(School of Chemistry and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083)

First, the content introduction

The technical achievements of this project include dry continuous surface modification technology, SLG continuous powder surface modification machine and wet surface modification technology; Surface modification technology of calcined kaolin, ceramic pigment, nano powder, etc.

Dry continuous surface modification technology of (1) nonmetallic mineral powder

This achievement is an industrial integration technology of dry continuous surface modification of nonmetallic mineral powder with SLG continuous powder surface modifier as the core, including surface modification process and formula.

This technology is suitable for surface modification of ultrafine powder of nonmetallic minerals such as ultrafine light calcium carbonate, ultrafine heavy calcium carbonate, ultrafine high whiteness calcined kaolin and talcum powder. Its main technical indicators are superior to other domestic technologies, and are equivalent to foreign advanced technologies in this field. When used for surface modification of superfine light calcium carbonate and superfine heavy calcium carbonate with d97≤ 10μm, the single machine production capacity can reach 3.5 t/h, the activation index can reach over 96%, and the energy consumption per unit product is ≤ 40 (kW h) t. ..

This technical achievement has passed the technical achievement appraisal organized by China Building Materials Industry Association on March 7, 2007 (Building Materials Jian Zi [2007] No.003). Among them, SLG continuous powder surface modifier has obtained the national invention patent (patent number: ZL0222 1 135.7, authorization announcement date: May 2003 14).

(2) Wet surface modification technology of ultrafine powder.

For wet ultrafine grinding or other wet grinding processes, ultrafine powder will form hard aggregates during drying, so it is necessary to set up a crushing and depolymerization device after drying (it is difficult to fully recover even after setting up crushing operation). Surface modification after wet ultrafine grinding and before drying can not only prevent ultrafine powder from forming hard aggregates that are difficult to depolymerize during drying, but also make the contact opportunities between molecules and particles of surface modifier more equal, and the surface coating modification is even and the surface modification effect is better.

The key technology of wet surface modification is the use method, formula and drying process equipment of surface modifier. The reason is that most organic surface modifiers are insoluble in water and cannot be added directly; In addition, the drying temperature should be controlled properly, not too high, so as to avoid the decomposition of the surface modifier. The characteristics of this technology are that these two problems are well solved: ① surface modifiers are selected and prepared according to the requirements of slurry use; ② The multifunctional dryer is adopted, which has high drying efficiency and the function of drying and depolymerization (soft agglomeration).

The research team of this project has completed the research and development of wet surface modification of nano-calcium carbonate, ultrafine aluminum hydroxide and ultrafine magnesium hydroxide for flame retardant, ultrafine silica (white carbon black), ultrafine sericite powder, ultrafine diatomite and iron oxide red, and some of them have been applied in industry.

Wet surface modification process is suitable for wet preparation of inorganic ultrafine powder, especially for surface modification of inorganic ultrafine and nano powder below 65438 0 μ m, such as ultrafine and nano calcium carbonate, ultrafine heavy calcium carbonate, ultrafine aluminum hydroxide and magnesium hydroxide, ultrafine silica (white carbon black), etc. Because both organic and inorganic coatings can be modified by wet method, the product has uniform surface coating and good dispersibility, and has good application performance and broad market prospects.

(3) Surface modification technology of ultrafine aluminum hydroxide

Ultrafine aluminum hydroxide is the inorganic flame retardant filler with the largest dosage at present. Because the application object is organic polymer materials, and in order to meet the requirements of flame retardant technology, Al(OH)3 must be modified when used as a flame retardant to improve its compatibility with polymer matrix and improve the mechanical properties of the material. The modification method of this technology is that in the slurry state before drying, according to the different polymer matrix materials, different surface modifier formulas are used for surface modification, so that ultrafine Al(OH)3 does not form hard agglomeration after drying, is in a good dispersion state, and has good compatibility with both organic and inorganic phases (water phase). Oil absorption rate, dispersibility and application performance indicators (oxygen index, tensile strength, elongation at break, etc.). ) the modified products are equivalent to the products of German Martin Company.

(D) Surface treatment technology of inorganic pigment powder

Compatibility of ultrafine and ultrafine inorganic powder pigments with binders (ceramic blank, glaze binder, powder coating binder, etc.). ) determines their dispersibility and uniform coloring in the binder. Fine or ultra-fine inorganic powder pigments without surface treatment are kneaded into dough and agglomerated for a long time, so it is difficult to disperse evenly in the base material when used, which leads to the increase of pigment consumption and uneven coloring. This surface treatment technology adopts a unique "inorganic-organic" compound surface treatment agent formula and a simple and easy heating (60 ~ 100℃) mixing process. The treated fine and ultra-fine inorganic powder pigment can not be pinched by hand (like fluid), and will not agglomerate for a long time, and can be dispersed spontaneously in water without strong stirring. This technology has been applied to the surface treatment of domestic green, yellow and other ceramic pigments. The performance of the treated ceramic pigment can be completely compared with that of high-grade imported pigments, and it has the characteristics of less investment (simple process equipment) and low production cost (< 0.2 yuan /kg pigment).

(V) Surface modification technology of calcined kaolin

Kaolin is a layered silicate mineral. The crushed kaolin is flaky particles with hydroxyl and oxygen-containing groups on the surface, which is acidic. Calcined ultrafine calcined kaolin has strong acidity and surface polarity. When used as filler and pigment of plastics, rubber, cables and coatings, and as chemical carrier, in order to improve the compatibility or dispersibility of calcined kaolin with the substrate and improve its application performance, it must be surface treated.

This technology includes the surface modification process and formula of calcined kaolin in the following application fields: ① cable insulation material; ②PE and PP plastic films; ③ Rubber products; ④ Engineering plastics; ⑤ Waterborne coatings; ⑥ oily coating; ⑦ Chemical carrier.

(VI) Wet surface modification technology of nanometer calcium carbonate.

The production and application of nano-calcium carbonate have been paid more and more attention in China. Because nano calcium carbonate is produced in liquid phase, it is very inconvenient to use and transport. However, when it is made into powder, because of its high surface energy, it cannot be completely redispersed, which affects its actual particle size, particle size distribution and application performance. The solution of this technology is to modify the surface of nano-calcium carbonate in slurry state before drying according to different uses, so that nano-calcium carbonate does not form hard agglomeration after drying, is in a good dispersion state, and has good compatibility with organic phase or polymer matrix material or inorganic phase (water phase), thus improving its performance and making nano-calcium carbonate can be used in more environments and fields. The application field of this technology includes the following two groups of surface modification processes and formulas:

1) polymer substrate (resin) and oily coating and ink.

2) Waterborne coatings and inks.

Second, popularization and application

Dry continuous surface modification technology has been applied in nearly 100 enterprises.

Three. Identification, awards and patents

Appraisal time: April 2007 17 (China Building Materials Industry Association).

PatentNo.: ZL 0222 1 135.7 (date of authorization announcement: May 65438+April 2003).

In 2007, he won the second prize of building materials science and technology award for scientific and technological progress.