SU1741870A1 - Inorganic chemical absorber - Google Patents

Abstract

This invention relates to a process for the preparation of molybdenum hexafluoride and, in particular, to the synthesis of granulated inorganic sorbents for purifying waste gases from MoFe, HF and Fa. The inorganic chemical carbonate-based absorber in the form of granules additionally contains magnesium hydroxide, magnesium oxide and magnesium carbonate in the following ratio, wt.%: Magnesium hydroxide 46-52, magnesium oxide 30-34, magnesium carbonate 4-7, sodium carbonate 10 - 17, This absorber is characterized by porosity (up to 67.7%) and crushing strength of granules

Description

WITH

with

The invention relates to a process for the preparation of molybdenum hexafluoride and, in particular, to the synthesis of granular inorganic sorbents used to purify the waste gases of the specified production from MoFe, HF and F2.

At the present time for these purposes are used the absorber lime KPI, soda absorber HPS and activated alumina.

The main requirements for granular absorbers are high porosity and strength of granules, combined with high efficiency in trapping MoFe, HF and F2 waste gases.

Used absorbers are characterized by the following value of the dynamic capacity for the main impurity of waste gases - HF, corresponding to 99% attenuation: KPI-0,56; CPS

- 0.35 and - 0.25 g / g. The greatest interest among them is the soda soda absorber HPS (TU 002.89-86). It has a sufficiently high porosity and, unlike other scavengers, is easily recycled in order to extract molybdenum from it by hydrometallurgical methods. For this reason, the soda absorber is adopted as a prototype.

Increasing demands on clean gases and environmental protection require the creation of a new, more effective granular absorber for MoFe, HF and F2, which is simultaneously characterized by high structural and mechanical properties.

The purpose of this invention is to increase the porosity and strength of granules, as well as the capacity of the absorber for fluorine, fluoride and molybdenum hexafluoride.

Vj

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one

ABOUT

The goal is achieved by the fact that the absorber additionally contains magnesium hydroxide, magnesium and carbonate ma, l: three as follows:

wt.%

Magnesium hydroxide fs - 52

Magnesium Oxide 30 - 34

Karbobag magni 4-7

er (4 g nato 10-17

. Yes-to. And the absorber is characterized by capacitance, o MoFe and F2 of the same size f, .aj g, on average 0.27 g / g (in the prototype loo1, this is 0.16 g / g and 0.02 g / g). Fi v m or / HF is 0.85 - i) i versus 0.36 g / g in the prototype.

I, 1,1 -1st absorber is characterized by 3. i.s i i ovigant porosity (62) V j-; 40 About jo in the prototype) oi elevation uT, -o (30 - 50 kg / sgg against vrst). When prohibitive

VAah.iflx in Logger MD

P

O., and anugs high porosity and | yu (ytichela on HF (as well as on, One; e thus significantly CJ 5 ° n: q (g 32.2 to 17 5 kg / cm) strength gy, g on Sectional Warmth For this reason, n 1 is the limit of the content of MdO in the popote / t o, vulnerable -) wt.%, a Mg (0h) 2 - 46 May. /.

 The cooking process is granulated by whom the visitor enters the trail by means of

 A pea crop with water is added to the calculated grade of oxide magnpe and stir at 10 ° C; Get this in the same solution /. This is the amount of sodium carbonate and at T: W 1: 7 is stirred for 2 hours. The excess liquid phase is decanted and the sol is formed into granules by any known method. Granules absorber cyiiur us air at room temperature and calcined at a temperature of 175 ° C.

Magnesium hydroxide in the final product a appears due to the hydrolysis of part of the magnesium oxide in the synthesis process, and carbonate: by the reaction:

Mg (OH) 2 + NaaCOs-- MdSOz f 2NaOH

The sodium hydroxide formed is due to its high dilution and is removed with the mother liquor.

The increased strength, porosity and capacity of the granules is due to the introduction of magnesium oxide into the scavenger, most of which in the process of synthesis nepe / odgy magnesium hydroxide and magnesium carbonate

The composition of the inorganic absorber is established on the basis of RSA / LHT of various methods for its analysis. X-ray structural analysis established

the presence in the absorber of the phases MgfOH) 2 and MDO and their quantitative ratio of the phases MDOzi va2C03. The content of total carbonate carbon is divided by coulometric method on an AN-7560 express analyzer and the magnesium content is determined by an atomic absorption method and the composition of the absorber is calculated on the basis of the sodium content of carbon magnesium and the determined content of the MD (OH) 2 and MDO phases.

