A method for producing high-phosphorus ore rutile titanium dioxide

Abstract

The invention discloses a method for producing high-phosphate rutile titanium dioxide, comprising the following steps: S1, taking the rinsed metatitanic acid slurry and beating it to prepare slurry A; S2, adding ammonia water to the slurry A, adjusting the pH value to 4.0-4.5, and obtaining slurry B; S3, adding 0.001-0.05% by weight of sodium citrate to the slurry B, and obtaining slurry C; S4, taking the slurry C, adding a crystal transformation promoter and a crystal transformation inhibitor, stirring, and filtering to obtain a filter cake D; S5, drying and calcining the filter cake D for 60-100 minutes, and preparing a calcined high-phosphate rutile titanium dioxide through dehydration, desulfurization, crystal transformation, and grain growth. The obtained product has uniform particles, moderate size, soft and brittle hardness, good pigment performance, good whiteness, high brightness, high tinting power, strong hiding power, low oil absorption, good dispersibility, and all indicators reach a good range.

Description

Technical Field

[0001] The invention relates to the technical field of titanium dioxide production, in particular to a method for producing high-phosphorus ore rutile titanium dioxide. Background Art

[0002] Titanium dioxide is an important inorganic chemical pigment, mainly divided into anatase titanium dioxide and rutile titanium dioxide. Rutile titanium dioxide is widely used because it has more stable performance, higher refractive index and lower thermal conductivity. Under the pressure of production cost control, more and more titanium dioxide manufacturers are forced to use unsuitable high-phosphate ore as the main raw material. However, phosphorus is an inhibitor that prevents the transformation of anatase to rutile. The main principle is that when metatitanic acid is calcined, phosphorus will not invade TiO2 as the temperature rises. 2 inside the lattice, but adsorbed on its surface, in the TiO 2 During the process of particle growth and crystal formation, these phosphates adsorbed on the surface of titanium dioxide will act as a barrier, preventing the transformation of titanium dioxide crystals and seriously affecting the quality of titanium dioxide.

[0003] After bleaching, direct calcination of titanic acid requires a relatively high temperature. Moreover, the crystal growth and stabilization of the dehydrated and desulfurized titanic acid is difficult to control. The resulting titanium dioxide particles are very hard, and the color is either yellowish gray or dark yellow, or even cement-like gray. If the calcination temperature is not increased, the sulfur in the titanic acid cannot be completely removed, and the resulting material has a low pH, high oil absorption, and poor color-reducing power, which cannot achieve the best application performance of the pigment. When the calcination temperature is high, the particles of the titanic acid are prone to sintering, which seriously affects the performance of the product. Therefore, the titanic acid must be treated before calcination, and a certain salt treatment agent must be added to allow the titanic acid to complete the dehydration and desulfurization process at a relatively low temperature.

[0004] Publication No. CN1559913A discloses a method for preparing rutile titanium dioxide. The process steps are: adding rutile calcined crystal seeds after bleaching and rinsing qualified metatitanic acid cake to make metatitanic acid slurry with deionized water, then adding a salt treatment agent composed of potassium compound, phosphorus compound and aluminum compound, and calcining to obtain rutile titanium dioxide.

[0005] However, when this method is used to prepare titanium dioxide, the pH value of the titanic acid slurry can only be controlled below 2.0, the salt treatment agent is easily lost, the production efficiency is reduced, the amount of salt treatment agent required is large, and the potassium compound used is expensive, resulting in high production costs. Summary of the invention

[0006] The present invention aims to solve the technical problem and provides a method for producing high-phosphate rutile titanium dioxide in view of the shortcomings of the prior art, thereby improving production efficiency, saving production costs and increasing the weather resistance of rutile titanium dioxide.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for producing high-phosphorus ore rutile titanium dioxide comprises the following steps:

[0009] S1, taking the rinsed metatitanic acid slurry and beating it to make slurry A;

[0010] S2. Add ammonia water to slurry A and adjust the pH value to 4.0-4.5 to obtain slurry B;

[0011] S3, adding 0.001-0.05% by weight of sodium citrate to slurry B to prepare slurry C;

[0012] S4, taking slurry C, adding a crystal transformation promoter and a crystal transformation inhibitor, stirring, and filtering to form a filter cake D;

[0013] S5. Dry and calcine the filter cake D for 60-100 minutes, and then dehydrate, desulfurize, transform the crystal form, and grow the grains until the titanium dioxide rutile content is ≥99.0% and the whiteness is L * ≥98.5, whiteness b * ≤1.8, tinting power ≥105%.

