WO2024187545A1 - Concrete deflocculating agent and preparation method therefor - Google Patents

Abstract

The present disclosure provides a concrete deflocculating agent and a preparation method therefor. Raw materials for preparing the concrete deflocculating agent comprise the following components in part by weight: 50-80 parts of a high-valence cationic inorganic polymer and 20-40 parts of an oxidant. A preparation method for the high-valence cationic inorganic polymer comprises the following steps: heating the aqueous solution of a high-valence small molecule inorganic matter, in a stirring state, dropwise adding an alkaline solution into a bottle, so that pH is 3.8-4.0, and carrying out heat preservation. According to the concrete deflocculating agent of the present disclosure, the high-valence cationic inorganic polymer and the oxidant are compounded, and the high-valence cationic inorganic polymer and the oxidant have a synergistic effect and weaken the flocculation effect of a polyacrylamide flocculating agent, thereby reducing the viscosity of concrete and improving the working performance of the concrete containing the manufactured sand.

Description

Concrete antiflocculant and preparation method thereof

This disclosure claims the priority of a patent application filed with the China Patent Office on March 16, 2023, with application number CN2023102530834 and patent name “Concrete antiflocculant and preparation method thereof”, the entire contents of which are incorporated by reference in this disclosure.

Technical Field

The present invention relates to the field of concrete building materials, and in particular to a concrete deflocculant. The present invention also relates to a method for preparing the concrete deflocculant.

Background Art

With the development of my country's construction industry and the improvement of environmental protection requirements, the proportion of natural sand in the sand and gravel industry is getting lower and lower. The substitute of natural sand, machine-made sand, has the advantages of low price, easy availability of materials, and controllable quality. It is increasingly widely used. However, machine-made sand needs to go through crushing, grinding and other processes during preparation, which makes the powder content in the sand too high. Therefore, machine-made sand is generally washed before leaving the factory. During the washing, flocculants are usually used to flocculate the powder, thereby reducing the powder content in the sand.

At present, the commonly used flocculant for sand washing is anionic polyacrylamide, which is cheap and has good flocculation effect, but some polyacrylamide will remain in the sand, resulting in a high viscosity of concrete mixed with the sand, which affects the construction performance. With the increasing use of machine-made sand, the problem of concrete becoming sticky has become more and more prominent.

At present, the common method to solve the problem of flocculants in machine-made sand is to increase the dosage of water reducer. Although increasing the dosage of water reducer can overcome the problems of excessive viscosity and poor fluidity of concrete caused by flocculants, increasing the dosage of water reducer will increase the production cost of concrete on the one hand, and on the other hand, it will cause the concrete to have poor encapsulation and the risk of water seepage and separation, affecting the quality stability of concrete. At present, no effective admixture has been developed on the market to solve the adverse effects of flocculants on concrete. Therefore, researching and developing a new admixture to prevent flocculants from affecting the quality of concrete is of great significance to the promotion and application of machine-made sand.

Summary of the invention

In view of this, the present disclosure proposes a concrete deflocculant to improve the working performance of concrete prepared with machine-made sand containing the flocculant.

To achieve the above objectives, the technical solution of the present disclosure is implemented as follows:

A concrete antiflocculant, wherein the raw materials for preparing the concrete antiflocculant include the following components in parts by weight: 50-80 parts of a high-valent cationic inorganic polymer and 20-40 parts of an oxidant;

The method for preparing the high-valent cationic inorganic polymer comprises the following steps: heating the aqueous solution of the high-valent small-molecule inorganic substance, dripping an alkaline solution into a bottle under stirring to adjust the pH to 3.8-4.0, and keeping the temperature.

Furthermore, the high-valent small-molecule inorganic substance includes at least one of aluminum sulfate, iron sulfate, zirconium sulfate, potassium aluminum sulfate, and chromium sulfate.

Furthermore, the oxidant includes at least one of potassium ferrate, potassium permanganate and potassium dichromate.

The present disclosure also proposes a method for preparing a concrete antiflocculant, which comprises the following steps: heating an aqueous solution of a high-valent small-molecule inorganic substance, dripping an alkaline solution into a bottle under stirring to adjust the pH to 3.8-4.0, and keeping the temperature to obtain a high-valent cationic inorganic polymer; adding an oxidant to the high-valent cationic inorganic polymer and dissolving it to obtain the concrete antiflocculant.

Furthermore, the heating temperature of the aqueous solution of the high-valent small-molecule inorganic substance is 55-65°C.

Furthermore, the alkaline solution includes at least one of sodium hydroxide, potassium hydroxide, ammonia water, magnesium hydroxide, and sodium silicate.

