Abstract:
A separation type metallurgical reduction method and an apparatus thereof. The separation type metallurgical reduction apparatus includes a reduction furnace and a multistage cooling device. By means of the separation type metallurgical reduction apparatus, the metallurgical reduction/smelting process and the cooling process are separately performed in different spaces at the same time to improve the operation of the conventional metallurgical reduction furnace within which the smelting process and the cooling process are totally limitedly performed. Accordingly, the shortcomings of too long waiting time, waste of great amount of energy and low yield rate that exist in the conventional metallurgical reduction furnace can be eliminated.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a separation type metallurgical reduction method and an apparatus thereof. By means of the separation type metallurgical reduction apparatus, the metallurgical reduction/smelting process and the cooling process are separately performed in different spaces at the same time. In contrast, in a convent ional metallurgical reduction furnace, the smelting process and the cooling process must be performed in the same space and it is necessary to repeatedly raise and lower the temperature of the reduction furnace. Accordingly, by means of the separation type metallurgical reduction apparatus of the present invention, the operation time of the metallurgical process is greatly shortened to overcome the shortcoming of too long waiting time that exists in the conventional metallurgical reduction furnace. Moreover, by means of the separation type metallurgical reduction apparatus of the present invention, the energy consumption is greatly reduced and the yield rate is greatly increased. 
         [0003]    2. Description of the Related Art 
         [0004]    It is known that the developments of all kinds of industries have relied on sufficient supply and full application of specific materials for so long, especially some metal materials. Therefore, the metallurgical technique plays an important role in the advance of human society. The most important material used in the current electronic industries is silicon (Si). The sale of silicon-made components is about 95% of the sale of the semiconductor components in the world. In natural field, all silicon materials exist not in element state. Instead, the silicon materials exist in form of silica (impure SiO 2 ) and silicate. Therefore, it is an important tropic in science and technology how to effectively and economically smelt silicon material from the natural raw material for manufacturing all kinds of silicon-made products. 
         [0005]    In the above materials, metallurgical-grade Si (MG-Si) is a material of solar cell. The metallurgical-grade Si can be divided into three major varieties, that is, monocrystalline silicon, multicrystalline silicon and non-crystalline silicon. The raw material from which multicrystalline silicon or monocrystalline silicon is smelted is mainly high-purity (&gt;97%) quartz sand, which is also a crystal of SiO 2 . The first step of manufacturing high-purity multicrystalline silicon is reducing silicon from silica. In a common manufacturing process, the materials of silica, coke, coal and woods are mixed and placed in a graphite electrical arc heating reduction furnace and heated at a high temperature of 1500° C.˜2000° C. to reduce SiO 2  into silicon. The chemical reaction formulas are follows: 
         [0000]      SiO 2 +C→Si+CO 2  
 
         [0000]      SiO 2 +2C→Si+2CO
 
         [0006]    In the conventional reduction technique, after the silica is placed into the reduction furnace, it is necessary to gradually raise the temperature of the reduction furnace from an ambient temperature to the high temperature of 1500° C.˜2000° C. for melting and reducing the material to be reduced. After the reduction process is completed, it is necessary to gradually lower the temperature of the reduction furnace to about 250° C. (approximate to the ambient temperature) for taking out the reduction product and avoiding abrupt temperature change, which may ill affect the equipment, the quality of the reduction product and the operation environment. After the reduction product is taken out from the reduction furnace, another crop of material to be reduced is placed into the reduction furnace. Then, it is necessary to gradually re-raise the temperature of the reduction furnace from the ambient temperature to the high temperature of 1500° C.˜2000° C. for melting and reducing the material. In the above process, it is necessary to repeatedly raise and lower the temperature of the reduction furnace. This is because in the case that the reduction furnace is opened under the high temperature of 1500° C.˜2000° C., there is a danger of explosion of the furnace body due to excessively great difference between the temperature of the furnace body and the temperature of the environment. Moreover, a great amount of high-temperature fluid will enter the operation environment to cause thermal contamination of the operation environment and injury to site workers. What is more, the abrupt temperature drop may lead to structural damage to the high-temperature smelted silicon product. Also, the silicon product will be inevitably contaminated with impurities in the environment and become useless. 
         [0007]    According to practical estimation, one single cycle of the conventional metallurgical reduction of the silicon material (filling material→heating→reducing→lowering temperature→releasing product) will cost a quite long time of about 32 hours. 
