RU2365682C2 - Means for cleaning of manufactured articles from corrosion products - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to chemical means for removing corrosion products from surface of black and colored metals, as well as from non-metal surfaces. Means includes orthophosphoric acid, starch and water, subjected to thermal processing with following component content, wt %: orthophosphoric acid 30.0-32.2, starch 8.0 - 10.0, water - the remaining part. Said means can be applied for cleaning rust from units of small thickness, different steel membranes, i.e. in cases, when application of mechanical methods is extremely undesirable.

EFFECT: invention allows increasing economical indices and ecological qualities of process of cleaning of manufactured articles from corrosion products.

3 tbl, 3 ex

Description

The invention relates to chemical means for removing corrosion products from the surface of ferrous and non-ferrous metals, as well as from non-metallic surfaces.

To clean corrosion products of various metal products, sanitary units, hard-to-reach areas of equipment and vehicles (threaded joints, blind holes of small diameter) it is advisable to use chemicals in the form of pastes and solutions.

Known pastes designed to clean the surface of corrosion products containing hydrochloric acid or other mineral acids - hydrofluoric, sulfuric, nitric (Yampolsky A.I. Etching of metals. M .: Metallurgy, 1980, p.225). However, the pairs of these acids are toxic, therefore, the use of anticorrosive products based on them is a certain danger.

Widely used abrasive pastes have a number of disadvantages, namely, as a result of their impact, the product deteriorates and deteriorates. The use of abrasive pastes is excluded when cleaning threaded holes and other inaccessible surface areas.

It is known to use solutions of orthophosphoric acid of various concentrations, most often 85 wt.%. The use of such a concentrated solution is also dangerous and inconvenient when processing vertical and ceiling surfaces.

Also known is the Teroxyon company (Germany), the Teroxyd product, and the Walrus paste, manufactured by the Baltkhim domestic enterprise in accordance with TU 48-1402-6-89.

Teroxyd is a colorless, clear liquid. It contains 10-25% phosphoric acid and organic substances that are detected by smell. In the annotation, it is recommended to store the drug away from sources of fire, and surface treatment in a well-ventilated area.

The treatment of the correlated surface consists in the fact that first it is cleaned with a steel wire brush, and then a liquid preparation is applied with a soft brush. All this information is set forth on the surface of a vial containing about 100 ml of said liquid. Both brushes are in the same package with the bottle.

It is obvious that cleaning the surface with the help of the indicated product contains elements of chemical and mechanical cleaning, therefore it cannot be recommended in the case of enameled and plastic products.

The closest in technical essence to the proposed invention, taken as a prototype, is a paste for removing rust "Walrus", presented in TU 48-1402-6-89, 2383-357-02068474-96.

Walrus paste includes water, 14-16% orthophosphoric acid, up to 1% alkyl hydroxamic acids, 1.7-1.9% normal or isostructural alcohol containing 2-5 carbon atoms in the hydrocarbon chain, as well as zinc stearate in an amount 1.5-1.6% and Aerosil from 4 to 5%.

The process of obtaining paste "Walrus" consists of two stages. Initially, the calculated amount of phosphoric acid is dissolved in water, and alkyl hydroxamic acid (or a mixture of alkyl hydroxamic acids) alcohol is added to the resulting solution. The mixture was then brought to a boil and refluxed at 95 ° C for one hour or two hours, depending on the composition of the alkyl hydroxamic acids.

The heat treatment product is cooled and powder components — aerosil and zinc stearate — are added with stirring. After the paste acquires the consistency of sour cream, it is ready for use.

The disadvantages of the walrus paste include the relatively high cost, which can be explained by the high cost of raw materials and the need to transport them over distances exceeding a thousand kilometers, since the points of production of raw materials are very scattered: Ivano-Frankivsk region of Ukraine (aerosil), Volgograd region of the Russian Federation ( alkyl hydroxamic acids), Stavropol (zinc stearate), Leningrad region or Tolyatti (phosphoric acid). The paste production process is a two-stage process, and filling the paste at room temperature presents a certain difficulty; heating significantly increases the energy intensity of the process as a whole.

The objective of the invention is to improve economic indicators and environmental properties of the process of cleaning products from corrosion products.

The problem is achieved in that the product for cleaning products from corrosion products, including phosphoric acid and a thickener, subjected to heat treatment, contains the following components, wt.%:

Starch 8.0-10.0 Orthophosphoric acid 30.0-32.0 Water Rest

The beneficial effect of the anticorrosive effect of the agent is a consequence of the synergistic action of the components subjected to the specified treatment in the newly obtained composition.

