JPS6364903A - High-purity metal phosphide and production thereof - Google Patents

Abstract

PURPOSE:To make it possible to industrially produce a high-purity metal phosphide usable as a raw material for amophous alloys, by heating and melting a blended raw material consisting of calcium phosphate, silica-containing substance, two or more kinds of metal raw materials and carbon in a reducing atmosphere and reducing the melt. CONSTITUTION:Mn, Cr, Cu, Co, Ni containing <=1ppm As, Sb, etc., which are impurities or two or more kinds of hydroxides and oxides as a precursor thereof are blended with calcium phosphate and silica-containing raw material, e.g. natural quartz, etc., and carbonaceous material, e.g. graphite, carbon black, etc., at <=1.2 Ca/Si molar ratio and the resultant blend is melted and reduced in a reducing atmosphere. The amount of C is 1.5 times based on the theoretical amount required fro reducing calcium phosphate and metal precursor and the amount of the metal raw material is 0.5-1.0 based on formed equivalents of the metal phosphide of the formula MenP (Mn is the above-mentioned metal; n is 1-3) expressed in terms of the metal. Thereby the aimed high-purity metal phosphide with >=99% total content of the two or more kinds of the above- mentioned metal and P, 10-30% P thereof, <0.5% amount of metal impurities contained and <1.0% C is obtained.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a high-purity metal phosphide and a method for producing the same, and particularly to industrially provide a high-purity metal phosphide that can be used as a raw material for an amorphous alloy. Regarding.

<Conventional technology> Iron phosphide, chromium phosphide, manganese phosphide, copper phosphide,
Cobalt phosphide and the like are used as constituent raw materials for amorphous metals, but the high vapor pressure of phosphorus makes these phosphides unsuitable for common alloying methods such as mixing, heating, and melting, and conventional methods are usually not used. Either the reaction is carried out in a high-pressure sealed container, or the reaction is carried out for a long time at a temperature that maintains the vapor pressure of phosphorus at about 1 atm.

In the former case, a container that can withstand high temperatures and pressures is required, and the unavoidable drawbacks are a decrease in productivity due to its structural limitations and contamination from the material of the container. In the latter case, material contamination can be avoided in many cases by using a container made of quartz or the like, but the reaction time becomes very long, so this is not industrially practical.

Additionally, a method is known in which phosphates such as iron phosphate are reduced with hydrogen or carbon monoxide, but since it requires the production of phosphates, it cannot be applied to all metal phosphides, and the production process Product contamination and increased costs associated with increased complexity are often unavoidable. Furthermore, complete reduction is difficult and oxides remain, which poses problems as a raw material for amorphous alloys.

<Problems to be Solved by the Invention> Since there is a limit to achieving high purity using any of the conventional methods, the present invention is directed to the production of high-purity metal phosphides directly from high-purity raw materials. It is in.

That is, high-purity metal phosphides are produced by reducing and melting raw materials such as calcium phosphate salts, silicic acid, metal powders, or their precursors, and carbon, which do not substantially contain impurity elements that are difficult to produce. The present invention was completed based on this knowledge.

Means for Solving the Problems and Effects The gist of the present invention is that the total amount of two or more metals and P is 99% by weight or more, and P is 10 to 30% by weight. %,
The total amount of impurity metals is 0.5% or less and C is 1.
A high-purity metal phosphide (hereinafter referred to as the "first invention") characterized by a content of 0% by weight or less, calcium phosphate, a silica-containing material, and two or more types of gold! ! A
This is a method for producing a high-purity metal phosphide (hereinafter referred to as the "second invention"), which is characterized by heating and melting a mixture consisting of a raw material and carbon in a reducing atmosphere.

The high-purity metal phosphide of the first invention is composed of P and two or more metals, but the metal component may be anything that forms an alloy with P, such as Fe s Cr.
-N i Two or more types selected from 1Co, Cu, etc. are mentioned.

Further, the metal phosphide of the first invention has a P content of 10 to
30% by weight, the rest being other metal components.

In order to obtain the high-purity metal phosphide of the first invention, it is preferable that the raw materials contain as few impurities as possible, and in particular, raw materials with few impurities such as arsenic, antimony, magnesium, aluminum, titanium, zirconium, etc., which are difficult to purify, are used. It is desirable to use such a material, and in particular, it is preferable to use as little amount of arsenic and antimony as possible, which are elements in the same group as phosphorus.

Examples of calcium phosphate salts that are raw materials for phosphorus include calcium phosphate, dicalcium phosphate, tricalcium phosphate, basic calcium phosphate, and calcium pyrophosphate.
It is better to select one below 1111) II.

Examples of the silica-containing material include high-purity natural quartz, silica sand, and synthetic silica.

Examples of carbon include graphite, carbon black, and activated carbon.

Fe, Mn, Cr, Ni as metal raw materials.

Metal powders of CQ or Cu or metal compounds that become these metals when reduced are preferable.Moreover, since high purity is required, metals produced by electrolytic methods, metal hydroxides obtained by chemical methods, or Preferred examples include metal hydroxides obtained by firing the metal hydroxides, and they are
It may be one species or two or more species.

The mixing ratio of raw materials is Ca/Si (molar ratio) of 1゜2J:X
The amount of carbon is preferably from 0.8 to 1.1, and the amount of carbon is preferably in the range of from the theoretical amount to 1.5 times the amount sufficient to reduce the calcium phosphate salt and the precursor to the metal.

The amount of the metal powder or metal compound used in the present invention varies depending on the composition of the calcium phosphate used;

P (Me is FelMn, Cr, Ni, Co, or C
u, and n is preferably 1 to 3) 0.5 to 1.0 times the production equivalent.

