FR2529802A1 - Absorption compsn. for removing mercury from gas or liq. - Google Patents

Abstract

The compsn. has total pore vol. at least 0.1 (0.2-0.7) cc/g, specific surface 10-250 (30-150) sq.m/g and S proportion 1-90 (5-60) wt.% w.r.t. binder. Opt. the compsn. contains, as auxiliary binder, 0.1-15 wt.%, w.r.t. total wt., of starch, PVA, Me cellulose, micro-polyethylene, epoxy-, polyester- or phenoplast resin. Prodn. comprises (1) shaping a mixt. of (a) hydratable or rehydratable Al2O3, SiO2, SiO2-Al2O3, cement, silicate, or Ca sulphate binder, (2) S, in natural condition, as flower of S, colloidal, in suspension or soln. opt. (c) porosity auxiliary, shrinking or volatilising below 150 deg.C, opt. (d) binder auxiliary and (2) drying below 150 (80-120) deg.C. Gases or liqs. are purified from Hg by contacting with the absorption compsn. The compsn. are stable, resist abrasion and crushing, neither disintegrate nor dissolve in water. The absorption capacity for Hg is 15-200 % w.r.t. initial mixt. Gases treated can contain 10 ng to 10 g Hg and the degree of purificn. can reach 99.9%.

Description

ABSORPTION MASSES FOR THE REMOVAL OF MERCURY
The present invention relates to absorption masses for the removal of mercury present in a gas or a liquid and to a process for their manufacture.

 Natural gases contain, depending on their origin, varying levels of mercury. These contents are generally of the order of 0.1 to 50 micrograms of mercury per m 3 of gas. Because of the toxicity of mercury and the ensuing risks of pollution, it is necessary to extract mercury from these natural gases and, more generally, the many atmospheres that may contain traces of mercury.

Many absorption masses have already been proposed to eliminate mercury. Thus, French Patent Application No. 2,310,795 describes a process for removing mercury in a gas or a liquid using a solid absorption mass containing
a) a solid support selected from the group formed by silica, alumina, silica-alumina, silicates, aluminates and silicoaluminates, and
b) at least one metal capable of forming an alloy with mercury, said mass having a specific surface area of at least 40 m 2 / g and the metal being present in said mass essentially in the form of crystallites with an average diameter of less than 400 A, the metal being selected from gold, silver, copper, nickel or some of their mixtures.

 Such masses, although satisfactory, were found to be of rather complex preparation and require the use of uneconomic metals. Moreover, such masses have difficulties during their regeneration because of the tendency to group the crystallites during it.

 The Applicant has developed absorption masses for the removal of mercury present in a gas or a liquid which obviates the aforementioned drawbacks and which have the particular advantage of having a significantly improved mercury absorption capacity, to be very simple to manufacture and to possess excellent mechanical resistance both to attrition and to crushing.

The present invention relates in fact to absorption masses for the removal of mercury present in a gas or a liquid, characterized in that they consist of sulfur and a binder chosen from: alumina, silica, silica-alumina, cements, silicates, calcium sulphates the total pore volume of the mass
is greater than or equal to 0.10 cm3 / g, its specific surface area is between 10 and 250 m2 / g; the proportion by weight of sulfur relative to the binder is between 1 and 90% and preferably between 5 and 60%.

 The absorption masses according to the invention preferably have a total pore volume of between 0.20 and 0.70 cm 3 / g, their specific surface area is preferably between 30 and 15 m 2 / g and the proportion by weight of sulfur. relative to the binder is preferably between 5 and 60%.

 The binder present in the absorption masses according to the invention is chosen from: alumina, silica, silica-alumina, cements, sodium or potassium silicates, calcium sulphates.

 The silica-alumina that can be used according to the invention is preferably a clay chosen from: kaolinite, bentonite, lhalloisite and attapulgite.

