A method of producing nickel oxide

 

(57) Abstract:

The invention relates to chemical production of oxides of Nickel, used in various industries to obtain ferrites, catalysts, pigments in paints for glass, etc., the Method involves the preparation of a solution of Ni(NO3)2evaporation it to the mass concentration of not less than 1.1 kg/l, thermal processing in the fluidized bed of particles of Nickel oxide. Formed after condensation of the gases nitric acid returns to the operation of the initial preparation of a solution of Nickel nitrate. Water vapor at the stage of heat treatment is used as a fluidizing agent in Apparate fluidized bed at a ratio where Cpthe concentration of the solution after evaporation , kg/kg; Gpthe solution flow rate, kg/h; GRR- the flow of water vapor, kg/H. the Method allows to obtain the oxide of certain chemical and granulometric composition and to prevent the emission of nitrogen oxides. 1 Il., table 2.

The invention relates to chemical production oxides, and in particular to methods of production of reactive oxide of Nickel, which is used in various industries to obtain ferrite is camping the task of obtaining the Nickel oxide has a specific chemical and granulometric composition.

Closest to the proposed technical essence is a way to obtain Nickel oxide by heat treatment of Nickel nitrate in the presence of water vapor [1] a Method of producing oxides of Nickel is in the preparation of Nickel nitrate, its heat treatment in an environment of water vapor, where the reaction occurs according to the mechanism of hydrolysis, condensation of the resulting reaction gases to obtain a solution of nitric acid and nitrogen oxides in the tail gas in an amount up to 5-7% of theoretical balance of nitric acid.

The original Nickel nitrate loads in progulochnuju oven to a certain extent, therefore, when thermal decomposition in the presence of water vapor will be observed irregularity of the interaction of the total volume of the loaded product with water vapor, which will result in a nonuniform chemical and fractional composition of the final product. The obtained Nickel oxide is a spec that is not conforming product. This spec is necessary to grind and sift to obtain a product of a certain fractional part.

Obtained in the reaction 6-10% nitric acid cannot be neposredstvena this acid must be subjected to additional processing to improve concentration. To solve environmental problems, elimination of emissions requires additional processing of tail gases.

The aim of the invention is the prevention of emissions of nitrogen oxides into the atmosphere, increasing productivity, efficiency of the production of oxides of Nickel and quality of the finished product waste by obtaining particles of oxides, homogeneous chemical and granulometric composition.

The aim is achieved in that in the known method of producing oxides of Nickel, comprising preparing a solution of Nickel nitrate, its heat treatment in the presence of water vapor, condensation of gases with the formation of nitric acid and return it to the stage of preparation of the solution, what's new is that before heat treatment, the original solution is evaporated to a concentration of not less than 1.1 kg/l, and water vapor at the stage of heat treatment is used as a fluidizing agent in the fluidized bed apparatus (COP) with a ratio of

1,68 where Cpthe concentration of the original solution, kg/kg;

Gpthe flow of the original solution, kg/h;

GRRthe flow of water vapor, kg/h

Thus, the proposed method of producing oxides hegemon method shows a new property with the exception of emissions of nitrogen oxides into the atmosphere.

Usually factories for the production of oxides of Nickel (and as an intermediate stage of obtaining of Nickel nitrate) for dissolution of metallic Nickel is used nitric acid with a concentration of not less than 25% (for example, at the Ural plant of chemical reagents).

Thus, when the mass concentration of the original solution of Nickel nitrate less than 1.1 kg/l after condensation of the resulting gases were obtained nitric acid, the concentration was low (15-20%) for direct use at the stage of preparation of the initial solution, which is uneconomical, so as to prepare a solution of Nickel nitrate requires additional operations to increase its concentration to 25%

It is significant that in the process of evaporation of aqueous solutions of nitric acid is the saturation vapor phase pairs of nitric acid and more than a concentrated solution, i.e. the concentration of an aqueous solution of nitric acid by the method of parki impossible without it losing steam phase. Moreover, losses are increased with increasing concentration of the acid in solution [2]

At the same evaporation of aqueous solutions of nitrates loss of nitric acid does not occur until thermal setting solution of Nickel nitrate corresponds to the composition of dehydrate its Ni(NO3)2.2H2O [3]

The concentration to which pariveda original solution required to improve the performance of the installed product (getting NiO) and due to the requirements concentration requirements regenerated nitric acid.

The drawing shows the installation for implementing the method of producing Nickel oxide. It works as follows:

nitrate of Nickel in the form of an initial solution of Nickel nitrate comes from the office of the solution 1 in the supply mongus 2, equipped with a steam jacket for doparse solution to the required concentration. One stripped off the solution from manjusa 2 under pressure is supplied to the fluidized-bed reactor 3, equipped with a heater, through a pneumatic nozzle 4. Here fluidized bed of granules prepared Nickel oxide at 400aboutSince there is a thermal decomposition of Nickel nitrate to Nickel oxide by reaction

Ni(NO3)26H2O __ NiO+2NO+3/2 O2+6H2O

In the period of heating installation as pending and spray environment was used compressed air, and during the workflow water vapor.