         [0008]    Moreover, after the temperature of the reduction furnace is continuously raised from about 250° C. to 1500° C.˜2000° C. for smelting the material and then gradually lowered to about 250° C. for taking out the reduction product, a great amount of thermal energy is lost and wasted. Furthermore, when re-raising the temperature of the reduction furnace from 250° C. to 1500° C.˜2000° C. for reduction, a great amount of electrical energy is consumed. Therefore, in the conventional metallurgical reduction method, a very long waiting time is wasted and the environment is contaminated. Also, a great amount of energy is wasted. This is not economic and fails to meet the requirement of environmental protection. 
         [0009]    It is therefore tried by the applicant to provide a novel metallurgical reduction method and an apparatus thereof. By means of the separation type metallurgical reduction apparatus, the operation time of the metallurgical process is greatly shortened and the energy consumption is greatly reduced and the yield rate is greatly increased. 
       SUMMARY OF THE INVENTION 
       [0010]    It is therefore a primary object of the present invention to provide a separation type metallurgical reduction method and an apparatus thereof. The separation type metallurgical reduction apparatus includes a reduction furnace and a multistage cooling device in cooperation with the reduction furnace. By means of the separation type metallurgical reduction apparatus, the reduction/smelting process of the material and the cooling process of the reduction product are separately performed in different spaces at the same time. Accordingly, the waiting time for re-rise of the temperature of the reduction furnace is greatly shortened so that the operation time of the metallurgical process is greatly shortened. Also, the energy consumption in each operation is greatly reduced in accordance with the requirement of environmental protect ion. Therefore, the production efficiency is greatly promoted and the yield rate is greatly increased. 
         [0011]    To achieve the above and other objects, the separation type metallurgical reduction apparatus of the present invention includes a reduction furnace and a multistage cooling device. The reduction furnace serves to provide a high temperature for melting and reducing a material placed in the reduction furnace. The cooling device is connected with the reduction furnace in alignment with a material release passage thereof. The reduction product is released from the material release passage into the cooling device for cooling. Accordingly, the reduction/smelting process of the material and the cooling process of the reduction product are separately performed in different spaces at the same time. The cooling device includes a load chamber arranged under the reduction furnace. The material release passage is positioned between the load chamber and the reduction furnace. The internal space of the load chamber communicates with the internal space of the reduction furnace through the material release passage. A material release gate is disposed in the material release passage for controlling unblocking/blocking of the material release passage. In addition, a preheating chamber is arranged on one side of the load chamber in communication with the load chamber. A first load gate is disposed between the load chamber and the preheating chamber to control communication/non-communication between the preheating chamber and the load chamber. The preheating chamber is provided with a carrier input gate through which the carrier device can be input from outer side. A cooling chamber is installed on the other side of the load chamber in communication with the load chamber. A second load gate is disposed between the cooling chamber and the load chamber to control communication/non-communication between the cooling chamber and the load chamber. The cooling chamber is provided with a carrier output gate through which the carrier device can be moved out of the cooling chamber. In addition, a continuous conveying device is arranged in a path extending from outer side of the carrier input gate through the carrier input gate, the preheating chamber, the first load gate, the load chamber, the second load gate, the cooling chamber and the carrier output gate to the outer side of the cooling chamber. The conveying device serves to convey the carrier device through the path to carry the reduction product for the preheating and cooling processes stage by stage. 
         [0012]    A material dropping device is disposed above the reduction furnace. A material dropping passage is positioned between the material dropping device and the reduction furnace, whereby the internal space of the material dropping device communicates with the internal space of the reduction furnace through the material dropping passage. A material dropping gate is arranged in the material dropping passage for controlling unblocking/blocking of the material dropping passage. The material to be reduced is filled in the internal space of the material dropping device. When the material dropping gate of the material dropping passage is opened to unblock the material dropping passage, the material to be reduced is allowed to drop into the reduction furnace through the material dropping passage. 
         [0013]    According to the above arrangement, the reduction/smelting process of the material and the cooling process of the reduction product are separately performed in different spaces at the same time. Accordingly, the metallurgical reduction process and cooling process can be overlapped and performed at the same time crop by crop to shorten time interval between reduction processes of two crops of material to be reduced. Therefore, the production efficiency is promoted and the yield rate is increased. Moreover, the cooling device is separated from the reduction furnace and the carrier device is separately conveyed through the cooling device section by section so that the quality of the reduction product can be ensured. Also, the energy consumption is greatly reduced in accordance with the requirement of environmental protection. 
