TW202246533A - Recycling aluminum grinding aid - Google Patents

Abstract

A recycling aluminum grinding aid, which uses polyethylene glycol (PEG) as the main component and is used to contact with the recycling aluminum by heating, spraying before ball grinding of the recycling aluminum, so as to form a blocking layer on the surface of the recycling aluminum, which enables the recycling aluminum to pass through the blocking layer to prevent the steam and suppresses the ammonia escape formed after the hydrolysis of the recycling aluminum, thereby, an effective and low-pollution recycling aluminum handling method is provided, so that the recycling aluminum including aluminum slag ash and aluminum ash can achieve a stable effect, and then be safely applied to other fields.

Description

Recycled Aluminum Grinding Aids

The invention relates to a grinding aid, in particular to a grinding aid used for ball milling recycled aluminum materials.

Aluminum is a metal material widely used in today's society. The way of refining aluminum can be divided into primary smelting and secondary smelting according to the source of aluminum raw materials. Among them, primary smelting refers to primary aluminum extracted from aluminum minerals, and secondary smelting refers to secondary aluminum extracted from recycled aluminum-containing materials. Aluminum (or recycled aluminum). Because of this, in recent years, the proportion of metal aluminum refined by secondary smelting procedures is getting higher and higher.

Secondary smelting is carried out by high temperature smelting. Aluminum is a highly active metal. During the smelting process of refining aluminum, it will be accompanied by the occurrence of oxidation reaction, coupled with impurities such as organic matter in the raw materials, which will lead to the generation of aluminum slag. The main components in aluminum slag are composed of alumina, metal aluminum, aluminum nitride, aluminum carbide, silicon oxide and some salts. The aluminum slag generated in the secondary smelting of aluminum is called primary aluminum slag ash, which contains 40% ~50% of the metal aluminum with recycling value, so the recycling process will be carried out again. After separation, the powdered aluminum slag is called secondary aluminum slag ash. The follow-up can continue to be ball milled, according to the secondary aluminum slag ash The physical properties of each component are different. After ball milling, the metal aluminum is separated from the secondary aluminum slag ash by screen separation, and the remaining mixture is called aluminum ash.

At present, most of the ways to deal with aluminum slag ash are buried, because the components in aluminum slag ash are very easy to chemically react with water or humid air in the environment, releasing ammonia, methane and other gases, which are easy to cause environmental pollution. In addition, aluminum slag ash contains many heavy metals, which will cause soil heavy metal pollution if not properly treated.

In view of the above technical problems, the object of the present invention is to provide a recycled aluminum grinding aid with polyethylene glycol as the main component, which is used to mix with the recycled aluminum by heating and spraying before the recycled aluminum is ball-milled. The materials are contacted and mixed, thereby forming a barrier layer on the surface of the recycled aluminum material, so that the recycled aluminum material can pass through the set of interlayers to prevent water vapor from causing hydrolysis, and at the same time inhibit the escape of ammonia gas formed after the hydrolysis of the recycled aluminum material; thereby , to provide an effective and low-pollution recycled aluminum processing method, so that recycled aluminum materials including aluminum slag ash and aluminum ash can achieve the effect of stabilization, and then be safely resourced and used in other fields.

In order to achieve the above purpose, the present invention provides a grinding aid for recycled aluminum materials, wherein the main component of the recycled aluminum material is aluminum nitride (AlN); the grinding aid is calculated according to the percentage of its total weight, including: polyol, 60~90wt%; and an additive, 10~40wt%; the additive is selected from at least one or more of the group consisting of stearates and alcohol amines, or the additive is a coupling agent; The grinding aid forms a barrier layer on the surface of the recycled aluminum material by heating and spraying before the recycled aluminum material is ball-milled; the recycled aluminum material slows down the degree of oxidation and hydrolysis of the aluminum nitride through the set of interlayers and inhibits the nitriding The ammonia gas formed by the hydrolysis of aluminum escapes.

Wherein, the polyhydric alcohol is selected from polyethylene glycol (PEG), polyalkylene glycol (PAG), or diethylene glycol (DEG).

Wherein, the grinding aid includes: polyethylene glycol (PEG), 80-90wt%; and stearate, 10-20wt%.

Wherein, the polyethylene glycol (PEG) is selected from PEG-200 or PEG-400.

Wherein, the alcohol amines include diethanolamine (DEA), triethanolamine (TEA), triisopropanolamine (TIPA), or diethanolmonoisopropanolamine (DEIPA).

Wherein, the grinding aid includes: PEG-400, 90 wt%; and sodium stearate, 10 wt%.