The cements that can be used according to the invention are preferably chosen from: natural cement, portland cement, metallurgical cements, special cements, Ferrari cements, pozzolan cements, aluminous cements. More particularly, it is possible to use refractory aluminous cements, such as, for example, cements
SECAR R marketed by Lafarge.The average composition of these cements is usually as follows

<tb> Type <SEP><SEP> of <SEP> binding <SEP> to203 <SEP><SEP> .CaO <SEP><SEP> .Fe203 <SEP>; .FeO <SEP><SEP>: Si02 <SEP><SEP> MgO <SEP><SEP>:<SEP> K20
<tb>: <SEP> SECAR <SEP> 150 <SEP>: <SEP> 50 <SEP>: <SEP> 27 <SEP>: <SEP> 5 <SEP>: <SEP> l <SEP><SEP> : <SEP> 5 <SEP>: 0.2 <SEP>: <SEP> 0.05 <SEP>:
<tb>: <SEP> SECAR <SEP> 250 <SEP>: <SEP> 70 <SEP>: <SEP> 26 <SEP>: <SEP> 0.1 <SEP>: <SEP> 0.2: <MS> 0.2 <SEP>: 0.2 <SEP>: <SEP> 0.05 <SEP>:
<tb>: <SEP> Super <SEP> SECAR <SEP> 250 <SEP>: <SEP> 80 <SEP>: <SEP> 19 <SEP>: <SEP> 0.1 <SEP>: <SEP> - <SEP>: <SEP> 0.1 <SEP>: 0.05: <SEP>
AFTER

<tb> Type <SEP><SEP> of <SEP> binding <SEP> Na20 <SEP><SEP>:<SE> S03 <SEP><SEP>:<SE> S <SEP>: P205 <SEP>: Mri <SEP> 203 <SEP><SEP>: Cr2O3 <SEP>: <SEP> 2 <SEP>, <SEP>
<tb> SECAR <SEP><SEP> 150 <SEP>: 0.05 <SEP>: 0.05 <SEP>: 0.05 <SEP>: 0.10 <SEP>: 0.02 <SEP>: 0.10 <SEP>: 3
<tb>: <SEP> SECAR <SEP> 250 <SEP>: 0.5 <SEP>: 0.03 <SEP>: 0.01 <SEP>: 0.05 <SEP>: 0.005 <SEP>: 0.002 <SEP>: 0.003
<tb>: <SEP>: <SEP>: <SEP>: <SEP>: <SEP>: <SEP>: <SEP>: <SEP>:
<tb>: <SEP> Super <SEP> SECAR <SEP> 250 <SEP>: 1.0 <SEP>: 0.05 <SEP>: 0.01 <SEP>: 0.05 <SEP>: 0.005 <SEP> 0.003 <SEP> 0.003
<Tb>
The alumina and the silica present in the absorption masses of the invention are in the forms which originate from their drying at a temperature below 1500C and preferably between 80 and 120 C. These forms may vary according to the raw materials used for the manufacture of the masses; they are widely described for alumina in the Kirk-Othmer Encyclopedia Vol. 2 (1974) or in ALCOA Paper No. 19 (1972) and for silica in "The Colold"
Chemistry of silica by Ralph K. Iler (1955 and 1979).

when the alumina is present as a binder in the absorption masses according to the invention, these preferably have a pore distribution such that
0.1 cm 3 / g at 0.15 cm 3 / g of the pore volume is constituted by
pores with a diameter greater than 1 micron,
- 0.15 to 0.65 cm3 / g of the pore volume is constituted by
pores with a diameter greater than 0.1 micron,
The absorption masses of the invention preferably contain sulfur such that the average diameter of the sulfur particles is less than 20 microns and preferably between 0.01 and 10 microns. Surprisingly, the presence of sulfur particles having these dimensions is particularly favorable for the elimination of mercury present in gases or liquids.

 The absorption masses of the invention may also contain from 0.1 to 15% by weight relative to the total weight of the mass of a compound chosen from: starch, polyvinyl alcohol, methylcellulose, micropolyethylene, epoxy resins, polyester resins and phenolic resins.

The present invention also relates to the method of manufacturing these absorption masses. This process is characterized in that it comprises the following steps 1) - Formatting a mixture comprising
a) a binder chosen from: hydrated or rehydratable alumina,
silica, silica-alumina, cements, silicates and
calcium sulphates,
(b) sulfur in the native state, in flower, colloldal, in
suspension, o> n in solution,
c) and, optionally, a porosity adjuvant
retractable, be volatile at a temperature below
Isooc.