         [0014]    The present invention can be best understood through the following description and accompanying drawings, wherein: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a front view of a preferred embodiment of the separation type metallurgical reduction apparatus of the present invention: 
           [0016]      FIG. 2  is a side view of the preferred embodiment of the separation type metallurgical reduction apparatus of the present invention; 
           [0017]      FIG. 3  is a front view according to  FIG. 1 , showing that the material to be reduced is filled into the material dropping device: 
           [0018]      FIG. 4  is a front view according to  FIG. 1 , showing that the material to be reduced is dropped from the material dropping device into the reduction furnace: 
           [0019]      FIG. 5  is a front view according to  FIG. 1 , showing that the material is heated, molten and reduced in the reduction furnace; 
           [0020]      FIG. 6  is a front view according to  FIG. 1 , showing that the preheated carrier device is conveyed to the load chamber; 
           [0021]      FIG. 7A  is a front view according to  FIG. 1 , showing that the reduction product is dropped from the reduction furnace into the load chamber; 
           [0022]      FIG. 7B  is a side view according to  FIG. 7A , showing that the reduction product is dropped from the reduction furnace into the load chamber; 
           [0023]      FIG. 8  is a front view according to  FIG. 1 , showing that the reduction product is completely released from the reduction furnace and the reduction furnace is re-filled with another crop of material to be reduced and the carrier device with the reduction product is ready to be conveyed into the cooling chamber; 
           [0024]      FIG. 9  is a front view according to  FIG. 1 , showing that the carrier device with the reduction product is conveyed into the cooling chamber for cooling and a vacant carrier device is conveyed into the preheating chamber for preheating; and 
           [0025]      FIG. 10  is a front view according to  FIG. 1 , showing that the cooled carrier device with the cooled reduction product is conveyed out of the cooling chamber. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Please refer to  FIGS. 1 and 2 . According to a preferred embodiment, the separation type metallurgical reduction apparatus of the present invention includes at least one reduction furnace  10  and a cooling device  20 . 
         [0027]    The reduction furnace  10  has an internal space in which the material to be reduced is placed (as shown in  FIG. 3 ). In practice, a reduction pot  11  is disposed in the reduction furnace  10  for containing the material  30  to be reduced. The material  30  to be reduced is molten and reduced in the reduction furnace  10  at a high temperature of 1500° C.˜2000° C. The material to be reduced can be silicon material such as silica or silica sand, chrome material, tungsten material, magnesium material, iron material, copper material or any other smeltable metal material. The present invention can be used to reduce and smelt any material that can be molten and reduced at high temperature. A heating device  13  is arranged in the reduction furnace  10  to uniformly heat the internal space of the reduction furnace  10 . The heating device  13  can heat the internal space in an electrical arc heating manner, high-frequency heating manner or any other suitable heating manner. A blending device  14  is installed in the reduction furnace  10  to extend into the reduction pot  11  and continuously blend the material for the heating device  13  to more uniformly heat and melt the material  30 . In addition, a heat insulation device  15  (preferably a liquid-cooled or water-cooled heat insulation device) is disposed between inner wall  101  and outer wall  102  of the reduction furnace to prevent the high heat in the reduction furnace  10  from being conducted to outer side of the reduction furnace  10 . In this case, the ambient environment of the reduction furnace  10  is protected from being thermally contaminated. Also, the thermal energy can be recycled for reuse. 
         [0028]    A material dropping device  17  is disposed above the reduction furnace  10 . A material dropping passage  171  is positioned between the material dropping device  17  and the reduction furnace  10 , whereby the internal space of the material dropping device  17  communicates with the internal space of the reduction furnace  10  through the material dropping passage  171 . A material dropping gate  172  is arranged in the material dropping passage  171  for controlling unblocking/blocking of the material dropping passage  171 . The material to be reduced is filled in the internal space of the material dropping device  17 . When the material dropping gate  172  of the material dropping passage  171  is opened to unblock the material dropping passage  171 , the material  30  to be reduced is allowed to drop into the reduction furnace  10  (or the reduction pot  11 ). A material filling port  173  is disposed on an upper side of the material dropping device  17 . An upper cover  174  is disposed at the material filling port  173  for blocking/unblocking the material filling port  173  so as to prevent the material  30  from being contaminated by ambient impurities. The material  30  to be reduced can be automatically regularly and quantitatively filled into the material dropping device  17  by means of a conveying belt to save labor and avoid inconvenience. 