Wherein, the grinding aid includes: polyethylene glycol (PEG), 60-70wt%; and coupling agent, 30-40wt%.

Wherein, the coupling agent includes a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

Among them, the grinding aid includes: PEG-400, 60 wt%; and monoalkoxy titanate coupling agent, 40 wt%.

Regarding the technology, means and other effects adopted by the present invention to achieve the above-mentioned purpose, preferred feasible embodiments are given and described in detail in conjunction with the drawings as follows.

In order to facilitate the understanding of the present invention, the following description will be made in conjunction with the drawings and embodiments.

The recycled aluminum material grinding aid provided by the present invention is used to fully contact and coat the recycled aluminum material particles by heating and spraying before the recycled aluminum material is ball milled, so as to form a barrier layer on the surface of the recycled aluminum material particles , allowing the recycled aluminum material to pass through the group of interlayers to slow down the degree of oxidation and hydrolysis of the aluminum nitride and to inhibit the escape of ammonia gas formed by the hydrolysis of the aluminum nitride.

In the embodiment of the present invention, the recycled aluminum material refers to the aluminum-containing product after smelting the recycled aluminum material, specifically including aluminum slag ash and/or aluminum ash. The composition of the aluminum-containing product includes metal aluminum, aluminum oxide, aluminum nitride, aluminum magnesium oxide, silicon and silicon oxide; wherein, the content of aluminum nitride (AlN) is about 20-30wt%.

In the embodiment of the present invention, the grinding aid is calculated according to the percentage of its total weight, including 60~90wt% of polyols, and 10~40wt% of additives; the additives are selected from stearates and alcohol amines At least one or more of the formed group, or the additive is a coupling agent.

Wherein, polyols refer to alcohols with multiple hydroxyl groups, or polymers with an average molecular weight between 200 and 10,000 and containing multiple hydroxyl groups. Specifically, the polyol is selected from polyethylene glycol (PEG), polyalkylene glycol (PAG), or diethylene glycol (DEG). More specifically, the polyethylene glycol (PEG) is selected from PEG-200 or PEG-400.

Wherein, alcoholamines refer to amine compounds with multiple hydroxyl groups. Specifically, the alcohol amines include diethanolamine (DEA), triethanolamine (TEA), triisopropanolamine (TIPA), or diethanolmonoisopropanolamine (DEIPA).

Wherein, stearate is added in the grinding aid of the present invention as lubricant.

Specifically, the coupling agent includes a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

In the embodiment of the present invention, the polyol is preferably polyethylene glycol (PEG), more preferably PEG-400.

In the embodiment of the present invention, the grinding aid includes 80-90wt% polyethylene glycol (PEG) and 10-20wt% stearate. More specifically, the grinding aid preferably includes 90wt% PEG-400 and 10wt% stearate.

In the embodiment of the present invention, the grinding aid includes 60-70wt% polyethylene glycol (PEG), and 30-40wt% coupling agent. Among them, the coupling agent is preferably a titanate coupling agent, more preferably a monoalkoxy titanate coupling agent. More specifically, the grinding aid preferably includes 60wt% PEG-400 and 40wt% monoalkoxy titanate coupling agent.

In the embodiment of the present invention, the recycled aluminum material is metal oxide slag, and its recycling process includes a crushing step, a magnetic separation step, a grinding step, a screening step, and a winnowing and collecting step.

Wherein, the crushing step is to crush the metal oxide slag to a size smaller than 20 mm.

Wherein, the magnetic separation step is to remove the iron-containing components in the metal oxide slag.

Wherein, the grinding step is carried out through a ball mill or/and a wheel rolling machine, and the purpose is to make the particle size of the metal oxide slag after grinding smaller than 3mm.

Wherein, the sieving step is to sieve and separate each component of the ground metal oxide slag through the difference in particle size.

Wherein, the winnowing aggregate step is to utilize the metal oxide (aluminum oxide) with small particle size and light weight so that the aggregate can be drawn by wind force (negative pressure).

In the embodiment of the present invention, the grinding aid used for surface physical modification includes polyhydric alcohol, and at least one or more additives selected from stearates and alcohol amines. The surface physical modification grinding aid can be added to the particle surface of the recycled aluminum material before the crushing step or the grinding step.

Polyols and alcohol amines contain hydroxyl groups, which are used as surface modifiers to coat recycled aluminum particles during the grinding process. In addition to controlling the particle size of recycled aluminum particles, reducing the agglomeration or re-agglomeration of recycled aluminum powder particles Agglomeration can also have better dispersion during the grinding step, and can also form a barrier layer on the surface of the recycled aluminum particle powder to achieve the purpose of physical surface modification.

