How calcium stearate deals with calcium carbonate and what are the surface treatment methods for cal

The most commonly used surface modifier for calcium carbonate is calcium stearate, and its modification process can be either dry or wet. In general, the wet process uses stearate, such as sodium stearate.

When dry modification of stearic acid, the calcium carbonate is dried to remove water, and then the material and stearic acid are fed into the surface modification machine at the same time for surface coating modification. When the continuous powder surface modifier equipment such as SLG powder surface modifier continuous and vortex mill is used, the material and the surface modifier are continuously and synchronously fed. When coating modification is carried out in high-speed mixers, horizontal paddle mixers and other temperature-controlled mixers, it is generally intermittent operation, and the measured and prepared materials and stearic acid are added to the modifier together, stirred and mixed for 15-60 seconds, and the reaction temperature is controlled at about 100 degrees.

In order for stearic acid to be better dispersed and act evenly with calcium carbonate, stearic acid can also be diluted with a solvent such as absolute ethanol. Other additives can also be added in an appropriate amount when modifying.

The mixed modification is to saponify the stearic acid first, then add it to the calcium carbonate slurry, and after a certain period of reaction, filter and dry. Calcium carbonate is easier to disperse in the liquid phase than in the gas phase, and the action of calcium carbonate particles and surface modifier molecules is more uniform in the liquid phase. The modified temperature is generally about 50-100 degrees.

Wet surface modification is often used for the surface modification of light calcium carbonate and wet grinding ultra-fine heavy calcium carbonate.

For details, you can go to Jiangxi Aote's company** to understand.

Hydrochloric acid. Removal method: Because calcium carbonate can react with hydrochloric acid to form gas and solution, silica will not react and will not dissolve, so it is filtered and separated.

Equation: CaCo +2HCl=CaCl +Co +H 0Note: Dilute nitric acid can also be used, but sulfuric acid cannot be added casually, because CaSO4 is also precipitated.

Calcium carbonate is neutral, basically insoluble in water, soluble in hydrochloric acid. It is one of the common materials found on the ground cover ball, which is found in aragonite, calcite, chalk, limestone, marble, travertine and other rocks, and is also the main component of animal bones or shells. Calcium carbonate is also an important building material and has a wide range of industrial uses.

Method 1: Removal method: Because calcium carbonate can react with hydrochloric acid to form gas and solution, silica will not react and will not dissolve, so it is filtered and separated.

Equation: CaCO3+2HCl=CaCl2+CO2!+H20Note: Dilute nitric acid can also be used, but sulfuric acid cannot be added casually, because CaSO4 is also precipitated.

Method 2: Strengthen the heating of alkali concentration solution.

Calcium carbonate can be obtained by filtration washing.

2NaOH + SiO2 = Heating = Na2SiO3 + H2O Sodium Silicate Soluble in Water Calcium carbonate does not react with alkali.

Dilute hydrochloric acid can also be used in the kitchen.

Calcium carbonate is heated to produce calcium oxide and carbon dioxide, carbon dioxide is a gas, which is easy to get lost with the air flow in an open container, so all the rest is calcium oxide, that is, the calcium carbonate in calcium oxide can be removed by heating.

Both calcium carbonate and calcium oxide can react with hydrochloric acid:

CaCO3 + 2HCl = CACl2 + CO2 + H2OCAO + 2HCl= CaCl2 + H2O removal method can be selected: the sample is placed in water, a sufficient amount of carbon dioxide is introduced, the mixture is heated to 80 degrees, and filtered for drying.

cao + co2 = caco3

CaCO3 + CO2 (excess) + H2O = Ca(HCO3)2Ca(HCO3)2 = CaCO3 +CO2 + H2O (over 60 degrees).

That. 1. Calcium carbonate.

The surface is hydrophilic and oleophobic, even in polymers.

Poor dispersion;

That. Second, calcium carbonate can not attract each other to polymers, resulting in almost no reinforcement, and will also lead to the decline of some properties.

Therefore, if the quality grade of calcium carbonate is improved, it is necessary to find ways to change the surface properties of calcium carbonate particles, that is, surface hydrophobicity.

Handling and activation. These are two different concepts: the former improves dispersion and the latter improves reinforce. Hydrophobicity is not the same as activation, but to activate, it must be hydrophobic.

Whether the final product is hydrophobic or further activated should depend on its use, and the surface treatment of calcium carbonate is to use the coupling agent.

active agent), dispersant back to hand.

Coated to the surface of calcium carbonate particles.

There are two methods of surface treatment, dry treatment and wet treatment.

Dry treatment, that is, the dried light calcium is added to the high-speed mixer, and then the surface treatment agent is added dropwise and heated while stirring, and the surface treatment agent is coated on the surface of the calcium carbonate particles. Because the dry process is a simple mechanical coating, the problem of uneven coating is difficult to overcome, so medium and high-end products do not use this method.

Wet treatment is to add the prepared surface treatment agent to calcium hydroxide before or after carbonization is completed.

or calcium carbonate suspension, under the action of stirring, the surface treatment agent is instantly coated to the surface of calcium carbonate particles to complete the surface treatment process. In order to increase the production capacity of the device, it is best to add an activation tank after the carbonization process, and send the calcium carbonate suspension after carbonization to the activation tank, and surface treatment is carried out in this tank. The activator should be treated in the activator preparation tank to make an emulsion before erection.