阅读说明：本技术 一种仿木材料生产用耐水性结合剂及其制备方法、应用 (Water-resistant bonding agent for wood-like material production and preparation method and application thereof ) 是由 严云 谢晓丽 李天鹏 杨旭 尹怀刚 张松涛 于 2020-05-11 设计创作，主要内容包括：本发明属于仿木材料生产技术领域,具体涉及一种仿木材料生产用耐水性结合剂及其制备方法、应用。其中,仿木材料生产用耐水性结合剂,包括以质量份计的如下组分：氧化镁420～570份,氯化镁210～290份,磷石膏50～690份,磷酸0.5～15份,矿粉20～210份,水200～310份。本发明通过添加磷酸进入氯氧镁水泥体系当中,在氯氧镁水泥提供强度的晶相表面生成薄膜,阻止内部晶相的溶解从而增加耐水性,磷石膏是湿法生产磷酸所产生的工业副产物,含有可溶性磷酸根,试验发现通过添加含有可溶性磷酸根的磷石膏进入氯氧镁水泥中,在减少磷酸加入的同时提高体系的耐水性,既消耗大量堆积的工业副产物,又减少环境污染。(The invention belongs to the technical field of wood-like material production, and particularly relates to a water-resistant bonding agent for wood-like material production, and a preparation method and application thereof. The waterproof bonding agent for producing the wood-like material comprises the following components in parts by mass: 420-570 parts of magnesium oxide, 210-290 parts of magnesium chloride, 50-690 parts of phosphogypsum, 0.5-15 parts of phosphoric acid, 20-210 parts of mineral powder and 200-310 parts of water. According to the invention, phosphoric acid is added into a magnesium oxychloride cement system, a film is generated on the surface of a crystal phase with strength provided by the magnesium oxychloride cement, and the dissolution of an internal crystal phase is prevented, so that the water resistance is improved.)

1. The water-resistant bonding agent for producing the wood-like material is characterized by comprising the following components in parts by mass:

420-570 parts of magnesium oxide, 210-290 parts of magnesium chloride, 50-690 parts of phosphogypsum, 0.5-15 parts of phosphoric acid, 20-210 parts of mineral powder and 200-310 parts of water.

2. The water-resistant bonding agent for producing the wood-like material as claimed in claim 1, wherein the mass part ratio of the magnesium oxide to the magnesium chloride is 1.9-2.7.

3. The water-resistant bonding agent for producing the wood-like material according to claim 1, wherein the mass part ratio of the phosphogypsum to the mineral powder is 2-15.

4. The water-resistant bonding agent for producing the wood-like material as claimed in claim 1, wherein the magnesium oxide is light-burned magnesium oxide, and the content of the magnesium oxide is 82-88%.

5. The water-resistant bonding agent for producing the wood-like material as claimed in claim 1, wherein the magnesia is prepared by calcining magnesite at a low temperature of 750-850 ℃, and the content of active magnesia is 50-70%.

6. The water-resistant bonding agent for producing wood-like materials according to claim 1, wherein the magnesium chloride is MgCl₂·6H₂O。

7. The water-resistant bonding agent for producing the wood-like material as claimed in claim 1, wherein the phosphogypsum is original phosphogypsum which is not calcined and contains CaSO₄·2H₂O, the particle size is less than 0.15 mm.

8. The water-resistant bonding agent for producing the wood-like material as claimed in claim 1, wherein the 28-day water resistance coefficient of the water-resistant bonding agent is greater than 0.85.

9. A method of preparing a water resistant binder as claimed in any one of claims 1 to 7, comprising the steps of:

dry-mixing magnesium oxide, phosphogypsum and mineral powder to obtain dry-mixed material; uniformly mixing magnesium chloride, phosphoric acid and water to obtain a mixed solution;

and adding the mixed solution into the dry mixture, and uniformly stirring to obtain the water-resistant bonding agent.

10. A wood-like material, characterized in that, the wood-like material is formed by mixing the water-resistant bonding agent as claimed in any one of claims 1 to 8 with a base material and then placing the mixture in a die for pressure forming.

Technical Field

The invention belongs to the technical field of wood-like material production, and particularly relates to a water-resistant bonding agent for wood-like material production, and a preparation method and application thereof.

Background

Wood is an important building and civil material, is easy to process, has the advantages of high strength, heat insulation, good acoustics and the like, and has the defects of flammability, easy decay, drying shrinkage, swelling and the like. Because the growth cycle of the wood is long, and the current production development needs a large amount of wood, but the problems of water and soil loss, environmental pollution and the like are inevitably caused by cutting a large amount of wood, so that the shortage of the wood is inevitably caused when the cutting is controlled in order to protect the environment. Due to the shortage of wood, various wood-like materials come into play, and a large amount of wood is replaced in various industries.

The wood-like material is mainly compounded by various agricultural and forestry wastes, such as wood chips, sawdust, wood powder, bamboo powder, rice hulls, straws and the like, and a bonding material; the appearance of the log has the same visual effect as that of a real log, and simultaneously has the relevant characteristics of the log, such as sawing, planing, nailing, similar density and the like. At present, the preparation technology of the wood-like material at home and abroad tends to be mature, the produced material not only has the characteristics of raw wood, but also can overcome some defects of the raw wood, can effectively resist wind and sunlight, obviously prolongs the service life of the product, solves the problem of wood supply shortage of environmental protection, and can meet the requirements of users on the use function of the product. The development and production of wood-like materials are mainly related to the selected binding agent.

