AU2008229963B1

AU2008229963B1 - Treatment method of aluminum slag and mixed material obtained by the same

Info

Publication number: AU2008229963B1
Application number: AU2008229963A
Authority: AU
Inventors: Tzong-Yu Su
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-10-16
Filing date: 2008-10-16
Publication date: 2010-03-04
Anticipated expiration: 2028-10-16

Description

AUSTRALIA Patents Act COMPLETE SPECIFICATION (ORIGINAL) Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Tzong-Yu Su Actual Inventor(s): Tzong-Yu Su Address for Service and Correspondence: PHILLIPS ORMONDE & FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: TREATMENT METHOD OF ALUMINUM SLAG AND MIXED MATERIAL OBTAINED BY THE SAME Our Ref: 840531 POF Code: 111926/489746 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): - 1- .A TREATMENT METHOD OF ALUMINUM SLAG AND MIXED MATERIAL OBTAINED BY THE SAME The invention relates to a treatment method, more particularly to a treatment method of aluminum slag. 5 Since aluminum is a very highly active metal, therefore, when waste aluminum is recycled and reused or when aluminum is smelted, oxidization of aluminum or reaction of aluminumwith other elements takes place, and aluminum slag is produced. Aluminum slag is mainly 10 composed of aluminum oxide, aluminum hydroxide, aluminummetal, siliconoxide, magnesiumoxide, a little salt, etc. In addition, aluminum nitride resulting from reaction with nitrogen in the air and aluminum carbide formed with burning gas are included. The content of 15 aluminummetal in the slag varies according todifferent operating conditions, raw material, etc. used by manufacturers. Nevertheless, the aluminum slag produced during the smelting process still contains aluminum metal with recycling values, so a process of 20 recycling aluminum is usually indispensable. However, there are still some tiny aluminum powders unable to be recycled due to the fact that they are mixed with other impurities, such as aluminum oxide, magnesium oxide, salt, aluminum nitride, aluminum carbide, etc., 25 and cannot be separated from them. At present, processing of aluminum slag is mostly handled by waste treatment companies by a landfill method.

