Sodium tripolyphosphate use in detergents. Sodium tripolyphosphate technical, China

Sodium tripolyphosphate (ST P P, food additive E451i)- salt of tripolyphosphoric acid

Physicochemical characteristics.

Appearance: white friable powder. It can be produced in the form of granules. Easily soluble in water. We will not dissolve in ethanol. pH 9.1-10.1 (1% aqueous solution). When stored in a dry place, the shelf life of sodium tripolyphosphate is not limited.

Sodium tripolyphosphate has two varieties:

1) Formula Na 5 O 10 P 3 (E451i, STPP, Sodium triphosphate 5-substituted anhydrous, sodium tripolyphosphate anhydrous). Loss on drying no more than 0.7% (105 °C, 1 hour). Solubility in water 15 g/100 g water (at 20°C).

2) Formula Na 5 O 10 P 3 × 6H 2 O (E451i, STPP, Sodium triphosphate 5-substituted hexahydrate, sodium tripolyphosphate hexahydrate). Loss on drying no more than 23.5% (60°C for 1 hour holding, then 105°C for 4 hours holding).

Application.

Sodium tripolyphosphate is produced for food and technical purposes.

Technical sodium tripolyphosphate is used:

For liquefaction of thick pastes, clays, kaolins;

To regulate the pH of the medium;

For the manufacture of synthetic detergents, cleaning, bleaching, disinfecting, decontaminating agents (dishes, sinks, toilets, bath and glass cleaners);

In the production of paper, leather, artificial materials (bleaching due to the stabilization of hydrogen peroxide);

In the production of medicinal and cosmetic preparations;

For corrosion protection, water treatment and other purposes (washing of boilers, softening of boiler feed water, prevention of precipitation and scale).

Food sodium tripolyphosphate is used:

To improve the texture of meat and fish products (increases pH and retains water in proteins, has the ability to break down myosin and actin);

As a melting salt in the production of processed cheeses,

As an additive in the production of cream, powdered and condensed milk, in the confectionery industry.

Sodium triphosphate according to GOST 13493-86 “Sodium tripolyphosphate. Specifications" is included in the list of raw materials in GOST 18236-85 "Cooked pork products. Specifications”, GOST 18255-85 “Smoked and boiled pork products. Specifications”, GOST 23670-79 “Cooked sausages, frankfurters and sausages, meat loaves. Specifications".

Meat processing, as a rule, is done by dipping in an aqueous solution of sodium tripolyphosphate with exposure to the solution for 10-30 minutes. The temperature of the solution during processing is 18-36°C. A higher temperature corresponds to a shorter holding time. It is advisable to process fatty bacon by injection. In this case, the solution is injected directly into the meat layer.

Sodium tripolyphosphate is used to process pork in the form of minced meat, cut pieces or semi-finished products. For the case of joint treatment with sodium polyphosphate with common salt in a ratio of 0.125:0.75% and subsequent storage at a temperature of -23 ° C for 4 weeks, an improvement in the quality indicators of pork can be observed: color, aroma, taste, texture, reduction of water loss during heat treatment, the level of juiciness.

Sodium tripolyphosphate is used in the production of smoked legs in order to reduce moisture loss, and, accordingly, increase the yield of the finished product. In this case, the meat is treated with sodium tripolyphosphate together with table salt in a ratio of 0.3:3.0%. Processing increases the yield of the finished product by 5%.

For the treatment of beef and ground beef, treatment with a mixture of sodium tripolyphosphate and sodium pyrophosphate E450iii in a ratio of 25:75% is most effective. Processing improves the quality of the finished product: reduces water loss, improves color, texture, improves yield.

Sodium tripolyphosphate is used in the production of smoked pork loin. Pork is injected with a solution of sodium tripolyphosphate with a concentration of 0.3-0.5%. The level of injection is 5-10%. This treatment does not increase the juiciness of the finished product, but increases its tenderness.

