SU1208093A1 - Method of cleaning surface - Google Patents

Description

one

The invention relates to physico-chemical cleaning of the surface of materials, products and machine parts from various kinds of contaminants and can be; {without prejudice to the environment in all areas of the national economy where the processes of cleaning and degreasing various materials and products are used . .

The purpose of the invention is to intensify the cleaning process and the possibility of using waste cleaning products, reducing the formation of

treated wastewater.

The invention is illustrated by the following examples.

Products are loaded into a basket and sprinkled with a 2-3% solution of polyvinyl alcohol (PVA), for preparation of which alcohols with a molecular weight of 40-80 thousand and a content of acetate groups of not more than 5% are used. Then the basket is immersed in a bath filled with a solution of sodium chloride or potassium with a concentration of i, 5-3.5 mol / l and treated with air bubbles dispersed by a porous partition with a pore size of 100-150 µm, set at a distance of 5-10 cm from the bottom of the basket parts and forming an air cavity with it. In the case of cleaning surfaces from grease and resinous substances of high viscosity, the solution is heated to 50-. In order to concentrate the contaminants in the form of compact mills, an additional PVA solution is added at the rate of 0.001-0.005 g PVA per 1 gram of contaminants to the foam layer formed during the purging of the solution with air bubbles. The time of surface treatment with air bubbles depends on the type of contamination and is 0.3-3 minutes. After the cessation of air supply, the contaminants concentrated on the surface of the solution are removed from the bath mechanically, for example with a sieve. Received psham easily gives water. After holding on a sieve for 5-7 minutes, its humidity is reduced to 30-45%.

In order to utilize the cleaning products and partial regeneration, the spent PVA, dried on a sieve, is placed in a container made of filter cloth and squeezed out liquid petroleum products, which after

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20

25

208093

washing the solution can be used repeatedly, the dry residue, which is a mixture of highly viscous petroleum products, mechanical impurities and polymerized PVA can be used, for example, as fuel, and part of the PVA can be washed from the dry residue with warm fresh water, and the resulting solution is used re-enter the foam layer.

Example. The cleaning was finished with hardware products (bolts, nuts, gaskets) made of steel, fluoroplastic and aluminum, covered with a mixture of MS-20 engine oil and quartz sand. The amount of impurities deposited in the form of a film on the surface of products with an area of 20 cm cons 10

pressure lo, g: oil 0.5, quartz

sand 1. Hardware was placed in a wire basket and treated with a 2% aqueous solution of PVA with a molecular weight of 60 thousand and a acetate content of 2%. Then the basket was immersed in a flotation column (the bottom of which was Schott filter No. 3) filled with a sodium chloride solution of 3 mol / l, for I min the product was treated with air bubbles blown through the column at a constant rate of 0.5 l / min. At the same time in the foam layer formed on the surface

injected with 0.3 ml of 2% PVA solution. After cessation of air supply to the column, gelatinous sludge floating on the surface of the solution was collected with a sieve. The weight of the sludge immediately after its collection was 3.1 g, and after soaking on the sieve for 5 minutes it was reduced to 2.2 g. The degree of purification was determined by washing residual contaminants with hexane from the cleaned surfaces and then determining the content of oil products and quartz sand weight method. Control tests showed that the degree of purification of products

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was 99%, while the solution did not contain contaminants. The composition of the PVA solution. In the industry, PVA is obtained by saponifying polyvinyl acetate, i.e. 55 by replacing the functional acetate groups of polyvinyl acetate with hydroxyl OH groups. Depending on the degree of polyvinyl acetate saponification, the final product (PVA) may contain different amounts of acetate groups in its molecule. For example, according to GOST 107-79-69, PVA brands containing from 0.08 to 27% by weight of acetate groups are produced. In the described technical solution, the authors use PVA containing in their molecule - 5% by weight of acetate groups, and the molecular weight of these alcohols is in the range of 40 to 80 thousand. (The molecular weight of the PVA produced is from 5 to 100 thousand). The substantiation of the molecular weight limits of the alcohols used and the content of acetate groups in them are presented in Table. one.

