RU2296787C1 - Composition for reducing or preventing corrosion of surface of building and road-building materials and metals - Google Patents

Abstract

FIELD: corrosion protection.

SUBSTANCE: invention provides homogenous corrosion-inhibiting composition, which contains 20-30% water-soluble phosphate, 5-20% starch, and balancing amount of zeolite and/or schungite, said water-soluble phosphate being selected from alkali or alkali-earth metal phosphates, orthophosphates, and dihydrogenorthophosphates, in particular dipotassium phosphate. Composition may further contain sodium or potassium silicofluoride. Composition is of especial importance for use as corrosion inhibitor for solid antiicing agents based on inexpensive and accessible chlorides, particularly magnesium chloride.

EFFECT: increased efficiency and stability of protective properties and duration of effect, especially on building and road-building materials.

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Description

The invention relates to compositions for reducing or preventing surface corrosion of building road materials and metals. It is of particular interest for use as a corrosion inhibitor for solid anti-icing agents based on cheap and affordable alkaline earth chlorides (mainly magnesium chloride).

It is known to use anti-icing agents — potassium and cadmium ferrocyanides in combination with a chelating agent (Pat. Norway N 131300, 1975), asphalt emulsion (AS USSR No. 935555, 1980) to prevent corrosion of road-building materials and metals. mixtures of saccharides and urea (US Pat. USA No. 4960531, 1990), polybenzylammonium or polybenzylpyridinium chlorides (US Pat. Russia, No. 2169751, 2001).

The disadvantages of this group of inhibitors are that their use does not provide a sufficiently significant and uniform decrease in the corrosiveness of chlorides with respect to metal exposure, their destructive effect on building materials (road surfaces, foundations, etc.) is not reduced, and the inhibitory effect of chlorides is not suppressed on the vegetation.

It is known to use monocalcium - or monoammonium phosphate to reduce corrosion when using anti-icing agents (3 UK application, No. 1308780, 1973).

It is known to use disubstituted alkali metal phosphates to reduce corrosion of chloride-based anti-icing agents (US Pat. No. 2209823, 2002). As disubstituted phosphates, sodium and potassium salts are used in an amount of 1.5-2.5% by weight of the anti-icing composition. The advantages of disubstituted phosphates over other phosphate inhibitors are that, having increased solubility, they more quickly reach contact with the metal surface and are better absorbed by roadside vegetation, partially compensating for the inhibitory effect of chlorides with useful elements (phosphorus, potassium). The disadvantages of this analogue a are as follows:

- soluble phosphates due to their lack of lubricating properties (slippage), the ability to convert alkaline earth metals in contact with them into an insoluble form, due to a sharp difference in the quantitative ratio of inhibitor and chlorine component, are not able to evenly distribute, for example, in solid magnesium chloride, and therefore are not able to ensure uniformity and stability of corrosion and other technological characteristics of the anti-icing agent; as a result, soluble phosphates are not effective enough as inhibitors of metal corrosion and, as part of solid chlorides, do not prevent its ulcerative nature;

- soluble phosphates quickly penetrate into the road surface and do not impede the deep penetration of mobile chlorine ions into it, which does not ensure the sufficient presence of de-icer on the road surface (sufficient “aftereffect” of the de-icing agent) and causes accelerated destruction of not only the surface itself, but also the road limestone "pillows", since the solubility of its main component in the presence of Cl-ions increases significantly; in addition, as a result of the rapid penetration of trace amounts of phosphate into the road surface, the aggressiveness of the chloride remaining on the surface increases sharply and rapidly; when the concentration of phosphate in a solution of anti-icer diluted with melting ice is less than 0.8% of the mass, its passivating effect is not manifested.

A known composition for preventing surface corrosion due to the formation of protective coatings on metal concrete, wood and other materials, containing latex, phosphate binder, ethoxylated monoalkylphenol, talc, kaolin, mono or di or triethanolamine and pigment (Russian patent 2017774, published 1994, )

A known composition for reducing corrosion of road construction materials, including alkali metal phosphate and sucrose or minose (Canadian patent 2057639, published 1992).

The objective of the present invention is to increase the efficiency and stability of protective properties and duration of exposure, especially on building and road materials, increasing the uniformity of the composition.

This goal is achieved due to the fact that the composition for reducing or preventing corrosion of the surface of building, road materials and metals contains water-soluble phosphate, starch and zeolite and / or shungite in the following ratio of components (wt.%): Water-soluble phosphate 20-30, starch 5 -20, zeolite and / or shungite rest. The composition as a water-soluble phosphate may contain phosphates or orthophosphates, or dihydroorthophosphates of alkali or alkaline earth metals. The composition as water-soluble phosphate may contain dipotassium phosphate. The composition may further comprise sodium or potassium silicofluoride in an amount up to 1%.

The composition according to the claimed invention may additionally contain various functional additives (surfactants, antiseptics, antiozonants, other inhibitors, etc.) in an amount that ensures the effectiveness of their target action.

The composition according to the invention is obtained by mixing the components in the required ratio; mixing time depends on the quantity of the product and the type of mixer used; the availability of the product is determined by analyzing the degree of homogeneity of the composition.

The essence of the claimed invention is as follows.