Lamb carcasses are treated with a mixture of sodium tripolyphosphate and table salt in a ratio of 0.5:2.0%. This improves the tenderness of lamb carcasses, reduces losses during heat treatment. The treatment increases the pH and there is no significant development of unfavorable microorganisms when stored for 6 days at temperatures between 0 and +4°C.

In order to increase the shelf life of chilled seafood fillets by 30-40%, treatment with an aqueous solution of a mixture of preservatives is used. The mixture has the composition: sodium tripolyphosphate 77%; potassium sorbate 12.7%; citric acid 10.3%. Processing is carried out by keeping the fillet in an aqueous solution. In this treatment, sodium tripolyphosphate inhibits the growth of microorganisms and stabilizes the state of the protein. Citric acid inhibits the development of microbiota by acidifying the fillet surface. Potassium sorbate inhibits the development of yeasts and molds.

Sodium tripolyphosphate is used to prevent corrosion of pipelines and heat exchangers. When using it, careful cleaning of heat exchangers and pipelines from deposits and fouling should be provided. When using sodium tripolyphosphate to create a protective phosphate film, the concentration of inhibitors in the water of the circulating system for 2-3 days should be taken as 100 mg / l (calculated as P 2 O 5), in additional water to maintain the phosphate film - 7-15 mg / l according to P 2 O 5 . In this case, the speed of water movement in heat exchangers must be at least 0.3 m/s.

Sanitary rules for food trade enterprises allow the use of detergents and disinfectants, which include sodium tripolyphosphate. After washing with such detergents, it is necessary to completely remove the cleaning solution from the treated surface.

The composition of synthetic washing powders depends on the hardness of the water. Three types of powders are produced: A, B, C.

Type A - for areas with water hardness above 5.35 meq.

Type B - for areas with water hardness below 5.35 mEq.

Type B - for areas with soft water, hardness not higher than 2 meq.

Type A and B powders prevent the formation of deposits in hard water.

Sodium tripolyphosphate is a component of DEZMOL, a synthetic detergent and disinfectant used to clean and disinfect equipment. The use of DEZMOL allows you to combine washing and disinfection of equipment in one operation. For manual washing, 0.5% aqueous solutions are used, and for mechanical processing, 1.0% aqueous solutions.

Sodium tripolyphosphate can be used as an independent detergent for washing linen and all types of fabrics, washing glasses, heavily soiled and greasy dishes, cleaning bathtubs, sinks and toilet bowls. Before washing, the laundry is pre-soaked in a warm solution of sodium tripolyphosphate (½ cup per bucket of water). Very soiled linen is recommended to be left in the indicated solution for 2-3 hours. Then the linen is washed and rinsed thoroughly in clean water.

Receipt.

Powdered sodium tripolyphosphate is a product of thermal phosphoric acid processing. Sodium tripolyphosphate is obtained by thermal dehydration of a mixture of orthophosphoric acids and its further vacuum crystallization.