2 However, since aluminum slag contains components of heavy metals, if the landfill sites are not suitably selected, or if the aluminumslag is not properly handled, such a landfill method easily results in environmental 5 pollution. On the other hand, in a few cases, since the aluminum slag is deemed to have some recycling value, they are flushed by clean water first before being further recycled for extracting aluminum metal. Nevertheless, waste water discharged as a result of 10 treating the aluminum slag usually has a pH value of less than 4, which is highly acidic, such that treatment of the waste water is further needed to comply with a waste water discharging standard, which results in a significant increase in treatment costs. Moreover, the 15 aluminum slag, when mixed with water, forms silt and produces very stink ammonia smell, and hence cannot be further utilized. People's awareness of environmental protection has grown in recent years. Therefore, the government of each country appreciates the importance 20 of environmental protection. As a result, recycle and reuse processing of aluminum slag has become an important issue pursued by many organizations. Therefore, an object of the present invention is to provide a treatment method of aluminum slag that can 25 reduce treatment cost and emission of stink gas so as to achieve a highlyeffective resource recycling result. Accordingly, in an aspect of this invention, a 3 treatment method of aluminum slag includes the steps of: (i) water flushing the aluminum slag inside a container; 5 (ii) tea water soaking the aluminum slag inside the container; and (iii) mixing the aluminum slag with a dry material in order to obtain a mixed material. In another aspect of this invention, amixedmaterial 10 comprising aluminum slag and a dry material is obtained by implementing the aforesaid treatment method of aluminum slag. Other features and advantages of the present invention will become apparent in the following detailed 15 description of the preferred embodiment with reference to the accompanying drawings, of which: Figure 1 is a flowchart illustrating a preferred embodiment of a treatment method of aluminum slag according to the present invention; 20 Figure 2 is a schematic diagram illustrating a step of water flushing and stirring the aluminum slag of the preferred embodiment; Figure 3 is a schematic diagram illustrating a step of tea water flushing and stirring the aluminum slag 25 of the preferred embodiment; Figure 4 is a graph illustrating a daily schedule for realizing the steps of the preferred embodiment; 4 and Figure 5 is a schematic diagram illustrating a step of mixing tealeaves with mixed material for producing compost. 5 Referring to Figure 1, the preferred embodiment of a treatment method of aluminum slag according to the present invention is shown to include the steps of a) sieve-filtering, b) grinding, c) clean water flushing, d) tea water flushing, e) tea water soaking, f) dry 10 material mixing, and g) pave drying. In the sieve-filtering step a), a 20-mesh sieve is used for sieve-filtering aluminum slag 3 (shown in Figures 2 and 3) , which is collected beforehand, so as to collect the aluminum slag 3 which can pass through 15 the sieve in a container 2. In the grinding step b), the portion of the aluminum slag 3 which can not pass through the sieve is ground into one having a particle size that can pass through the 20-mesh sieve. It should be noted that the grinding 20 step b) does not have to be conducted after the sieve-filtering stepa) . If necessary, the grinding step b) can be conducted after all the aforementioned steps a) to g) are completed. Referring to Figure 2, in the clean water flushing 25 step c) , clean water 5 having high pressure is poured into the container 2 to flush the aluminum slag 3. At the same time, the aluminum slag 3 is stirred using a 5 stirrer 9 while the clean water 5 is continuously poured into the container 2. When the clean water 5 reaches a predetermined volume, the pouring of the clean water 5 is stopped, while the stirring of the aluminum slag 5 3 is continued. In the clean water flushing stepc), since impurities of tiny granular diameters still adhere to surfaces of the aluminum slag 3, the clean water 5 having high pressure is poured into the container 2 to flush the 10 aluminum slag 3, and the stirrer 9 is used to stir the clean water 5 with the aluminum slag 3 so that the impurities can be suspended and separated from the aluminumslag3. In thispreferredembodiment, the weight ratio of the clean water 5 to the aluminum slag 3 is 15 3:1. After the cleanwater flushing step c) is completed, the water 5 in the container 2 is poured out so as to remove the impurities together with the water 5. It should be noted that the clean water flushing step c) can be repeated at least once, if necessary, so as 20 to further remove the impurities and to achieve a better cleaningeffect. In this preferredembodiment, the clean water flushing step c) is conducted twice. The number of the clean water flushing step c) is determined and adjusted by the actual practice of the manufacturer and 25 the volume of the aluminum slag 3 to be treated, and hence is not limited to what is disclosed herein. In order to avoid the undesired side effects of volume 6 swelling of the aluminum slag 3 due to over-soaking in water and of production of stink gas like ammonia thereby, preferably, each of the clean water flushing steps c) should be completed within 30 minutes. 5 Referring to Figure 3, in the tea water flushing step d) , tea water 6 is used for flushing the aluminum slag 3, and the stirrer 9 is also used to stir the aluminum slag 3 in the container 2. In the tea water flushing step d), tannic acid component of the tea water 6 is 10 adsorbed onto the surfaces of the aluminum slag 3 so that the aluminum slag 3 is not prone to react with water and hence results in a more stable state. Therefore, the production of stink gas caused by absorption of water by the aluminum slag 3 can be reduced significantly. 