Method for determining phosphorus content in clear titanium solution

Abstract

The invention belongs to the technical field of sulfuric acid process titanium dioxide production, and particularly discloses a method for measuring phosphorus content in a clear titanium solution, which comprises the following steps: taking the settled clear titanium solution, evaporating and concentrating, drying in a muffle furnace, cooling, tabletting to prepare a sample, and detecting. The method solves the problem that the phosphorus content in the production system can only be monitored in a white area and cannot be monitored in the whole system in the sulfuric acid process titanium dioxide production. According to the method, the feedback time of the phosphorus content of a production system is shortened from 5-6 days to 1-1.5 days, so that a production plan can be adjusted in time in the raw ore crushing and acidolysis feeding process sections, abnormity can be known and treated in advance, and the method has great significance in control of sulfate process titanium dioxide phosphor salt; the data reproducibility is good, the measurement error of a parallel sample is within 0.001% through repeated experiments, and production operation can be guided; by means of the method, the optimal blending proportion of the low-phosphorus titanium concentrate and the high-phosphorus titanium concentrate can be found out, and the production cost is reduced more furthest.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium dioxide production by sulfuric acid process, and specifically relates to a method for determining the phosphorus content of titanium clearing liquid. Background Art

[0002] The sulfuric acid method titanium dioxide production process mainly uses titanium ore as raw material. Sulfuric acid is used to dissolve the titanium element in the titanium ore into TiOSO4 solution. The insoluble impurities in the titanium liquid are removed by sedimentation, filtration and other methods to obtain clear titanium liquid. The FeSO4·7H2O in the clear titanium liquid is then removed by crystallization and solid-liquid separation. The liquid is then concentrated and thermally hydrolyzed to obtain titanic acid slurry. After washing, bleaching and other processes, a crystal conversion agent is added and filtered. After calcination, dehydration, desulfurization, conversion, etc., anatase or rutile titanium dioxide primary product is obtained.

[0003] The phosphorus content in titanium concentrate varies. Some domestic titanium concentrates are low in price but high in phosphorus. Blending low-phosphorus titanium concentrate with low-priced high-phosphorus titanium concentrate can reduce raw material costs. In the current sulfuric acid method titanium dioxide production, the influence of phosphorus in the production process cannot be ignored. Since the phosphorus content in the production system cannot exceed the standard, it is very important to determine the blending ratio of low-phosphorus titanium concentrate to high-phosphorus titanium concentrate.

[0004] In the production of sulfuric acid titanium dioxide in the industry, a salt treatment process is specially set up to add phosphoric acid (or phosphate) to adjust the phosphorus content in the production system. The right amount of phosphorus can improve the whiteness of the product, reduce the calcination temperature, and inhibit the transformation of crystal forms and the excessive growth of crystals. The phosphorus content of the titanium concentrate put into the production system directly determines the phosphorus content in the titanium dioxide pulping and finished products. When the phosphorus content is at the lower limit, phosphoric acid can be added in the salt treatment process to adjust the phosphorus content, but when the phosphorus content exceeds the upper limit, the material can only be returned, resulting in a waste of raw materials and increased costs. It takes about 5-6 days from the time the titanium concentrate is put into the production system to the time the phosphorus content test results of the corresponding batch of titanium dioxide pulping process are measured. For a continuous production line such as sulfuric acid titanium dioxide, the test result feedback time is too long, and the production line cannot be adjusted in time according to the test results. Titanium liquid is different. After the titanium concentrate is put into the production system, the settled clear titanium liquid can be obtained in about 1-1.5 days. Moreover, the phosphorus element in the sulfuric acid titanium dioxide production system only comes from the phosphate salt in the titanium concentrate put into the production system. By detecting the phosphorus content in the titanium liquid, the phosphorus content in the production system can be indirectly determined. The original ore section can immediately adjust the ore use according to the test results to reduce or even eliminate the quality problems of the finished product caused by the phosphorus content. Based on this, it is necessary to design a method for determining the phosphorus content in the sulfuric acid titanium dioxide production line system, and a method for determining the phosphorus content in the clear titanium liquid that can quickly detect the phosphorus content in the simulation experiment to determine the optimal blending ratio of low-phosphorus titanium concentrate and high-phosphorus titanium concentrate. Summary of the invention