Sodium tripolyphosphate is widely used in the national economy. Sodium tripolyphosphate is intended for use:
- when thinning thick pastes, clays, kaolins;
- to regulate the pH of the medium;
- for the manufacture of synthetic detergents, cleaning, bleaching, disinfecting, decontaminating agents;
- in the production of paper, leather, artificial materials;
- in the production of medicinal and cosmetic preparations;
- in the production of food products;
- for protection against corrosion, water treatment and other purposes.
The main part of the produced sodium tripolyphosphate is spent on the production of detergents. Technical tripolyphosphate is widely used in the chemical industry as an additive to synthetic detergents to ensure washing at any temperature. It is also used for the manufacture of detergents for washing dishes, sinks, toilet bowls, cleaning bathtubs and washing glasses; for washing boilers and water treatment for industrial purposes.
It is also widely used in the textile and leather industries for bleaching and washing, for flotation of ores, for dispersing paints, in the production of synthetic rubber, in electrolysis processes, for softening water in order to prevent precipitation and scale, for stabilizing perhydrol, in oil drilling. wells, in the production of paper for bleaching and a number of other industries.
It is also used for water treatment, as a dispersing agent in the paper and varnish and paint industries, as a thinner in the ceramics industry, as a degreaser in the surface treatment of metals, and as a surface improver in the enamel industry.
Food sodium tripolyphosphate is used in the food industry. In the meat industry it is used as a stabilizer, acidity regulator, color fixative, antioxidant.
In the food industry, it is used as a color fixative, acidity regulator, emulsifier, stabilizer. Sodium tripolyphosphate is used to improve the texture of meat and fish products, as a melting salt in the production of processed cheeses, as an additive in the production of cream, powdered and condensed milk, in the confectionery industry.
Tripolyphosphate E451 (STPP) food application is used in the form of hexahydrate in the production of canned and frozen meat and fish products to improve texture, as well as in the production of processed cheeses as a melting salt. Often used along with other phosphates and citrates. Alone or in combination with other stabilizers, it is used in the production of cream, condensed milk, milk powder and cream. Sodium triphosphate according to GOST 13493-86 “Sodium tripolyphosphate. Specifications" is included in the list of raw materials in GOST 18236-85 "Cooked pork products. Specifications”, GOST 18255-85 “Smoked and boiled pork products. Specifications”, GOST 23670-79 “Cooked sausages, frankfurters and sausages, meat loaves. Specifications".
In the food industry, sodium tripolyphosphate is used as a stabilizer and has an index of E 451. The main purpose of sodium tripolyphosphate is the binding of moisture content in proteins. The use of powder increases the pH and as a result of the alkaline reaction in protein-containing products (meat, fish), a stabilized process of water binding in products occurs. Sodium tripolyphosphate has the ability to break down myosin and actin, which is the main reason for its use in the food industry.
Almost all food phosphates and their mixtures, which are used in the meat processing and fish industries, have an alkaline reaction. The addition of alkaline phosphates to meat and fish leads to an increase in pH, and as a result, to an increase in the water-binding property of proteins.
In addition to the food industry, triphosphates are widely used in the production of household chemicals and cosmetics.

Magazine "Heat Supply News", No. 11, (27), November, 2002, pp. 29 – 30, www.ntsn.ru

A.N. Fedenko, General Director, Rosplast LLC

Water treatment in industrial closed systems of energy and water and heat supply is a complex and rather expensive task. In the coolant of these systems, the concentration of impurities (anions, cations, suspended particles) occurs, exceeding the limits of their solubility. As a result, they form hard scale, interfere with heat transfer and reduce the performance of boilers by 10-20% or more.

Incorrect chemical water treatment or its absence can lead to an emergency situation at the enterprise.

PFN properties

Polyphosphate (PFN) has a large crystalline appearance, it is highly soluble in water, with stirring and for ease of use, it is currently produced in crushed form.

PFP is characterized by good solubility and the ability to form water-soluble complexes (chelates) with salts of Ca, Mg, Fe, Pb, Cd, Ni, Hg.

On fig. Table 1 shows data characterizing the amount of binding of Ca, Mg, Fe ions by some of the most common phosphates used in power plants for chemical water treatment. The calculation is based on the formation of complexes at room temperature.

Rice. 1. Chelating ability of phosphates.

A unique property of an inorganic polymer is its ability to maintain the polymer structure, both in the solid state and in aqueous solutions and melts.

Sodium polyphosphate is the most active water softener, because. forms stable complexes in a shorter time and at lower temperatures (20-40 o C) than sodium tripolyphosphate (STPP) and other phosphates.

The advantage of sodium polyphosphate over trisodium phosphate (TSP) is a higher content of phosphate in terms of P 2 O 5 - more than 63%. Compared to PFP, the content of phosphates in TNF in terms of P 2 O 5 does not exceed 25%. Recommendations and regulatory documents indicate that the rate of application of PPP is 3-4 times less than that of TNF.

The advantages of PFN also include lower caking during storage, anti-corrosion properties, the ability to reduce iron oxide and copper scale formation on the internal heating surfaces of boilers.

Chelating ability (the ability to form water-soluble complexes, the stability of which is more than 1 year) makes it possible to apply SPF only once during the entire heating season. For comparison: the stability of sodium tripolyphosphate complexes is from 2 to 6 months, and trisodium phosphate is even less.