The concrete anti-flocculant disclosed in the present invention is a compound of a high-valent cationic inorganic polymer and an oxidant. The high-valent cationic inorganic polymer can be electrically neutralized with an anionic polyacrylamide flocculant to weaken the electrostatic adsorption of polyacrylamide, and the molecular network of the inorganic polymer can be molecularly entangled with polyacrylamide to play a role of network patching and sweeping, so that polyacrylamide is separated from adsorption. The oxidant can oxidize polyacrylamide to crack the polymer chain. The high-valent cationic inorganic polymer and the oxidant work synergistically to weaken the flocculation effect of the polyacrylamide flocculant, thereby reducing the viscosity of the concrete and improving the working performance of the concrete containing flocculant-made sand.

DETAILED DESCRIPTION

It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are purchased from conventional biochemical reagent stores unless otherwise specified. In addition, except for special instructions in this example, the terms and processes involved in this example are understood according to the general cognition and conventional methods in the prior art.

A concrete deflocculant, the preparation raw materials of which include the following components by weight: 50-80 parts of high-valent cationic inorganic polymers and 20-40 parts of oxidants; the preparation method of the high-valent cationic inorganic polymers includes the following steps: heating an aqueous solution of a high-valent small-molecule inorganic substance, dripping an alkaline solution into a bottle under stirring to adjust the pH to 3.8-4.0, and keeping the temperature.

The concrete antiflocculant disclosed in the present invention is a compound of a high-valent cationic inorganic polymer and an oxidant. The high-valent cationic inorganic polymer can be electrically neutralized with an anionic polyacrylamide flocculant to weaken the electrostatic adsorption of polyacrylamide, and the molecular network of the inorganic polymer can be molecularly entangled with polyacrylamide to play a role of network patching and sweeping, so that polyacrylamide is separated from adsorption. The oxidant can oxidize polyacrylamide to crack the polymer chain. The high-valent cationic inorganic polymer and the oxidant work synergistically to weaken the flocculation effect of the polyacrylamide flocculant, thereby reducing the viscosity of the concrete and improving the fluidity of the concrete containing machine-made sand.

The high-valent small-molecule inorganic substance includes at least one of aluminum sulfate, iron sulfate, zirconium sulfate, potassium aluminum sulfate, and chromium sulfate.

The oxidant includes at least one of potassium ferrate, potassium permanganate and potassium dichromate.

The present disclosure also proposes a method for preparing a concrete antiflocculant, which specifically includes the following steps: heating an aqueous solution of a high-valent small-molecule inorganic substance to 55-65° C. in a water bath, dripping an alkaline solution into a bottle under stirring to adjust the pH to 3.8-4.0, keeping the solution warm and then cooling to obtain a high-valent cationic inorganic polymer; adding an oxidant to the high-valent cationic inorganic polymer and dissolving it to obtain the concrete antiflocculant.

The alkaline solution includes at least one of sodium hydroxide, potassium hydroxide, ammonia water, magnesium hydroxide and sodium silicate.

The above reaction reagents can all be purchased from the market. The specific implementation scheme of the present disclosure is described in detail below.

Example 1

Dissolve 70 parts of aluminum sulfate in water, heat to 60°C, add 30% by mass sodium hydroxide solution in a four-necked flask, stop adding when the pH rises to 3.5, keep warm for 3 hours, cool down to obtain a high-valent cationic inorganic polymer, add 30 parts of potassium ferrate and dissolve it.

Example 2

Dissolve 70 parts of ferric sulfate in water, heat to 63°C, add 30% by mass potassium hydroxide solution into a four-necked flask, stop adding when the pH rises to 3.8, keep warm for 3 hours, cool down to obtain a high-valent cationic inorganic polymer, add 20 parts of potassium permanganate and dissolve it.

Example 3

Dissolve 55 parts of zirconium sulfate in water, heat to 60°C, add aqueous ammonia solution dropwise into a four-necked flask, stop adding when the pH reaches 4.0, keep warm for 3 hours, cool down to obtain a high-valent cationic inorganic polymer, add 20 parts of potassium dichromate and dissolve it.

Example 4

Dissolve 60 parts of chromium sulfate in water, heat to 60°C, add magnesium hydroxide solution dropwise into a four-necked flask, stop adding when the pH reaches 3.8, keep warm for 3 hours, cool down to obtain a high-valent cationic inorganic polymer, add 30 parts of potassium ferrate and dissolve it.

Example 5

Dissolve 80 parts of potassium aluminum sulfate in water, heat to 55°C, add sodium silicate solution dropwise into a four-necked flask, stop adding when the pH reaches 3.8, keep warm for 3 hours, cool down to obtain a high-valent cationic inorganic polymer, add 30 parts of potassium permanganate and dissolve.

