sedimentation flocculant for acid hydrolysis of titanium liquid according to claim 1, characterized in that: The output flow rate of the supernatant of solution A in step 3 is 30-40m 3 / h.

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