METHOD OF REMANUFACTURING MINING USED-SCRAPER TECHNICAL FIELD The present disclosure mainly relates to the technical field of mining 5 machinery, and more particularly to a method of remanufacturing a mining used-scraper. BACKGROUND Any discussion of the background art throughout the specification should in 10 no way be considered as an admission that such background art is prior art nor that such background art is widely known or forms part of the common general knowledge in the field in Australia or worldwide. Scrapers are conveying media which are used to hold up a scraper conveyor. The scraper conveyor is used to convey coal through its link chain 15 pulled by the sprocket wheels. When working, the scrapers are driven by connecting with the sprocket-wheel sockets on the head and tail of the scraper conveyor. Because the scrapers bear rough friction with baseboard, coal and waste rock, the surface of the scraper needs to have enough hardness and hardening depth, and the center texture of the scrapers should has good 20 toughness. It can cut down the cost effectively through recycling the waste/used mining scraper, but it has taken years to study the remanufacturing of the waste mining scraper on how to do surface modification to raise its wear-resistance and prolong working life. 25 In a traditional repairing technology, the waste mining scraper is directly repaired by manual surfacing with welding wire and manual grinding, but this cannot get rid of hidden trouble from tiny endurance crack, the low precision of the scraper, and bad consistency effect the transmission accuracy of equipment. Therefore, in the existing technology, the repairing for the waste mining 1 scraper almost is on the abrasion parts which can be watched via human eyes by manual surfacing, which lead to a very low efficiency and accuracy. SUMMARY 5 Throughout this specification, unless the context requires otherwise, the words "comprise", "comprises" and "comprising" will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. Any one of the terms: "including" or "which includes" or "that includes" as 10 used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, "including" is synonymous with and means "comprising". It is an object of the present invention to overcome or ameliorate at least one or more of the disadvantages of the prior art, or to provide a useful alternative. 15 In one aspect, the present disclosure accordingly provides a method of remanufacturing a mining used-scraper, so as to solve the problem of repairing the mining used-scraper with a very low efficiency and accuracy in prior art. In order to have basic understanding of some aspects of some embodiments, a neat summary is provided here below. This summary is not intended to identify key features or 20 essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter, which is as a preface of specification hereinafter by giving some concepts in a brief way. According to a first aspect, there is provided a method for remanufacturing a mining used-scraper. The method may comprise detecting the size and 25 mechanical properties of a mining used-scraper to determine whether it satisfies a remanufacturing standard. The method may further comprise comparing the used-scraper which satisfies the remanufacturing standard with a new scraper to determine the repaired size of the used-scraper's worn portion. The method may further comprise making corresponding repair processing for modifying the surface 2 of the worn portion based on the position of the worn portion on the used-scraper. The method may further comprise recovering the worn portion's size according to the determined repaired-size with the corresponding repair processing. According to a particular arrangement of the first aspect, there is provided a 5 method for remanufacturing a mining used-scraper, comprising: detecting the size and mechanical properties of a mining used-scraper to determine whether it satisfies a remanufacturing standard; comparing the used-scraper which satisfies the remanufacturing standard with a new scraper to determine the repaired size of the used-scraper's worn portion; making corresponding repair processing for 10 modifying the surface of the worn portion based on the position of the worn portion on the used-scraper; and recovering the worn portion's size according to the determined repaired-size with the corresponding repair processing. The step of making corresponding repair processing for modifying the surface of the worn portion based on the position of the worn portion on the 15 used-scraper may comprise: perform surface modification on the worn portion of a inclined surface or a horizontal surface of the used-scraper using a laser cladding technology; perform surface modification on the worn portion of a pile head of the used-scraper using a surfacing technology. The step of performing surface modification on the worn portion of a inclined 20 surface or a horizontal surface of the used-scraper using a laser cladding technology may comprise: perform surface modification on the worn portion of the horizontal surface of the used-scraper using a laser cladding