         [0029]    The cooling device  20  is arranged under a material release passage  16  of the reduction furnace  10 . The cooling device  20  is provided with a load chamber  21 . The internal space of the reduction furnace and the internal space of the load chamber  21  communicate with each other through the material release passage  16 . A material release gate  161  is disposed in the material release passage  16  for controlling unblocking/blocking of the material release passage  16 . The material can be previously input to at least one carrier device  40  in the internal space of the load chamber  21 . The carrier device  40  is aligned with an exit of the material release passage  16  to accept the material output from the material release passage  16 . 
         [0030]    A preheating chamber  22  is installed on one side of the load chamber  21 . A first load gate  221  is disposed between the load chamber  21  and the preheating chamber  22  to control communication/non-communication between the preheating chamber  22  and the load chamber  21 . When the first load gate  221  is opened, the carrier device  40  can pass through the first load gate  221  into the load chamber  21 . The preheating chamber  22  is further provided with a carrier input gate  222  through which the carrier device  40  can be input from outer side. In addition, a heating device  223  is further disposed in the preheating chamber  22  for heating the internal space thereof. The preheating chamber  22  mainly serves to preheat the input carrier device  40  and then input the carrier device to the load chamber  21  before the reduction product is input to the load chamber  21 . This can avoid too large difference between the temperature of the carrier device  40  and the temperature of the reduction product so as to avoid ill affection on the reduction product or accident in the loading process. 
         [0031]    A cooling chamber  23  is installed on the other side of the load chamber  21 . A second load gate  231  is disposed between the cooling chamber  23  and the load chamber  21  to control communication/non-communication between the cooling chamber  23  and the load chamber  21 . When the second load gate  231  is opened, the carrier device  40  can pass through the second load gate  231 . A cooling fan  232  or the like circulation cooling device can be disposed in the cooling chamber  23  to speed the cooling operation. In addition, the cooling chamber  23  is provided with a carrier output gate  233  through which the cooled reduction product and the carrier device  40  are conveyed to outer side of the cooling chamber  23 . 
         [0032]    A continuous or multisection conveying device  24  is disposed in the preheating chamber  22 , the load chamber  21  and the cooling chamber  23  between the gates thereof for conveying the carrier device  40 . By means of the conveying device  24 , the carrier device  40  can be input from outer side through the carrier input gate  222  to the preheating chamber  22 . The carrier device  40  then is conveyed through the first load gate  221  into the load chamber  21  and then conveyed through the second load gate  231  into the cooling chamber  23 . Finally, the carrier device  40  is conveyed through the carrier output gate  233  to the outer side. Accordingly, the carrier device (or the reduction product) can be conveniently and continuously conveyed. In addition, two carrier transportation trolleys  50  are respectively disposed behind the carrier input gate  222  of the preheating chamber  22  and in front of the carrier output gate  233  of the cooling chamber  23  for inputting the carrier device  40  to the conveying device  25  and outputting the carrier device  40  from the conveying device  25 . Accordingly, the preheating chamber  22 , the load chamber  21 , the cooling chamber  23  and the conveying device cooperate with each other to form a separation type multistage cooling device, which can continuously convey the carrier device  40 . 
         [0033]    In addition, heat insulation devices  25  (preferably liquid-cooled or water-cooled heat insulation devices) are respectively disposed between inner walls and outer walls of the separated spaces of the cooling device  20  to prevent the high heat in the spaces from being conducted to outer side and protect the ambient environment from being thermally contaminated. Moreover, the internal spaces of the reduction furnace  10  and the cooling device  20  are all clean rooms (or vacuum rooms) to avoid contamination of the material or the product and ensure stable quality of operation. 