[0014] Among them, the TiO 2 The content is 280-330g / L

[0015] Wherein, the P of the metatitanic acid slurry described in S1 is 2 O 5 Mass ratio>0.35%.

[0016] Among them, the crystal transformation promoter in S4 is composed of zinc salt and lithium salt, and the crystal transformation inhibitor is composed of sodium salt and sodium aluminate. The amount of zinc salt added is calculated as zinc oxide, and its amount is 0.15-0.35% of the mass of titanium dioxide; the amount of lithium salt added is calculated as lithium oxide, and its amount is 0.02-0.15% of the mass of titanium dioxide; the amount of sodium salt added is calculated as sodium bicarbonate, and its amount is 0.05-0.45% of the mass of titanium dioxide; the amount of sodium aluminate added is 0.01-0.04% of the mass of titanium dioxide.

[0017] Wherein, the sodium salt is at least one of sodium hydroxide, sodium bicarbonate and sodium carbonate.

[0018] Among them, the calcination temperature in S5 is 910-930°C.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention uses low-priced sodium salt, which can greatly reduce production costs;

[0021] 2. In the present invention, ammonia water is added to slurry A to adjust the pH value to 4.0-4.5, and sodium citrate is added to make the dispersibility of slurry A better, and the salt treatment agent can be better attached to TiO 2 The surface of the particles makes the salt treatment agent work better and is not easy to cause loss, which greatly reduces the amount of salt treatment agent used;

[0022] 3. A small amount of lithium salt is added during the production process of the present invention to promote crystal transformation during the preparation of titanium dioxide, which can effectively reduce the calcination temperature, reduce energy consumption, and improve pigment performance.

[0023] 4. The present invention also adds sodium aluminate, a crystal transformation inhibitor. Lithium salt has a strong promoting effect on the crystal transformation of titanium dioxide. Sodium aluminate has the function of stabilizing the crystal lattice. When the pH value of metatitanic acid is between 4.0 and 4.5, sodium aluminate is coated on the TiO2 with a dense aluminum oxide film. 2 A protective layer is formed on the surface of the particles, which can enhance the weather resistance and light resistance of titanium dioxide as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of the production method of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides: a method for producing high-phosphorus ore rutile titanium dioxide,

[0027] Embodiment 1:

[0028] A method for producing high-phosphorus ore rutile titanium dioxide is carried out according to the following steps:

[0029] S1, take the rinsed P 2 O 5 The mass ratio of 0.35% titanate slurry was made into TiO 2 Slurry A with a content of 280 g / L;

[0030] S2, adding ammonia water to slurry A, adjusting the pH value to 4.0 to obtain slurry B;

[0031] S3, adding 0.001% by weight of sodium citrate to slurry B to prepare slurry C;

[0032] S4, weigh 215g of slurry C, add 1.55mL of zinc oxide, add 0.42mL of lithium oxide, add 0.7mL of sodium bicarbonate, add 0.25mL of sodium aluminate, stir for 1 hour, filter out water through a Buchner filter, and make a filter cake D;

[0033] S5, drying the filter cake D and calcining it at 910°C for 1 hour, dehydrating, desulfurizing, crystal transformation, and grain growth until the titanium dioxide rutile content is 99.0%, the whiteness is L * The value is 98.8, whiteness b * The value is 1.4 and the tinting power is 110%.

[0034] Specifically in S4: the amount of zinc oxide added is 0.15% of the mass of titanium dioxide and the concentration is 208g / L; the amount of lithium oxide added is 0.02% of the mass of titanium dioxide and the concentration is 102g / L; the amount of sodium bicarbonate added is 0.05% of the mass of titanium dioxide and the concentration is 152g / L; the amount of sodium aluminate added is 0.01% of the mass of titanium dioxide and the concentration is 87.5g / L.

[0035] Embodiment 2:

[0036] A method for producing high-phosphorus ore rutile titanium dioxide is carried out according to the following steps:

[0037] S1, take the rinsed P 2 O 5 The mass ratio of 0.45% titanate slurry was made into TiO 2 Slurry A with a content of 280 g / L;

[0038] S2, adding ammonia water to slurry A, adjusting the pH value to 4.2 to obtain slurry B;

[0039] S3, adding 0.002% by weight of sodium citrate to slurry B to prepare slurry C;

[0040] S4, weigh 215g of slurry C, add 2.07mL of zinc sulfate, 1.05mL of lithium oxide, 1.41mL of sodium bicarbonate, 0.25mL of sodium aluminate, stir for 1 hour, filter out water through a Buchner filter, and prepare filter cake D;

[0041] S5, drying the filter cake D and calcining it at 910°C for 1 hour, dehydrating, desulfurizing, crystal transformation, and grain growth until the titanium dioxide rutile content is 99.5% and the whiteness is L * The value is 99, whiteness b * The value is 1.3 and the tinting power is 110%.

