Preparation method of gallium-indium alloy

Abstract

The invention provides a preparation method of a gallium-indium alloy. The preparation method comprises the steps that after a mixture of gallium-containing waste and indium-containing waste is subjected to roasting and negative-pressure smelting, cooling is conducted, liquid gallium indium is obtained, and the liquid gallium indium is evenly mixed to obtain the gallium-indium alloy. Wherein the roasting treatment is used for removing part of chlorides and sulfides in the raw materials so as to reduce corrosion to subsequent equipment; the negative-pressure smelting is divided into three stages, the first negative-pressure smelting is used for removing reduced low-melting-point substances, the second negative-pressure smelting is used for removing zinc and lead elements, the third negative-pressure smelting enables gallium and indium to become steam in corresponding temperature sections to be volatilized along with a flue and then become liquid through cooling, and the gallium-indium alloy can be obtained after uniform mixing. In conclusion, the preparation method provided by the invention is short in production flow and good in impurity removal effect, and meanwhile, byproducts with economic value are generated.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous smelting, and in particular relates to a method for preparing a gallium-indium alloy. Background Art

[0002] Scattered gallium is an important strategic resource. A series of compounds prepared with gallium as the matrix, such as semiconductor materials, electronic optical materials, new functional materials, special alloys and organic metal compounds, are important basic supporting materials in the fields of modern electronic computers, communications, aerospace, new energy, medicine and health, and military industry. At present, about 90% of primary gallium is recovered from the production process of alumina, with a mature industrial chain. At the same time, some gallium is also enriched in the process of zinc smelting and coal ash, but the gallium enriched in these two raw materials has not been industrialized due to the long extraction process and high cost. At present, a small amount of gallium can be recycled and reused through gallium-containing waste, but due to the low melting point characteristics of some gallium-based materials, the energy consumption of impurity removal is high, and the process flow is also relatively complicated, resulting in a high cost for gallium recovery.

[0003] The content of indium in the earth's crust is extremely low, and the distribution is small and scattered. The abundance in the earth's crust is only 0.05~0.072ppm. It can hardly form a mineral deposit independently. It usually exists as a companion element dispersed in sulfide minerals composed of other elements. At present, 80% of primary indium comes from sphalerite, followed by galena, lead sulfide ore, copper sulfide ore and cassiterite, but the recovery rate is low, generally only about 50%. Similar to gallium, indium-containing waste can be recycled and reused to obtain metallic indium. However, due to the low melting point characteristics of some indium-based materials, there are also problems such as high energy consumption in impurity removal, complex process flow, and high cost.

[0004] However, at present, in the traditional process of preparing gallium-indium alloy, it is necessary to first extract crude gallium and crude indium, and then undergo deep processing to become high-purity gallium and high-purity indium. The gallium-indium alloy is prepared using high-purity gallium and high-purity indium as raw materials, and the process is long and complicated. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a method for preparing a gallium-indium alloy. The preparation method has simple steps and a short process flow, and the obtained gallium-indium alloy meets the purity requirements.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a gallium-indium alloy, which comprises the following steps:

[0008] The mixture of gallium-containing waste and indium-containing waste is roasted, smelted under negative pressure, cooled to obtain liquid gallium and indium, and mixed evenly to obtain a gallium-indium alloy;

[0009] The negative pressure smelting includes: first negative pressure smelting, second negative pressure smelting and third negative pressure smelting;

[0010] The temperature of the first negative pressure smelting is 350~450 o C, time is 0.1~1 h;

[0011] The temperature of the second negative pressure smelting is 500~700 o C, time is 0.1~1 h;

[0012] The temperature of the third negative pressure smelting is 1000~1400 o C, time 0.1~1h.

[0013] Preferably, the pressure of the negative pressure smelting is 3000~10000 Pa.

[0014] Preferably, the mass ratio of the gallium-containing waste to the indium-containing waste is (0.1~1):1.

