阅读说明：本技术 复合高包覆二氧化钛生产工艺 (production process of composite high-coating titanium dioxide ) 是由 褚立峰 高培勇 于 2019-08-26 设计创作，主要内容包括：本发明涉及钛白粉生产技术领域,尤其是复合高包覆二氧化钛生产工艺。本发明的复合高包覆二氧化钛生产工艺,以高岭土浆料和TiCl<Sub>4</Sub>为原料,通过湿磨、TiCl<Sub>4</Sub>水溶液制备、二氧化钛包覆、包覆物过滤和煅烧盐预处理、煅烧、研磨和包装等步骤制得高包覆二氧化钛,制得的复合高包覆二氧化钛具备二氧化钛的优异功能,且大大降低成本,减少二氧化钛生产中的“三废”污染。(The invention relates to the technical field of titanium dioxide production, in particular to a production process of composite high-coating titanium dioxide. The invention relates to a production process of composite high-coating titanium dioxide, which uses kaolin slurry and TiCl 4 is prepared from raw materials through wet grinding and TiCl 4 The high-coating titanium dioxide is prepared by the steps of aqueous solution preparation, titanium dioxide coating, coating material filtration, calcined salt pretreatment, calcination, grinding, packaging and the like, and the prepared composite high-coating titanium dioxide has the excellent function of titanium dioxide, greatly reduces the cost and reduces the three-waste pollution in the production of titanium dioxide.)

1. The production process of the composite high-coating titanium dioxide is characterized by comprising the following steps of: the method comprises the following steps:

(1) Wet grinding: preparing kaolin slurry by using deionized water, controlling the concentration of the kaolin slurry to be 500-650g/L, controlling the pH to be 9-10, controlling the temperature to be 30 +/-5 ℃, adding 75-85 parts by weight of the kaolin slurry into a wet grinding system, adding 2-5 per mill of a dispersed grinding aid in solid phase mass ratio into the wet grinding system, starting the wet grinding system, circularly grinding until the particle size distribution D501um is more than 90%, and pumping the kaolin slurry after grinding into a storage tank;

(2)TiCl₄Preparation of an aqueous solution: TiCl preparation in a sealed reaction tank with a Cooling Water System₄Water solution, opening a cooling water system to keep the water temperature of the reaction tank less than 4 ℃, operating the exhaust absorption circulating spraying system of the reaction tank, and starting TiCl₄Discharge valve, start stirring, water and TiCl₄In a ratio of (4-6):2, TiCl₄the water solution is in a light yellow transparent state; (3) coating with titanium dioxide: pumping the kaolin mixed slurry prepared in the step (1) into a coating reaction tank, setting the stirring speed to be 100-130r/min, and adding TiCl with the weight fraction of 20-25% of the kaolin slurry₄Adding the aqueous solution into a coating reaction tank, and adding TiCl₄adding NaOH solution into the mixture while adding the aqueous solution, continuously stirring, stopping the reaction when the pH is detected to be 7.0-7.5, and continuing to reactstirring for 50-70min, and aging;

(4) Coating filtration and calcined salt pretreatment: adding phosphoric acid and potassium hydroxide before filtering, and calculating P according to the mass ratio₂O₅0.15-0.18％，k₂0.35-0.45% of O, separating and filtering the materials by centrifugal separation or plate-and-frame filter pressing, returning the filtered mother liquor to the previous process for proportioning, and feeding the filter cake into a material preparation tank for preparing materials for calcination;

(5) And (3) calcining: calcining in a rotary kiln, wherein the calcining temperature is controlled as follows: the temperature of a combustion section is 980-1030 ℃, the temperature of a kiln tail is 300-420 ℃, and the rotating speed of a rotary kiln is as follows: 5-6r/min, and cooling the calcined material for later use;

(6) grinding and packaging: and grinding the calcined product by a Raymond mill to obtain a composite titanium dioxide product, and then packaging.

2. The production process of the composite high-coating titanium dioxide according to claim 1, characterized in that: the kaolin adopted in the process of preparing the kaolin slurry is 4000 meshes, the whiteness is more than or equal to 93 percent, the proportion of the granularity between 0 and 2 mu m is more than or equal to 88 percent, the residue of the 325 meshes is less than or equal to 0.02 percent, the refractive index is 1.62 percent, the water content is less than 0.5 percent, the pH value of the water extract is 6 to 7, and the covering rate is more than or equal to 93 percent.

3. The production process of the composite high-coating titanium dioxide according to claim 1, characterized in that: the water and TiCl in the step (2)₄The ratio was 5:2.

4. The production process of the composite high-coating titanium dioxide according to claim 1, characterized in that: and (3) setting the stirring speed to be 110r/min, finishing the reaction when the pH is detected to be 7.0-7.5, and continuing stirring for 60 min.

Technical Field

the invention relates to the technical field of titanium dioxide production, in particular to a production process of composite high-coating titanium dioxide.

