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Application of sodium hexametaphosphorate (SHMP) in various industries
1. Boiler water treatment - scale inhibitor, water softener
Sodium hexametaphosphate is a commonly used scale inhibitor, which is commonly used in water treatment field, especially in boiler water treatment. The following are some technical parameters of sodium hexametaphosphorate scale inhibitor:
1. Chemical composition: The chemical formula of sodium hexametaphosphate is Na4P6018. It is an inorganic compound, usually in the form of white crystal powder.
2. Molecular structure: The molecular structure of sodium hexametaphosphate consists of 6 phosphate ions and 4 sodium ions, which has good complexation and chelation properties.
3. Technical indicators, technical indicators of sodium hexametaphosphate include appearance, effective phosphate content, water solubility, PH value, water quality stability, etc. Generally speaking, the appearance is white crystalline powder, the effective phosphate content should meet the corresponding standard requirements, good water solubility, PH value is usually between 8-10, high water quality stability.
4. Application field, sodium hexametaphosphate is mainly used as water treatment agent, especially as scale inhibitor in boiler water treatment. It has good scale inhibition and dispersion performance, can have common ground to prevent the formation of scale, keep the boiler system clean.
4. Application field, sodium hexametaphosphate is mainly used as water treatment agent, especially as scale inhibitor in boiler water treatment. It has good scale inhibition and dispersion properties, which can effectively prevent the formation of scale and keep the boiler system clean.
5. Method of use, sodium hexametaphosphate is usually added to the water treatment system in solid form, but also in solution form. In the process of use, it is necessary to determine the appropriate dosage and method according to the specific water quality situation and treatment demand.
In general, as a common scale inhibitor, sodium hexametaphosphate has a wide range of applications in the field of water treatment. Its technical parameters include chemical composition, molecular structure, technical index, application field and use method, etc. These parameters are very important for the correct and effective use of sodium hexametaphosphorate scale inhibitor.
2.. Printing and dyeing - water softener, PH regulator, training agent
As a water softener, so that dye, soap do not precipitate, do not agglomerate hard water softening methods, generally can be selected according to the hardness of water quality and specific conditions. The principle of using sodium hexametaphosphorate to soften hard water is that the calcium ion Cat+ or magnesium ion Mg++ that causes the hardness in the water enters the sodium hexametaphosphorate molecule and becomes a very stable soluble complex: Na2 (Ca2 (P03) 6) and Na2 (Mg2 (P03) 6), the Ca++ or Mg++ in this complex, is not easy to run out, so it will not cause Ca++ or Mg++ to meet the dye or soap precipitation or agglomeration, so as to save the dye and soap, to achieve the effect of water purification.
Note:
（1）. It is impossible to find Ca++ in water softened by sodium hexametaphosphate, even with a reagent as sensitive as ammonium oxalate.
（2）. Sodium hexametaphosporate is used as a water softness in dyeing or post-treatment. It can capture calcium and magnesium ions from the insoluble calcium soap, magnesium soap or calcium dye and magnesium dye precipitation, and make the precipitation dissolve again. In other words, when sodium hexametapphosphonate is introduced into the liquid, sodium soap can be regenerated, and even when calcium or magnesium soap has been formed, the clot of calcium or magnesium soap will disappear. Similarly, sodium hexametapphosphonate can regenerate dyes.
（3）. The reaction between sodium hexametapphosphonate and calcium or magnesium soap is carried out according to the following equation:
(RCOO) 2Ca +Na2 (Na4 (PO3) 6) - Na2 [Ca2 (PO3) 6) +4RCOONa
(RCOO) 2Mg+Na2 (Na4 (PO3) 6) - Na2 (Mg2 (PO3) 6) +4RCOONa
（4）. When dyeing rayon cloth with direct dyes, soft water is an important condition to ensure quality, especially for some direct copper salt dyes, the relationship is greater.
When dyeing cotton fiber fabrics, soda soft water is often used: but when dyeing viscose fiber fabrics, the following issues should be considered:
(1) The pH value of soda is high. Due to the low degree of polymerization of viscose fiber, if the rolling temperature is set at the boiling point, it is easy to cause the breakage and hydrolysis of the molecular chain of the fiber, affecting the strength and causing the rough feel of the fabric. In addition, it can lead to the reduction of aldehyde group and glucose products in the alkaline dyeing bath, so that some direct dyes that are not resistant to reduction are destroyed by reduction.
(2) Soda is an electrolyte, which will cause the increase of sodium ions in the dyeing bath and produce the effect of promoting dyeing. For rayon, the stakes are even higher. Some dyes with large dyeing affinity and very sensitive to electrolyte, especially direct copper salt dyes, such as soft water with soda, often occur serious surface staining phenomenon, affecting product quality.
(3) The ideal water softener should be sodium hexametaphosphorate. The pH of sodium hexametaphosphate is close to neutral, so it does not have the above-mentioned disadvantages of soda ash. Sodium hexametaphosphate can form complex with calcium ion in hard water, and "block" calcium ion, so as to achieve the purpose of soft water.
(4) The general amount of sodium hexametaphosphate is 10ppm of hard water, about 10 grams of sodium hexametaphosphate per 100 liters.
