A method removes phosphorus from a phosphorus-containing substance. In the method, the phosphorus-containing substance that is used as a raw material for metal smelting or refining is reacted with a nitrogen-containing gas so that phosphorus in the phosphorus-containing substance is removed through nitriding. Prior to a treatment of a nitriding removal of phosphorus from the phosphorus-containing substance, a treatment is performed in which the phosphorus-containing substance is heated to an unmolten state temperature range so as to react with a reducing agent, thereby reducing at least a part of metal oxide in the phosphorus-containing substance.

The invention discloses a phosphorus nitride adsorbent with high-efficiency selectivity, and its application thereof. The phosphorus nitride adsorbent has a mutually cross-linked hollow tubular structure. The adsorbent can have an adsorption capacity of 435.58 mg.Math.g.sup.−1 and 7.01 mg.Math.g.sup.−1 for spiked seawater and natural seawater with a uranium concentration of 350 ppb, and the adsorbent has a long service life, and can still maintain 91.14% of the initial adsorption capacity after 5 cycles of adsorption and desorption. Taking into account the advantages of a short material preparation cycle, a wide range of raw material sources, a low cost, an excellent adsorption performance, and long service life, the adsorbent can be used in technical fields such as uranium-containing wastewater treatment, uranium ore resource recovery, uranium extraction from seawater and the like.

The invention discloses a phosphorus nitride adsorbent with high-efficiency selectivity, and its application thereof. The phosphorus nitride adsorbent has a mutually cross-linked hollow tubular structure. The adsorbent can have an adsorption capacity of 435.58 mg.Math.g.sup.−1 and 7.01 mg.Math.g.sup.−1 for spiked seawater and natural seawater with a uranium concentration of 350 ppb, and the adsorbent has a long service life, and can still maintain 91.14% of the initial adsorption capacity after 5 cycles of adsorption and desorption. Taking into account the advantages of a short material preparation cycle, a wide range of raw material sources, a low cost, an excellent adsorption performance, and long service life, the adsorbent can be used in technical fields such as uranium-containing wastewater treatment, uranium ore resource recovery, uranium extraction from seawater and the like.

The invention discloses a phosphorus nitride adsorbent with high-efficiency selectivity, and its application thereof. The phosphorus nitride adsorbent has a mutually cross-linked hollow tubular structure. The adsorbent can have an adsorption capacity of 435.58 mg.Math.g.sup.−1 and 7.01 mg.Math.g.Math..sup.1 for spiked seawater and natural seawater with a uranium concentration of 350 ppb, and the adsorbent has a long service life, and can still maintain 91.14% of the initial adsorption capacity after 5 cycles of adsorption and desorption. Taking into account the advantages of a short material preparation cycle, a wide range of raw material sources, a low cost, an excellent adsorption performance, and long service life, the adsorbent can be used in technical fields such as uranium-containing wastewater treatment, uranium ore resource recovery, uranium extraction from seawater and the like.

The invention discloses a phosphorus nitride adsorbent with high-efficiency selectivity, and its application thereof. The phosphorus nitride adsorbent has a mutually cross-linked hollow tubular structure. The adsorbent can have an adsorption capacity of 435.58 mg.Math.g.sup.−1 and 7.01 mg.Math.g.Math..sup.1 for spiked seawater and natural seawater with a uranium concentration of 350 ppb, and the adsorbent has a long service life, and can still maintain 91.14% of the initial adsorption capacity after 5 cycles of adsorption and desorption. Taking into account the advantages of a short material preparation cycle, a wide range of raw material sources, a low cost, an excellent adsorption performance, and long service life, the adsorbent can be used in technical fields such as uranium-containing wastewater treatment, uranium ore resource recovery, uranium extraction from seawater and the like.

A lithiated carbon phosphonitride material is made by, for example, reacting P(CN).sub.3 with LiN(CN).sub.2 in solution (for example, dimethoxyethane or pyridine), then drying the solution to obtain the product. The material is a thermoset that is stable to over 400° C. and exhibits up to 10.sup.−3 S.Math.cm2 of Li.sup.+ conductivity.

A lithiated carbon phosphonitride material is made by, for example, reacting P(CN).sub.3 with LiN(CN).sub.2 in solution (for example, dimethoxyethane or pyridine), then drying the solution to obtain the product. The material is a thermoset that is stable to over 400° C. and exhibits up to 10.sup.−3 S.Math.cm2 of Li.sup.+ conductivity.

Provided is a novel imidic acid compound having a divalent anion useful as a pharmaceutical intermediate, an agrochemical intermediate, an acid catalyst, a battery electrolyte or an antistatic agent. The imidic acid compound is a divalent imidic acid compound represented by the following general formula (1) or (2).

##STR00001##

[In formulae (1) and (2), R.sup.1 to R.sup.3 represent a fluorine atom or an organic groups selected from a linear or branched C1-10 alkoxy group, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group, a C3-10 cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10 aryloxy group, and wherein a fluorine atom, an oxygen atom or an unsaturated bond may also be present in the organic group. M.sup.1 and M.sup.2 represent protons, metal cations or onium cations.]

Provided is a novel imidic acid compound having a divalent anion useful as a pharmaceutical intermediate, an agrochemical intermediate, an acid catalyst, a battery electrolyte or an antistatic agent. The imidic acid compound is a divalent imidic acid compound represented by the following general formula (1) or (2).

##STR00001##

[In formulae (1) and (2), R.sup.1 to R.sup.3 represent a fluorine atom or an organic groups selected from a linear or branched C1-10 alkoxy group, a C2-10 alkenyloxy group, a C2-10 alkynyloxy group, a C3-10 cycloalkoxy group, a C3-10 cycloalkenyloxy group and a C6-10 aryloxy group, and wherein a fluorine atom, an oxygen atom or an unsaturated bond may also be present in the organic group. M.sup.1 and M.sup.2 represent protons, metal cations or onium cations.]

To provide a method for producing a phosphoryl imide salt represented by the following general formula (1) at a satisfactory yield by cation exchange. The method comprises the step of performing cation exchange by bringing a phosphoryl imide salt represented by the following general formula (2) into contact with a cation exchange resin having M.sup.1 n+ or a metal salt represented by the general formula (4) in an organic solvent having a water content of 0.3% by mass or less. ##STR00001##