[0015] Preferably, the composition of the gallium-containing waste includes: 89~95 wt% iron oxide, 0~2 wt% SiO2, 1~5wt% ZnO, and a total amount of less than 10 wt% of any one or more combinations of Na2O, MgO, CaCO3, Al2O3, TiO2, V2O5, Cr2O3, MnO, PbO, CuO, NiO, chlorides or sulfides.

[0016] The gallium content in the gallium-containing waste is 100-500 g / t.

[0017] Preferably, the components of the indium-containing waste include: 40~62 wt% TFe, 5~15 wt% Zn, 8~20 wt% C, and a combination of any one or more of Ca, Ti, Al, Mg, K, Mn, Na, Cl, Pb, Si, and S with a total amount less than 15 wt%.

[0018] The indium content in the indium-containing waste is 40-100 g / t.

[0019] Preferably, the calcination temperature is 400-550 o C, time is 0.1~1 h.

[0020] Preferably, after the negative pressure smelting, the purity of the obtained gaseous gallium indium is 6-8 N.

[0021] Preferably, the cooling is performed in an inert atmosphere.

[0022] Preferably, the cooling temperature is 31~50 o C.

[0023] Preferably, the mixing is performed under stirring conditions.

[0024] Preferably, the mixing time is 0.5 to 2 h.

[0025] Preferably, the mass ratio of gallium to indium in the gallium-indium alloy is (10-60):(40-90).

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a short process, which utilizes low gallium-containing wastes mixed with low indium-containing wastes in the vanadium-titanium magnetite smelting process in the Panxi area, and after roasting, vacuum smelting (i.e., negative pressure smelting), cooling, and mixing, high-purity gallium-indium alloy can be directly produced. Among them, the roasting treatment is used to remove part of the chlorides and sulfides in the raw materials to reduce corrosion to subsequent equipment; the first negative pressure smelting is used to remove the reduced low-melting point substances, the second negative pressure smelting is used to remove zinc and lead elements, and the third negative pressure smelting makes gallium and indium become steam in the corresponding temperature range and volatilize with the flue, and then become liquid by cooling, and after uniform mixing, the gallium-indium alloy can be obtained.

[0028] The raw materials for preparing the gallium-indium alloy in the present invention are unique, and no additional auxiliary materials are required except for gallium-containing waste and indium-containing waste. The preparation method provided by the present invention has a short production process, good impurity removal effect, and produces by-products with economic value. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides a method for preparing a gallium-indium alloy, which comprises the following steps:

[0031] The mixture of gallium-containing waste and indium-containing waste is roasted, smelted under negative pressure, cooled to obtain liquid gallium and indium, and mixed evenly to obtain a gallium-indium alloy.

[0032] In the present invention, the gallium-containing waste is waste from the vanadium-titanium magnetite smelting process in the Panxi area, specifically vanadium-extracting converter sludge. In the present invention, the composition of the vanadium-extracting converter sludge ranges from 89 to 95 wt% iron oxide, 0 to 2 wt% SiO2, 1 to 5 wt% ZnO, and a total amount of less than 10 wt% of any one or more of Na2O, MgO, CaCO3, Al2O3, TiO2, V2O5, Cr2O3, MnO, PbO, CuO, NiO, chlorides or sulfides; preferably 90 to 92 wt% iron oxide, 0.5 to 1.5 wt% SiO2, 1 to 4 wt% ZnO, and a total amount of less than 8 wt% of any one or more of Na2O, MgO, CaCO3, Al2O3, TiO2, V2O5, Cr2O3, MnO, PbO, CuO, NiO, chlorides or sulfides. In the present invention, the gallium content of the gallium-containing waste is a trace amount, specifically 100-500 g / t, preferably 200-500 g / t, and more preferably 300-500 g / t.