         [0034]    Please now refer to  FIGS. 3 to 10 . The separation type metallurgical reduction method of the present invention includes: 
         [0035]    step  201  of filling the material  30  to be reduced into the material dropping device  17  and preparing the material  30 ; 
         [0036]    step  202  of opening the material dropping gate  172  to quantitatively drop the material  30  to be reduced through the material dropping passage  171  into the internal space of the reduction furnace  10  (or the reduction pot  11 ); 
         [0037]    step  203  of closing the material dropping gate  172  and the material release gate  161  to form a closed space in the reduction furnace  10 ; 
         [0038]    step  204  of using the heating device  13  of the reduction furnace  10  to heat the material  30  to a high temperature so as to melt and reduce the material  30 , in this step, the material  30  in the reduction furnace  10  being heated to a high temperature of 1500° C.˜2000° C. and molten, when heated and molten, a blending device  14  being used to uniformly blend the material  30  for reducing the material  30  into a reduction product  301 ; 
         [0039]    step  205  of using the conveying device  24  to convey the preheated carrier device  40  from the preheating chamber  22  into the load chamber  21  in a position under the material release passage  16 , then the first and second load gates  221 ,  231  being closed and then the material release gate  161  being opened to drop the reduction product  301  through the material release passage  16  into the carrier device in the load chamber  21 ; 
         [0040]    step  206  of closing the material release gate  161  and further dropping another crop of material  30  to be reduced from the material dropping device  17  into the reduction furnace  10  for heating and reduction process, in the meantime, the second load gate  231  of the cooling device  20  being opened to convey the carrier device  40  with the reduction product  301  from the load chamber  21  into the cooling chamber  23  for cooling; 
         [0041]    step  207  of closing the carrier output gate  233  and simultaneously (later) opening the carrier input gate  222  to convey the carrier device  40  from the outer side (the trolley  50 ) into the preheating chamber  22  for preheating: 
         [0042]    step  208  of previously conveying the carrier device  40  into the load chamber  21  before step  205  is performed again; and 
         [0043]    step  209  of cooling the reduction product  301  in the cooling chamber  23  to a set temperature relatively approximate to ambient temperature and then opening the carrier output gate  233  to convey the cooled reduction product  301  and the carrier device  40  out of the cooling chamber  23 . The set temperature can be under 150° C.˜100° C. according to the current normal operation. In steps  206  to  208 , a cooling fan  232  or the like cooling device can be used to speed the cooling process of the reduction product  301  and the carrier device  40  carrying the reduction product  301 . The operation is performed in a clean or vacuum room. In addition, an inert gas can be released during the cooling process to keep the reduction product  301  in a stable state to complete the reduction process of one crop of material. 
         [0044]    According to the aforesaid, the heating/reduction operation of the material  30  in the reduction furnace  10  and the cooling operation of the reduction product  301  are performed in different spaces at the same time. The blocking/unblocking of the material release passage  16  and the opening/closing of the respective gates are effectively controlled to keep the reduction furnace  10  at a high temperature. It is unnecessary to repeatedly raise/lower the temperature of the reduction furnace as in the conventional reduction furnace. Therefore, the energy consumption can be greatly reduced. Moreover, the time for each re-rise of the temperature of the internal space of the reduction furnace to a high temperature necessary for the reduction operation is greatly shortened. Therefore, the product ion efficiency is greatly promoted. Furthermore, the reduction stage of operation and cooling stage of operation are performed in separated environments and thus can be independently more flexibly and conveniently controlled as necessary to ensure high quality of the reduction product  301 . 
         [0045]    According to the above arrangement, the present invention has the following advantages:
   1. By means of the separation type metallurgical reduction method and the apparatus thereof, the heating/reduction operation of the material and the cooling operation of the reduction product are performed in different spaces at the same time. Therefore, the waiting time for each re-rise of the temperature of the reduction furnace to the reduction temperature is greatly shortened and the energy consumption is greatly reduced. Therefore, the product ion efficiency is greatly promoted and a great amount of energy is saved.   2. By means of the separation type metallurgical reduction method and the apparatus thereof, the steps of dropping material, reduction, cooling and achieving reduction product can be integratedly and continuously performed to save the time for closedown of the furnace, lowering of the temperature, release of the material, preparation of the material, holdup for lack of material, restart of the furnace and reheating. Therefore, the yield rate can be greatly increased.   3. The present invention includes a unique cooling device connected with the reduction furnace to independently cool the reduction product. Therefore, it is unnecessary to repeatedly cool the reduction furnace for cooling the reduction product. This can reduce loss of thermal energy in the reduction furnace and save electrical energy for repeatedly raising the temperature of the reduction furnace in accordance with the environmental protection requirements of energy-saving and carbon reduction,   4. By means of the separation type metallurgical reduction method and the apparatus thereof, the heating/reduction operation of the material and the cooling operation of the reduction product are performed in different spaces at the same time. Therefore, the reduction product is provided with a better and more stable cooling environment to minimize the possibility of contamination of the reduction product by ambient impurities during the cooling process. Therefore, the reduction stage of operation and the cooling stage of operation are performed in separated environments and thus can be independently and more flexibly controlled to ensure high quality of the reduction product.   
 
         [0050]    The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.