The finished product in the form of granules of Nickel oxide is removed from reactor 3 in PR who are consistently cyclone 6 and the capacitor 7.

The cyclone is cleaned gases from Nickel oxide, which is the accumulation disposed in the container of the finished product. In the condenser 7 is catching concentrating gases. They are displayed in the receiving part 8 in the form of a solution of nitric acid which is fed to the device for preparation of an initial solution of Nickel nitrate 1. For fluidization is air and water vapor, which comes from the pump through the heater 5 to the gas distribution device of reactor 3.

P R I m m e R. the Original solution of Nickel nitrate before heat treatment was evaporated to the mass concentration of not less than 1.1 kg/L. After concentration of the gases resulting from thermal decomposition of Nickel nitrate to Nickel oxide, was obtained nitric acid, the concentration of which was more than 25% Acid was used at the initial stage of preparation of the starting solution by dissolving Nickel metal.

When the mass concentration of the original solution of Nickel nitrate 0.75 to 0.8 kg/l, the concentration of nitric acid obtained after the condensation of gases thermal decomposition of Nickel nitrate to Nickel oxide was about 10-15% and could not be used directly to study the ora of Nickel nitrate, made from filtered process solutions industrial production (concentration of nitrate Nickel 0.5 kg/l) by parki in the apparatus with a steam jacket, poured in the amount of 95 l Mangus steam jacket 2. After that, in the fluidized-bed reactor 3 downloaded a "cushion" of powder of Nickel oxide in the amount of 35 kg with an average grain size of 0.2 mm, Then the nozzle 4 filed compressed air with a flow rate of 2 m3/h in order to avoid clogging particles "pillows". Later in the reactor 3 through the heater 5 was applied to the air for fluidization with a flow rate of 20 m3/h and included the electric heater 5 and the reactor 3. After heating the reactor up to 400aboutWith air supplied to the nozzle 4 and fluidization in the reactor 3, replaced water steam expenses 2.5 kg/h 20 kg/h, respectively.

Then using compressed air from manjusa 2 in the nozzle 4 was applied to the solution of Nickel nitrate with a flow rate of 10 to 17 l/h, which during the heating of the reactor was under the pressure of its own vapor in order to avoid more parki. The temperature in the reactor at the time of filing of a solution of Nickel nitrate through the injector was maintained in the range from 350 to 450aboutC. the Exhaust gases from the reactor was passed through the cyclo is VA heater and reactor. The resulting condensate was continuously merged into the container 8. From the reactor 3 through every hour whenever the Nickel oxide in the amount of 4 kg

Conducted 65 technological experiments. Total time was 286,5 o'clock In the course of these experiments recycled 3000 kg of Nickel nitrate in the form of highly concentrated solutions containing nitrate of Nickel from 0.8 to 1.4 kg/l at a temperature of "boiling" layer from 350 to 450aboutC.

Data defining experiments are summarized in table. As can be seen from the table, when the evaporation source solution of Nickel nitrate from 1.1 to 1.4 kg/l (experiments 1-6) and the compliance ratio 1,68 the process is stable in the absence of nitrogen oxides on the "tail" and the production of standard nitric acid at the stage of condensation. The process runs smoothly at all stages of redistribution: Parke, decay, dust cleaning and condensation. From the fluidized-bed reactor was unloaded granulated powder of Nickel oxide in the absence of agglomerates of class. The obtained dry product had good flowability. Granulometric composition of Nickel oxide in all tests performed varied from 0.1 to 0.5 mm

Failure to comply with the ratio 1,68 (experiments 7-9) the process is unstable with the presence of oxides of nitrogen "tail" formation of nitric kiouni "goat" in the fluidized-bed reactor.

Thus, the present invention has the following technical and economic advantages compared to the method of the prototype:

1. Eliminates the emission of nitrogen oxides in the atmosphere after condensation of the exhaust gases of the reaction.

2. Through the use of a solution of higher concentration increases the productivity of the process for the finished product.

3. Improving the quality of the finished product of Nickel oxide by eliminating any impurities and the need for additional processing.

4. Obtained at the stage of condensation of the exhaust gases of nitric acid is directly used for the preparation of the starting solution of Nickel nitrate.

5. The wasteless production and elimination of liquid and gaseous emissions solve the environmental problem.

A METHOD of producing NICKEL OXIDE, comprising preparing a starting solution of Nickel nitrate, its heat treatment in the presence of water vapor with obtaining the target product, the condensation of the gases with the formation of nitric acid and return it to the stage of preparation of a solution, characterized in that, to prevent emission of nitrogen oxides into the atmosphere, before termicheskaya processing, used as a fluidizing agent in the fluidized bed apparatus, a support in accordance with a ratio of

< / BR>
where Cpthe concentration of the solution after evaporation, kg/kg;

Gpthe solution flow rate, kg/h;

Gin.pthe flow of water vapor, kg/h

 

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