EXAMPLE: Pour 700 g of water into the reactor and, with stirring, pour 50 g of f / jO firstly in small portions, and then 50 g of H2SO3. After a total of 6 hours of stirring at T: L - 1 7, the suspension is filtered and cylindrical (4x4) granules are formed from the pasty gel by the matrix method

For drying and calcining, the granules absorbed by the bodies had a composition of 47 May% MrjiQH) 2 + 35 wt.% MgO + 6 May. % MgCCh - 1 wt.% Na2COz and the following properties:

5- strength oazdzrli nge 41, L

KI / LM;

- relative porosity is 57.7%

-dynamic capacity ps ng 0 9 pg

- dynamic capacity of go MoFe 0.3 g I 0 - dynamic capacitance 1 F 0.27 g / g

The properties and composition of the horn p; .gLO | Ithel obtained by three other co-compounds of the CTG during the synthesis are given in the L L table. Composition of grapugs, igigeg

5 depends on the ratio of TF. The smaller the liquid phase, the more in the caso-sodium and magnesium granules. In turn, the porosity of the absorber granules and

0, their crushing strength decreases. Since the dynamic capacity of granules pg glotigel for MoFe, HF, F2 practically depends on the ratio of T: W, the consumed should be given to the absorber,

Mamus 5 optimal values of durability and strength for handing out; l , s - and granules. These values of the p-p, and their practical properties are given by pr.t.t granular absorber С „„ a А 46 0 52 Mar,% Mf (- 30 - 34 May L 4 - -7 May% MDCO3 4–17 wt.% Na2COz

nocpdBHPHiisoc lpom prog (CPS) proposed absorber is characterized by greater porosity and strength of granules

5 ne rzg.davlenie

Phromy 1 of the Invention. An organic chemical potassium-based potassium lottery in the form of a granule is characterized in that in order to increase the porosity and strength of the granules.

as well as the absorber capacity for fluorine, hydrogen fluoride and molybdenum hexafluoride, it additionally contains magnesium hydroxide, magnesium oxide and magnesium carbonate in the following ratio, wt.%:

Structural-mechanical properties and dynamic capacity of MoF, HF and F2 absorber granules

46-52

30-34

4-7

10-17

Claims (1)

Claim Inorganic chemical absorber based on sodium carbonate in the form of granules. characterized in that, in order to increase the porosity and strength of the granules, as well as the capacity of the absorber for fluorine, hydrogen fluoride and molybdenum hexafluoride, it additionally contains magnesium hydroxide, magnesium oxide and magnesium carbonate in the following ratio of components, wt.%: magnesium hydroxide 46-52 magnesium oxide 30-34 magnesium carbonate 4-7 sodium carbonate 10-17 Structural and mechanical properties and dynamic capacity of the absorber granules according to MoF ^, HF and F ₂ N * Absorber synthesis conditions The composition of the granular absorber, wt.% Structural and mechanical properties Dynamic capacity g / g Mg0: Na ₂ C0 ₃ T: F Mg (0H) _a MgO - MgC0 ₃ Na _z C0 ₃ Hf MoF * ^{? 2} Poris toast>% Strength, kg / cm ² 1 1: 1 1:10 56 37 2 5 40,0 76.0 0.90 0.25 0.28 2 1: 1 1: 7 52 34 4 10 62,4 52.1 0.83 0.31 0.23 3 1: 1 1: 7 47 33 6 14 67.7 41.0 0.90 0.30 0.27 4 1: 1 1: 7 46 zo 7 17 69.8 32,2 0.87 0.29 0.29 5 1: 1 1: 4 41 27 10 22 71.9 17.5 0.87 0.24 0.22 6 1: 1 1: 4 37 24 12 27 73.1 12.7 0.84 0.27 oh zo 7 1: 1 1: 4 34 23 thirteen thirty 73.8 9.2 0.89 0.26 o.zo 8 Prototype HPS 100 40,0 4.0 0.35 0.17 0.02