20) - Drying of the mass obtained at a temperature below 150 C and preferably between 80 and 1200C.

 According to the process of the invention, the shaping of the mixture is carried out by conventional means and, in particular, by extrusion, pelletization, shaping at the rotating bezel, merumerisation (as described, for example, in the Belgian patent ne 840 770), dripping in the oil "il-drop", etc.

 According to the process of the invention, the essential function carried out by the hydrated alumina mu rehydratable alumina, silica, silica-alumina, cements, silicates or calcium sulphates is to serve as a binder for the sulfur of way to get after shaping and drying a product that does not disintegrate and does not disintegrate in contact with water.

 However, it is possible, according to a variant of the process of the invention when this binder function is not satisfactorily provided to use as binder, at least in part, and preferably from 0.1 to 15% by weight. polymers such as starch, polyvinyl alcohol, methylcellulose, micropolyethylene or thermosetting resins such as: epoxy resins, polyester resins and phenolic resins.

 The hydrated alumina that can be used according to the process of the invention may be in the form of a sol or gel of peptable alumina. The peptizing agent may be water, or a weak acid such as formic acid, acetic acid, propionic acid or a strong acid such as hydrochloric acid or nitric acid. The amount of peptizing agent must be sufficient to convert the gel into a flexible plastic mass.

 The alumina sols may in particular be dispersions or suspensions of fine or ultra-fine boehmites or pseudo-boehmites which are composed of particles having dimensions in the collosal field, that is to say less than about 2000 A.

 The aqueous dispersions or suspensions of fine or ultra-fine boehmites can be obtained as is well known to those skilled in the art by peptization in water or acidulated water of these products. The fine or ultra-fine boehmites used according to the present invention may in particular have been obtained according to the process described in French patents No. 1,261,182 and 1,381,282 or in European Patent Application No. 15,196.

 Can be used according to the method of the invention, the aqueous suspensions or dispersions of ultra-pure boehmite or pseudo-boehmite prepared according to the method described below.

 This process is of the type in which the reaction of an alkali aluminate with carbon dioxide is carried out to form a precipitate of amorphous aluminum hydroxycarbonate, the precipitate obtained is separated by filtration and the latter is then washed (the process is described in US Pat. No. 3,268,295).

Then,
a) in a first step, the washed precipitate of amorphous aluminum hydroxycarbonate is mixed with a solution of an acid, a base or a salt or mixtures thereof; this mixture is carried out by pouring the solution on the hydroxycarbonate, the pH of the medium thus constituted being less than 11,
b) in a second step, the reaction medium thus formed is heated to a temperature below 900 ° C. for a time of at least 5 minutes,
c) in a third step, the medium resulting from the second step is heated to a temperature between 900C and 2500C.

 According to this method, the treatment temperature of the second step is between 50 and 850C, the duration of treatment being between 5 minutes and 5 hours.

 According to this process, the acid used in the first step is a strong or weak mineral or organic acid which is soluble in water and preferably chosen from: nitric acid, perchloric acid, sulfuric acid, hydrochloric acid, hydroiodic acid, hydrobromic acid, formic acid, acetic acid, propanoic acid, butanone acid, oxalic acid, maleficent acid, succinic acid, glutaric acid, chloro and bromoacetic acids.

 According to this process, the base used in the first step is a weak base which is soluble in water and preferably chosen from: ammonia, amines such as methylethylpropylamines, aminoalcohols such as mono, di or tri ethanol amines and 2-aminopropanol, quaternary ammonium hydroxides and products which may decompose under the reaction conditions to give a base such as, for example, hexamethylenetetramine or urea.

 According to this process, the salt used in the first step is chosen from salts derived from ammonia and amines and those containing the aluminum cation and comprising the nitrate, chloride, formate, citrate, acetate or oxalate anions.

 According to this method, in the first step, the concentration of aluminum compound expressed in Au 203 of the mixture is between 20 and 400 g / l expressed in Al 2 O 3 and preferably between 40 and 200 g / l.