[0005] In response to the above technical problems, the present invention provides a method for indirectly determining the phosphorus content in a titanium dioxide production system by a sulfuric acid process by measuring the phosphorus content in a titanium dioxide clear liquid, so as to solve the problem of finished product quality caused by the long feedback time of the phosphorus content detection results in the current titanium dioxide production system by a sulfuric acid process, which leads to the inability to adjust the phosphorus content in the production system according to the detection results in a timely manner.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: a method for determining the phosphorus content of a titanium cleaning solution, comprising the following steps:

[0007] S1 Evaporation and concentration: take the clear titanium liquid after sedimentation into a crucible, place it on a heating furnace and heat it until no bubbles emerge, so as to obtain a nearly dry sample to be tested;

[0008] S2 Drying: After the sample is almost dried in S1, move it together with the corundum crucible into a muffle furnace for drying;

[0009] S3 cooling: taking out the sample to be tested after drying in S2 from the muffle furnace and cooling it to room temperature;

[0010] S4 Sample preparation: Grind the solid sample to be tested cooled to room temperature in S3 into powder with a mortar, and add it to a tablet press for tableting;

[0011] S5 detection: XRF fluorescence detection method is used to detect the phosphorus content in the sample to be tested in S4.

[0012] Further, in S2, the muffle furnace drying temperature is set to 900°C, and the drying time is set to 15-20 minutes.

[0013] Further, in S4, the tablet pressing pressure of the tablet press is set to 30 KPa, and the tablet pressing stabilization time is set to 30 s.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. The present invention solves the problem that the phosphorus content in the production system of titanium dioxide produced by the sulfuric acid process can only be monitored in the white area but not in the whole system.

[0016] 2. The data of the present invention has good reproducibility. After repeated experiments, the error of parallel sample determination is within 0.001%, which can guide production operation. The present invention reduces the feedback time of phosphorus content in the production system from 5-6 days to 1-1.5 days, so that the production plan can be adjusted in time during the ore crushing and acid hydrolysis feeding process sections, and any abnormalities can be known in advance and handled in advance, which is of great significance to the control of titanium dioxide phosphate salts by sulfuric acid process.

[0017] 3. By using the present invention to simulate the sulfuric acid process titanium dioxide production in the laboratory, the optimal blending ratio of low-phosphorus titanium concentrate and high-phosphorus titanium concentrate can be explored, thereby further reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the embodiments.

[0020] The titanium clear liquid obtained in the present invention is the supernatant obtained by sedimentation after titanium concentrate reacts with sulfuric acid in the sulfuric acid process titanium dioxide production process.

[0021] Embodiment 1:

[0022] Under laboratory conditions, high-phosphorus titanium concentrate with a phosphorus content of 0.065% and low-phosphorus titanium concentrate with a phosphorus content of 0.035% were used in a blending ratio of 25% high-phosphorus ore: 75% low-phosphorus ore. The simulated process of producing titanium dioxide using the sulfuric acid method, including premixing, acid hydrolysis, aging, leaching, reduction, and sedimentation, was used to obtain 133g / L of clear titanium liquid after sedimentation.

[0023] Take 30 ml of clear titanium liquid into a corundum crucible and place it on an electric heating furnace to evaporate until it is almost dry.

[0024] The nearly dry solid material together with the corundum crucible was transferred to a muffle furnace and dried at 900°C for 15 min, taken out, and cooled to room temperature.

[0025] The solid material in the cooled corundum crucible is added into a mortar and ground into powder, and then put into a tablet press for tableting.

[0026] The phosphorus content in the solid material was measured by X-ray fluorescence spectrometer and was 0.145%.

[0027] Embodiment 2:

[0028] Under laboratory conditions, high-phosphorus titanium concentrate with a phosphorus content of 0.065% and low-phosphorus titanium concentrate with a phosphorus content of 0.035% were used in a blending ratio of 30% high-phosphorus ore: 70% low-phosphorus ore. The simulated process of sulfuric acid method production of titanium dioxide, including premixing, acid hydrolysis, aging, leaching, reduction, and sedimentation, was carried out to obtain 131g / L of sedimentation clear titanium liquid.

[0029] Take 30 ml of clear titanium liquid into a corundum crucible and place it on an electric heating furnace to evaporate until it is almost dry.

[0030] The nearly dry solid material together with the corundum crucible was transferred to a muffle furnace and dried at 900°C for 15 min, taken out, and cooled to room temperature.