From the presented data it can be seen that when using alcohols containing less than 1% and more than 5% of the acetate groups, the degree of cleaning of the surfaces decreases. This is associated with a decrease in the adhesiveness of the resulting PVA dispersions. The lower limit for the content of acetate groups is also limited by production possibilities. The results of determining the limits of the alkali metal chloride (WaCl) content in the solution are given in Table. 2

From the presented data it is seen that with an increase in the electrolyte concentration above 3.5 mol / l, the degree of purification decreases. The decrease in the degree of purification is due to the fact that in solutions with a concentration of more than 3.5 mol / l the PVA electrolyte is quickly salted out and forms too hard associates that have a low adsorption and adhesion activity with respect to the contamination. The concentration of NaCl is below 1 , 5 mol / l gives an insufficient degree of purification.

Comparative results of the cleaning are given in accordance with the known and known methods given in Table. 3

In tab. 4 shows examples of cleaning surfaces at different speeds.

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Growth of air blowing through porous partitions with different pore diameter.

The data show that

5, the maximum degree of purification is achieved in the case of surface treatment with chunks of 0.4 mm in size, and the bubbles should float in the free movement mode. In the case of surface treatment with bubbles that are smaller or larger than the suggested dimensions (0.3-0.6 mm), or in the case of air blowing at a speed exceeding the free movement of the bubbles, the degree of purification decreases.

Dp achieve the maximum effect of cleaning surfaces by the proposed method, it is necessary to treat with bubbles with a size of 0.3-0.6 mm, the latter should be splashed in a free-motion mode.

25 From the presented data it can be seen that in the case of cleaning parts with the proposed method, the speed and quality of cleaning does not depend on the number of products cleaned and remain constant (0.5-3 min and 97-99.5%) in each of the subsequent cycles. Due to the fact that in the process of cleaning the surface of the soil is completely removed from the solution, the service life

es of working solutions is extended to their full physical development, which eliminates the formation of harmful effluents.

Thus, this method of

.Q compared to the known, it allows to increase the cleaning speed by 2-8 times, to increase the degree of cleaning of surfaces by 7-9%, to increase the utilization of contaminants by 83-89%, as well as

5 to exclude the formation of effluents containing harmful for the environment, hardly manageable (sodium polyphosphates, emulsified oil products, surfactants) substances.

12080936

1 a b l and c a 1

The amount of contaminants applied to 20 cm of the surface to be cleaned in each cleaning cycle,

The proposed method

MS-20 oil

Oil MS-2P 0.5

Quartz sand1

Oil conservation NG-2031,5

Quartz sandI

0.5

Quartz sand I

Sodium chloride 150 1 99.5 99.3 99 99.3 99 99 99 99 98 9V

PVA 0,2 3 98 97

Known method

Sodium phosphorus single substituted 12 298 96

Sodium phosphate499 97 two-substituted 12

899 97

Sintanol DS-Yu 3

Foam rubber 10 99 96

98 98 98 98 97 97 97 97

91 85 80 20 18 15 15 13

92 86 81 22 21 16 16 15

93 88 83 23 21 17 17 16

93 88 85 23 21 17 17 16

Conservation oil NG-203 1,5

Quartz sand

300

400 500 600Barbotage

Ascent-chain 0.2

0.25

0.5

t

The degree of color surface in each of the subsequent cycles L

.L.E ......

Table- 3

The amount of recycled contaminants. In each of the subsequent cleaning cycles, Z

lEIIDI

98 98 98 98 97 97 97 97

91 85 80 20 18 15 15 13

92 86 81 22 21 16 16 15

93 88 83 23 21 17 17 16

93 88 85 23 21 17 17 16

97 95 .90 84 79 10 8 7

498 97 91 85 82 12 10 8 6 6

898 97 91 87 83 12 JO 8 7 7

16 99 97 92 87 83 12 10 8 7 7

Tab. faces A

93 "

90

2 6

100 + 20

0t20

7bO 100 200 300 400 500 600 700 800 900 100 200 300 400

500 600 700 800 900 1000

Free movement

Chained popup

Warboat

Free movement

Vshoshtie chain 1.0

Warboat

87

93.3

96 95 93 90

6 6

.4 2 1 1

6

6

6

6

0.8

94

90 89 87 -

6 6

6 11

Claims (2)

A SURFACE CLEANING METHOD, including treatment with a polymer and dispersed air, characterized in that, in order to intensify the cleaning process and the possibility of using waste cleaning products, the polymer is used A 2-ZH solution of polyvinyl alcohol with a molecular weight of 40-80 thousand, and a content of acetate groups of 1-5%, and then the treatment is carried out in a 1.5-3.5 mol / L solution of sodium or potassium chloride while passing through the solution air bubbles 0.3-0.6 mm in size.