 According to this process in the mixture, according to the first step, the molar ratio between the sum of the anions and cations present (excluding Ht and OH) and the equivalent expressed in Al 2 O 3 of the aluminum compound is between 0 , 01 and 2 and preferably between 0.03 and 0.9.

 According to this method, the heating temperature according to the third step is between 100 and 1600 C, the heating time being between 10 minutes and 30 hours and preferably between 30 minutes and 10 hours.

 The dispersions or suspensions of boehmite and pseudo-boehmite obtained according to this process have an alkali content of less than 0.005% expressed as the weight ratio of alkali metal oxide / Al 2 O 3.

 The aqueous suspensions or dispersions obtained from pseudo-boehmite9 of amorphous alumina gels, of aluminum hydroxide gels or of ultra-fine hydrargillite can also be used as hydrated alumina according to the invention.

 The pseudo-boehmite may in particular have been prepared according to the process described in US Pat. No. 3,630,670 by reacting a solution of an alkaline aluminate with a solution of a mineral acid. It may also have been prepared as described in French Patent No. 1,357,830 by precipitation at pH 99 a temperature slightly above ambient from reagents of concentrations such that approximately 50 g / l of alumina is obtained. in the dispersion.

 The amorphous alumina gels may in particular have been prepared according to the processes described in the article "Aleoa Paper No. 19 (1972) - pages 9 to 12" and in particular by reaction of aluminate and acid, or a salt of aluminum and a base or pure aluminate and an aluminum salt or by hydrolysis of aluminum alkoxides or by hydrolysis of basic aluminum salts.

The aluminum hydroxide gels may especially be those prepared by the processes described in US Pat. Nos. 3,268,295 and 3,245,919.
The ultra-fine hydrargillite may in particular have been prepared according to the process described in French Patent No. 1,371,508, by evolution at a temperature between room temperature and 600 ° C. of alumina gels in the form of a cake and containing, with respect to alumina counted in dVA1203 molecules, 0.10 monovalent acid ions.

 According to the process of the invention, it is possible to use hydrated aluminas of boehmite type obtained as a by-product in the manufacture of the alcohol by hydrolysis of an alkoxide or aluminum alkoxide (Ziegler synthesis). The Ziegler alcohol synthesis reactions are described in particular in US Pat. No. 2,892,858. According to this process, triethylaluminum is first prepared from aluminum, hydrogen and ethylene, the reaction being carried out in two stages with partial recycling of triethylaluminum.

on oxyde ensuite le produit obtenu en alcoolate d'aluminium.

Ai + 3/2 H2 + 2 Al (C2H5) 3 3A1 (C2H5) 2H
3 Al (C2H5) 2 H + 3 C2H4 3 Al (C2H5) 2 is added ethylene in the polymerization step

the product obtained is then oxidized to aluminum alkoxide.

la pête d'hydroxyde d'aluminium obtenue peut être éventuellement après séchage et calcination utilisée selon le procédé de l'invention. the alcohols being obtained by hydrolysis

the aluminum hydroxide peak obtained may be optionally after drying and calcination used according to the process of the invention.

The hydrated alumina obtained as a by-product in the Ziegler reaction is described in particular in a bulletin of the
Conoco Company of January 19, 1971.

 The dehydrated or partially dehydrated forms of the hydrated aluminas which consist of transition aluminas and which comprise in particular at least one of the phases taken from the group consisting of rho, chi, eta, gamma, kappa, theta, may also be used. delta (excluding preferably alpha alumina).

 The alumina that can be used according to the process of the invention may be in the form of alumina comprising a predominant proportion of rehydratable alumina. Such an alumina has a poorly crystallized structure and / or amorphous and for example can be obtained according to the process as described in French Patent No. 1,438,497. (This alumina is sometimes referred to generically as "Flash Alumina").

 For the purposes of this process, the term "poorly crystallized structure alumina" is understood to mean an alumina such that X-ray analysis gives a diagram having only one or a few diffuse lines corresponding to the crystalline phases of the low temperature transition aluminas and essentially comprising the chi, rho, eta, gamma and pseudogamma phases and their mixtures.