[0031] The solid material in the cooled corundum crucible is added into a mortar and ground into powder, and then put into a tablet press for tableting.

[0032] The phosphorus content in the solid material was measured by X-ray fluorescence spectrometer and was 0.188%.

[0033] Embodiment 3:

[0034] The titanium clearing liquid and all the steps used in Example 3 are the same as those in Example 2, except that in the S2 drying step in Example 3, the nearly dry solid material together with the corundum crucible is moved to a muffle furnace and dried at 900° C. for 20 min, taken out, and cooled to room temperature.

[0035] The phosphorus content in the solid material was measured by X-ray fluorescence spectrometer and was 0.182%.

[0036] Embodiment 4:

[0037] Under laboratory conditions, high-phosphorus titanium concentrate with a phosphorus content of 0.065% and low-phosphorus titanium concentrate with a phosphorus content of 0.035% were used in a blending ratio of 35% high-phosphorus ore: 65% low-phosphorus ore. The simulated process of sulfuric acid method production of titanium dioxide, including premixing, acid hydrolysis, aging, leaching, reduction, and sedimentation, was used to obtain 130g / L of sedimentation clear titanium liquid.

[0038] Take 30 ml of clear titanium liquid into a corundum crucible and place it on an electric heating furnace to evaporate until it is almost dry.

[0039] The nearly dry solid material together with the corundum crucible was transferred to a muffle furnace and dried at 900°C for 15 min, taken out, and cooled to room temperature.

[0040] The solid material in the cooled corundum crucible is added into a mortar and ground into powder, and then put into a tablet press for tableting.

[0041] The phosphorus content in the solid material was measured by X-ray fluorescence spectrometer and was 0.213%.

[0042] Embodiment 5:

[0043] Under laboratory conditions, high-phosphorus titanium concentrate with a phosphorus content of 0.065% and low-phosphorus titanium concentrate with a phosphorus content of 0.035% were used in a blending ratio of 40% high-phosphorus ore: 60% low-phosphorus ore. The simulated process of sulfuric acid method production of titanium dioxide, including premixing, acid hydrolysis, aging, leaching, reduction, and sedimentation, was used to obtain 132g / L of sedimentation clear titanium liquid.

[0044] Take 30 ml of clear titanium liquid into a corundum crucible and place it on an electric heating furnace to evaporate until it is almost dry.

[0045] The nearly dry solid material together with the corundum crucible was transferred to a muffle furnace and dried at 900°C for 15 min, taken out, and cooled to room temperature.

[0046] The solid material in the cooled corundum crucible is added into a mortar and ground into powder, and then put into a tablet press for tableting.

[0047] The phosphorus content in the solid material was measured by X-ray fluorescence spectrometer and was 0.251%.

[0048] It should be noted that before using an X-ray fluorescence spectrometer to test the pressed samples, multiple titanium dioxide base materials with known equivalent amounts of phosphorus elements added must be used as standard samples, and the samples must be prepared by pressing according to step S4. By testing these standard samples and establishing a phosphorus standard curve in the XRF spectrometer, the samples to be tested can then be tested.

Claims

1. A method for determining phosphorus content in titanium cleaning solution, characterized in that: The following steps are involved: S1 Evaporation and concentration: take the clear titanium liquid after sedimentation into a crucible, place it on a heating furnace and heat it until no bubbles emerge, so as to obtain a nearly dry sample to be tested; S2 Drying: After the sample is almost dry in S1, move the sample together with the crucible into a muffle furnace for drying; S3 cooling: taking out the sample to be tested after drying in S2 from the muffle furnace and cooling it to room temperature; S4 Sample preparation: Grind the solid sample to be tested cooled to room temperature in S3 into powder with a mortar, and add it to a tablet press for tableting; S5 detection: XRF fluorescence detection method is used to detect the phosphorus content in the sample to be tested in S4.

2. The method for determining phosphorus content in titanium-clearing liquid according to claim 1, characterized in that: In S2, the muffle furnace drying temperature is set to 900°C, and the drying time is set to 15-20min.

3. The method for determining phosphorus content in titanium-clearing liquid according to claim 1, characterized in that: In S4, the tablet pressing pressure of the tablet press is set to 30 KPa, and the tablet pressing stabilization time is set to 30 s.

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