RU2571967C1 - Method of obtaining plasticiser for concrete mixtures - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of plasticiser obtaining includes sulphonation of phenol production wastes by concentrated sulphuric acid, successive two-stage neutralisation of sulphomass: by sodium metasilicate (silicate module-4) and 15% solution of caustic soda (NaOH). To obtain additive in dry form the following drying of plasticiser solution to 0.5% humidity is provided. Components are taken in the following ratio, wt %: wastes from phenol production by cumene method - 3.0-5.0, concentrated sulphuric acid - 15.0÷18.0, sodium metasilicate - 5.5-8.5, caustic soda - 8.5-13.0, water - the remaining part.

EFFECT: reduction of air-involving, increase of density of concrete mixtures and density of products from them.

1 tbl

Description

 The invention relates to the construction and construction materials industry, in particular to the manufacture of additives in cement concrete for plasticizing concrete mixtures.

A known method of producing plasticizer (see the description of the patent of the Russian Federation No. 2323390 "Method for producing plasticizer for concrete mixtures", IPC C04B 24/22, publ. 05/10/2008, bull. No. 13), which includes sulfonation of phenolic resin - waste cumene phenol concentrated sulfuric acid method, cooling the reaction mass, diluting the reaction sulfomass with water, polycondensation of sulfomass with formalin, cooling the polycondensation products, neutralizing the polycondensation product with 40% sodium hydroxide solution, mixing antifoam OP-neutralized product of polycondensation and subsequent drying. The specified method allows to obtain a plasticizer with good consumer characteristics, using hazardous waste products, while solving environmental problems. This method is the closest analogue. The disadvantage of this method is the length of the process of obtaining a plasticizer due to the polycondensation of sulfomass with formalin and the use of an additional stage of defoaming, as well as increased air absorption in the manufacture of concrete mix with the specified plasticizer, which entails a decrease in the operational characteristics of the resulting concrete products.

The objective of the invention is to develop a method for producing a plasticizer from phenol production wastes, in which the amount of entrained air decreases in the concrete mixture, due to which the density of the concrete mixture increases, the basic operational properties of the finished concrete product, in particular, strength, are improved.

The problem is solved by a method for producing a plasticizer, including sulfonation of phenol production waste (obtained by the cumene method) with concentrated sulfuric acid, cooling the reaction mixture to 60 ° C, with sequential 2-stage neutralization with sodium metasilicate solutions (silicate module - 4) and sodium hydroxide solution (15% solution) followed by drying to a moisture content of 0.5%. The components are taken in the following ratio, wt. %:

the phenol production waste by the cumene method - 3.0-5.0,

concentrated sulfuric acid - 15.0-18.0,

sodium metasilicate (silicate module - 4) - 5.5-8.5,

caustic soda (15% solution) - 8.5-13.0,

water is the rest.

Sulfonation of the phenol production waste with 92-98% sulfuric acid is carried out in a 4-necked glass flask equipped with a stirrer, a thermometer and a reflux condenser, sulfuric acid and phenol production waste are sequentially charged at room temperature, and the reaction mixture is heated to a temperature of 60- 65 ° C, then heating the oil bath to a temperature of 150-160 ° C is connected with continuous stirring, the sulfonation process is carried out for 1.5-2.0 hours until the sulfonation stage is completed (until water sulphomass), the reaction mass is cooled with continuous stirring to 60 ° C, then the reaction mass is sequentially neutralized with sodium metasilicate solutions (silicate module - 4) and sodium hydroxide solution (15% solution) until a pH of 11.5-12 is reached, 5 (while maintaining the neutralization temperature not higher than 50 ° C). The resulting 20% solution of the finished plasticizer, if necessary, is sent for drying to a moisture content of 0.5%. The completeness of sulfonation is controlled by the solubility of the reaction mass in water, the absence of oily spots on the surface of the aqueous sample solution, and the absence of a characteristic odor of organic impurities such as acetophenol.

To obtain a plasticizer in the described method, the following components were used:

- waste phenol production by the cumene method according to TU 38 10286-75 of the following composition, mass. %:

Phenol 4.9-11

Acetophenol 7.5-23.9

Dimethylphenolcarbinol 2.9-19.64

Dimer-methylstyrene 10.64-19.8

Cumylphenol 23.9-49.0

Heavy hydrocarbons 1.3-11.73

Peck 4.9-13.97

- sulfuric acid technical in accordance with GOST 2184-77

- technical caustic soda according to GOST 2263-69

- sodium metasilicate according to GOST 13078-81 *.

The effectiveness of the new plasticizer was evaluated according to GOST 30459-2008 "Additives for concrete and mortar." Concrete samples were manufactured and tested in accordance with GOST 10180-2012 and GOST 310.1-310.4-81. The obtained compositions with boundary quantitative values and sample properties for these compositions are shown in Table 1. Table 1 also shows the characteristics of the prototype plasticizer and calculated the plasticizer parameters of the new method and concrete mix indicators using it. As can be seen from Table 1, a new method of preparing a plasticizer using components within the specified limits allows you to abandon the processes of polycondensation and defoaming. According to GOST 24211-2008, the obtained plasticizer according to the main criterion of effectiveness belongs to the subclass “superplasticizers” (increasing the grade of concrete mix for workability from P1 to P5), the developed additive improves the technological and operational characteristics of concrete mixtures, increases the density of concrete mixtures and the strength of products made from them.

Claims (1)

A method of producing a plasticizer includes sulfonation of phenol production waste with concentrated sulfuric acid at a temperature of 150-160 ° C for 1.5-2.0 hours to obtain a water-soluble sulfomass, followed by cooling with continuous stirring of the reaction mixture to a temperature of 60 ° C, followed by a two-stage neutralization with sodium metasilicate (silicate module - 4) and 15% sodium hydroxide solution until a pH of 11.5-12.5 is reached, followed by drying to a moisture content of 0.5% in the following ratio, wt.%:
cumene method waste of phenol production 3.0-5.0 concentrated sulfuric acid (92-98% solution) 15.0-18.0 sodium metasilicate (silicate module 4) 5.5-8.5 caustic soda (15% solution) 8.5-13.0 water rest