The disadvantages include the reduced pH value of aqueous solutions (pH ~ 7.5), as well as a more complex analysis of the concentration of aqueous solutions, a decrease in the alkalinity of boiler water. The pH value of the PFN solution is 7.5-8.0 versus pH 11-12 for TNF. To raise the pH value in the working solution of SPF, trisodium phosphate can be added in a small amount (about 50 g per 1 m 3 of the solution). Our company can produce ready-made mixtures based on PPP with specified indicators of the required pH values ​​and depending on the degree of hardness of the water consumed.

It should be noted that there is no corrosive activity of the PFN solution. The calculations of the NIIGIPROKHIM Institute, St. Petersburg, confirm the anticorrosive properties of PPP and give recommendations for its inclusion in the formulations of industrial inhibitors.

Ongoing studies of corrosion inhibitors with SPF show a decrease in the rate of corrosion in the water circulation systems of the enterprise from 0.6 mm to 0.1 mm per year. To prevent corrosion of carbon steels in water, a concentration of PFI of less than 10 mg/l is sufficient, depending on the hardness of the water.

Application practice

Consumer enterprises provide the following technology for the use of PFS. During the production tests of the PFP at the Zakamskaya CHPP-5 of Permenergo JSC, 3 boilers with a total steam capacity of 400-500 t/h were constantly in operation (purge - 8-12%).

The preparation of the solution is carried out in mixing tanks. Tanks are equipped with drainage, supply of coagulated water and steam 1.2 atm. To store the finished solution, there are measuring tanks.

The supply of phosphate solution to the boilers is carried out according to an individual-group scheme. From the measuring tanks, the working solution is fed to the inlet of the dosing pumps operating on a common manifold. Feed water is supplied to the collector through a check valve. Through control valves and limiting washers dy 3 mm, the diluted phosphate solution is distributed to the operating boilers.

The concentration of the working solution of trisodium phosphate before testing was 0.5-0.6% by RO 4 -3.

In comparative tests in the mixer V = 6.2 m 3 loaded 30 kg of PFP instead of 114 kg of TNF.

The polyphosphate dissolved fairly quickly with slight heating. The concentration of the resulting solutions was 0.62-0.65% by RO 4 -3 .

In order not to change the established performance of dosing pumps, the concentration of working solutions of polyphosphate is calculated based on the percentage of the content of the active substance - RO 4 -3 in working solutions of polyphosphate and previously used reagents should be the same.

It should be noted that for the preparation of working solutions of any type of phosphate, especially trisodium phosphate, chemically purified water or condensate should be used, because. when raw water is used, calcium phosphate deposits form, which leads to the drift of drainage systems.

During tests, it was noted that the decrease in the alkalinity of boiler water in boilers with alkalinity of make-up water of 0.3 mg-eq / l when switching from trisodium phosphate to polyphosphate is extremely insignificant - for salt compartments, the difference is no more than 0.2-0.4 mg-eq / l, which is lower than the accuracy of the analysis.

Our customers, who have been using PFR for several years already, are such enterprises as SE Siberian Chemical Combine, most Russian nuclear power plants, energy systems of JSC Kazanorgsintez and JSC Kirishiorgsintez. These enterprises speak positively about the effectiveness of the use of PFR, both in technological and economic aspects.

conclusions

1. Sodium Polyphosphate is the most concentrated of the industrially produced phosphates.

2. Estimated savings when using PPP is 6000-7000 rubles per ton of consumed TNF. When using tripolyphosphate, the savings are 900-1200 rubles/t.

3. Polyphosphate is a corrosion inhibitor. To prevent corrosion of pipelines, especially in soft water conditions, it is recommended to maintain the content of polyphosphate at the level of 2-3 kg / m 3 of water or 0.2-0.3% of the weight of running water and pH = 7-8.

4. Reduction of Ca deposits in pipelines, when using PFP, prolongs the life of boilers, prevents a decrease in the heat output of water heaters and the throughput of pipelines.

5. PFN can be used in individual heat supply of private buildings and requires a single application, for the heating season.