If the equivalent is less than 0.5, the amount of elemental phosphorus produced increases and the yield of metal phosphide decreases, making it difficult to separate it from the slag components and making it impossible to obtain a product with a high degree of MA. Even if it is obtained, its purification operation will be extremely difficult. On the other hand, when the equivalent weight exceeds 1, metal components other than phosphides increase, the usefulness as a phosphide decreases, and there is a tendency for unreacted raw materials to be mixed in more.

In the present invention, a metal phosphide is produced by preparing each raw material in the above proportions and heating and melting the mixture in a reducing atmosphere. The heating temperature varies depending on the composition of the metal phosphide produced, but
The temperature must be at least higher than the melting point of the metal phosphide.

In addition, in order to ensure specific gravity separation between the metal phosphide and the melt of unreacted raw materials and slag components such as calcium silicate, it is necessary to at least exceed the melting point of the metal phosphide, although it depends on the composition of the metal phosphide. Although the holding time of the melt varies depending on the temperature, it is necessary to hold the melt for at least 10 minutes.

Generally, one of the causes of strength reduction in amorphous alloys is crystallization during rapid cooling and solidification.
gO1ZrO2, A1゜03, TiO2, Si3N4,
The presence of these factors is considered to be a factor other than the amorphous alloy composition.

Therefore, it is desired that the metal phosphide contains very few of these impurities as a raw material for an amorphous alloy. However, in the present invention, in order to avoid the incorporation of CaO and SiO2 components as much as possible, the Ca/Si molar ratio is set in the range of 0.8 to 1. So 5i0
When the excess degree of 2 is increased and the reduction temperature is increased to 1500°C or higher, which is higher than the melting temperature in normal yellow phosphorus production, SiO2 is also reduced and becomes 3i, which no longer induces crystallization of the amorphous alloy, and the effect is This can be substantially avoided, and contamination of CaO components can be avoided as well.

Furthermore, since the metal phosphide and the slag component are easily separated, extremely high purity metal phosphide can be produced.

The heating method is not particularly limited as long as it is sealed and maintains a reducing atmosphere, but preferably an arc furnace, a resistance furnace, a high frequency induction furnace, etc. are commonly used.

Elemental phosphorus, which is produced as a by-product as vapor by heating and melting, is condensed by cooling with a hot water shower (40 to 60° C.) and collected as liquid yellow phosphorus.

On the other hand, silica M salts such as metal phosphides and calcium silicate accumulate at the bottom of the furnace as molten metal, and are allowed to flow out through tap holes.

The separation of the two is done by the difference in specific gravity of the liquid, but there are two methods: either the liquid is separated in the furnace and each is taken out from two tap holes on the top and bottom, or the liquid is flowed out from one tap hole and left to separate outside the furnace. It may be either.

The success or failure of this step greatly affects the purity of the metal phosphide, so sufficient temperature and time must be used for separation.

The molten metal after separation is recovered by being solidified by rapid cooling or slow cooling to room temperature, respectively.

The metal phosphide produced by the method of the present invention is a high-purity product with an amount of impurities not found in conventional products, and in many cases, the purity (Me + p) on a weight basis is 99% or more, and it does not induce crystallization. The total impurity metal ffi (Ca
+Mg+A1+zr+V) is 0.5% by weight or less, and C is 1.0% by weight or less.

Furthermore, if the metal phosphide according to the present invention is rapidly cooled, it becomes amorphous, but if it is slowly cooled, it becomes MelMeP due to its composition.
It can be confirmed by X-ray diffraction that there are crystal layers mainly composed of lMe P, Me3P, or a mixture thereof.

<Example> Examples 1 to 7 The raw materials shown in Table 1 were mixed in the proportions shown in Table 2,
A raw material mixture was prepared.

Then add 500! of each mixture! J was sampled and charged into an electric furnace maintaining an Ar gas flow atmosphere, and heated at 10°C/10°C until 500°C.
lin, heated at a temperature increase rate of 30°C/11 in up to 1550°C, and when the temperature was returned to 1550°C, it was held for 30 minutes and then slowly cooled.

During the temperature raising process, phosphorus and Co gases began to be generated in the range of 1100°C to 1350'C, and extremely active reduction and volatilization of phosphorus and Co gas was observed as the temperature progressed.
Reduction and volatilization stopped when the temperature was maintained at 1550°C for about 10 minutes.

In this way, the slag was gradually cooled and separated into the upper layer of the slag and the lower metal layer from the reaction vessel in the electric furnace, and the lower metal layer was recovered. The analysis results for each component of the neglected metal phosphide are shown in Table 3.

<Effects of the Invention> According to the method of the present invention, a highly pure metal phosphide can be industrially advantageously produced, and this high-purity product can be used as it is or further purified to achieve even higher purity. By doing so, it can be used as a raw material for new materials in recent years.

Claims (5)

[Claims] (1) The total amount of two or more metals and P is 99% by weight or more, and P is 10 to 30% by weight, the total amount of impurity metals is 0.5% by weight or less, and C is 1.0% by weight. A high-purity metal phosphide characterized by a content of % by weight or less. (2) Two or more metals are Fe, Mn, Cr, Ni, Co
The high-purity metal phosphide according to claim 1, which is two or more metals selected from Cu and Cu. (3) A method for producing a high-purity metal phosphide, which comprises heating and melting a mixture consisting of calcium phosphate, a silica-containing material, two or more metal raw materials, and carbon in a reducing atmosphere. (4) Metal raw material is Fe, Mn, Cr, Ni, Co or C
The method for producing a high purity phosphide according to claim 3, which is a metal powder of u or a metal compound that becomes these metals when reduced. (5) The method for producing a high-purity phosphide according to claim 4, wherein the metal compound is an oxide or a hydroxide.