An important characteristic of the tool is a small metal removal value of 2 × 10 ^-5 cm. Therefore, the proposed tool can be used to clean parts of small thicknesses and various steel membranes from rust, i.e. in cases where the use of mechanical methods is extremely undesirable, since it can change the functional characteristics of the device or device due to the abrasive effect. Hence, economic indicators are improved by using the proposed tool by eliminating special methods of surface cleaning, including mechanical.

Economic indicators are also improving due to the fact that one hundred of the proposed product can be obtained quite simply by industrial means, since the composition of the product includes non-deficient substances, the raw material base is available and produced by Russian industry.

The environmental properties of the process of cleaning products from corrosion products are improved, since the product is environmentally friendly for the work of personnel and the environment, does not contain harmful reaction products that do not require special disposal methods.

The effect of using the proposed tool is achieved due to the chemical interaction of the components of the composition with oxidized metal forms, forming easily removable products from the cleaned surface. After using the product, high quality of the processed surface is maintained.

The quality was evaluated by the effectiveness of the anticorrosive action in accordance with the conditions of use of the product. For this, sheet steel-3 in the form of plates with a size of 100 × 100 × 3 mm was used.

These plates were subjected to atmospheric corrosion in St. Petersburg during the year, for which they were installed in an upright position, unprotected from precipitation, and their orientation relative to the countries of the world changed at regular intervals so that the degree of corrosion was the same on both sides of the plate.

The thickness of the rust layer that appeared after this treatment was measured with a micrometer and amounted to 0.16-0.25 mm.

To assess the degree of purification, the correlated samples were placed in a horizontal position and a paste layer 3-4 mm thick was applied, and the prototype paste was also applied. The exposure time of the paste on the surface being cleaned in all experiments was 40 minutes. After this time, the paste layer was removed with a dry clean rag, and then rubbed with a 15% solution of copper sulfate (copper sulfate (P). The surface of the steel, cleaned from rust, was covered with a coating of copper in accordance with the reaction equation: CuSO ₄ + Fe = FeSO ₄ + Cu.

The area covered with copper coating was measured using a curvimeter, which made it possible to quantify it.

Processing in all cases was carried out twice, and once after applying the paste the plate was fixed in a vertical position and once in a horizontal position.

Example 1. Preparation of funds.

A three-necked flask equipped with a stirrer and reflux condenser was charged with 85% phosphoric acid and water taken in a volume ratio of 1: 4, then starch was added in an amount of 10% of the total weight of the charge.

The contents of the flask were heated to 60-70 ° C with stirring in a water bath until it turned into a jelly-like mass. The resulting mass was poured into a consumable container and kept at room temperature for 2-4 hours, after which it was used as intended.

A ready-to-use agent is a product of the interaction of a complex of substances of the claimed composition and neoplasms in the form of polyesters formed by polysaccharides with phosphoric acid in various ratios of the claimed components with different molecular weights (in aligomeric and polymeric forms),

It is not possible to determine the content of a particular polymer ester in the resulting agent.

Example 2

4 plates of steel 3, subjected to corrosion in the conditions of St. Petersburg, as described above, were treated with various means:

No. 1 - means of "Teroxyd" German production (in accordance with the instructions attached to each unit of packaging).

No. 2 - an aqueous solution of phosphoric acid (concentration of 85%).

No. 2 - an aqueous solution of phosphoric acid (concentration of 85%).

No. 3 - walrus paste in accordance with the instructions given in the application for invention.

No. 4 - the proposed tool.

The results of the experiments are presented in table 1.

TABLE 1 Composition for cleaning Plate number Surface cleanliness,% Note Famous (prototype) 3 99.0 Individual points of under-grass Known (analog) 1,2 95.0 Several points of under-grass Proposed four 100.0 The surface is completely etched

From the data of table 1 it follows that using the proposed composition, a full degree of cleaning the surface of the steel is achieved, while using known compositions - analogues and prototype - up to 5% of corrosion products remain on the surface.

Example 3

In a steel rod (steel 3) with a cross section of 10 × 10 mm, holes were drilled and a thread M3, M4, M6 was cut - 4 holes for each size. The samples were subjected to atmospheric corrosion under the conditions of St. Petersburg for 1 year, as a result of which it was impossible to screw the bolts into the holes corresponding to them even with a significant effort on a wrench.

To evaluate the proposed and known methods of cleaning corrosion products, one hole of each size (12 in total) was processed: No. 1, 6, 7 with Teroxyd, No. 2, 8, 11 with Walrus paste, No. 3, 5, 10 - 85% solution of phosphoric acid, No. 4, 6, 9 of the proposed paste in accordance with example 2.

In all cases, the holes were cleaned from the remains of pastes the same way, dragging a piece of cloth dipped in a solution of baking soda through the hole.