processing machine; construct processing equipment whose inclined surface has the same inclination angle with the used-scraper's inclined surface, fix the used-scraper on the inclined 25 surface of the processing equipment, and then perform surface modification on the worn portion of the inclined surface of the used-scraper using the laser cladding processing machine. The remanufacturing standard may comprise a standard of failure size and a standard of metal-fatigue proportion. The standard of failure size may mean that 3 the failure size of every worn portion is not larger than 10% of the size of a new one. The standard of metal-fatigue proportion may mean that 5% of the total used-scrapers which satisfy the failure-size standard do not incur metal fatigue. Before detecting the used-scraper, the method may further comprise initially 5 selecting the used-scraper according to a standard of surface crack-free; performing surface cleaning and sand blasting to the used-scraper with no crack on its surface after primary election. The step of performing surface cleaning to the used-scraper with no crack on its surface after primary election may comprise: immerse the used-scraper in a 10 phosphoric acid solution in which the mass percent concentration of phosphoric acid is 8%-13% for 10-15 minutes; immerse the used-scraper taken out from the phosphoric acid solution in soft water for 20-30 minutes; and dry the used-scraper taken out from the soft water for 10-15 minutes. The step of performing sand blasting to the used-scraper with no crack on its 15 surface after primary election may comprise: perform the sand blasting on the used-scraper treated with the surface cleaning by using of sand grains with the diameter of 1.1-1.4 mm; immerse the used-scraper in soft water for 5-10 minutes after the sandblasting processing, and then take it out to dry for 5~10 minutes. After recovering the size of the used-scraper's worn portion, the method may 20 further comprise: testing the quality of the repaired scraper to determine whether it satisfies a new mining-scraper quality specification in a coal mining industry standard; and painting the used-scraper which satisfies the coal mining industry standard, and storing it. After recovering the size of the used-scraper's worn portion and before 25 storing it, the method may further comprise: performing sand blasting and coping treatment on a size-repaired position of the used-scraper; and treating the upper and lower surfaces of the repaired scraper with laser strengthening. In some alternative embodiments, the method includes the following processes: detect the size and mechanical properties of a mining used-scraper to 4 determine whether it satisfies a remanufacturing standard; compare the used-scraper which satisfies the remanufacturing standard with a new scraper to determine the repaired size of the used-scraper's worn portion; make corresponding repair processing for modifying the surface of the worn portion based 5 on the position of the worn portion on the used-scraper; and recover the worn portion's size according to the determined repaired-size with the corresponding repair processing. In some alternative embodiments, the step of making corresponding repair processing for modifying the surface of the worn portion based on the position of the 10 worn portion on the used-scraper may include the following processes: perform surface modification on the worn portion of a inclined surface or a horizontal surface of the used-scraper using a laser cladding technology, and perform surface modification on the worn portion of a pile head of the used-scraper using a surfacing welding technology. 15 In some alternative embodiments, the step of performing surface modification on the worn portion of a inclined surface or a horizontal surface of the used-scraper using a laser cladding technology may include the following processes: perform surface modification on the worn portion of the horizontal surface of the used-scraper using a laser cladding processing machine, and 20 construct processing equipment whose inclined surface has the same inclination angle with the used-scraper's inclined surface, fix the used-scraper on the inclined surface of the processing equipment, and then perform surface modification on the worn portion of the inclined surface of the used-scraper using the laser cladding processing machine. 