175 results about "Magnesium silicide" patented technology

A thermoelectric conversion material is provided which stably exhibits high thermoelectric conversion performance at about 300 to 600° C. and has high physical strength, resistance to weathering, durability, stability, and reliability. A method for manufacturing the same, and a thermoelectric conversion element are also provided. Also provided is a thermoelectric conversion material produced using, as a raw material, silicon sludge which has had to be disposed of in landfill. The thermoelectric conversion material of the invention is characterized by containing, as a main component, a sintered body composed of polycrystalline magnesium silicide containing at least one element selected from As, Sb, P, Al, and B. The manufacturing method uses purified and refined silicon sludge.

The invention discloses a preparation method of a porous silicon-carbon composite material.The preparation method specifically comprises the steps that magnesium silicide powder is placed in a CO2-Ar mixed atmosphere to be subjected to heat treatment at the temperature of 700 DEG C-900 DEG C and then subjected to acid pickling and aftertreatment to obtain the porous silicon-carbon composite material, wherein the volume fraction of CO2 in the CO2-Ar mixed atmosphere is 10%-90%.According to the preparation method, the technology is simple, repetition is easy to achieve, and large-scale industrialized production can be achieved.When the porous silicon-carbon composite material prepared through the method is applied to a lithium ion battery by serving as a negative electrode material, the circulating stability of the lithium ion battery can be significantly improved.

The invention relates to the field of lithium battery materials, and specifically relates to a magnesium-containing silicon oxide negative electrode material for lithium ion batteries and a preparation method thereof. The preparation method mainly comprises the steps of raw material preparation, magnesium silicide preparation and magnesium-containing silicon oxide negative electrode material preparation. The preparation method in the invention can realize batch production and is easy for industrial application. The lithium ion battery prepared by adopting the negative electrode material obtained according to the preparation method provided by the invention has excellent electrochemical properties such as high specific capacity and good cycle performance.

The invention discloses a preparation method of a high capacity porous silicon material. The method is characterized by specifically including: placing magnesium silicide powder in nitrogen atmosphere, conducting 600-800DEG C heat treatment, then performing pickling and aftertreatment to obtain the porous silicon material with high capacity. The preparation method of the high capacity porous silicon material provided by the invention uses nitrogen atmosphere to replace air atmosphere, avoids oxidation of silicon at the same time of porous silicon preparation, and has no need of high volatility hydrofluoric acid to conduct treatment, and the process is simple, efficient and environment-friendly. The prepared porous silicon has very low oxygen content, can be applied as a negative electrode material in a lithium ion battery to remarkably improve the specific capacity and cycle stability of the lithium ion battery.

Belonging to the technical field of inorganic material preparation, the invention more specifically discloses a carbon coated micron silicon, a preparation method and application thereof. The method includes: reacting magnesium silicide with carbon dioxide in an atmosphere containing carbon dioxide, or decomposing magnesium silicide, then reacting the decomposed product with carbon dioxide, and conducting pickling to obtain the carbon coated micron silicon material. The preparation method is simple and practicable, can be used for large-scale production of carbon coated micron silicon, and cansolve the technical problems of complex technology, poor security, and no good for mass production application of carbon coated micron silicon materials in the prior art.

The invention provides a method for preparing porous nanometer silicon through air auxiliary. The method comprises the following steps that silicon dioxide and an appropriate amount of magnesium powder which are obtained from different sources are evenly mixed and then put into a tube furnace to fully react in an inert atmosphere to obtain magnesium silicide (4Mg+SiO2=Mg2Si+2MgO); the reaction product is put in air or other mixed gas containing oxygen to react (Mg2Si+O2=Si+2MgO) under the appropriate temperature condition to obtain a product, and the product is processed through acid pickling to obtain the high-yield superfine porous nanometer silicon. According to the method, the steps are simple and easy to operate, and a large amount of the porous nanometer silicon can be obtained only by directly heating the obtained magnesium silicide in the air or the gas containing the oxygen; in addition, the source of the raw material silicon dioxide is wide, pollution is little, the yield is high, the obtained nanometer silicon has the advantages that particles are uniform and mesoporous exists, and the method can be widely applied to the field of lithium ion battery anode materials.