[0042] Specifically in S4: the amount of zinc sulfate added is 0.20% of the mass of titanium dioxide and the concentration is 208g / L; the amount of lithium oxide added is 0.05% of the mass of titanium dioxide and the concentration is 102g / L; the amount of sodium bicarbonate added is 0.1% of the mass of titanium dioxide and the concentration is 152g / L; the amount of sodium aluminate added is 0.01% of the mass of titanium dioxide and the concentration is 87.5g / L.

[0043] Embodiment 3:

[0044] A method for producing high-phosphorus ore rutile titanium dioxide is carried out according to the following steps:

[0045] S1, take the rinsed P 2 O 5 The mass ratio of 0.5% titanate slurry is made into TiO 2 Slurry A with a content of 280 g / L;

[0046] S2, adding ammonia water to slurry A, adjusting the pH value to 4.5 to obtain slurry B;

[0047] S3, adding 0.05% by weight of sodium citrate to slurry B to prepare slurry C;

[0048] S4, weigh 215g of slurry C, add 2.58mL of zinc chloride, 2.1mL of lithium hydroxide, 2.12mL of sodium bicarbonate, 0.74mL of sodium aluminate, stir for 1 hour, filter out water through a Buchner filter, and prepare filter cake D;

[0049] S5, drying the filter cake D and calcining it at 920°C for 1 hour, dehydrating, desulfurizing, crystal transformation, and grain growth until the titanium dioxide rutile content is 99.8% and the whiteness is L * The value is 98.7, whiteness b * The value is 1.26 and the tinting power is 110%.

[0050] Specifically in S4: the amount of zinc chloride added is 0.25% of the mass of titanium dioxide and the concentration is 208g / L; the amount of lithium hydroxide added is 0.1% of the mass of titanium dioxide and the concentration is 102g / L; the amount of sodium bicarbonate added is 0.15% of the mass of titanium dioxide and the concentration is 152g / L; the amount of sodium aluminate added is 0.03% of the mass of titanium dioxide and the concentration is 87.5g / L.

[0051] Embodiment 4:

[0052] A method for producing high-phosphorus ore rutile titanium dioxide is carried out according to the following steps:

[0053] S1, take the rinsed P 2 O 5The mass ratio of 0.35% titanate slurry was made into TiO 2 Slurry A with a content of 280 g / L;

[0054] S2, adding ammonia water to slurry A, adjusting the pH value to 4.5 to obtain slurry B;

[0055] S3, adding 0.05% by weight of sodium citrate to slurry B to prepare slurry C;

[0056] S4, weigh 215g of slurry C, add 3.10mL of zinc chloride, 2.1mL of lithium hydroxide, 3.54mL of sodium bicarbonate, 0.74mL of sodium aluminate, stir for 1 hour, filter out water through a Buchner filter, and prepare filter cake D;

[0057] S5, drying the filter cake D and calcining it at 930°C for 1 hour, dehydrating, desulfurizing, crystal transformation, and grain growth until the titanium dioxide rutile content is 99.8% and the whiteness is L * The value is 98.9, whiteness b * The value is 1.25 and the tinting power is 110%.

[0058] Specifically in S4: the amount of zinc chloride added is 0.30% of the mass of titanium dioxide and the concentration is 208g / L; the amount of lithium hydroxide added is 0.1% of the mass of titanium dioxide and the concentration is 102g / L; the amount of sodium bicarbonate added is 0.25% of the mass of titanium dioxide and the concentration is 152g / L; the amount of sodium aluminate added is 0.03% of the mass of titanium dioxide and the concentration is 87.5g / L.

[0059] Embodiment 5:

[0060] A method for producing high-phosphorus ore rutile titanium dioxide is carried out according to the following steps:

[0061] S1, take the rinsed P 2 O 5 The mass ratio of 0.4% titanate slurry was made into TiO 2 Slurry A with a content of 280 g / L;

[0062] S2, adding ammonia water to slurry A, adjusting the pH value to 4.5 to obtain slurry B;

[0063] S3, adding 0.05% by weight of sodium citrate to slurry B to prepare slurry C;

[0064] S4, weigh 215g of slurry C, add 3.62mL of zinc chloride, 3.16mL of lithium hydroxide, 6.37mL of sodium bicarbonate, 0.98mL of sodium aluminate, stir for 1 hour, filter out water through a Buchner filter, and prepare filter cake D;

[0065] S5, drying the filter cake D and calcining it at 910°C for 1 hour, dehydrating, desulfurizing, crystal transformation, and grain growth until the titanium dioxide rutile content is 99.1% and the whiteness is L * The value is 98.6, whiteness b * The value is 1.5 and the tinting power is 110%.

