阅读说明：本技术 羟基乙叉二膦酸改性的磷酸盐粘结剂及其制备方法 (Phosphate binder modified by hydroxyethylidene diphosphonic acid and preparation method thereof ) 是由 张友寿 喻双喜 夏露 周磊 于 2019-10-15 设计创作，主要内容包括：本发明提供一种羟基乙叉二膦酸改性的磷酸盐粘结剂及其制备方法,所述羟基乙叉二膦酸改性的磷酸盐粘结剂主要由以下原料按质量百分比制得：工业磷酸51.59％～52.45％、氢氧化铝粉末11.83％～12.03％、硅酸0.61％～0.62％、硼酸1.83％～1.86％、轻质氧化镁1.22％～1.24％、羟基乙叉二膦酸0.76％～2.4％、水30.53％～31.04％。本发明提供的羟基乙叉二膦酸改性的磷酸盐粘结剂采用羟基乙叉二膦酸作为改性剂,在少量的加入量下就能显著降低粘结剂的粘度和提高所制备砂样的强度,使加入的原料最大化的参与反应,产生的残渣较少,减少水分流失以保证粘结剂有较低的粘度,提高型砂流动性。(The invention provides a hydroxyl ethylidene diphosphonic acid modified phosphate binder and a preparation method thereof, wherein the hydroxyl ethylidene diphosphonic acid modified phosphate binder is mainly prepared from the following raw materials in percentage by mass: 51.59-52.45% of industrial phosphoric acid, 11.83-12.03% of aluminum hydroxide powder, 0.61-0.62% of silicic acid, 1.83-1.86% of boric acid, 1.22-1.24% of light magnesium oxide, 0.76-2.4% of hydroxyethylidene diphosphonic acid and 30.53-31.04% of water. The phosphate binder modified by the hydroxyethylidene diphosphonic acid provided by the invention adopts hydroxyethylidene diphosphonic acid as a modifier, and can obviously reduce the viscosity of the binder and improve the strength of the prepared sand sample under the condition of a small amount of addition, so that the added raw materials participate in the reaction to the maximum extent, less residues are generated, the water loss is reduced, the lower viscosity of the binder is ensured, and the fluidity of the molding sand is improved.)

1. A phosphate binder modified by hydroxyethylidene diphosphonic acid is characterized in that: the material is mainly prepared from the following raw materials in percentage by mass:

51.59-52.45% of industrial phosphoric acid, 11.83-12.03% of aluminum hydroxide powder, 0.61-0.62% of silicic acid, 1.83-1.86% of boric acid, 1.22-1.24% of light magnesium oxide, 0.76-2.4% of hydroxyethylidene diphosphonic acid and 30.53-31.04% of water.

2. The hydroxyethylidene diphosphonic acid modified phosphate binder of claim 1, wherein: the mass percentage of the industrial phosphoric acid is 85%.

3. The hydroxyethylidene diphosphonic acid modified phosphate binder of claim 1, wherein: the silicic acid, the boric acid and the light magnesium oxide are analytically pure.

4. The hydroxyethylidene diphosphonic acid modified phosphate binder of claim 1, wherein: the hydroxyethylidene diphosphonic acid is white crystal particles with the mass percentage of more than or equal to 90 percent.

5. A method for preparing a hydroxyethylidene diphosphonic acid modified phosphate binder according to any one of claims 1 to 4, wherein: comprises the following steps:

(1) adding industrial phosphoric acid into a reaction kettle, and heating to 180-200 ℃ while stirring;

(2) adding a small amount of aluminum hydroxide powder into the reaction kettle in the step (1) for many times, and continuously stirring until the reaction solution is transparent;

(3) adding water of which the amount is one fourth of the total water amount into the reaction kettle in the step (2), and heating and stirring until the temperature of the reaction solution is restored to the temperature before adding the water;

(4) adding boric acid into the reaction kettle in the step (3), and continuously heating and stirring until the reaction solution is transparent;

(5) adding silicic acid into the reaction kettle in the step (4), and continuously heating and stirring until the reaction solution is transparent;

(6) adding water of which the amount is one fourth of the total water amount into the reaction kettle in the step (5), and heating and stirring until the temperature of the reaction solution is restored to the temperature before adding the water;

(7) adding light magnesium oxide into the reaction kettle in the step (6), and continuously heating and stirring until the reaction solution is transparent;

(8) adding water of which the amount is one fourth of the total water amount into the reaction kettle in the step (7), and heating and stirring until the temperature of the reaction solution is restored to the temperature before adding the water;

(9) adding hydroxyethylidene diphosphonic acid into the reaction kettle in the step (8), and continuously heating and stirring until the reaction solution is transparent;

(10) and (4) adding the residual water in the total water amount into the reaction kettle in the step (9), continuously heating and stirring until the reaction solution is transparent and clear, discharging, and removing the bottom layer precipitate to obtain the hydroxyethylidene diphosphonic acid modified phosphate binder.

Technical Field

The invention belongs to the field of casting industry, and particularly relates to a phosphate binder modified by hydroxyethylidene diphosphonic acid and a preparation method thereof.

Background

The phosphate binder is used as an environment-friendly inorganic casting binder, has the characteristics of good collapsibility, no color and no pungent smell, can obviously reduce the pollution to the environment, and has the defects of unstable performance, poor moisture absorption resistance, higher viscosity, poor molding sand flowability and the like compared with the traditional organic resin binder. The phosphate binder is modified according to the relevant characteristics of the phosphate binder, such as the addition of some simple small molecular weight acid modifiers, so that the performance of the phosphate binder is improved to a certain extent, but the sand-like strength and flowability are not obviously improved. To achieve the same strength of use requirements as conventional organic resin binders, more phosphate binder addition is required. How to modify the phosphate binder, improve the strength of the phosphate binder to reduce the addition of the phosphate binder and improve the fluidity of the molding sand so as to meet the actual production requirements is a problem at present.