25 In some alternative embodiments, the remanufacturing standard may include a standard of failure size and a standard of metal-fatigue proportion; the standard of failure size means that: the failure size of every worn portion is not larger than 10% of the size of a new one; the standard of metal-fatigue proportion means that: 5% of the total used-scrapers which satisfy the standard of failure size do not incur 5 metal fatigue. In some alternative embodiments, before detecting the used-scraper, the method further includes the following process: initially select the used-scraper according to a standard of surface crack-free, and perform surface cleaning and 5 sand blasting to the used-scraper with no crack on its surface after primary election. In some alternative embodiments, the surface cleaning may include the following process: immerse the used-scraper in a phosphoric acid solution with the mass percent concentration of 8%-13% for 10-15 minutes; then immerse the used-scraper taken out from the phosphoric acid solution in soft water for 20-30 10 minutes, and then dry the used-scraper taken out from the soft water for 10-15 minutes. In some alternative embodiments, the sand blasting may include the following process: perform the sandblasting on the used-scraper treated with the surface cleaning by using of sand grains with the diameter of 1.1~1.4 mm; 15 immerse the used-scraper in soft water for 5-10 minutes after the sandblasting processing, and then take it out to dry for 5~10 minutes. In some alternative embodiments, after recovering the size of the used-scraper's worn portion, the method further includes the following process: test the quality of the repaired used-scraper to determine whether it is up to a new 20 mining-scraper quality specification in a coal mining industry standard; and then perform paint treatment on the used-scraper which is up to the coal mining industry standard and store it. In some alternative embodiments, after recovering the size of the used-scraper's worn portion and before storing it, the method further includes the 25 following process: perform sand blasting and coping treatment on a size-repaired position of the used-scraper; and treat the upper and lower surfaces of the repaired scraper with laser strengthening. By contrast with the prior art, this present disclosure has these advantages as below: 6 This disclosure provides a method for remanufacturing a mining used-scraper. In this method, by comparing the used-scraper which satisfies the remanufacturing standard with the new scraper, the repaired size and the worn portion of the used-scraper are determined accurately. Further, repair the worn 5 portion by using of different repair processing separately according to the position of each worn portion on the used-scraper, which implements more precise repairing, and the quality after test is more in line with the standard. Accordingly, the quality of the used-scraper repaired by this method totally is up to the standard for a new scraper, which highly improves the reuse ratio of the used-scraper. 10 For the above described and the related purpose, the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which one or more exemplary embodiments of this disclosure are shown. These and other aspects of the present disclosure will become apparent from the following description of the example embodiment taken in conjunction with 15 the following drawings, although variations and modifications therein may be effected without departing from the spirit and scope of the novel concepts of the disclosure. Other features, details, utilities, and advantages of the present disclosure will be apparent from the following more particular written description of various embodiments as further illustrated in the accompanying drawings and 20 defined in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flowchart of a method for remanufacturing a mining used-scraper according to an embodiment of the present disclosure; 25 Fig. 2 is a schematic structural view of a mining used-scraper according to an embodiment of the present disclosure; Fig. 3 is a top view of a mining used-scraper in Fig. 2 according to an embodiment of the present disclosure; Fig. 4 is a schematic structural view of technological equipment for 7 remanufacturing a mining used-scraper according to an embodiment of the present disclosure; and Fig. 5 is a schematic structural view of technological equipment for remanufacturing a mining used-scraper according to an embodiment of the present 5 disclosure. DETAILED DESCRIPTION The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the 10 disclosure are shown, so that those skilled in the art can realize them. The embodiments just present possible changes, a single part and function are selectable, and also the operation order can be changed. Parts and technical features of some embodiments may be included in or replaced to other embodiments. This disclosure may, however, be embodied in many different 15 forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. The scope of the embodiments of the present disclosure not only includes the scope of its claims, but also includes all equivalents obtained from the claims. In 20 this text, these embodiments may be described as "invention" singly or generally, which is just for convenient to express, but the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The present disclosure will be described in detail with reference to the 25 accompanying drawings and the embodiments as follows. Fig. 1 is flowchart of a method for remanufacturing a mining used-scraper in some alternative embodiments. Fig. 2 is a schematic structural view of a mining used-scraper in some alternative embodiments. Fig. 3 is a top view of a mining used-scraper shown in Fig. 2 in some alternative embodiments. Fig. 4 is a schematic structural 8 view of technological equipment for remanufacturing a mining used-scraper in some alternative embodiments. Fig. 5 is a schematic structural view of technological equipment for remanufacturing a mining used-scraper in some alternative embodiments. 