A comparative assessment of the effectiveness of the means used to remove corrosion products was carried out qualitatively - by the physical force exerted on the wrench when tightening the bolt. In this case, the screwing of the bolts into the holes No. 2, 4, 6, 8, 9, 11, processed by the prototype and the proposed tool, occurred with normal force on a wrench.

When screwing the bolts into the holes No. 3, 5, 10, treated with an aqueous solution of phosphoric acid, the force was also almost normal, but additional treatment with a stream of water and additional processing by pulling a piece of dry cloth was required.

It was not possible to screw the bolts into the holes No. 1, 6, 7, treated with Teroxyd.

Thus, the presented data, as well as table 1 indicate the advantages of the proposed paste in comparison with the prototype and similar products in the effectiveness of rust removal, especially on vertical and hard-to-reach threaded surfaces.

The possibility of using various starches in the paste was tested, since it is known that the structure and properties of these polymers vary significantly

In the manufacture of the product of Example 1, various starches were used, as presented in Table 2. The same table shows the test results in accordance with Example 2 of the product manufactured in Example 1 using various starches.

Since starch is a natural biopolymer, it is impossible to characterize it chemically in detail, the corresponding study requires too much material cost. Therefore, in table 2, starches are indicated by the names of the manufacturing companies indicated in the labeling of the transport packaging.

The product of each of these manufacturers was used for the manufacture of five samples of paste, therefore, the results presented in table 2 reliably characterize starches as a starting material for the manufacture of paste.

table 2 Test results of a product obtained using various starches №№ pp Used starch Surface cleanliness with treated paste,% one. Beslan Tortilla Plant 100.0 2. Prommix LLC, Moscow 100.0 3. GOST 7699-78 starch 100.0 four. Dnepropetrovsk starch - syrup mill. Ukraine 100.0 5. Unmarked, RF 100.0

The experimental data presented in table 2 indicate that the use of starches of various origin in the proposed paste does not change its activity with respect to corrosion products.

The total ratio of the components of the funds, wt.%:

Starch 8.0-10.0 Phosphoric acid 30.0-32.0 Water Rest

is optimal for its effective action, as evidenced by the data in table 3.

Table 3 №№ The content of components wt.% Surface cleanliness,% Note starch Orthophosphoric acid one 2 3 four 5 one 0 30,0 22 On a vertical surface is not held 2 2.0 30,0 25 " 3 4.0 30,0 25 " four 6.0 30,0 40 " 5 8.0 30,0 55 The paste is held on a vertical surface. 6 10.0 30,0 75 Smeared in a thin layer and held 7 12.0 30,0 70 The paste does not spread well in a thin layer. 8 10.0 32,0 100.0 Smeared in a thin layer and held 9 10.0 34.0 100.0 Pasta quickly liquefies 10 10.0 33.0 100.0 Pasta liquefies in 7 days eleven 12.0 34.0 95.0 Pasta liquefies in 3 days

Thus, the effectiveness of the paste is caused by unpredictable synergies in a composition composed of water, phosphoric acid and starch, taken in the ratio, wt.%:

Orthophosphoric acid 30.0-32.0 Starch 9.0-10.5 Water Rest

None of these elements can be changed beyond the specified limits without impairing the quality of the paste, reducing its functional characteristics. An important characteristic of the paste is the small amount of metal removal. To determine it, the plates of steel 3 were mechanically cleaned from rust, weighed, treated with the paste according to Example 2 and again weighed. The difference in the mass of the plate before and after processing and the treated area made it possible to calculate the amount of metal removal, it turned out to be equal to 2 · 10 ^-5 cm. This means that the proposed tool can be used to clean parts of small thickness, various steel membranes from rust, those. in cases where the use of mechanical methods is extremely undesirable, since it can change the functional characteristics of the device or device due to the abrasive effect.

The elimination of the need for mechanical cleaning of products ultimately leads to increased productivity. The tool can be quite simply obtained industrially, since all the starting materials are produced by Russian industry.

St. Petersburg Center for Sanitary and Epidemiological Supervision has concluded that, according to the toxicological characteristics, the paste belongs to substances of hazard class IV.

Of great interest was the proposed product at the Russian Farmer International Exhibition, all consumer reviews turned out to be positive, and you can count on the widespread use of the product in everyday life, industry and agricultural production.

The tool was tested with positive results in the hotel "Pribaltiyskaya" and LLC "Hlebtranss".

Claims (1)

Means for cleaning products from corrosion products, including phosphoric acid, starch and water, subjected to heat treatment with the following components, wt.%:
orthophosphoric acid 30.0-32.2 starch 8.0-10.0 water rest