Background

Titanium dioxide (TiO)₂) The titanium dioxide is an important inorganic chemical product, and has three crystal forms in nature, namely a brookite form, an anatase form and a rutile form, and the commercial titanium dioxide mainly has the anatase form and the rutile form. It is mainly used in the industries of paint, plastics, paper making, printing ink, rubber, chemical fiber and the like, and is called as the king of white pigment.

In the commonly used white pigments, the titanium dioxide has the lowest relative density, and in the same quality white pigment, the titanium dioxide has the largest surface area and the highest pigment volume. Titanium dioxide is chemically very stable and is a meta-acidic amphoteric oxide. Hardly reacts with other elements and compounds at normal temperature, does not act on oxygen, ammonia, hydrogen sulfide, carbon dioxide and sulfur dioxide, is insoluble in water, fat, dilute acid and alkali, is only soluble in hydrofluoric acid, and has good thermal stability.

Existing titanium dioxide (TiO)₂) The production cost is high, and the pollution of three wastes is easily generated in the production process, so if a composite material is provided, the composite material has the excellent function of titanium dioxide, the cost is greatly reduced, and the pollution of three wastes in the production of titanium dioxide is reduced, which is a technical problem to be solved by the technical personnel in the field.

Disclosure of Invention

the invention aims to provide a production process of composite high-coating titanium dioxide, which overcomes the defects of the prior art, and the produced composite material has the excellent functions of the titanium dioxide, greatly reduces the cost and reduces the three-waste pollution in the production of the titanium dioxide.

The technical scheme adopted by the invention for solving the technical problems is as follows:

The production process of the composite high-coating titanium dioxide comprises the following steps:

(1) Wet grinding: preparing kaolin slurry by using deionized water, controlling the concentration of the kaolin slurry to be 500-650g/L, controlling the pH to be 9-10, controlling the temperature to be 30 +/-5 ℃, adding 75-85 parts by weight of the kaolin slurry into a wet grinding system, adding 2-5 per mill of a dispersed grinding aid in solid phase mass ratio into the wet grinding system, starting the wet grinding system, circularly grinding until the particle size distribution D501um is more than 90%, and pumping the kaolin slurry after grinding into a storage tank;

(2)TiCl₄preparation of an aqueous solution: TiCl preparation in a sealed reaction tank with a Cooling Water System₄Water solution, opening a cooling water system to keep the water temperature of the reaction tank less than 4 ℃, operating the exhaust absorption circulating spraying system of the reaction tank, and starting TiCl₄Discharge valve, start stirring, water and TiCl₄In a ratio of (4-6):2, TiCl₄The water solution is in a light yellow transparent state;

(3) Coating with titanium dioxide: coating with titanium dioxide: pumping the kaolin mixed slurry prepared in the step (1)Coating a reaction tank, setting the stirring speed at 100-130r/min, and adding 20-25 wt% of TiCl into the kaolin slurry₄Adding the aqueous solution into a coating reaction tank, and adding TiCl₄Adding the aqueous solution and adding NaOH solution in parallel, continuously stirring, stopping reaction when the pH is detected to be 7.0-7.5, continuously stirring for 50-70min, and aging;

(4) Coating filtration and calcined salt pretreatment: adding phosphoric acid and potassium hydroxide before filtering, and calculating P according to the mass ratio₂O₅0.15-0.18％，K₂0.35-0.45% of O, separating and filtering the materials by centrifugal separation or plate-and-frame filter pressing, returning the filtered mother liquor to the previous process for proportioning, and feeding the filter cake into a material preparation tank for preparing materials for calcination;

(5) and (3) calcining: calcining in a rotary kiln, wherein the calcining temperature is controlled as follows: the temperature of a combustion section is 980-1030 ℃, the temperature of a kiln tail is 300-420 ℃, and the rotating speed of a rotary kiln is as follows: 5-6r/min, and cooling the calcined material for later use;

(6) Grinding and packaging: and grinding the calcined product by a Raymond mill to obtain a composite titanium dioxide product, and then packaging.

Preferably, the kaolin adopted in the process of preparing the kaolin slurry is 4000 meshes, the whiteness is more than or equal to 93 percent, the proportion of the particle size between 0 and 2 mu m is more than or equal to 88 percent, the residue of 325 meshes is less than or equal to 0.02 percent, the refractive index is reduced by 1.62 percent, the water content is less than 0.5 percent, the pH value of a water extraction liquid is 6 to 7, and the covering rate is more than or equal to 93 percent.

Preferably, the water and TiCl in the step (2)₄The ratio was 5:2.

Preferably, the stirring speed in the step (3) is set to be 110r/min, when the pH value is detected to be 7.0-7.5, the reaction is ended, and the stirring is continued for 60 min.

The invention has the beneficial effects that: compared with the prior art, the production process of the composite high-coating titanium dioxide has the following advantages: the prepared composite high-coating titanium dioxide has the excellent functions of titanium dioxide, the cost is greatly reduced, and the three-waste pollution in the production of titanium dioxide is reduced.

Detailed Description