[0033] In the present invention, the indium-containing waste is the waste in the vanadium-titanium magnetite smelting process in the Panxi area, specifically blast furnace gas mud. In the present invention, the composition range of the blast furnace gas mud is 40~62 wt% TFe, 5~15 wt% Zn, 8~20 wt% C, and a total amount of less than 15 wt% of any one or more of Ca, Ti, Al, Mg, K, Mn, Na, Cl, Pb, Si, S combination; preferably 45~60 wt% TFe, 8~12 wt% Zn, 10~15 wt% C, and a total amount of less than 10 wt% of any one or more of Ca, Ti, Al, Mg, K, Mn, Na, Cl, Pb, Si, S combination. In the present invention, the indium content of the indium-containing waste is a trace amount, specifically 40~100 g / t, preferably 50~100 g / t, and more preferably 70~100 g / t.

[0034] According to the present invention, gallium-containing waste and indium-containing waste are first mixed to obtain a mixture of the two. Since the content of gallium and indium in gallium-containing waste and indium-containing waste has a certain influence on the ratio of gallium to indium in the final product gallium-indium alloy, and the carbon content in indium-containing waste will affect the degree of dissociation of gallium and indium from the raw material under vacuum (i.e., negative pressure) conditions. Therefore, after screening, the present invention preferably mixes gallium-containing waste and indium-containing waste in a ratio of (0.1~1):1, more preferably (0.3~0.8):1, and further preferably (0.5~0.6):1.

[0035] Then, the mixture of the two is subjected to roasting treatment. In the present invention, the purpose of the roasting treatment is to remove part of the chloride and sulfide in the raw material to reduce its corrosion to subsequent equipment. In the present invention, the roasting temperature is 400-550 o C, preferably 450~500 o C; time is 0.1-1 h, preferably 0.3-0.5 h. In the present invention, the roasting treatment can be carried out in a normal pressure heating device such as a rotary kiln.

[0036] After the roasting treatment is completed, the obtained material is preferably subjected to negative pressure smelting, i.e., vacuum smelting. In the present invention, the negative pressure smelting is preferably carried out in a closed smelting furnace, and the closed furnace needs to maintain a negative pressure, which is controlled at 3000-10000 Pa, preferably 5000-7000 Pa. The slightly negative pressure state can reduce the temperature of gasification of cations and other volatile elements.

[0037] In some preferred embodiments of the present invention, the negative pressure smelting includes: a first negative pressure smelting, a second negative pressure smelting and a third negative pressure smelting, and the smelting temperatures are increased in sequence. The present invention has no particular limitation on the heating rate of the temperature during the negative pressure smelting process, which is generally between 5 and 20 o C / min are both acceptable.

[0038] Wherein, the temperature of the first negative pressure smelting is 350~450 o C, preferably 380~400 o C; the residence time is 0.1~1h, preferably 0.3~0.5h; until the low melting point substances (such as sulfides and chlorides) in the material are reduced and volatilized along the flue in the closed smelting furnace. In the present invention, the residence time depends on the temperature of the first negative pressure smelting and the content of the low melting point substance. That is, the higher the temperature of the first negative pressure smelting and the lower the content of the low melting point substance, the shorter the residence time; conversely, the lower the temperature of the first negative pressure smelting and the higher the content of the low melting point substance, the longer the residence time.

[0039] The temperature of the second negative pressure smelting is 500~700 o C, preferably 350~650 o C; the residence time is 0.1~1 h, preferably 0.3~0.5 h. This process is mainly to convert all zinc and lead elements into steam and evaporate them through the flue.

[0040] The temperature of the third negative pressure smelting is 1000~1400 o C, preferably 1100~1200 oC; residence time 0.1~1 h, preferably 0.3~0.5 h. In this process, only gallium and indium will turn into steam and evaporate along the flue in this temperature range. It should be noted that the residence time in this temperature range depends on the actual molten pool temperature of the closed smelting furnace in this temperature range. That is, the higher the molten pool temperature, the shorter the residence time; conversely, the lower the molten pool temperature, the longer the residence time.

[0041] In the present invention, after the third negative pressure smelting is completed, the gallium and indium volatilized with the flue are still present in the gaseous form with a purity of 6-8 N.

