DE394370C - Process for the production of substances containing nitrogen - Google Patents

Description

Process for the production of substances containing nitrogen. the Eyfindung aims to break down alumina-containing substances in conjunction with the Binding of nitrogen with the achievement of products which are easily based on pure clay and ammonia can be further processed. This aim is achieved according to the invention achieved in a simple manner and with little energy expenditure by using bauxite, Clay, alunite or the like with considerable amounts of oxides of the alkaline earth metals (e.g. B. to i mol. Alumina i to 3 mol. Or more of darium oxide or calcium oxide) and with carbonaceous substances, possibly with the addition of further additives (e.g. from iron or fluxes or oils), melts together and then the obtained, advantageously finely comminuted .Schmelzprodukte by in a known manner Treatment with nitrogen azotized. This requires the required alkaline earth not to be used in the form of expensive oxides; one can rather use alkaline earth compounds, which oxides to deliver - are able to, z. B. alkaline earth hydroxide, alkaline earth carbonates or sulphates, especially in the form of raw materials, since the alumina due to the formation of aluminate, the decomposition of the carbonates or sulfates is greatly promoted.

It is already known to produce aluminum-nitrogen compounds by mixing mixtures of alumina-containing substances and coal, optionally with the addition of oxides or Oxvdverbindungen, which, such. B. silica or the oxides of titanium, zirconium, molybdenum, etc., are able to form nitrides, with nitrogen for a long time, z. B. 15 to 20 hours, to high temperatures, e.g. B. those of about 1500 ' and more heated.

This well-known process, which requires constant mixing of the material has the disadvantage that the endothermic process is the supply of a Requires a great deal of heat and because of its long duration and high temperatures the furnace material is very heavily used.

The difficulties of this known method become more apparent Invention overcome by working in two, possibly also in three stages will. In the first stage z. B. of bauxite, barium oxide and coal, if necessary with the addition of iron and flux, a liquid melt product is shown, which is then azoated after cooling and crushing in the second stage.

Since stirring is not necessary, the melting process can e.g. B. in ordinary Carbide furnaces are carried out. The formation of the melt under the supply of heat goes on so quickly that the melting process is only a fraction of the duration of the known azotation process and therefore requires the furnace material much less claimed. On the other hand, in the present process, it is the azotization of the melt product If the process is exothermic, the material to be azotized is only needed at one point at reaction temperature to bring what the reaction to automatically through the whole Mass propagates through. Even with the Azotiei uilg, there is no stirring of the food necessary.

In exercising the invention you can, for. B. proceed in such a way that one the alumina-containing material, e.g. B. 66 parts of bauxite (equivalent to .40 parts of alumina), with appropriate amounts of one or more alkaline earth compounds, e.g. B. 265 parts Barium carbonate (equivalent to 2o6 parts of barium oxide), and the required amount of carbon z_. B. 5o parts of coke, anthracite, charcoal, or the like, optionally with the addition of surcharges, e.g. B. iron or iron ores or fluxes, e.g. B. alkaline earth chloride, -fluoride, -carbide, -oxvd, common salt etc., possibly several of these substances in one electrical Furnace, e.g. B. a carbide furnace melts together. This creates a mixture of Alkaline earth aluminum oxide (barium aluminum oxide), alkaline earth metal carbide (barium carbide) and further (depending on the working conditions, such as temperature, etc.), both amounts of Aluminum as carbide or metal or alloy with iron or alkaline earth metals.

After cooling, the melted product is finely comminuted and then in the glowing state with or without pressure in closed Azotierungsöfen or z. B. also in sewer stoves, such as those used in calcium cyanamide production, treated with nitrogen. Your finely chopped up Schiiielz product can do this before the azotization still unreactive; B. alkaline earth chloride, Alkaline earth fluoride. Alkaline earth oxide can be added. Since 'the azotization process is exothermic it is sufficient to (read Gut to bring it to the reaction temperature. Once this has been reached, this means that there is no need for additional heat.

By heating the azotized product, Jas essentially alkaline earth metal, Aluminum, iron, silicon, carbon, nitrogen, oxygen and optionally Titanium contains, with water, alkali sulphate and carbonate. -hydroxide, etc. at usual or increased pressure, the nitrogen obtained can be driven out in the form of ammonia and win the aluminum in the form of pure aluminum oxide.

It has proven to be very beneficial to start with the alumina Material or the alkaline earth compound, each for itself or both together, is advantageous in finely crushed form, for the purpose of removing all volatile components, such as Water, carbon dioxide, sulfur dioxide, alkalis or the like. To glow. Here can add coke, anthracite, charcoal or the like to the substances or mixtures to be glowed. or iron, e.g. B. Add scrap or flux or several of the substances mentioned.