6. It should be noted that polyphosphate is non-toxic and biodegradable.

Literature

1. Yu.F. Zhdanov "Chemistry and technology of polyphosphates". "Chemistry" 1979

2. M.S. Baburina "Properties and applications of sodium hexametaphosphate". "Niigiprokhim-science" 2000

corrective treatment of boiler water at medium-pressure power plants. JSC "Permenergo", 1999

4. A.P. Vetrova “Investigation of changes in the pH of PPP solutions. OJSC "Kamteks-khimprom", 2001

Chemically pure sodium tripolyphosphate has the formula Na5P3O10. The molecular weight of salt is 368 g/mol, and its true density is 2500 kg/m3. The melting point is 622 °C, and the melting is accompanied by the decomposition of sodium tripolyphosphate to sodium metaphosphate (Na(PO3)x) and sodium pyrophosphate (Na4P2O7).

Two anhydrous crystalline forms are known: high temperature (phase 1) and low temperature (phase 2). The transition from phase 2 to phase 1 corresponds to a temperature range from 410 to 425°C. The 1st phase of sodium tripolyphosphate is also called "clumping", since its dissolution in water leads to the formation of dense lumps. When the product is in a finely divided state, the transition from phase 1 to phase 2 proceeds very slowly, therefore, the entire phase 1, in the case of the formation of a mixture of orthophosphates during dehydration, remains almost unchanged in the cooled product.

In air, sodium tripolyphosphate powder slowly hydrates to form a hexahydrate (Na5P3O10 6H2O).

The bulk of sodium tripolyphosphate is used in the production of CMC, but it is also widely used in other industries:

• - for softening water for feeding boilers in order to prevent precipitation and scale;
• - in the textile and leather industry for bleaching and washing;
• - for flotation of ores;
• - for dispersion of paints;
• - in the production of synthetic rubber;
• - in electrolysis processes;
• - for stabilization of perhydrol;
• - when drilling oil wells;
• - in the production of paper for bleaching;
• - in the glass and ceramic industry, etc.

Physical and chemical indicators of technical sodium tripolyphosphate must meet the requirements of TU 2148-095-23380904-2004 specified in table 1. The declared trademark is Poliformattm, sold under the following trademarks:

Poliformattm 1211 - fast hydrating powder according to the specification of the company "Procter and Gamble" (P&G);

Poliformattm 1212 "A" - slow hydrated powder according to the specification of the company "Procter and Gamble" (P&G);

Poliformattm 1212 - powdery anhydrous category 1;

Poliformattm 1213 - powdery anhydrous category 2;

Poliformattm 1226 - sodium tripolyphosphate hexahydrate crystalline;

Table 1 - Quality indicators of technical sodium tripolyphosphate

The food grade product complies with GOST 13493-77. The use of tripolyphosphates and products containing these compounds helps to preserve the nutritional properties of products, facilitates their processing and gives them a more attractive presentation. These compounds are also added to animal food.

Sodium tripolyphosphate technical - a product obtained as a result of the processing of phosphoric acid, through the use of an extraction method.

The formula expression sodium tripolyphosphate is displayed as follows:

Na5P3O10

Also, in publications and reference books of chemicals and compounds, the abbreviation for the substance (abbreviation) is used - STPP.

General description of the drug

STPP is used in the form of a powdery low-hygroscopic dry matter with white particles. Sodium tripolyphosphate is practically harmless to humans, as it is non-toxic, provided there is no influence of catalysts and violation of the rules of storage and use.

Sodium tripolyphosphate is not harmful to production and industrial enterprises due to its explosive and fire safety.

There are two types of sodium tripolyphosphate used in industry and the household, on the basis of which the distribution and purpose of each type is divided:

• . Industrial (technical);
• . Household (food).

Sodium tripolyphosphate is intended for the manufacture of synthetic detergents, cleaning, bleaching, disinfecting, deactivating agents, in the pulp and paper, pharmaceutical, food industries, for corrosion protection in water treatment and other purposes.

