SU887508A1 - Method of producing plastifying additive - Google Patents

Description

(54) METHOD FOR OBTAINING PLASTIFICATION ADDITIVE

one

The invention relates to the building materials industry, and specifically to the production technology of plasticizing agents for cement mortars and concretes.

Sulfite-alcohol or sulphite-drouke bard is used as plasticizing agents based on lignosulphonates, which is subjected to heat treatment 1.

The plasticizer obtained by a known method significantly slows down the hardening of the concrete.

There is also known a method for producing a plasticizer by thermally treating bards with pretreatment with ammonium salts or ammonia together with carbon dioxide 2.

The product obtained after separation of the sulfate or calcium carbonate slurry is dried and then co-milled.

This method is closest to the proposed technical essence and the achieved result.

A disadvantage of the known method is the complexity of the technological process, as a result of which, however, a plasticizer is also obtained which retards hardening.

The aim of the invention is to increase the strength of concrete at three days of age.

This is achieved by the fact that in the method of obtaining a plasticizing agent for concrete by mixing an aqueous solution of sulfite-alcohol

10 bards with the reaction substance, followed by removal of harmful impurities from the solid precipitate, a water solution of sulphite-alcohol bards is mixed with cement in a weight ratio of 5: 1 to 1: 1 for 15300 minutes.

To more completely remove harmful impurities from sulphite-alcohol bards, the filtrate is repeatedly mixed with cement.

In order to intensify the interaction of lignosulfonates with the reaction substance, the mixing of an aqueous solution of lignosulfonate with an inorganic substance can be carried out simultaneously with its grinding.

The method is carried out as follows.

Sulfite-alcohol bard in the form of a 10-20% oh aqueous solution is mixed with Portland cement in a weight ratio of: sulfite-alcohol bard: cement (on a dry basis) from 5: 1 to 1: 1. Mixing is carried out for 15-300 minutes in a forced-action mixer or in a ball mill, where grinding into a binder occurs at the same time. Upon completion of the stirring, the liquid phase of the suspension is separated from the solid by filtration or centrifugation, followed by removal of the precipitate. The separation of the solid phase can be carried out by decantation after the suspension of the suspension. In the process of the interaction of sulfite-alcohol bards with cement, the latter, in turn, adsorbs components, which especially strongly inhibit the hardening of cement mortars and concretes. When grinding, the surface of cement particles is renewed, which contributes to the intensification of adsorption processes and a more complete separation of components that slow down hardening. The separated liquid phase is treated with a new portion of Portland cement in the same weight ratio as in the method described above one or more times. The proposed method is illustrated by examples. Example 1. Prepare plasticizing additive by treating sulfite-alcohol bards with Portland cement. A 10% aqueous solution of sulfite-alcohol stillage in an amount of 1000 ml is mixed for 180 minutes in a ball mill with 20 g of portlan cement, after which the suspension is filtered through paper; filter on a Buchner funnel and remove the solid precipitate. The liquid phase is again mixed in a ball mill with a new batch of Portland cement weighing 20 g. The liquid phase obtained after the secondary removal of sediment is treated for the third time with a new batch of Portland cement weighing 20 g. The plasticizer obtained is used as a 0.5% additive (dry matter ) to the weight of cement for concrete preparation of the following composition: cement: sand: crushed stone 1: 1.7: 2, FDI, 53. Samples of 10x10x10 cm cubes are made from the concrete mixture of the above composition. Simultaneously, control samples are made from a concrete mixture of the same composition b additives of plasticizers and 0.5% sulphite-alcohol bards raw. The mobility of the concrete mix without additives on the draft of the cone is 2-3 cm, and the mobility of cm s with the additive is 15-18 cm. The average compressive strength of concrete on the third day without a plasticizing additive is 215 kg / cm -, the average compressive strength with the addition of untreated sulfite-alcohol stillage is 100 kg / cm, while the compressive strength of the concrete with a plasticizer obtained according to the proposed method with a bard: cement ratio of 5: 1 is 145 kg / cm. Examples 2-4. A plasticizing additive is prepared by mixing 1500, 1000 and 500 ml of a 10% aqueous solution, sulphite-alcohol stillage with 50 g of portland cement. Mixing is performed for 180 minutes in a ball mill. The treatment of bards in the experiments described in these examples was carried out 3 times as in example 1. The plasticizers obtained were used as a 0.5% additive to the weight of cement to prepare a concrete mix of the same composition as in example 1. Results of the study samples of examples 1, 2, 3, 4 are given in table. 1. From this table it is clear that samples of concrete mixture with the addition of a plasticizer obtained by treating sulphite-alcohol stillage with cement in a weight ratio of 2: 1 and 1: 1 have the highest compressive strength. Examples 5-8. A plasticizing agent is prepared by mixing 1000 ml of an aqueous 10% solution of sulfite-alcohol stillage, i.e. bard: cement ratio was 2: 1 with 50 g of portland cement. Mixing is carried out in a ball mill for 15, 60, 180 and 300 minutes, after which the suspension is filtered through a filter paper on a Buchner funnel, followed by removal of solid sediment. In each of the examples, the processing of the liquid phase with new portions of Portland cement weighing LOg is carried out for 15, 60, 180 and 300 minutes (with a total of three processing cycles) The plasticizer obtained in each example is used as a 0.5% additive to weight of cement in the preparation of concrete mix of the same composition as in the previous examples. Samples-cubes 10x10x10 cm from the same concrete are tested in a three-day age. The test results are shown in Table. 2. As a zidno-from the table above, the concrete reaches the greatest strength with the addition of a plasticizer, processed in each cycle for 180-300 minutes. With bard processing time of more than 300 minutes, the strength of the concrete is almost stabilized. Therefore, the optimal treatment time is 180 minutes.