15 After the tea water flushing step d) is completed, the tea water 6 is poured out of the container 2. In the preferred embodiment, the weight ratio of the tea water 6 to the aluminum slag 3 is 3:1. For a better stink-proof effect, those green or black teas with high 20 contents of tannic acid are preferred in making the tea water 6. The source of the tea water 6 can be derived from soaking of used tealeaves, such as re-soaking of only-used-once waste tealeaves left by food-processing 25 factories so as to reduce the cost of treating the aluminum slag 3. Alternatively, new tealeaves can be used formaking the tea water 6. The tealeaves left after 7 the soaking can be used for subsequent composting (to be described later) . Since there are many sources for the tea water 6, it is not further detailed herein. It should be noted that the tea water flushing step 5 d) can be repeated, if necessary. In this embodiment, the tea water flushing step d) is repeated once. The number of the tea water flushing step d) is to be determined and adjusted by the concentration of tea in the tea water 6 and the volume and quality of the aluminum 10 slag 3 to be treated, and hence is not limited to what is disclosed herein. In order to avoid the undesired side effect resulting from the reaction of the aluminum slag 3 with water before the tannic acid component of the tea water 6 is adsorbed 15 onto the surfaces of the aluminum slag 3, preferably, each of the tea water flushing steps d) should be completed within 30 minutes. After completing the tea water flushing step d) , the tea water soaking step e) is conducted. In the tea water 20 soaking step e), the tea water 6 is used to soak the aluminum slag 3 for a consecutive 24-hour period, and is then poured out of the container 2. The tannic acid of the tea water 6 can be more thoroughly adsorbed over the aluminum slag 3 through soaking of the aluminum slag 25 3 in the tea water 6. Therefore, the stink gas attributed to the reaction of water with the aluminum slag 3 is effectively reduced. On the other hand, the pH value 8 of the poured tea water 6 falls within the range of 6 to 8. Therefore, compared with the pH value of less than 4 of wastewater obtained from the conventional treatment of the aluminum slag 3, the acidity of the poured tea 5 water 6 is reduced significantly. In this manner, secondary environmental pollution is avoided, and no extra high cost for treating highly acidic waste water is needed. In this preferred embodiment, after completing the 10 tea water soaking step e) , the aforementioned tea water flushing steps d) are further repeated twice, and the tea water soaking step e) is then repeated once. Again, it is noted that each of the tea water flushing steps d) should not exceed 30 minutes. 15 The dry material mixing step f) is then executed. The aluminum slag 3 and the dry material are mixed in a ratio ranging from 1:1 to 1:3 to result in a mixed material 7 (as shown in Figure 5) . After the aluminum slag 3 and the dry material are mixed, the robustness 20 of the mixed material 7 is enhanced. In this embodiment, the dry material is commercially available sand, and the aluminum slag 3 and the sand are mixed in a ratio of 1:lsoas to result in themixedmaterial7. Inpractice, the ratio can be adjusted according to the specific 25 requirement, andhenceisnotlimitedtowhatisdisclosed herein. After completing the dry material mixing step f), 9 the pave drying step g) is executed. In the pave drying step g) , a moisture absorbent material with strong moisture absorbability is dispersed over the mixed material 7. The moisture absorbent material may include 5 carbon powders having smaller granular diameters or carbon granules having larger granular diameters. A drying operation by dispersing evenly the carbon material over the mixed material 7 has a better moisture absorbing effect, and excess water can thus be removed 10 from the mixedmaterial7 very quickly. In this preferred embodiment, after the mixed material 7 is paved over a planar surface, a carbon material having a thickness of5 cmis dispersed over the mixedmaterial 7. However, in practice, the thickness can be adjusted according 15 to the condition f the mixed material 7, and hence is not limited to what is disclosed herein. Itshouldbenotedthat, in thispreferredembodiment, in order to avoid generation of stink gas after the mixed material 7 is heated as a result of direct exposure to 20 sunlight, the mixed material 7 should be dried in the shade (air drying) for 3 to 7 days so as to achieve a better stink-proof effect. Referring to Figure 4, it is shown that the period for completing all of the aforesaid steps takes 4 to 25 7 days. The sieve-filtering step a), the grinding step b), two of the clean water flushing steps c) and two of the tea water flushing steps d) can be completed on 10 the first day. The tea water soaking step e) lasting 24 hours is proceeded subsequently. On the second day, two of the tea water flushing steps d) and the tea water soaking step e) lasting 24 hours are proceeded. On the 5 third day, the dry material mixing step f) is conducted, followed by the pave drying step g) which is conducted for 4 to 7 days. The mixed material 7 obtained by processing through the aforesaid steps has the characteristics of stability 10 and environmental standard compliance, and hence is suitable for use as artificial sand and for application in sand blasting, industrial sand grading, cementing, land filling, road paving, etc. Referring to Figure 5, since aluminum is one of the 15 essential chemical components in fertilizers, the mixed material 7 obtained from the treatment method of aluminum slag of this invention can also be inter-stacked with the soaked waste tea leaves 8 to form compost. In sum, the treatment method of aluminum slag of this 20 invention involves the tea water flushing step d) and the tea water soaking step e) to isolate the aluminum slag 3 through the adsorptive effect of tannic acid in the tea water 6, so as to stabilize the chemical property of the aluminum slag 3 and to reduce generation of stink 25 gas due to water absorption of the aluminum slag 3. The dry material mixing step f) and the pave drying step g) are then proceeded to yield the mixed material 7 that 11 is suitable for application as artificial sand and for further use with the waste tealeaves 8 to form compost. This invention not only results in a good resource recycling effect, but also reduces cost in treatment 5 of waste and in recycling and reusing of resource significantly by virtue of the fact that the waste water produced in this invention has much lower acidity and is easier to handle. For the purpose of this specification, it will be 10 clearly understood that the word "comprising" means "including but not limited to," and that the word "comprises" has a corresponding meaning. It is to be understood that, if any prior art publication is referred to herein, such reference does 15 not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