[0066] Specifically in S4: the amount of zinc chloride added is 0.35% of the mass of titanium dioxide and the concentration is 208g / L; the amount of lithium hydroxide added is 0.15% of the mass of titanium dioxide and the concentration is 102g / L; the amount of sodium bicarbonate added is 0.45% of the mass of titanium dioxide and the concentration is 152g / L; the amount of sodium aluminate added is 0.04% of the mass of titanium dioxide and the concentration is 87.5g / L.

[0067] Comparative Example:

[0068] Based on the above technical solution, a group of embodiments of treating calcined products of low-phosphate ore are now provided, and the specific steps include:

[0069] S1, take the rinsed P 2 O 5 The mass ratio of 0.02% titanate slurry is made into TiO 2 Slurry A with a content of 280 g / L;

[0070] S2. Weigh 215 g of slurry A, add 8.49 mL of potassium carbonate, 2.07 mL of zinc sulfate, and 2.9 mL of phosphoric acid;

[0071] S3, stirring for 1 hour, filtering out water with a Buchner funnel, drying and calcining at 910°C for 1 hour, taking samples to measure the rutile content of 99.2%, whiteness L * The value is 98.8, whiteness b * The value is 1.26 and the tinting power is 110%.

[0072] Compared with the examples, it can be seen that the quality of the salt-treated calcined product of high-phosphate ore is comparable to that of the conventional low-phosphate ore salt-treated calcined product. The use of low-priced sodium salt in the present invention can greatly reduce production costs;

[0073] In the present invention, ammonia water and sodium citrate are added simultaneously, the pH value is adjusted to 4.0-4.5 by ammonia water, and sodium citrate is used to improve the dispersibility of slurry A, so that the salt treatment agent can be better attached to TiO 2 The surface of the particles allows them to fully exert their functions, avoid loss, and greatly reduce the amount of salt treatment agent used;

[0074] In the production process of the present invention, a small amount of lithium salt can promote the crystal transformation in the titanium dioxide preparation process, effectively reduce the calcination temperature, thereby reducing energy consumption and ultimately improving the pigment performance. In this embodiment, by adding sodium aluminate, a crystal transformation inhibitor, the promotion effect of lithium salt in the crystal transformation of titanium dioxide is enhanced, and sodium aluminate is used to stabilize the crystal lattice. When the pH value of metatitanic acid is between 4.0 and 4.5, sodium aluminate is coated on TiO2 with a dense aluminum oxide film. 2 A protective layer is formed on the surface of the particles, which can enhance the weather resistance and light resistance of titanium dioxide as much as possible.

[0075] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing high-phosphorus ore rutile titanium dioxide, characterized in that: The steps include: S1, taking the rinsed metatitanic acid slurry and beating it to make slurry A; S2. Add ammonia water to slurry A and adjust the pH value to 4.0-4.5 to obtain slurry B; S3, adding 0.001-0.05% by weight of sodium citrate to slurry B to prepare slurry C; S4, taking slurry C, adding a crystal transformation promoter and a crystal transformation inhibitor, stirring, and filtering to form a filter cake D; S5. Dry and calcine the filter cake D for 60-100 minutes, and then dehydrate, desulfurize, transform the crystal form, and grow the grains until the titanium dioxide rutile content is ≥99.0% and the whiteness is L * ≥98.5, whiteness b * ≤1.8, tinting power ≥105%; The content of TiO2 in the slurry A in S1 is 280-330 g / L; The mass ratio of P2O5 in the metatitanic acid slurry in S1 is greater than 0.35%; The crystal transformation promoter in S4 is composed of zinc salt and lithium salt, and the crystal transformation inhibitor is composed of sodium salt and sodium aluminate. The amount of zinc salt added is calculated as zinc oxide, and its amount is 0.15-0.35% of the mass of titanium dioxide; the amount of lithium salt added is calculated as lithium oxide, and its amount is 0.02-0.15% of the mass of titanium dioxide; the amount of sodium salt added is calculated as sodium bicarbonate, and its amount is 0.05-0.25% of the mass of titanium dioxide; the amount of sodium aluminate added is 0.01-0.04% of the mass of titanium dioxide; The sodium salt is at least one of sodium hydroxide, sodium bicarbonate and sodium carbonate; The calcination temperature in S5 is 910-930°C.

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