(5) In order to prevent the fiber hydrolysis caused by strong alkali in the dyeing bath, resulting in the destruction of dye reduction, anti-dyeing salt
Scan be added in the dyeing bath, 2~5 grams per liter. To oxidize
Sodium alginate slurry is the most suitable slurry for reactive dyes, but attention should be paid to prevent sodium alginate from infiltrating into 1/2 of hard water during manufacturing
Calcium to form calcium alginate.
Note:
（1）. Calcium alginate (CO0) 2Ca precipitate makes the carboxyl ion -- COO- in the sodium alginate structural formula lose the negative charge, not only has no repulsion effect on the negatively charged reactive dye, but also makes the secondary hydroxyl group =CHOH in the sodium alginate structural formula may bond with some reactive dyes and produce color spots. And make printing paste is not easy to wash out and produce staining. This not only damages the performance of the color paste, but also affects the color fastness.
（2）. Sodium hexametaphosphate must therefore be added to prevent the formation of calcium alginate. Under normal conditions, the dosage of 5 ~ 10 g/L is sufficient, and can be increased to 15 ~ in special circumstances
20 g/L, which can be added either to the printing paste or to the original paste (see page 528 for the use of sodium alginate in printing and dyeing).
(3). as cooking aid nylon twisted yarn (polyamide fiber) in the dyeing before the treatment of soap, soda boiling, adding sodium hexamephos (about 0.3% of the weight of the grain silk) can make the soap will not be consumed by hard water, improve the cooking effect.
(4) The treatment of recycled water in recycled water, due to the addition of sodium hexamethosphosponate, reduce the hardness, it is not easy to produce calcium carbonate precipitate, to avoid blocking the water pipe. About two parts per million is enough.
(5) Treatment of boiler water furnace treatment of hard water can also be used sodium hexaphosphate, not only can avoid the production of pot scale, but also can make the generated pot scale redissolved, but the price is higher than phosphoric acid
(6) Ingredients for synthetic detergent sodium hexametaphosphate is an important ingredient in synthetic detergent (such as sodium alkyl sulfonate, sodium alkyl benzene sulfonate), because it has good soft water ability and washing ability.
3. Concrete (construction) admixture - water reducing agent
As a water reducing agent, promote concrete hardening. The principle of action is to promote the hardening of concrete, and improve the ultimate strength of concrete. The main function of sodium hexametapphosphonate as a water reducing agent is to reduce the surface tension of cement slurry and water in concrete, reduce the charge on the surface of cement particles, so as to reduce the adhesion of slurry and achieve the purpose of reducing the amount of cement.
At the same time, sodium hexametaphosphate can also improve the fluidity of slurry, reduce its setting time and flow resistance, and make concrete easier to pour and vibrate. In addition, sodium hexametaphosphate can also reduce shrinkage, cracks and foaming of concrete, and enhance the durability of concrete.
When sodium hexametaponate is added to concrete, it can react with the hydroxide ion in the concrete, produce phosphorus attachment in the concrete, and slow down the hydration reaction, thus reducing the water loss in the concrete. At the same time, sodium hexametapphosphonate can also control the concentration of calcium ions in concrete and reduce the amount of porosity in concrete, thus improving the strength and density of concrete.
In addition, sodium hexametapphosphonate can also control the concentration of chloride ions and salts in the concrete and help to reduce cracks in the concrete, thereby enhancing the durability and durability of the concrete.
Usage: The addition of sodium hexametaphosphorate in the concrete production process can significantly improve the performance of concrete under appropriate conditions. The typical amount of addition is 0.1%~0.5% of the total weight of concrete, which should be adjusted according to the needs and the nature of sodium hexametaphosphate.
When sodium hexametaphosphates is added, the aqueous solution method is generally applied to inject the juice into the concrete mixing. Before using sodium hexametapphosphonate, it needs to be added to a small amount of water and stirred to disperse to avoid it gathering and blocking the pipe.
4. Snow melting agent
The main principles of sodium hexametaphosphate as a snow melting agent are as follows:
1. The melting point of snow is changed by the release of heat from water by sodium hexametaphosphate. 2. Change the ion charge to destroy the crystal structure of snow to achieve snow melting effect.
Sodium hexametaphosphorate (NaPO36) is an inorganic compound with the chemical formula (NaPO3)6, usually in the form of a white powder or clear glass sheet, which is soluble in water but insoluble in organic solvents. When dissolved in water, it forms soluble substances, which can interact with the crystalline structure of water molecules in ice and snow, breaking the crystalline structure of ice and snow, making ice and snow more loose and easy to melt 12.
In addition, sodium hexametaphosphate releases heat when dissolved in water, further accelerating the melting process of ice and snow 4. This property makes sodium hexametaphosphorate perform well in snowmelting agents, especially in industries with high water quality requirements, such as boiler water, textile industry and electrolysis industry, etc. Sodium hexametaphosphorate is widely used because of its unique water softening effect 2.
Sodium hexametaphosphate is not only used in snow melting agent, but also plays an important role in other fields. For example, in the food industry, it is used as a quality improver, pH regulator, metal ion chelator, binder, and expander 5. In industrial applications, sodium hexametaphosphorate is also used in manufacturing water treatment agents, corrosion inhibitors, metal surface treatment agents, cement hardening promoters, oil drilling, etc
Author: RIel Chemical. Release date: April 2022. Last edited: January 2023