[0042] Subsequently, according to the present invention, gaseous gallium and indium are introduced into a dry low-temperature furnace protected by an inert gas, preferably high-purity argon gas. The pressure in the furnace should be 150-500 Pa higher than the atmospheric pressure, preferably 200-400 Pa. The furnace temperature is controlled at 31-50 o C, preferably 35~45 o C. At this time, after cooling, the gallium and indium elements change from gaseous state to liquid state. It should be noted that the liquid state is not the liquid state of water, but can be understood as having fluidity, specifically a fluid gallium-indium alloy.

[0043] In order to ensure that gallium and indium are mixed evenly, the present invention preferably stirs the high-purity gallium and indium in the low-temperature furnace for 0.5 to 2 h, and a gallium-indium alloy with a purity of 6 to 8 N can be obtained.

[0044] In the present invention, in the final finished gallium-indium alloy, the mass ratio of gallium to indium is (10-60):(40-90), preferably (15-45):(55-85).

[0045] In summary, the preparation method of the gallium-indium alloy provided by the present invention not only has simpler steps, but also unique raw materials. Except for the two wastes, no additional auxiliary materials are needed. The gallium-containing and indium-containing wastes contain trace amounts of gallium and indium. There is no need to obtain intermediate products of crude gallium / indium and high-purity gallium / indium. The gallium-indium alloy is directly produced. The process flow is short and the impurity removal effect is good. A gallium-indium alloy with a purity of 6N~8N can be obtained, which is conducive to large-scale production or industrial production.

[0046] In order to further illustrate the present invention, the following examples are provided for detailed description.

[0047] Example 1

[0048] The raw materials for preparing the gallium-indium alloy in this embodiment are vanadium-extracting converter sludge and blast furnace gas mud, both of which are wastes in the vanadium-titanium magnetite smelting process in the Panxi area. Among them, the composition of vanadium-extracting converter sludge is 95 wt% iron oxide, 4 wt% ZnO, 0.1 wt% Na2O, 0.05 wt% MgO, 0.02 wt% CaCO3, 0.03 wt% Al2O3, 0.1 wt% TiO2, 0.15 wt% V2O5, 0.1 wt% Cr2O3, 0.05 wt% MnO, 0.1 wt% PbO, 0.1 wt% CuO, 0.05 wt% NiO, and the balance is chloride, and the gallium content in the raw material is 500 g / t. The composition of blast furnace gas mud is 60 wt% TFe, 15 wt% Zn, 10 wt% C, 1wt% Ca, 2 wt% Ti, 2 wt% Al, 1 wt% Mg, 1 wt% K, 1 wt% Mn, 1 wt% Na, 2 wt% Cl, 1 wt% Pb, 2 wt% Si, and the balance is S. The indium content in the blast furnace gas mud in this embodiment is 100 g / t, wherein carbon exists in a single substance form, cations mainly exist in the form of oxides, and Na and K exist in the form of chlorides and sulfides.

[0049] The specific preparation method is as follows:

[0050] (1) Mixing vanadium-extracting converter sludge and blast furnace gas mud in a ball mill, wherein the mass ratio of vanadium-extracting converter sludge to blast furnace gas mud is 0.5:1;

[0051] (2) The mixture of vanadium-extracting converter sludge and blast furnace gas mud was roasted at a temperature of 550 o C, calcination time is 0.1 h;

[0052] (3) Using a closed smelting furnace, the material obtained after roasting in step (2) is reduced. The closed furnace needs to maintain a negative pressure, which is controlled at 3000 Pa. This process includes the first stage of negative pressure smelting, the second stage of negative pressure smelting and the third stage of negative pressure smelting:

[0053] 3.1 During the first stage of negative pressure melting, the temperature was controlled at 350 o C, stay for 1 h;

[0054] 3.2 As the temperature continues to rise, in the second stage of negative pressure melting, the temperature is 700 o C, stay 0.1 h;