STPP used for the food industry is also in high demand in the field of manufacturing medicines and medical preparations. Sodium tripolyphosphate solution is a part of various cosmetic products.

The production, sale and quality characteristics of edible sodium tripolyphosphate are regulated by GOST 13493 - 86, which applies to a powdered substance and establishes the basic requirements for indicators of finished products that are used in the national economy and export.

The standards and norms of this GOST will also apply to the category of technical sodium tripolyphosphate.

Methodology for obtaining Na5P3O10

STPP in powder form is obtained by processing phosphoric acid at elevated temperatures. The industrial method for the production of sodium tripolyphosphate involves the thermal dehydration of orthophosphoric acid mixtures with a further crystallization step under absolute vacuum.

Possible ways to obtain sodium tripolyphosphate also include tower technology, where the substance is formed as a result of the neutralization of H3PO4 under the influence of soda ash. The final stage of this technology is the drying of the resulting solution and the subsequent calcination of orthophosphate salts.

Basic chemical reactions involving STPP

All existing methods for obtaining sodium triphosphate can be reflected in the following formulas:

• . 6H3PO4 + 5Na2CO3 → 2Na5P3O10 + 5CO2 + 9H2O, where the synthesis of sodium triphosphate occurs through the interaction of STPP condensate and phosphoric acid. As a result of the reaction, sodium tripolyphosphate, carbon dioxide and water are formed;
• . NaPO3 + Na4P2O7 → Na5P3O10, where the reaction requires laboratory conditions. In this case, its synthesis occurs with the participation of sodium phosphates and diphosphates;
• . Na3P3O9 + 2NaOH → Na5P3O10 + H2O, where the synthesis of the main substance with sodium trimetaphosphate is acceptable.

Scopes of sodium tripolyphosphate

Sodium tripolyphosphate, as well as sodium carbonate, is included in the active composition of the compounds:

• . Synthetic washing - detergents;
• . Cleaners and professional bleaches;
• . Preparations for disinfection and decontamination.

It should be noted that in modern powder detergents for dishwashers and washing machines, sodium tripolyphosphate and sodium carbonate can be present both simultaneously and separately.

In addition to household chemicals, sodium tripolyphosphate is in demand:

• . In the pulp and paper industry;
• . In modern pharmaceuticals;
• . in food production;
• . In mechanical engineering and vehicle maintenance services, for example, during anti-corrosion treatment;
• . in water treatment activities.

Most of the STPP is undoubtedly used as an ingredient in household and professional cleaning products. This fact can be explained by excellent properties for maximum softening of water.

Due to the main function of STPP, which is to enhance the action of surfactants, compounds with sodium tripolyphosphate effectively remove any contamination, including traces of soil, dirt and other things.

Among other things, industrial (technical) sodium tripolyphosphate is often used:

• . As a tinting agent for leather goods;
• . As an auxiliary substance for coloring;
• . As a highly effective agent that provides high-quality dispersion on surfaces and coatings.
• . In the papermaking process to resist oil contamination.

The main enterprises for the production of STPP

The largest manufacturers of sodium tripolyphosphate are organizations such as:

• . Khim - Plus LLC, Nizhny Novgorod region, Dzerzhinsk;
• . AquaChem Trading House LLC with official representative offices throughout the Russian Federation, including the cities of Moscow, St. Petersburg, Arkhangelsk, Yekaterinburg, Barnaul, Ivanovo, Vladimir, Krasnodar, Makhachkala, Yoshkar-Ola and others;
• . LLC "SNABROS", St. Petersburg.
• The price of finished products differs depending on the STPP brand, averaging 86 rubles per 1 kg. When purchasing goods of this category, you should pay attention to the reliability and compliance with the original packaging. As a rule, sodium tripolyphosphate is packaged in the following types of containers:
• . Woven plastic bags with a polyethylene inner liner;
• . Industrial polyethylene bags with a capacity of 25 to 1,000 kg.

When packaging of any type, water, excessive moisture, even on closed packages with the drug, should be avoided. Do not expose the chemical to excessive overheating and the ingress of oxygen from the outside.