The annealing products obtained in this way are called finite coal, if necessary with the addition of further surcharges, e.g. B. iron, in an electric furnace, z. B. a carbide furnace, melted together, whereupon the melt, as previously described, is azotized.

For the annealing process you can, for. B. to 1 mole of aluminum oxide 3 MO]. Alkaline earth oxide and for the melting process to 3: 1i01. Alkaline earth oxide of the glow product Use 6 to i3.5 atony carbon, plus that to reduce the amount in the glow product contained oxides of iron, silicon and possibly titanium Amount of coal comes.

A suitable way of working is e.g. B. in the fact that it is expedient Annealed Tonj Erdeinmaterial with the for the reduction of the oxides contained in it of Iron, silicon and possibly titanium required amount of carbon for a first mixture mixes the suitably annealed alkaline earth compound with the alkaline earth metal carbide and that required to reduce the oxides of iron and silicon contained therein Mix the amount of coal to a second mixture and then alternate these two mixtures enters the furnace or the first mixture by melting the second generated liquid alkaline earth carbide or the second mixture by melting add liquid alumina produced to the first mixture. Another embodiment of the melting process consists in the fact that either the alumina material or mixing the alkaline earth compound with an excess of coal, the mixture melts and the third component enters the melt for itself.

According to a well-known method specified by S e r p e k, alumina is made (e.g. 40 parts) with coal (e.g. 12 parts) and small amounts of in this case Alkaline earth metal acting as a flux (e.g. 1 part of barite) melted together. During the azotization of the melt product obtained in this way, the nitrogen practically goes out only on aluminum with the formation of aluminum nitride.

This procedure is fundamentally different from the present one in that that it aims to solve the double problem with as little energy as possible to bind a lot of nitrogen and at the same time minerals containing alumina for the purpose of extraction to open up pure clay. Accordingly, the present method does not work Alumina, but from raw materials containing alumina, and furthermore it requires the Use of alkaline earth oxide levels, which are a multiple of those used by S e r p e k Amounts, e.g. B. to i mol. Tonerle i to 311i01. and more alkaline earth oxide.

In the present invention, the alkaline oxide has a To fulfill a threefold purpose, namely firstly after conversion into carbide as a means for the formation of nitrogen, and secondly for the decomposition of the clay material Conversion of the alumina into alkaline earth aluminate, thirdly for the formation of an easily separable one and thereby a melt product that enables continuous operation.

While in Serpek's method only r mol per molecule of Alp O3. n ', are bound, are in the present method with a relatively lower Energy expenditure per molecule ale 0s of the clay material 2 to d. Mol. KZ bound.

The known processes for the extraction of alumina are known to work only economical if the silica content of the raw materials is no longer than 5 percent, since the silica loses expensive disintegrating agents (alkalis) caused. In addition, silica and iron oxide form an annoying waste product today's alumina production, the so-called red mud. The cheapest clay material, the clay, which usually contains more than 50 percent silica, comes afterwards for the toners: production up to now practically out of the question. In contrast, permitted The present invention also covers the processing of clay and other high silica Raw materials; because in the present process all of the iron oxide is used as well most of the silica from all raw materials used (also coal, etc.), and these impurities are separated in the melting process as ferrous, calcium, and especially in considerable quantities when sufficient amounts of iron are added Care is taken. It is therefore still a valuable one in the form of ferrosilicon By-product obtained.

Claims (3)

PATENT CLAIMS: i. Process for the production of nitrogen-containing products from substances such as bauxite, clay or the like, characterized in that these substances are mixed with considerable amounts of oxides of the alkaline earth metals (e.g. 1 mol. Alumina 1 to 3 mol. And more of alkaline earth oxide) or with corresponding amounts of alkaline earth oxide-containing substances and with carbon-containing substances, optionally with the addition of further additives, e.g. B. iron or fluxes or both together, melts and then the resulting melt products, advantageously in a finely comminuted state, optionally in a mixture with reaction-promoting additives, in a known manner. 2. The method according to claim i, characterized characterized in that in place of or in addition to oxides of the alkaline earth metals, alkaline earth compounds, which pass over into the oxide form, z. B. Bariumca, carbonate or substances, which contain them. 3. The method according to claims i and 2, characterized characterized in that the alumina-containing material or the alkaline earth compound or both together or individually, optionally with the addition of coal, or of Iron or both in the presence or absence of other supplements, e.g. B. of fluxes, Glows and the glow product or the glow products for the production of melts Claim i used. q. Process according to claims i to 3, characterized in that that the alumina-containing material or the alkaline earth compound or both substances, after they have been suitably annealed beforehand - with coal, if necessary under Addition of further aggregates, mixes and these mixes for the production of melts used according to claims i to 3, for. B. such that a mixture is melted and the second is entered in this melt or vice versa, or in such a way that the Mixtures are fed alternately into the melting furnace.