[0055] 3.3 As the temperature continues to rise, in the third stage of negative pressure melting, the temperature is 1400 oC, and stay for 0.1 h, at which time gallium and indium become steam and evaporate along the flue, existing in gaseous form with a purity of 8 N;

[0056] (4) The gaseous gallium and indium are introduced into a dry low-temperature furnace protected by high-purity argon gas. The pressure in the furnace is 500 Pa higher than the atmospheric pressure and the furnace temperature is controlled at 31 o C. At this time, gallium and indium elements change from gas to liquid;

[0057] (5) The high-purity gallium and indium in the low-temperature furnace are stirred for 0.5 h to obtain a gallium-indium alloy with a purity of 8 N. At this time, the gallium content in the gallium-indium alloy is about 55 wt%, and the indium content is about 45 wt%.

[0058] Example 2

[0059] The raw materials for preparing the gallium-indium alloy involved in this embodiment are vanadium-extracting converter sludge and blast furnace gas mud, both of which are wastes from the vanadium-titanium magnetite smelting process in the Panxi area. Among them, the composition range of the vanadium-extracting converter sludge is 89 wt% iron oxide, 2 wt% SiO2, 1 wt% ZnO, 1 wt% Na2O, 0.3 wt% MgO, 1 wt% CaCO 3， 0.2 wt% Al2O3, 0.3 wt% TiO2, 0.7 wt% V2O5, 0.5 wt% Cr2O3, 1 wt% MnO, 1 wt% PbO, 0.99 wt% CuO, 0.5 wt% NiO, the balance is sulfide, and the gallium content in the raw material is 100 g / t. The composition of blast furnace gas mud ranges from 60 wt% TFe, 5 wt% Zn, 20wt% C, 1 wt% Ca, 2 wt% Ti, 2 wt% Al, 1 wt% Mg, 1 wt% K, 1 wt% Mn, 1 wt% Na, 2 wt% Cl, 1 wt% Pb, 2 wt% Si, and the balance is S. The indium content of blast furnace gas mud in the Panxi vanadium-titanium magnetite smelting process is 80g / t, in which carbon exists in the form of a single substance, cations mainly exist in the form of oxides, and Na and K exist in the form of chlorides and sulfides.

[0060] The specific preparation method is as follows:

[0061] (1) Mixing vanadium-extracting converter sludge and blast furnace gas mud, wherein the mass ratio of vanadium-extracting converter sludge to blast furnace gas mud is 0.1:1;

[0062] (2) The mixture of vanadium-extracting converter sludge and blast furnace gas mud is roasted at a temperature of 400 o C, calcination time is 1 h;

[0063] (3) Using a closed smelting furnace, the material obtained after roasting in step (2) is reduced. The closed furnace needs to maintain a negative pressure, which is controlled at 10,000 Pa. This process includes the first stage of negative pressure smelting, the second stage of negative pressure smelting and the third stage of negative pressure smelting:

[0064] 3.1 During the first stage of negative pressure melting, the temperature was controlled at 450 o C, stay for 1 h;

[0065] 3.2 As the temperature continues to rise, during the second stage of negative pressure melting, the temperature is controlled at 500 o C, stay for 1 h;

[0066] 3.3 As the temperature continues to rise, in the third stage of negative pressure melting, the temperature is 1000 o C, stay for 1 hour, at which time gallium and indium turn into steam and evaporate along the flue, existing in gaseous form with a purity of 6 N;

[0067] (4) The gaseous gallium and indium are introduced into a dry low-temperature furnace protected by high-purity argon. The pressure in the furnace should be 150 Pa higher than the atmospheric pressure, and the furnace temperature should be controlled at 31 o C. At this point, gallium and indium elements have changed from gas to liquid;

[0068] (5) The high-purity gallium and indium in the low-temperature furnace are stirred for 2 h to obtain a gallium-indium alloy with a purity of 6 N. The gallium accounts for 11 wt% and the indium accounts for 89 wt%.