The binding agents for the wood-like materials can be divided into organic, biomass and inorganic binding agents, the organic binding agents such as polystyrene and modified polyurethane are mostly used at present, the wood-like materials prepared from bamboo and wood waste materials are mostly used in the market, and the wood-like materials using the biomass and the inorganic materials as the binding agents are rarely used.

Magnesium Oxychloride Cement (MOC) mainlyThe MOC has the advantages of fast hardening, early strength, high compressive strength, good wear resistance, good cohesiveness of various materials, easy processing and the like, is widely applied to the field of building materials, and is mainly used in the aspects of wood-like materials, building engineering, refractory material industry, traffic transportation engineering, environmental protection engineering and the like. The hydration product of magnesium oxychloride cement mainly has 2 phase (2 MgO. MgCl)₂·4H₂O), 3 phase (3 MgO. MgCl)₂·8H₂O), 5 phase (5 MgO. MgCl)₂·8H₂O), 9 phase (9 MgO. MgCl)₂·5H₂O), studies have shown that phase 5 is the most dominant strength-providing phase of MOC. Moreover, the magnesium oxide can be obtained again by calcining the waste of the magnesium oxychloride cement, and can be effectively and continuously applied to resources, thereby protecting the environment and saving the production cost.

Phosphogypsum is an industrial byproduct generated in the wet-process production of phosphoric acid, and according to statistics, 4-5t of phosphogypsum (CaSO) is generated every 1t of phosphoric acid is produced₄·2H₂O). Nowadays, the global phosphogypsum reserves reach 60 hundred million t, and the annual growth rate is 1.5 hundred million t; the storage capacity of the phosphogypsum in China reaches 4 hundred million tons, and the annual growth rate is 5000 million tons. The phosphogypsum belongs to a monoclinic system, has a layered microstructure, is wet powder attached with 10-30% of water, has the pH value of about 1.9-5.3, the particle diameter of 40-200 mu m generally, and has the gray color of gray, some yellow and gray colors, but the chemical composition of the by-product is complex and contains impurities such as soluble phosphorus, soluble fluorine, organic matters and the like, so that the phosphogypsum cannot be directly utilized in many fields. Wherein soluble phosphorus impurities (H)₃PO₄、 H₂PO₄ ^-1、HPO₄ ^-2) The secondary utilization of the phosphogypsum is influenced the most, so that the stacking of the phosphogypsum occupies a large amount of land resources. Wherein, the soluble components seep into the soil along with the rainwater when being piled in the open air, which causes huge pollution to the land resources and the underground water resources and seriously restricts the development of related enterprises.

Disclosure of Invention

Based on the defects in the prior art, the invention provides a water-resistant bonding agent for wood-like material production, and a preparation method and application thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a water-resistant bonding agent for producing wood-like materials comprises the following components in parts by mass:

420-570 parts of magnesium oxide, 210-290 parts of magnesium chloride, 50-690 parts of phosphogypsum, 0.5-15 parts of phosphoric acid, 20-210 parts of mineral powder and 200-310 parts of water.

Preferably, the mass part ratio of the magnesium oxide to the magnesium chloride is 1.9 to 2.7.

Preferably, the mass ratio of the phosphogypsum to the mineral powder is 2-15.

Preferably, the magnesium oxide is light-burned magnesium oxide, and the content of the magnesium oxide is 82-88%.

Preferably, the magnesium oxide is prepared by calcining magnesite at a low temperature of 750-850 ℃, and the content of active magnesium oxide in the magnesium oxide is 50-70%.

Preferably, the magnesium chloride is MgCl₂·6H₂O。

Preferably, the phosphogypsum is original phosphogypsum which is not calcined and contains CaSO₄·2H₂O, the particle size is less than 0.15 mm.

Preferably, the 28-day water resistance coefficient of the water-resistant bonding agent is greater than 0.85.

The invention also provides a preparation method of the waterproof bonding agent, which is characterized by comprising the following steps:

dry-mixing magnesium oxide, phosphogypsum and mineral powder to obtain dry-mixed material; uniformly mixing magnesium chloride, phosphoric acid and water to obtain a mixed solution;

and adding the mixed solution into the dry mixture, and uniformly stirring to obtain the water-resistant bonding agent.

The invention also provides application of the water-resistant bonding agent in any scheme, namely a wood-like material which is formed by mixing the water-resistant bonding agent in any scheme and a base material and then placing the mixture in a die for pressing and molding. The base material can be wood chips, bamboo powder, bamboo fibers and other base materials commonly used as wood-like materials.

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

(1) the mechanism for increasing the water resistance of the magnesium oxychloride provided by the invention is as follows: experiments show that the water resistance of the system can be improved while the addition of the phosphoric acid is reduced by adding the phosphogypsum containing the soluble phosphate radical into the magnesium oxychloride cement, so that a large amount of accumulated industrial byproducts can be consumed, the environmental pollution is reduced, and the concept of green development at present is met.

(2) The mineral powder of the invention can be excited by sulfate radicals in phosphogypsum to generate a hydraulic cementing material which can fill the internal pores of a magnesium oxychloride cement system to increase the water resistance of the system.

(3) The phosphogypsum used in the invention is the original phosphogypsum which is not calcined, and the phosphogypsum is directly used without grinding when in use, thereby reducing the energy consumption and the use cost.

(4) The water-resistant bonding agent has the advantages of simple preparation process, simple and convenient working procedure, easy operation and waste material recycling.

(5) The wood-like material of the invention has excellent performance.

Detailed Description

The technical solution of the present invention will be further explained by the following specific examples.