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What Is a Scale Inhibitor?


Scale inhibitor is a class of agents that can disperse insoluble inorganic salts in water and prevent or interfere with the precipitation and scaling of insoluble inorganic salts on metal surfaces.

Classification of scale inhibitors

1. Polycarboxylic acid scale inhibitor and dispersant

Polycarboxylic acid compounds have a good scale inhibitory effect on calcium carbonate scale, and the amount is very small. Commonly used are polyacrylic acid PAA, hydrolyzed maleic anhydride HPMA, AA/AMPS, multi-component copolymers, etc.

2. Organic phosphonate

Organic phosphonates are more effective in inhibiting calcium sulfate scale, but are less effective in inhibiting calcium carbonate scale. It has low toxicity and is easily hydrolyzed.

3. Organic phosphonic acid scale inhibitor

Commonly used are ATMP, HEDP, EDTMPS, DTPMPA, PBTCA, BHMT, etc., which have a good effect on inhibiting the precipitation or precipitation of calcium carbonate, hydrated iron oxide or calcium sulfate.

4. Polyphosphate

Commonly used polyphosphoric acids are sodium tripolyphosphate and sodium hexametaphosphate. Long-chain anions formed in water are easily adsorbed on tiny calcium carbonate crystals. At the same time, this anion is easy to replace with CO32-, thereby preventing the precipitation of calcium carbonate.

The mechanism of action of scale inhibitor

1. Complexation and solubilization in the scale inhibitor. The copolymer dissolves in water and then ionizes to form a negatively charged molecular chain. It forms a water-soluble complex or chelate with Ca2+ to make the inorganic salt solubility Increase, play a role in scale inhibition.

2. The effect of lattice distortion is that part of the functional groups in the molecule occupy a certain position on the inorganic salt crystal nucleus or crystallites, which hinders and destroys the normal growth of inorganic salt crystals, slows down the growth rate of crystals, and reduces The formation of salt scale.

3. The effect of electrostatic repulsion is that the copolymer is dissolved in water and adsorbed on the crystallites of the inorganic salt, which increases the repulsion between the particles, hinders their coalescence, and keeps them in a good dispersion state, thereby preventing or reducing the formation of scales.

It can be seen that the scale inhibitor can effectively disperse inorganic salts that are difficult to dissolve, and the chemicals in it can effectively prevent the coalescence of dirt, thereby achieving the effect of scale inhibition, and also has a great industrial effect. Promising.

Performance of scale inhibitor

We know that the scale inhibitor has a scale inhibitory effect. Its scale inhibitory effect is due to its ability to prevent the growth of small carbonate crystals and distort the crystal lattice, so that the carbonate does not exchange heat in the circulating cooling water. Hard scale is formed on the surface of the device, and at the same time, the organic phosphate and other components in the tissue form a protective film with metal, so that it can be combined with calcium ions in the circulating cooling water to prevent metal corrosion. This product has a wide application range of PH, which can have scale and corrosion inhibition effects between pH 7.0 and 10.0, so that industrial production and operation are simple and will not cause corrosion and scaling due to out of control of PH. The ultimate carbonate hardness of this product can reach about 680mg/L, and the scale inhibition effect is good.

By understanding the performance of scale inhibitors, they can be widely used in various industries, so that their performance can be fully utilized. At the same time, with the continuous development of technology, the performance of scale inhibitors is also constantly improving, thereby expanding the scope of use of products and promoting The development of scale inhibitors.

The above information is provided by chemical supplier.