Anti-flocculating agent for washed sand concrete as well as preparation method and application of anti-flocculating agent

Abstract

The invention relates to a deflocculating agent for washed sand concrete. The deflocculating agent is prepared from the following components in percentage by mass: 50-90% of a neutralizer, 3-20% of a reducing agent, 0-20% of a retarder and 0-10% of a surfactant, wherein the neutralizing agent is an inorganic double salt, and the reducing agent is at least one of sodium nitrite, ferrous chloride and sodium pyrosulfite. According to the anti-flocculating agent disclosed by the invention, through addition and compounding of specific contents and components, concrete containing more flocculating agents can be subjected to targeted adsorption of the flocculating agents; therefore, the damage of the flocculating agent to the dispersing performance of polycarboxylic acid molecules in the concrete is reduced, a good anti-flocculation effect is further achieved, the use amount of a water reducing agent in the concrete is reduced, and the flowability and working performance of the concrete are enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of building material admixtures, in particular to an antiflocculant for washed sand concrete and a preparation method and application thereof. Background Art

[0002] In recent years, due to the strict supervision of the environmental protection department, it is clearly required that sand and gravel production enterprises should not discharge wastewater. Therefore, a large number of sand and gravel production enterprises use flocculants in the sewage treatment process to accelerate the sedimentation of suspended matter in the sewage, so that they can quickly and effectively treat the sewage after sand washing for recycling. In order to achieve the desired effect, sand and gravel production enterprises use a high amount of flocculants, and the amount of flocculants remaining in the sand leaving the factory is very high, which has an adverse effect on the performance of concrete mixtures.

[0003] In response to the problem of flocculants often contained in machine-made sand, the current commonly used strategy is to increase the amount of water reducer. Although this method can effectively alleviate the problem of high viscosity and insufficient fluidity of concrete caused by flocculants, it is also accompanied by significant disadvantages: first, it directly pushes up the production cost of concrete, and second, it weakens the packaging performance of concrete, thereby threatening the overall quality stability of concrete. It is worth noting that there has not yet been a widely used and easy-to-produce anti-flocculant for washed sand concrete on the market.

[0004] At present, the flocculants commonly used by sand and gravel enterprises in the existing technology are polyacrylamide, polyaluminium chloride and polyferric sulfate. The flocculants remaining in the washed sand will not only increase the dosage of admixtures, but also cause large collapse, more slurry, and high viscosity of concrete, and will affect the strength of concrete. Concrete mixing plants often increase the dosage of admixtures to improve the fluidity of concrete, but the effect is not satisfactory. Increasing the dosage of admixtures still has problems such as poor concrete workability and segregation and bleeding, and the degree of improvement in concrete fluidity is limited. Fundamentally reducing the flocculation effect of flocculants is the key to solving the problem.

[0005] Therefore, there is an urgent need to develop an anti-flocculant to reduce the adverse effects of flocculants on concrete, which is of great significance to the long-term development and progress of machine-made sand. Summary of the invention

[0006] The technical purpose of the present invention is to provide a deflocculant for washed sand concrete, which can carry out targeted adsorption of flocculants on concrete containing more flocculants through the addition and compounding of specific contents and components, thereby reducing the damage of the flocculants to the dispersion properties of polycarboxylic acid molecules in the concrete, thereby achieving a better deflocculant effect, reducing the amount of water reducer in the concrete, and enhancing the fluidity and working performance of the concrete.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a deflocculant for washed sand concrete, composed of the following components in percentage by mass: 50-90% of a neutralizer, 3-20% of a reducing agent, 0-20% of a retarder and 0-10% of a surfactant; wherein the neutralizer is an inorganic complex salt, and the reducing agent is at least one of sodium nitrite, ferrous chloride and sodium pyrosulfite.

[0008] Furthermore, the neutralizing agent is at least one of potassium aluminum sulfate, ammonium aluminum sulfate, potassium magnesium chloride and potassium hydrogen sulfate.

[0009] Furthermore, the retarder is at least one of sodium gluconate, boric acid and molasses.

[0010] Furthermore, the surfactant is at least one of rosin thermal polymer, triterpenoid saponin and sodium dodecyl sulfate.

[0011] A method for preparing a deflocculant for washed sand concrete comprises the following steps: weighing a neutralizing agent, a reducing agent, a retarder and a surfactant according to mass percentage, and mixing them sufficiently to obtain a finished deflocculant.

[0012] Furthermore, the mixing method is shear mixing, and the mixing time is 10-20 minutes.

[0013] Application of deflocculants in the preparation of washed sand concrete.

[0014] Beneficial effects: 1. The antiflocculating agent for washed sand concrete of the present invention is composed of raw materials with specific contents and components. It can effectively reduce the damage of the flocculant to the dispersion performance of the water reducing agent polycarboxylic acid molecules in the concrete by targeted adsorption of the flocculant in the concrete, thereby reducing the negative impact of more flocculants in the concrete on the concrete as a whole, so as to achieve a better antiflocculating effect, reduce the amount of water reducing agent in the concrete, and significantly enhance the fluidity and working performance of the concrete. It is suitable for various types of washed sand concrete and has a broad prospect for promotion and application. It has far-reaching strategic significance for promoting the widespread application of machine-made sand in the field of building materials.