Examples 9-12. To prepare the plasticizer, 1000 ml of a 10% aqueous solution of vinasse is mixed with 50 g of portland cement in a ball mill for 180 minutes.

The treatment with new portions of cement is carried out one, two, three and five times.

The resulting plasticizer is used as a 0.5% cement additive in a concrete mix of the same composition as in the previous examples. The test data for the samples from examples 9-12 are given in table. 3

From tab. 3, it is clear that treating the sulfite alcohol bards three times is optimal. With a long weight ratio of bard: cement used in compressive strength on the 3rd day, kg / cm 145 190 205 15-17 16-18 16-18 Mobility, cm

The processing time of each cycle, min 15

Compressive strength at three-day age, kg / cm 120. 185

By increasing the multiplicity of processing, the properties of concrete with the plasticizing additive obtained according to the described method are stabilized,

Thus, the treatment of sulfite-alcohol stillage with Portland cement has the following optimal parameters: the ratio of bard: solid (for solids) is 2: 1; processing time 180 min; the multiplicity of processing 3.

0

The use of the proposed method allows to obtain a concrete mix, the workability of which is the same as that of the concrete mix with

5 by the addition of well-known plasticizers.

At the same time, the obtained additive practically does not slow down the hardening of the concrete.

Table 1

Table

60

180

300

204

210 210 95 100 17-18 15-17 15-17

The multiplicity of processing new portions of cement

Compressive strength on the third day, kg / cm

Claims (2)

1. A method for producing a plasticizer additive for concrete by mixing an aqueous solution of sulfite-alcohol stillage with the reaction substance, followed by removing the solid sediment of harmful impurities, which, in order to increase the strength of concrete at three days of age, an aqueous solution of sulfite-alcohol stillage is mixed with cement in weight Table 3 100 210 210 110 the ratio of 5: 1 - 1: 1 for 15-300 minutes 2. A method according to claim 1, characterized in that, in order to more completely remove harmful impurities from sulfite-alcohol stillage, the filtrate is repeatedly mixed with cement.  Information sources, taken into account in the examination 1, USSR Author's Certificate No. I3772, cl. From 04 To 13/14, 1947. 2. Authors certificate of the USSR 113773, cl. From 04 To 13/24, 1948.