The preliminary distribution of phosphate on starch, zeolite or shungite increases the uniformity of the distribution of the inhibitor in the salt deicer, providing the possibility of the complex action of the components and reducing the risk of contact of the aggressive chloride contained in the deicer with the unprotected phosphate surface of building or road material, or metal. The starch present in the composition forms a thin protective film on the treated surface of both silicate and carbonate building materials, reduces the mobility of phosphate ions and reduces the harmful effects of deicing components on these materials. Shungite and / or zeolite present in the composition, acting as a sorption carrier, retains phosphate on the treated surface. At the same time, it prevents the formation of slippery films on roads and protects building and road materials from the harmful effects of exhaust gases by sorbing them.

The presence of a creme oil fluoride additive in a complex inhibitor helps to strengthen the road surface material by converting unstable alkaline earth (sulfates, carbonates) salts into fluorides or fluoroapatites that are resistant to aggressive atmospheres and acid rains with fixing them in the bulk of the building material formed during the decomposition of silico fluoride and having adhesive properties of silicic acid .

The effectiveness of the claimed composition is illustrated by the following examples.

Example 1

Dipotassium phosphate, starch and zeolite are charged and mixed for 1 hour in the mixer. The resulting composition is mixed with bischofite. For testing, the most aggressive 5% de-icing solution (AOS) is prepared, which is close in concentration to the solution resulting from the melting of snow-ice formations on road surfaces. The resulting solution is tested for exposure to metal (steel-3), the most vulnerable building material of a carbonate nature (limestone).

Example 12

Sodium dihydroorthophostat, starch and zeolite are loaded and mixed for 1 hour in the mixer. The resulting composition is mixed with sodium chloride. For testing, the most aggressive 5% AOS solution is prepared, which is close in concentration to the solution resulting from the melting of snow-ice formations on road surfaces. The resulting solution is tested for exposure to metal (steel-3), the most vulnerable building material of a carbonate nature (limestone).

Example 13

Dipotassium phosphate, starch and zeolite are charged and mixed for 1 hour in the mixer. The resulting composition is mixed with magnesium acetate. For testing, the most aggressive 5% AOS solution is prepared, which is close in concentration to the solution resulting from the melting of snow-ice formations on road surfaces. The resulting solution is tested for exposure to metal (steel-3), the most vulnerable building material of a carbonate nature (limestone).

Example 14

Dipotassium phosphate, starch, schungite and cremnefluoride are loaded and mixed for 1 hour in the mixer. Prepare a 5% suspension of the obtained composition. The suspension is tested on metal (steel-3) and the most vulnerable building material is limestone. AO (MgCl ₂ ) is applied to the limestone after accelerated aging in a suspension of the composition.

The nature of the effect of AOS on limestone was determined by the method of accelerated aging, in accordance with which the degree of aggressiveness of the reagent is assessed by the ability of the structural material to maintain the state of the surface (presence or absence of chips, cracks, peeling, talus) and to preserve the mass of samples of the material when it is repeatedly soaked - frozen - thawing and drying. For this purpose, 3 standard samples of limestone (cubes 5 · 5 · 5 cm with a ground surface) were soaked in a 5% AOC solution for 2 days, frozen at -20 ° С for 10 hours, dried at 30 ° C to constant weight. The nature of the change in the surface of the samples and weight loss after 100 test cycles were monitored.

The effectiveness of the anti-corrosive action of AOS was evaluated according to the method adopted for testing anti-icing materials, in accordance with which pre-defatted steel plates (steel-3) are kept in a 5% solution of AOS, then in air and in a humid atmosphere, followed by washing of the plates, chemical removal corrosion products in accordance with GOST 9.907-83, repeated washing, drying and weighing. The nature of corrosion was also evaluated by the appearance of the plates before their chemical treatment. Examples of the composition of the claimed composition and its properties are shown in the table.

The proposed composition has the potential for active beneficial effects on vegetation and road building materials, especially of carbonate nature (road "pillows") due to the suppression of their solubility and the binding of alkaline earth metals to insoluble phosphates and fluorides. The protection effect of the road "pillows" is also ensured by the fact that the claimed composition reduces the mobility of chlorine ions, in combination it reduces the penetration depth of aggressive chlorides into the roadway and increases the proportion of anti-icing material dumped on less dangerous areas for road surfaces and road "pillows" . In General, the use of the composition reduces the aggressiveness of chlorides and allows the use of these cheap and affordable reagents as de-icing agents in certain sections of the road routes with less damage to road materials and the environment.

Claims (4)

1. Composition for reducing or preventing surface corrosion of building and road materials and metals, characterized in that it contains water-soluble phosphate, starch and zeolite and / or shungite in the following ratio, wt.%: Water soluble phosphate 20-30 Starch 5-20 Zeolite and / or shungite Rest 2. The composition according to claim 1, characterized in that as a water-soluble phosphate, it contains phosphates, or orthophosphates, or dihydroorthophosphates of alkali or alkaline earth metals. 3. The composition according to claim 1, characterized in that as water-soluble phosphate it contains dipotassium phosphate. 4. The composition according to any one of claims 1 to 3, characterized in that it further comprises sodium or potassium silicofluoride in an amount up to 1%.