[0069] Comparative Example 1

[0070] The raw materials for preparing the gallium-indium alloy in this comparative example are vanadium-extracting converter sludge and blast furnace gas mud, both of which are wastes from the vanadium-titanium magnetite smelting process in the Panxi area. Among them, the composition of vanadium-extracting converter sludge is 95 wt% iron oxide, 4 wt% ZnO, and the rest is 0.1 wt% Na2O, 0.05 wt% MgO, 0.02 wt% CaCO3, 0.03 wt% Al2O3, 0.1 wt% TiO2, 0.15wt% V2O5, 0.1 wt% Cr2O3, 0.05 wt% MnO, 0.1 wt% PbO, 0.1wt% CuO, 0.05 wt% NiO, and the balance is chloride, and the gallium content in the raw material is 500 g / t. The composition of blast furnace gas mud is 60 wt% TFe, 15wt% Zn, 10 wt% C, 1wt% Ca, 2 wt% Ti, 2 wt% Al, 1 wt% Mg, 1 wt% K, 1 wt% Mn, 1 wt% Na, 2 wt% Cl, 1 wt% Pb, 2 wt% Si, and the balance is S. The indium content in the blast furnace gas mud in this embodiment is 100 g / t, wherein carbon exists in a single substance form, cations mainly exist in the form of oxides, and Na and K exist in the form of chlorides and sulfides.

[0071] The specific preparation method is as follows:

[0072] (1) Mixing vanadium-extracting converter sludge and blast furnace gas mud in a ball mill, wherein the mass ratio of vanadium-extracting converter sludge to blast furnace gas mud is 0.5:1;

[0073] (2) Roasting the mixture of vanadium-extracting converter sludge and blast furnace gas mud at a temperature of 550 o C, calcination time is 0.1 h;

[0074] (3) Using a closed smelting furnace, the material obtained after roasting in step (2) is reduced. The closed furnace needs to maintain a negative pressure, which is controlled at 3000 Pa. This process includes the first stage of negative pressure smelting, the second stage of negative pressure smelting and the third stage of negative pressure smelting:

[0075] 3.1 During the first stage of negative pressure melting, the temperature was controlled at 350 o C, stay for 1 h;

[0076] 3.2 As the temperature continues to rise, in the second stage of negative pressure melting, the temperature is 700 o C, stay for 3 min;

[0077] 3.3 As the temperature continues to rise, in the third stage of negative pressure melting, the temperature is 1400 o C, and stay for 0.1 h.

[0078] At this time, gallium and indium become steam and evaporate with the flue, existing in gaseous form. However, due to the short residence time in 3.2, some impurity elements are mixed in, and the purity of gallium and indium is only 4 N, which does not meet the purity of the gallium-indium alloy raw material and needs to be further purified before the gallium-indium alloy can be prepared.

[0079] Comparative Example 2

[0080] The raw materials for preparing gallium-indium alloy involved in this comparative example are vanadium-extracting converter sludge and blast furnace gas mud, both of which are wastes from the vanadium-titanium magnetite smelting process in the Panxi area. Among them, the composition range of vanadium-extracting converter sludge is 89 wt% iron oxide, 2wt% SiO2, 1 wt% ZnO, 1 wt% Na2O, 0.3 wt% MgO, 1 wt% CaCO3, 0.2 wt% Al2O3, 0.3 wt% TiO2, 0.7 wt% V2O5, 0.5 wt% Cr2O3, 1 wt% MnO, 1 wt% PbO, 0.99 wt% CuO, 0.5 wt% NiO, and the balance is sulfide, and the gallium content in the raw material is 100 g / t. The composition of blast furnace gas mud ranges from 60 wt% TFe, 5 wt% Zn, 20wt% C, and the remaining elements include 1 wt% Ca, 2 wt% Ti, 2 wt% Al, 1 wt% Mg, 1 wt% K, 1 wt% Mn, 1wt% Na, 2 wt% Cl, 1 wt% Pb, 2 wt% Si, and the balance is S. The indium content of blast furnace gas mud in the Panxi vanadium-titanium magnetite smelting process is 80 g / t, in which carbon exists in the form of a single substance, cations mainly exist in the form of oxides, and Na and K exist in the form of chlorides and sulfides.