 Amorphous structure alumina means an alumina such that its X-ray analysis does not detect any line characteristic of any crystalline phase.

 The rehydratable active alumina used is generally obtained by rapid dehydration of aluminum hydroxides such as bayerite, hydrargillite or gibbsite, nordstrandite or aluminum oxyhydroxides such as boehmite and diaspore.

This dehydration can be carried out in any suitable apparatus using a stream of hot gas. The inlet temperature of the gases in the apparatus generally varies from approximately 400 ° C. to 12 ° C. and the contact time of the hydroxide or of the oxyhydroxide with the hot gases is generally between a fraction of a second and 4 to 5 seconds.

 The specific surface area measured by the BET method of the rehydratable active alumina obtained by rapid dehydration of hydroxides or oxyhydroxides generally varies between approximately 50 and 400 m 2 / g, the diameter of the particles is generally between 0.1 and 300 microns and preferably between 1 and 120 microns. The loss on ignition measured by calcination at 10,000 generally varies between 3 and 15%, which corresponds to an H 2 O / Al 2 O 3 molar ratio of between approximately 0.17 and 0.85.

 According to a particular embodiment, an active alumina is preferably used, resulting from the rapid dehydration of the hydrate Bayer (hydrargillite), which is the industrial aluminum hydroxide easily accessible and very cheap such an active alumina is well known to those skilled in the art, its preparation process has been described in particular in French Patent No. 1,108,011.

The silica that can be used according to the process of the invention is any silica having the desired binder properties and in particular those sold under the trademark Ludox ~
The silica-alumina and the cements which can be used according to the process of the invention are those which have been described above.

 The sulfur used according to the process of the invention is in the native state, in fl ure, in suspension, in solution, in the colloidal state or dissolved in an organic solvent such as toluene for example.

 The size of the sulfur particles must be such that their average diameter is less than 20 microns and preferably between 0.01 and 10 microns.

 The volatile porosity adjuvants at a temperature below 1500C are chosen from: niphthalene, ammonium carbonate, ammonium thydrogenocarbonate, methylcellulose, ethylcellulose, carboxymethylcellulose, sugars, gums, microcrystalline cellulose. These adjuvants have the function of creating macroporosity, that is to say pores whose diameter is greater than or equal to 0.1 micron. They must be removable by heating at a temperature below 1500C.

 Pore adjuvants at a temperature below 1500C are chosen from: textile fibers, glass fibers, asbestos fibers and alumina fibers.

 These adjuvants have the function of also creating macroporosity, they also improve the mechanical strength of absorption masses that contain them.

 In the process according to the invention, the mixture may further comprise the use in a proportion by weight relative to the total weight of the mixture of 0.1 to 15% of a compound chosen from: starch, polyvinyl alcohol, methylcellulose, micropolyethylene, epoxy resins, polyester resins and phenolic resins. These compounds, as described above, have the function of improving, when necessary, the mechanical strength of the masses when the binder function is not satisfactorily provided by the alumina, silica, silica-alumina or cements.

 The mixture between the sulfur and the binder is operated in such a way that in the mass obtained, the proportion by weight of sulfur relative to the binder is between 1 and 90% and preferably 5 and 60%.

 The shaping of the binder mixture, sulfur and optionally pore-forming agent is carried out by the conventional means which have been recalled above: e # truing, pelletizing, rotating bevelling, merumerization, draining in the oil ...

 This shaping is preferably carried out by extrusion.

This extrusion can advantageously be carried out in the presence of various anionic, cationic and nonionic surface-active agents, provided that they do not leave harmful residues in the masses for their subsequent use. Among the suitable surfactants, mention may be made of alcohols
C3-C12 polyethers of linear primary alcohols, dimethylsilicones, silicon-polyether copolymers, as well as the various known polymeric compounds of the polyoxyethylene alkylphenol, polyoxyethylene fatty acid esters, polyoxyethylene alcohols, polyoxyethylene mercaptans, polyoxyethylene Alkylamines, polyoxyethylene alkylamides, etc. is particularly suitable as surfactant for a linear primary alcohol polyether, commercially available under the trademark Antarox.
BL-240. preferably, the surfactant is used in the proportion of about 0.1 to 10.0% by weight of the mixture.