For aluminum slag, aluminum nitride (AlN) contained in aluminum slag can greatly reduce the chance of generating ammonia gas by reacting with water vapor, and the hydroxyl group of the grinding aid can also reduce ammonia gas by bonding with ammonia gas. release. In this way, the activity of the active components (such as aluminum nitride) in the aluminum slag is still retained, so it can be reused as a resource.

In a specific embodiment, the grinding aid used for physical surface modification includes 90wt% PEG 400 and 10wt% sodium stearate. After the grinding aid is subjected to high temperature to make the components uniformly mixed, the mixed solution is atomized and sprayed onto the surface of the recovered aluminum particles (metal oxide slag).

In the embodiment of the present invention, the grinding aid used for surface chemical modification includes polyhydric alcohol and coupling agent. The surface chemically modified grinding aid can be added to the particle surface of the recycled aluminum material before the sieving step or the wind-selected aggregate step.

The coupling agent is a compound that has both polar groups that can react with the surface of inorganic particles and organic functional groups that are reactive or compatible with organic matter. One end of the coupling agent can combine with the surface of the powder (that is, the ground recycled aluminum particles) to modify the surface of the recycled aluminum particles, and the other end can have a strong interaction with the dispersion medium, so the powder can be improved. The affinity with other polymer materials enables the dispersion of powder in polymer materials. Therefore, the recycled aluminum particle composition after adding the coupling agent can be evenly mixed with polymer materials such as coatings and resins, which improves the dispersion of the recycled aluminum particle composition as a filling material, improves processing performance, and increases recycling. The scope of application of the recycling of aluminum particles and aluminum ash.

In a specific embodiment, the grinding aid composition used for chemical surface modification is 60wt% PEG 400 and 40wt% monoalkoxy titanate coupling agent. . After the grinding aid is subjected to high temperature to make the components uniformly mixed, the mixed solution is atomized and sprayed onto the surface of the recovered aluminum particles (metal oxide slag).

The following provides a specific embodiment in which a grinding aid comprising polyethylene glycol (PEG) is applied and coated on the surface of aluminum ash particles, so as to better understand the connotation of the present invention.

Qualitative and quantitative analysis of aluminum ash components

The types of components contained in the aluminum ash were analyzed by X-ray diffraction analysis (XRD), as shown in Table 1.

Table 1 Aluminum ash composition content list Element Proportion(%) Metal aluminum (Al) 9.8% Alumina (Al ₂ O ₃ ) 18.8% Aluminum Nitride (AlN) 25.8% Aluminum magnesium oxide (Al ₂ MgO ₄ ) 22.3% Nickel oxide (NiO ₂ ) 0.3% Silicon (Si) 2.8% Silicon dioxide (SiO ₂ ) 4.9% other 15.2%

Ball milling experiment of aluminum ash

In the process of ball milling, the components in the aluminum ash can be adjusted according to the ductility, so that the metal aluminum with good ductility is agglomerated during the ball milling process, while other oxides with lower ductility are impacted by the metal balls in the ball mill tank. The finer the grinding, due to the difference in particle size, the metal aluminum can be sieved and separated for utilization.

PEG200 and PEG400 were used as grinding aids to carry out ball milling of aluminum ash. Experimental parameters were operated at 300rpm for 10 minutes, and then the samples were taken out and placed in transparent test tubes, and the changes were observed. The results show that PEG has a good effect as a grinding aid. There is no obvious bubble generation in the sample after ball milling, and there is no obvious ammonia smell after ball milling.

Please refer to Figure 1. It is a comparison experiment of harsh conditions of soaking aluminum ash in water. The experimental group is the sample treated with PEG, and the control group is the aluminum ash without any treatment. It can be seen from Figure 1 that the aluminum ash sample soaked in water has obvious air bubbles, but the PEG sample does not. It can be seen that the aluminum ash is relatively stable in a water-containing environment after adding PEG for dry grinding. Adding PEG as a grinding aid to ball mill aluminum ash can be relatively stable for ball milling experiments.

Particle size analysis of aluminum ash after ball milling

The samples after ball milling were measured and analyzed with a particle size analyzer (DLS). The sample in Figure 2 was only dry-milled with aluminum ash, and the sample in Figure 3 was dry-milled with aluminum ash and PEG400 at the same time. The results show that only the aluminum ash (Fig. 2) sample has a wider particle size distribution and produces two separated peaks, while the sample milled with PEG (Fig. 3) has a narrower particle size distribution.

