Method of preparing layered hydrotalcite-like PVC heat stabilizer from vermiculite

A method of preparing layered hydrotalcite-like PVC heat stabilizer from vermiculite, comprising the following steps:

• (1) pretreating vermiculite to obtain expanded vermiculite, and removing impurities in the expanded vermiculite after washing with water;
• (2) performing shearing ultrasonic and fine grinding on the expanded vermiculite in step (1) to obtain nano sized vermiculite flake colloidal solution, then adding fluoride, and obtaining a mixture of powder layered hydrotalcite-like compound and liquid fluorosilicate by reaction under microwave assisted heating and ultrasonic stirring;
• (3) filtering the mixture obtained in step (2) to obtain a solid layered powder layered hydrotalcite-like compound and a liquid fluorosilicate solution, and performing spray drying on the solid layered powder layered hydrotalcite-like compound to obtain a layered hydrotalcite-like compound;
• (4) adding ammonia water or gaseous ammonia into the liquid fluorosilicate solution filtered in step (3), generating fluoride and white colloidal precipitate through reaction, filtering to obtain a filtered solid and a filtrate liquid, washing the filtered solid and dispersing it in water, then performing spray drying to obtain silica powder, and leaving the filtrate liquid for standby;
• (5) concentrating the filtrate liquid in step (4) under negative pressure to obtain a fluoride for recycling in step (2);
• (6) adding the layered hydrotalcite-like compound in step (3) or the silica in step (4) to acetone solution, performing ultrasonic assisted centrifugal washing 3-5 times, adding acetone solution, and then performing ultrasonic assisted dispersion, adding PVC powder and performing ultrasonic assisted dispersion again to obtain a homogeneous suspension;
• (7) centrifuging the homogeneous suspension in step (6) at 1000-30000 r/min to obtain layered hydrotalcite-like compound and PVC mixture or silica and PVC mixture, drying at 20-300° C. for 2-30 hours, and obtaining a uniform heat stabilizer and a PVC solid mixture;
• and
• (8) adding a plasticizer into the heat stabilizer and the PVC solid mixture in step (7), then heating and plasticizing to obtain PVC products.