Heavy calcium carbonate surface modification

The influencing factors of surface modification of heavy calcium carbonate determined the optimal modifier. The optimum modifier and starch modification process for heavy calcium carbonate were studied. The effects of modifier dosage, gelatinization temperature, gelatinization time and holding time on the modification of heavy calcium carbonate were discussed. , optimized its operating process conditions. Let's take a brief look at it.

1. The water bath was warmed to the specified temperature, and then a three-necked flask containing 5 grams of the heavy calcium carbonate suspension was placed therein and the suspension was stirred at a certain speed. Add a certain amount of corn raw starch, stir at 400r-min for a specified time, then add a certain amount of modifier and quickly adjust the pH to 1, continue to stir and keep for a while, then adjust the pH of the solution to 5, after standing for 30s, the composite modified calcium carbonate can be prepared, the mixture is centrifuged, the precipitate is washed with distilled water, and the composite modified heavy calcium carbonate is collected on the filter paper;

2. Add a mixture of starch to calcium carbonate in different proportions to the bleached sulphate softwood pulp with a pulping degree of 320SR and a pulp concentration of 0.5%, then stir at 700r-min to 1st speed for 3min without any help. Under the condition of leaving the filter, it is made into a quantitative amount of 60gm to 2 handsheets, and 0.05%, 0.1% cationic polyacrylamide (based on absolute dryness) is added to the unmodified calcium carbonate and the modified calcium carbonate. Comparison of the amount of pulp).