5 With reference to Fig. 1, a method for remanufacturing a mining used-scraper is provided in some alternative embodiments. The method for remanufacturing a mining used-scraper includes the following steps: S1 1: detect the size and mechanical properties of the mining used-scrapers and determine whether they satisfy a remanufacturing standard. 10 In some alternative embodiments, the remanufacturing standard includes a standard of failure size and a standard of metal-fatigue proportion. The standard of failure size means that: the failure size of every worn portion is not larger than 10% of the size of a new one. The standard of metal-fatigue proportion means that: 5% of the total used-scrapers which satisfy the failure-size standard do not 15 incur metal fatigue. In a specific implementation process, generally, the failure size of every worn portion of the used-scraper is determined by comparing the used-scraper with a new scraper using reverse engineering techniques. Then, detect the failure size of the used-scraper and select the used-scraper whose failure size is less than or equal to 10% of the new one's size, and conduct a spot check of 20 metal fatigue for 5% of the selected used-scrapers. If the 5% of the checked used-scrapers do not incur the metal fatigue, then determine whether the used-scraper which reaches the failure-size standard satisfies the remanufacturing standard; otherwise, perform the spot check on 1% of the rest scrapers without being conducted a spot check to determine whether they incur the metal fatigue, if 25 they do not incur the metal fatigue, then determine that the used-scraper reached the failure-size standard satisfies the remanufacturing standard, if they have been in the metal fatigue, then continue to check 1% of the rest scrapers without being conducted a spot check, until the result of the spot check shows that the used-scraper does not incur the metal fatigue. 9 In some alternative embodiments, before the size and mechanical properties of the mining used-scraper are detected, pick out scrapers with no crack on the surface at first, then treat them with surface cleaning and sand-blasting, so as to make them more convenient to be detected and modified. 5 In some alternative embodiments, the process of conducting the surface cleaning onto the used-scrapers with no surface crack which have passed through the primary election in the method includes these steps: the used-scraper is immersed in a phosphoric acid solution for 10-15 minutes and the mass percent concentration of phosphoric acid is 8%-13%, then the used-scraper is taken out to 10 put in soft water for 20-30 minutes, and then the used-scraper taken out from the soft water is dried for 10-15 minutes. Thus, after the surface cleaning, not only the waste oil, rusty spot, dirt impurities and the like are removed, but also the surface features of the used-scraper are changed, which is easier to conduct sandblasting processing to them afterwards. 15 In some alternative embodiments, the process of performing the sandblasting on the used-scrapers with no surface crack which have passed through the primary election in the method includes these steps: perform the sandblasting on the used-scraper treated with the surface cleaning by using of the sand grains with the diameter of 1.1 ~ 1.4 mm; after the sandblasting processing, 20 immerse the used-scraper in soft water for 5-10 minutes, and then take it out to dry for 5-10 minutes. After the sandblasting processing, the surface performance of the used-scraper is improved, and then the used-scraper is treated with the cladding or surfacing welding, so that the performance of the processed used-scraper is further easier to reach the new one's standard, wherein the 25 hardness is up to 45-50HRC. S12: compare the used-scraper which satisfies the remanufacturing standard with the new scraper, so as to determine the repaired size of the used-scraper's worn portion. In some alternative embodiments, the reverse engineering technique is used 10 to compare the used-scraper with the new scraper, which determines indexes of the used-scraper's worn portion according to the new scraper' standards to obtain the size standard to be repaired, that is the repaired size. S13: make the corresponding repair processing for modifying the surface of 5 the worn portion according to the position of the worn portion on the used-scraper. S14: repair the worn portion's size according to the determined repaired-size using the corresponding repair processing. With reference to Figs. 2~5, in some alternative embodiments, the processing of repair the worn portion's size according to the determined 10 repaired-size with the corresponding repair processing includes these operations: for the worn portion on the used-scraper's inclined surface, construct the processing equipment whose inclined surface has the same inclination angle with the used-scraper's inclined surface; fix the used-scraper on