# US 11,439,974 B2 · Method for preparing high-absorptivity silica as lutein carrier

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- Number: US 11,439,974 B2
- Document ID: US11439974B2
- Status: Granted
- Kind: B2
- Application number: 16/766,729
- Filed: 2019-05-07
- Published: 2021-07-29
- Granted: 2022-09-13
- Earliest claimed: 2019-01-03
- Assignees: Shandong Link Science and Technology Co., Ltd.
- Applicants: Shandong Link Science and Technology Co., Ltd.
- Inventors: Xiaolin Wu; Jinxing Hu; Haiming Gao; Hongxin Xu; Xiangkai Li; Pin Li
- Web page: https://patentgrep.com/patent/US11439974B2

## CPC

- B01J 20/103: {comprising silica}
- A23K 50/75: for poultry
- A23K 50/80: for aquatic animals, e.g. fish, crustaceans or molluscs
- B01J 20/28061: {being in the range 100-500 m2/g}
- B01J 20/28073: {being in the range 0.5-1.0 ml/g}
- B01J 20/3071: {Washing or leaching}
- C01B 33/193: of aqueous solutions of silicates
- A23K 20/179: Colouring agents, e.g. pigmenting or dyeing agents
- A23K 20/28: Silicates, e.g. perlites, zeolites or bentonites
- C01P 2006/12: Surface area
- C01P 2006/14: Pore volume
- C01P 2006/19: Oil-absorption capacity, e.g. DBP values
- C01P 2006/80: Compositional purity
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- A23K: FODDER
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

The invention discloses a preparation method of high-absorptivity silica as lutein carrier. The method includes adding sodium silicate into a synthesis kettle, introducing steam for heating while stirring, adding water, stirring for reaction to obtain a reaction substrate A, and adding sulfuric acid to the reaction substrate A to obtain reaction solution B; simultaneously adding sulfuric acid and sodium silicate into the reaction solution B, performing synthesis reaction for a given period of time, stopping feeding of sodium silicate, adding sulfuric acid only for post-acidification, and aging to obtain dilute slurry D; and filtering the dilute slurry D, washing, slurrying, drying and packaging to obtain silica microspheres as lutein carrier. The invention accurately controls each process so that the prepared high-absorptivity silica as lutein carrier has high adsorption and good dispersibility and flowability after adsorbing lutein.

## Claims

### Claim 1

A method for preparing absorptive silica as lutein carrier, comprising the steps of:
(1) adding sodium silicate into a synthesis kettle, introducing steam for heating while stirring, adding water, stirring for reaction to obtain a reaction substrate A, and adding sulfuric acid for pre-acidification until the solution pH is 8.5-10.5 to obtain reaction solution B;
(2) simultaneously adding sulfuric acid and sodium silicate into the reaction solution B, and performing synthesis reaction to obtain reaction solution C;
(3) adding sulfuric acid only into the reaction solution C, for post-acidification, until the solution pH reaches 3.5-4.0, and aging to obtain dilute slurry D;
(4) filtering the dilute slurry D, washing to obtain a filter cake E, transferring to a slurrying machine, and adding a slurry viscosity reducer to obtain slurry F; and
(5) drying the slurry F and packaging to obtain absorptive silica microspheres as lutein carrier, wherein:
the sodium silicate has a modulus of 3.30-3.60;
the slurry viscosity reducer is food-grade organic acid;
the organic acid is citric acid; and
in step (1):
the feeding amount of the sodium silicate is 4.0-8.0 m3;
the concentration of the sodium silicate in the reaction substrate A is 15-20 Baume;
the sulfuric acid is water solution of sulfuric acid with a mass fraction of 15-30%;
the feeding speed and feeding time of the sulfuric acid are, respectively, 15 m3/h and 10-30 minutes;
the reaction temperature is 30-60° C.; and
the stirring speed is 45-80 rpm.

### Claim 2 (depends on 1)

The method in claim 1, wherein in step (2):
the sulfuric acid is water solution of sulfuric acid with a mass fraction of 93-99%;
the feeding speed of the sulfuric acid is 0.6 m3/h;
the feeding speed of the sodium silicate is 4-8 m3/h;
the feeding time of the sulfuric acid and the sodium silicate is 30-60 minutes; and
the reaction temperature is 75-95° C.

### Claim 3 (depends on 2)

The method in claim 2, wherein in step (3):
the sulfuric acid is water solution of sulfuric acid with a mass fraction of 93-99%;
the feeding speed of the sulfuric acid is reduced to 50-75% of what is designated in step (2);
the feeding time is 30-60 minutes; and
the reaction temperature is 75-95° C. and the aging time is 15-30 minutes.

### Claim 4 (depends on 1)

The method in claim 1, wherein:
the discharged water electrical conductivity of washing water in the washing process is 3.0-8.0 mS/cm; and
pH of the filter cake is 6-7.

### Claim 5 (depends on 1)

The method in claim 1, wherein in step (5):
the drying method involves drying at an atomization rotation speed in a centrifugal drying tower;
the centrifugal drying tower has an inlet temperature of 450-550° C., an outlet temperature of 110-150° C. and a pressure of −150-−50 Pa; and
the rotation speed of the atomizer is 5,000-9,000 rpm.

### Claim 6 (depends on 1)

The method in claim 1, wherein, in step (5), the packaging step is performed by a vacuum packaging machine under −300-−100 Pa.