The invention provides a method for preparing three-dimensional porous nanometer silicon at low temperature through a molten-salt growth method. The method includes the following steps that silica particles obtained from different sources and magnesium powder are uniformly mixed and then are placed in a tube furnace to be fully reacted under an inert atmosphere, magnesium silicide is obtained, then the reaction product and anhydrous chloride metal salt are uniformly mixed and then are placed in a tube furnace filled with inert atmosphere to be fully reacted, reaction products are subjected to acid pickling, and the high-yield super-fine three-dimensional porous nanometer silicon is obtained. The method is simple and easy to implement, the raw materials are wide in source, most importantly, by adding the anhydrous chloride (MxCly), the nanometer silicon has the advantages of being small in pollution, high in yield and purity, large in specific area and uniform in particle and having mesopores, and the nanometer silicon can be applied to the fields of lithium ion battery cathode materials, semiconductor materials, medicine, high-quality alloy and the like.

The invention discloses a method for producing disilane by the chemical reaction of magnesium silicide and ammonium chloride in a liquid ammonia medium. A silicide is synthesised at 600-900 DEG C and may be high-order magnesium chloride, i.e., Mg2Si2. The silicide is good for forming disilane. Once the mixed airflow of a crude silane purification device flows through a cold trap at minus 110 DEG C, the disilane is changed into liquid and condensed in a liquefaction bottle for disilane, and then the silane and hydrogen continue to enter in a working procedure of purification along a pipeline.

The high-strength non-combustible magnesium alloy is obtained by adding at least one supplementary additive selected from among carbon (C), molybdenum (Mo), niobium (Nb), silicon (Si), tungsten (W), alumina (Al₂O₃), magnesium silicide (Mg₂Si) and silicon carbide (SiC) to small chip-like blocks of a non-combustible magnesium alloy resulting from adding 0.5 to 5.0% by mass of calcium to a magnesium alloy to produce a crushed product, and subjecting the same to forming, sintering and plastic working. The high-strength non-combustible magnesium alloy exhibits excellent joining ability, and can therefore enhance weldability when used in a filler metal.

The present invention provides a method of making a substantially phase pure compound including a cation and an anion. The compound is made by mixing in a ball-milling device a first amount of the anion with a first amount of the cation that is less than the stoichiometric amount of the cation, so that substantially all of the first amount of the cation is consumed. The compound is further made by mixing in a ball-milling device a second amount of the cation that is less than the stoichiometric amount of the cation with the mixture remaining in the device. The mixing is continued until substantially all of the second amount of the cation and any unreacted portion of anion X are consumed to afford the substantially phase pure compound.

The invention discloses a method for separating and recycling magnesium chloride hexammoniate and liquid ammonia during silane production by a magnesium silicide method, which comprises the following process steps of: inputting the magnesium chloride hexammoniate and liquid ammonia salt slurry produced during silane production by the magnesium silicide method into a filter; inputting the liquid ammonia coming out of the top of the filter into a liquid ammonia storage tank for recycle; conveying the salt slurry coming out of the lower part of the filter into a dryer through a salt slurry feeder; conveying the ammonia gas coming out of the upper part of the dryer into a condenser to liquefy the ammonia gas in the condenser in which the temperature is lower than 33.5 DEG C below zero; and inputting the ammonia gas into the liquid ammonia storage tank for recycle. The invention further discloses a device implementing the method. With the device and method, the invention realizes large-scale industrial production, and magnesium chloride hexammoniate and liquid ammonia are separated and recycled through a continuous liquid-solid filter with fast separation, high efficiency and little liquid in solid. In addition, the filtered wet magnesium chloride hexammoniate is continuously dried at high temperature with high drying efficiency, and the complex ammonia is effectively recycled.

The invention discloses a production method for silane gas, relating to a production method for gas. The invention solves the problems that the existing method for producing silane gas has low product purity and low yield, and the method can not meet the need of commercial process. The method comprises the following steps: 1. silica fume, magnesium powder and ammonium chloride are weighed and taken out; 2. magnesium silicide is obtained after the silica fume is mixed and reacted with the magnesium powder; and 3. the weighed and taken out ammonium chloride and the magnesium silicide are mixed and reacted in a reactor which takes liquid ammonia as the media, and then silane gas is obtained after the obtained reactant undertakes molecular sieve adsorption and deep cooling purification. The obtained silane gas has the purity of 99.99 percent and the yield of over 95 percent, and the method also meets the need of commercial process.