Disclosure of Invention

One of the purposes of the invention is to provide a phosphate binder modified by hydroxyethylidene diphosphonic acid, compared with the traditional phosphate binder, the phosphate binder modified by hydroxyethylidene diphosphonic acid provided by the invention has the advantages of high bonding strength, good stability, good moisture resistance, lower viscosity and good fluidity of the prepared molding sand.

The second purpose of the invention is to provide a preparation method of the phosphate binder modified by hydroxyethylidene diphosphonic acid, which is simple and rapid, convenient to operate and low in cost.

One of the purposes of the invention adopts the following technical scheme:

a phosphate binder modified by hydroxyethylidene diphosphonic acid is mainly prepared from the following raw materials in percentage by mass:

51.59-52.45% of industrial phosphoric acid, 11.83-12.03% of aluminum hydroxide powder, 0.61-0.62% of silicic acid, 1.83-1.86% of boric acid, 1.22-1.24% of light magnesium oxide, 0.76-2.4% of hydroxyethylidene diphosphonic acid and 30.53-31.04% of water.

The mass percentage of the industrial phosphoric acid is 85%.

The silicic acid, the boric acid and the light magnesium oxide are analytically pure.

The hydroxyethylidene diphosphonic acid is white crystal particles with the mass percentage of more than or equal to 90 percent.

The second purpose of the invention is realized by adopting the following technical scheme:

a method for preparing a hydroxyethylidene diphosphonic acid modified phosphate binder, comprising the steps of:

(1) adding industrial phosphoric acid into a reaction kettle, and heating to 180-200 ℃ while stirring;

(2) adding a small amount of aluminum hydroxide powder into the reaction kettle in the step (1) for many times, and continuously stirring until the reaction solution is transparent;

(3) adding water of which the amount is one fourth of the total water amount into the reaction kettle in the step (2), and heating and stirring until the temperature of the reaction solution is restored to the temperature before adding the water;

(4) adding boric acid into the reaction kettle in the step (3), and continuously heating and stirring until the reaction solution is transparent;

(5) adding silicic acid into the reaction kettle in the step (4), and continuously heating and stirring until the reaction solution is transparent;

(6) adding water of which the amount is one fourth of the total water amount into the reaction kettle in the step (5), and heating and stirring until the temperature of the reaction solution is restored to the temperature before adding the water;

(7) adding light magnesium oxide into the reaction kettle in the step (6), and continuously heating and stirring until the reaction solution is transparent;

(8) adding water of which the amount is one fourth of the total water amount into the reaction kettle in the step (7), and heating and stirring until the temperature of the reaction solution is restored to the temperature before adding the water;

(9) adding hydroxyethylidene diphosphonic acid into the reaction kettle in the step (8), and continuously heating and stirring until the reaction solution is transparent;

(10) and (4) adding the residual water in the total water amount into the reaction kettle in the step (9), continuously heating and stirring until the reaction solution is transparent and clear, discharging, and removing the bottom layer precipitate to obtain the hydroxyethylidene diphosphonic acid modified phosphate binder.

The phosphate binder modified by hydroxyethylidene diphosphonic acid provided by the invention is based on the following principle: the hydroxyethylidene diphosphonic acid is an organic phosphonic acid, and is characterized in that the hydroxyethylidene diphosphonic acid is easy to dissolve in water in a large amount and can dissolve in acid, tests show that under the condition of very small addition amount of the hydroxyethylidene diphosphonic acid modified phosphoric acid binder, the strength of the prepared sand sample is improved, the viscosity is obviously reduced, under the condition of 2.5 wt% of the addition amount of the hydroxyethylidene diphosphonic acid modified phosphoric acid binder, the immediate strength of the sand sample can still reach 1.52MPa, the 6h strength can reach 1.3MPa, and the viscosity is reduced from 261mPa s to 200mPa s. The above effects may be caused by the fact that the structural formula of hydroxyethylidene diphosphonic acid is very similar to that of phosphoric acid, it is linked to the phosphoric acid network structure in an acidic environment, and the flexibility of the network structure is increased and the length of the main chain is increased, thereby enhancing the encapsulation effect and the adhesive property. And the hydroxyethylidene diphosphonic acid can form a macromolecular structure with a complex structure with metal ions such as acid radical ions, aluminum ions and the like through chelation or bonding, and the macromolecules play a key role in the stability and water retention effect on the modified binder, so that the performance of the modified binder is improved. In addition, the addition of silicic acid, boric acid and light magnesium oxide further enhances the high-temperature resistance of the phosphate binder, and influences the strength and moisture absorption resistance of the sand mold.

Compared with the prior art, the invention has the following beneficial effects:

the phosphate binder modified by the hydroxyethylidene diphosphonic acid provided by the invention adopts hydroxyethylidene diphosphonic acid as a modifier, and can be connected to a phosphate network structure under the condition of a small addition amount, so that the flexibility of the network structure and the length of a chain segment are increased, the viscosity of the binder is obviously reduced, the fluidity of molding sand is improved, and the strength of preparing a sand sample by the molding sand is improved. The method for preparing the hydroxyethylidene diphosphonic acid modified phosphate binder provided by the invention can ensure that the added raw materials participate in the reaction to the maximum extent, the generated residues are less, and the loss of water is reduced to ensure that the binder has lower viscosity.

Detailed Description

Further features and advantages of the present invention will be understood from the following examples and detailed description. The examples provided are merely illustrative of the method of the present invention and do not limit the remainder of the disclosure in any way.