[0015] 2. The anti-flocculant for washed sand concrete of the present invention is composed of a neutralizer, a reducing agent, a retarder and a surfactant. The flocculant generally used for washed sand is PAM, and its adsorption effect and the charge it carries will destroy the dispersion effect of the polycarboxylic acid molecules of the water reducer, so that the polycarboxylic acid molecular chain is adsorbed by the flocculation structure, the amount of water reducer increases, and the amount of mother liquor increases. At the same time, the flocculant residue in the washed sand is generally not uniform. It follows the different water content of the sand, the different sand sampling positions, and the different amounts used during sand washing, resulting in more and less flocculants in the washed sand, which in turn causes the amount of water reducer opened with pure mother liquor to vary too much and the amount is unstable. After the anti-flocculant for washed sand concrete provided by the present invention is added to concrete and used, its own dissolution effect will cause it to ionize more metal ions in the solution and release molecules containing hydrophobic groups and hydrophilic group structures. These metal ions will combine with the hydroxide ions in the concrete solution to form difficultly ionized hydroxides. The hydroxide carries an electric charge and has strong adsorption. It is easy to combine with the flocculation structure formed by the flocculant, thereby reducing its large adsorption of polycarboxylic acid molecules, thereby achieving the effect of anti-flocculation. At the same time, the molecules containing hydrophobic groups and hydrophilic groups in the solution will quickly adsorb on the interfaces of each phase in the cement-air system to form a directional adsorption film. During the mixing process, the tiny spaces in the concrete system are further filled, the fluidity of the concrete is improved, and the finished concrete has good fluidity and excellent working performance. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the following embodiments cannot be used as a limitation on the protection scope of the present invention.

[0017] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all of the specifications required for conventional experiments in the art.

[0018] A deflocculant for washed sand concrete, comprising the following components in percentage by mass: a neutralizer: 50-90%, a reducing agent: 3-20%, a retarder: 0-20%, and a surfactant: 0-10%.

[0019] The neutralizing agent is an inorganic complex salt, which is at least one of potassium aluminum sulfate, ammonium aluminum sulfate, potassium magnesium chloride and potassium hydrogen sulfate.

[0020] The reducing agent is at least one of sodium nitrite, ferrous chloride and sodium pyrosulfite.

[0021] The retarder is at least one of sodium gluconate, boric acid and molasses.

[0022] The surfactant is at least one of rosin thermal polymer, triterpenoid saponin and sodium dodecyl sulfate.

[0023] The present invention also proposes a method for preparing a deflocculant for washed sand concrete, which comprises the following steps: weighing a neutralizer, a reducing agent, a retarder, and a surfactant respectively according to mass percentage, and mixing them in a shear mixing manner for 10-20 minutes.

[0024] The above reagents can be purchased from the market. The specific implementation scheme of the present invention is described in detail below.

[0025] Several examples are given below to verify the performance of the deflocculant of the present invention. The specific proportion (mass percentage) of each example is shown in Table 1 below.

[0026] Table 1 Proportions of various examples (Note: " / " in this table means no addition) The deflocculants obtained in Example 1, Example 5 and Example 7 were selected for comparison with the control group (blank), and the results are shown in Table 2 below.

[0027] Table 2 Performance comparison The following mix ratio is used as a unified test standard (washed sand contains 0.0005% flocculant) It can be seen from the performance comparison that when the deflocculant for washed sand concrete of the present invention is added, the "slump", "slump after 1 hour", "expansion" and "expansion after 1 hour" indicators of the concrete are better than those when the water reducer is used alone.

[0028] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. A variety of simple modifications are made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

[0029] 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 invention will not further describe various possible combinations.

Claims

1. A deflocculant for washed sand concrete, characterized in that: It is composed of the following components in percentage by mass: 50-90% of a neutralizer, 3-20% of a reducing agent, 0-20% of a retarder and 0-10% of a surfactant; wherein the neutralizer is an inorganic complex salt, and the reducing agent is at least one of sodium nitrite, ferrous chloride and sodium pyrosulfite.

2. The antiflocculant for washed sand concrete according to claim 1, characterized in that: The neutralizing agent is at least one of potassium aluminum sulfate, ammonium aluminum sulfate, potassium magnesium chloride and potassium hydrogen sulfate.

3. The antiflocculant for washed sand concrete according to claim 1, characterized in that: The retarder is at least one of sodium gluconate, boric acid and molasses.

4. The antiflocculant for washed sand concrete according to claim 1, characterized in that: The surfactant is at least one of rosin thermal polymer, triterpenoid saponin and sodium dodecyl sulfate.

5. The method for preparing a deflocculant for washed sand concrete according to any one of claims 1 to 4, characterized in that: The neutralizing agent, reducing agent, retarder and surfactant are weighed respectively according to the mass percentage, and after being fully mixed, the finished antiflocculant is obtained.

6. The method for preparing a deflocculant for washed sand concrete according to claim 5, characterized in that: The mixing method is shear mixing, and the mixing time is 10-20 minutes.

7. Use of the deflocculant according to any one of claims 1 to 4 in the preparation of washed sand concrete.

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