Claims

1. A treatment method of aluminum slag, comprising the steps of: (i) water flushing the aluminum slag inside a 5 container; (ii) tea water soaking the aluminum slag inside the container; and (iii) mixing the aluminum slag with a dry material in order to obtain a mixed material. 10

2. The treatment method according to claim 1, wherein water is stirred with the aluminum slag before the step (ii).

3. The treatment method according to claim 1 or claim 2, wherein the aluminum slag is flushed with tea water 15 during the step (i).

4. The treatment method according to any one of claims 1 to 3, wherein the aluminum slag is flushed with clean water during the step (i).

5. The treatment method according to any one of claims 20 1 to 4, wherein the water flushing step (i) comprises the sub-steps of: (il) clean water flushing the aluminum slag inside the container; (i2) pouring the clean water from the container; 25 (i3) tea water flushing the aluminum slag inside the container; and (i4) pouring the tea water from the container. 13

6. The treatment method according to any one of claims lto5, whereinrepeatedcleanwater flushingstepsand/or repeated tea water flushing steps are implemented in sequence during the step (i). 5

7. The treatment method according to claim 5 or claim 6, wherein each of the clean water flushing step and the tea water flushing step does not exceed thirty minutes.

8. The treatment method according to any one of claims 10 1 to 7, wherein suspended impurities are removed from the aluminum slag during the water flushing step (i), and wherein the weight ratio of the water and the aluminum slag is 3:1.

9. The treatment method according to any one of claims 15 1 to 8, further comprising a sieve-filtering step before the step (i), wherein the aluminum slag is sieved to obtain particles with a predetermined size.

10. The treatment method according to claim 9, wherein the aluminum slag is sieved with a 20-mesh sieve. 20

11. The treatment method according to claim 9 or claim 10, furthercomprisinggrindingaportionofthealuminum slag that does not pass through the sieve.

12. The treatment method according to any one of claims 1 to 11, wherein the tea water soaking step (ii) is 25 implemented for 24 hours.

13. The treatment method according to any one of claims 1 to 12, further comprising at least an additional clean 14 water flushing step and an additional tea water soaking step between the tea water soaking step (ii) and the mixing step (iii).

14. The treatment method according to any one of claims 5 1 to 13, wherein the dry material and the aluminum slag are -mixed in a ratio ranging from 1:1 to 3:1 in the step (iii).

15. The treatment method according to any one of claims 1 to 14, wherein the dry material is sand. 10

16. The treatment method according to any one of claims ltol5, furthercomprisingpavedryingthemixedmaterial by spreading the mixed material over a surface.

17. The treatment method according to claim 16, wherein a moisture absorbent material is dispersed over the mixed 15 material during the pave drying step.

18. The treatment method according to claim 17, wherein the moisture absorbent material is a carbon powder.

19. A mixed material comprising aluminum slag and a dry material obtained by implementing the treatment method 20 according to any one of claims 1 to 18.

20. A treatment method of aluminum slag substantially as hereinbefore described with reference to and illustrated in the accompanying drawings.

21. A mixed material substantially as hereinbefore 25 described with reference to and illustrated in the accompanying drawings.