the inclined surface of the processing equipment, and install the processing equipment on the working 15 platform of a laser cladding processing machine to conduct the laser cladding on the inclined surface of the used-scraper, so as to perform the surface modification on the inclined surface of the used-scraper. For the worn portion on the used-scraper's horizontal surface, fix the used-scraper directly on the working platform of the laser cladding processing machine to conduct the laser cladding on 20 the horizontal surface of the used-scraper, so as to perform the surface modification on the horizontal surface of the used-scraper. For the worn portion on the pile head of the used-scraper, perform the surface modification on the horizontal surface of the used-scraper by manual surfacing with the wear-resisting welding wire. For example, regarding the used-scraper shown in the Figs. 2~3, there are 25 four different worn portions on the used-scraper repaired by using of different processing. The worn surface 1 and worn surface 2 are repaired on the laser cladding processing machine for repairing their sizes. For the worn surface 3, firstly construct the processing equipment 6 as shown in Fig. 4, and the inclination angle of the inclined surface 7 of the processing equipment 6 is same with the 11 inclination angle of the worn surface 3. The used-scraper is fixed on the rotation axis 8 of the processing equipment 6 so as to rotate around the working plate 6. After the used-scraper fixed on the processing equipment 6, the processing equipment 6 is installed on the working platform of the laser cladding processing 5 machine to perform the laser cladding on the worn surface 3 to repair its size. For the worn surface 4, the processing equipment 9 of which inclination angle of the inclined surface 10 is same with the inclination angle of the worn surface 4 is built as shown in Fig. 5, and the used-scraper is fixed on the working platform 10 through the rotation axis 11 so as to perform the laser cladding on the worn surface 4 to 10 repair its size. When performing the laser cladding, the worn portion of the used-scraper is repaired by a semiconductor laser, and it needs to adjust the indexes of repairing processing to obtain a cladding layer with good surface quality, choose alloy power with low intensity to build a bottom player on which cover by alloy power with high intensity and hardness, so as to construct double tough and 15 wear-resistant protective layers with a hardness gradient which has a structural feature of hard inside and soft outside, and subsequently cooperate manual welding to repair its size. As the worn surface 5 is on the pile head of the used-scraper, where is not suitable to be repaired with the technology of laser cladding, the size of the worn surface 5 is repaired by manual surfacing-welding with wear-resisting 20 welding wire. Thus, using different repair processing to repair different worn portions can implement more precise repairs and acquire a repaired scraper with higher quality. In some alternative embodiments, after repairing the size of the used-scraper, the size-repaired positions of the used-scraper will be further 25 processed with sand blasting and coping treatment, and the upper and lower surfaces of the repaired used-scraper will be treated with laser strengthening. After the laser strengthening treatment, the hardness of the upper and lower surfaces of the used-scraper is HRC50-HRC55. After the laser strengthening treatment, the repaired-scraper is compared with the new scraper by means of the 12 reverse engineering technique. Further, the repaired scraper is tested on the surface quality, size and force-flexure according to the scraper quality inspection specification MT/T812-1999 of the coal mining industry standard, so as to determine whether the size and the mechanical property of the repaired scraper are 5 up to the standard. After the repaired scraper pass the test, the repaired scraper is treated with spray paint and then will be put in the storage to be reused. In the method of this disclosure, by comparing the used-scraper which satisfies the remanufacturing standard with the new scraper, the repaired size and the worn portion of the used-scraper are determined accurately. Further, different 10 repairing processes for repairing the worn portion are used separately based on the position of each worn portion on the used-scraper, which can implement more precise repairing, and the quality after test is more in line with the standard. Accordingly, the quality of the used-scraper repaired by this method totally satisfies the standard for a new scraper, which highly improves the reuse ratio of the 15 used-scraper. In generally, the mentioned above is only exemplary embodiments of the present disclosure but not limitation for the present disclosure, various modification and variations can be devised by those skilled in this art, and it should be understood that any modification, equivalent and improvement devised without 20 departing from the spirit and scope of the present disclosure belong to the protection scope of the present disclosure. 13