Comparative Example 1

This comparative example uses a commercially available product, model X007, from Sichuan Luhua Lingtuo Building Materials Co., Ltd.

Comparative Example 2

The raw materials and method of this comparative example are basically the same as those of Example 1, except that no oxidant is added.

Comparative Example 3

The raw materials and method of this comparative example are basically the same as those of Example 1, except that the amount of the oxidant used is 15 parts.

Comparative Example 4

The raw materials and method of this comparative example are basically the same as those of Example 1, except that the amount of the high-valent small molecule inorganic substance used is 45 parts.

The deflocculants prepared in the above embodiments and comparative examples were used in concrete tests. To simulate the effect of polyacrylamide flocculants on the working performance of concrete, 0.15% of the mass of anionic polyacrylamide (molecular weight 1200w) was added to the concrete mixing water. According to GB/T 50080-2016 "Standard for the performance test method of ordinary concrete mixtures", the initial and 1h expansion, slump and inversion time of the concrete were tested. The cement used to prepare the concrete was P.O42.5 Esheng cement, the fly ash was Mingxiang I grade fly ash, the water reducer was GK-3000 polycarboxylic acid high-performance water reducer (product of Shijiazhuang Changan Yucai Building Materials Co., Ltd.), the water reducer dosage was 1.0% of the mass of the cementitious material, and the deflocculant dosage prepared in the embodiments and comparative examples was 0.05% of the mass of the cementitious material. The concrete benchmark mix is shown in Table 1, and the test results are shown in Table 2. The blank group is concrete without adding the deflocculant.

Table 1 Concrete standard mix ratio (kg/m ³ )

Table 2 Working properties of concrete

By comparing the test results of each embodiment, comparative example 1 (commercially available product) and the blank group, the concrete antiflocculant disclosed in the present invention can effectively reduce the viscosity of concrete, shorten the pouring time, and improve the working performance of concrete.

Comparison between Comparative Example 2 and Example 1 shows that the concrete antiflocculant without the addition of an oxidant cannot oxidatively cleave the polymer chains of polyacrylamide and cannot destroy the flocculation state of the mixture. Only the high-charge polymer plays a role. Therefore, the inversion time is shortened, but not significantly. The initial and 1h expansion degrees are also smaller than those in Example 1.

Comparison between Comparative Example 3 and Example 1 shows that although the addition of an oxidant has a certain oxidizing effect, the molecular structure of polyacrylamide cannot be completely destroyed when the amount is insufficient, so the inversion time is slightly longer than that of Example 1.

Comparison of Comparative Example 4 with Example 1 shows that the dosage of high-valent small-molecule inorganic substances is low, resulting in insufficient content of high-valent cationic inorganic polymers, which cannot effectively neutralize the static electricity of polyacrylamide, and thus cannot more effectively eliminate the viscosity-increasing effect of polyacrylamide.

The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

Claims (6)

1. A concrete deflocculant, characterized in that the raw materials for preparing the concrete deflocculant include the following components by weight: 50-80 parts of a high-valent cationic inorganic polymer and 20-40 parts of an oxidant;

   The method for preparing the high-valent cationic inorganic polymer comprises the following steps: heating the aqueous solution of the high-valent small-molecule inorganic substance, dripping an alkaline solution into a bottle under stirring to adjust the pH to 3.8-4.0, and keeping the temperature.
2. The concrete deflocculant according to claim 1 is characterized in that the high-valent small-molecule inorganic substance includes at least one of aluminum sulfate, iron sulfate, zirconium sulfate, potassium aluminum sulfate, and chromium sulfate.
3. The concrete deflocculant according to claim 1 or 2, characterized in that the oxidant comprises at least one of potassium ferrate, potassium permanganate and potassium dichromate.
4. A method for preparing a concrete deflocculant, characterized in that the method comprises the following steps: heating an aqueous solution of a high-valent small-molecule inorganic substance, dripping an alkaline solution into a bottle under stirring to adjust the pH to 3.8-4.0, and keeping the temperature to obtain a high-valent cationic inorganic polymer; adding an oxidant to the high-valent cationic inorganic polymer for dissolution to obtain the concrete deflocculant.
5. The method for preparing a concrete deflocculant according to claim 4 is characterized in that the heating temperature of the aqueous solution of the high-valent small-molecule inorganic substance is 55-65°C.
6. The method for preparing a concrete deflocculant according to claim 4 or 5, characterized in that the alkaline solution comprises at least one of sodium hydroxide, potassium hydroxide, ammonia water, magnesium hydroxide, and sodium silicate.