[0081] The specific preparation method is as follows:

[0082] (1) Mixing vanadium-extracting converter sludge and blast furnace gas mud, wherein the mass ratio of vanadium-extracting converter sludge to blast furnace gas mud is 0.1:1;

[0083] (2) Roasting the mixture of vanadium-extracting converter sludge and blast furnace gas mud at a temperature of 400 o C, calcination time is 1 h;

[0084] (3) Using a closed smelting furnace, reducing the material obtained after roasting in step (2), the closed furnace uses normal pressure; the process includes a first stage of normal pressure smelting, a second stage of normal pressure smelting and a third stage of normal pressure smelting:

[0085] 3.1 During the first stage of normal pressure smelting, the temperature is controlled at 450 o C, stay for 1 h;

[0086] 3.2 As the temperature continues to rise, in the second stage of normal pressure smelting, the temperature is 500 o C, stay for 1 h;

[0087] 3.3 As the temperature continues to rise, in the third stage of normal pressure smelting, the temperature is 1000 o C, and stay for 1 h.

[0088] At this time, the detection of the smoke showed that there was almost no gallium, but other low melting point substances (such as lead, zinc, etc.) and a small amount of indium existed. This showed that in this method, negative pressure smelting conditions were required to volatilize gallium and indium in the raw materials and effectively remove other impurities.

[0089] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a gallium-indium alloy, characterized in that: The following steps are involved: The mixture of gallium-containing waste and indium-containing waste is roasted, smelted under negative pressure, cooled to obtain liquid gallium-indium, and mixed evenly to obtain a gallium-indium alloy; The negative pressure smelting includes: first negative pressure smelting, second negative pressure smelting and third negative pressure smelting; The temperature of the first negative pressure smelting is 350~450 o C, time is 0.1~1 h; The temperature of the second negative pressure smelting is 500~700 o C, time is 0.1~1 h; The temperature of the third negative pressure smelting is 1000~1400 o C, time 0.1~1h.

2. The preparation method according to claim 1, characterized in that: The pressure of the negative pressure smelting is 3000~10000Pa.

3. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of the gallium-containing waste to the indium-containing waste is (0.1~1):

1.

4. The preparation method according to any one of claims 1 to 3, characterized in that The gallium-containing waste comprises: 89-95 wt% of iron oxide, 0-2 wt% of SiO2, 1-5 wt% of ZnO, and a total amount of less than 10 wt% of any one or more of Na2O, MgO, CaCO3, Al2O3, TiO2, V2O5, Cr2O3, MnO, PbO, CuO, NiO, chloride or sulfide; The gallium content in the gallium-containing waste is 100-500 g / t.

5. The preparation method according to any one of claims 1 to 4, characterized in that The components of the indium-containing waste include: 40-62 wt% TFe, 5-15 wt% Zn, 8-20 wt% C, and any one or more combinations of Ca, Ti, Al, Mg, K, Mn, Na, Cl, Pb, Si, and S with a total amount less than 15 wt%; The indium content in the indium-containing waste is 40-100 g / t.

6. The preparation method according to any one of claims 1 to 5, characterized in that The calcination temperature is 400-550 o C, time is 0.1~1 h.

7. The preparation method according to any one of claims 1 to 6, characterized in that After the negative pressure smelting, the purity of the obtained gaseous gallium indium is 6-8 N.

8. The preparation method according to any one of claims 1 to 7, characterized in that The cooling is carried out in an inert atmosphere; The temperature of the cooling is 31~50 o C.

9. The preparation method according to any one of claims 1 to 8, characterized in that The mixing is carried out under stirring conditions; The mixing time is 0.5 to 2 h.

10. The preparation method according to any one of claims 1 to 9, characterized in that The mass ratio of gallium to indium in the gallium-indium alloy is (10-60):(40-90).