This result shows that there are samples with PEG added as grinding aid, because PEG is coated between the particles, which avoids the chance of contact between particles, reduces the occurrence of agglomeration of particles after grinding, and makes the particle size larger. The narrow distribution range can reduce the overall particle size and avoid agglomeration.

Analysis of ball-milled aluminum dust

Please refer to FIG. 4 , which is a scanning electron microscope (SEM) observation of the morphology of samples with/without adding PEG after drying the aluminum ash after ball milling. The difference between the two is that the particles on the surface of the sample containing PEG are covered by substances similar to polymers. This result echoes the results of the previous particle size analysis. Due to the coating of PEG, the chance of contact between particles is reduced and the occurrence of agglomeration is inhibited.

Hydrolysis analysis of aluminum ash after ball milling

When PEG is used as a grinding aid, in order to confirm whether PEG can achieve a certain degree of effect on the hydrolysis of aluminum ash during the ball milling process, Raman analysis will be used for analysis. Please refer to Figure 5. Among the three samples above (sample a, b, c), there is no PEG added and aluminum ash with water added. These two samples have a peak at 518 cm ^-1 , which is the signal of Al(OH) ₃ , and Al(OH) ₃ is the product of complete hydrolysis of aluminum ash, while the aluminum ash sample with PEG as grinding aid has no such signal. In the three samples below (sample d, e, f), the signal of AlOOH (semi-hydrolyzed transient product shown in the following chemical formula) also appeared (284 cm ^-1 and 518 cm ^-1 ) in aluminum ash and Add aluminum ash to the sample of water.

However, the sample with PEG added is not obvious. This result can indicate that using PEG as a grinding aid for aluminum ash ball milling can reduce the chance of hydrolysis of aluminum ash during ball milling.

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Fig. 1 is the result figure of the severe condition that the aluminum ash of the specific embodiment of the grinding aid of the present invention is soaked in water; Fig. 2 is the particle size distribution figure of aluminum ash after the dry grinding of specific embodiment of grinding aid of the present invention; Fig. 3 is the particle size distribution figure after the dry grinding of aluminum ash and PEG of the specific embodiment of the grinding aid of the present invention; Fig. 4 is the SEM appearance figure of the specific embodiment of the grinding aid of the present invention after the drying of the ball-milled aluminum ash; Fig. 5 is a Raman spectrogram of hydrolyzed ball-milled aluminum dust of a specific embodiment of the grinding aid of the present invention.

Claims (9)

A grinding aid for recycled aluminum, wherein the main component of the recycled aluminum is aluminum nitride (AlN); the grinding aid is calculated by the percentage of its total weight, including: Polyol, 60~90wt%; and Additive, 10~40wt%; the additive is selected from at least one or more of the group consisting of stearates and alcohol amines, or the additive is a coupling agent; Make the grinding aid form a barrier layer on the surface of the recycled aluminum material by heating and spraying before the recycled aluminum material is ball-milled; the recovered aluminum material slows down the degree of oxidation and hydrolysis of the aluminum nitride through the set of interlayers and inhibits the nitrogen The ammonia gas formed by the hydrolysis of aluminum oxide escapes. The grinding aid for recycled aluminum materials as described in Claim 1, wherein the polyol is selected from polyethylene glycol (PEG), polyalkylene glycol (PAG), or diethylene glycol (DEG). The recycled aluminum material grinding aid as described in claim 1, wherein the grinding aid includes: Polyethylene glycol (PEG), 80~90wt%; and Stearate, 10~20wt%. The recycled aluminum grinding aid according to any one of claims 1 to 3, wherein the polyethylene glycol (PEG) is selected from PEG-200 or PEG-400. The recycled aluminum grinding aid as described in claim 1, wherein the alcohol amines include diethanolamine (DEA), triethanolamine (TEA), triisopropanolamine (TIPA), or diethanol monoisopropanolamine (DEIPA). The recycled aluminum material grinding aid as described in claim 1, wherein the grinding aid includes: PEG-400, 90 wt%; and Sodium stearate, 10 wt%. The recycled aluminum material grinding aid as described in claim 1, wherein the grinding aid includes: Polyethylene glycol (PEG), 60~70wt%; and Coupling agent, 30~40wt%. The grinding aid for recycled aluminum materials as described in claim 7, wherein the coupling agent includes a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent. The recycled aluminum material grinding aid as described in claim 1, wherein the grinding aid includes: PEG-400, 60 wt%; and Monoalkoxy titanate coupling agent, 40 wt%.

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