 As regards the extrusion shaping of the compositions of the invention containing hydrated alumina, this can be carried out under the conditions well known to those skilled in the art and which have in particular been described in the Belgian Pat. Nos. 830,652 and 840,770 as well as French patents Nos. 2,265,452, 2,307,576, 2,364,063, 2,374,956, 2,387,683 and British Pat. No. 1,094,360.

 With regard to the extrusion shaping of the compositions of the invention containing rehydratable alumina, this can be carried out under the conditions well known to those skilled in the art and which, in particular, have been described. in French Patents 2,351,071, 354,815, 2,397,375, 2,398,540 and 2,413,323 as well as in US Pat. No. 3,404,111.

 the absorption masses of the invention have a very improved stability, excellent mechanical resistance to both attrition and crushing, good water resistance: they do not disintegrate or disintegrate on contact. In addition, the compositions of the invention have a considerably improved mercury absorption capacity, generally this capacity is greater than 15% and can be as high as 200% by weight of absorbed mercury relative to the weight of the initial mass.

 the temperature range in which these masses can be used is usually between - 5000 and 15000 the optimum temperatures may differ depending on the gases to be treated and their composition to avoid excessive condensation of water or other condensables .

 This uptake can be carried out at atmospheric pressure or at a lower or higher pressure, the total pressure possibly reaching, for example, 200 bar.

 V.V.H. (volume of charge expressed at temperature and normal pressure per volume of capture mass and per hour) may vary for example from 50 to 50,000 but it will operate preferably at V.V.H. between 200 and 20,000, depending on the pressure to be operated and the mercury content of the gases to be treated and the rate of purification that we want to achieve.

 The treated gases may contain, for example, from 10 nanograms to 10 grams or more of mercury per cubic meter.

 The mercury removal device may consist of a single reactor or at least two reactors in parallel, but preferably at least two reactors in series will be used.

 The efficiency of the mercury trapping masses is evaluated by means of two apparatus, one operating at atmospheric pressure and the other at 30 bars.

 The apparatus consists of a metal tube whose inactivity for the fixation of mercury has been controlled, containing 30 ml of the capture mass to be tested and in which an adjustable flow rate of gas is passed through.

The determination of the mercury content is made using a COLEMAIA mercury analyzer based on the HATCH method and
OTT described in Analytical Chemistry of December 1968.

 The liquid phase tests are carried out at room temperature with pentane containing 4 g of mercury per liter, injected with the aid of a metering pump.

 The following examples are intended to illustrate the invention and should in no way limit its scope to the specific embodiments described therein.

EXAMPLE
A - MASS PREPARATION
MASS A
80 kg of hydrated alumina gel powder of boehmite type are carefully kneaded with 20 kg of sulfur microns.

 The alumina gel is obtained as by-product in the manufacture of alcohols by hydrolysis of an alcoholate or an aluminum alkoxide, its specific surface is 150 m 2 / g, its water content is 20% by weight and its particle size is less than 20u.

 50% of the weight of the micronized sulfur used has a particle size less than 9p and there are no sulfur particles with a diameter greater than 24U.

 During mixing, 44 liters of water, 1.2 liters of 12N hydrochloric acid and 5.2 kg of naphthalene are added.

 The paste thus obtained is then extruded into extrudates of 3 mm in diameter and 4 mm in length. After drying in an oven at 800 ° C. for 8 hours and then at 1200 ° C. for 3 hours, the extrudates have a specific surface area of 50 m2 / g, a crushing strength of 1 kg / mm 2 and a total pore volume of 28 cm 3 / g, of which 0.09 cm 3 has a porosity greater than 1 micron.

 The sulfur content of the mass is 22%.

MASS B
80 kg of rehydratable activated alumina powder obtained by fast dehydration of bayerite at a temperature of 800 ° C. are carefully mixed with 20 kg of an aqueous suspension of colloidal sulfur at 60% by weight of sulfur and 300 g of methylcellulose.

 The alumina has an average particle size of 4 microns and a specific surface area of 300 m 2 / g.

 50% by weight of the collofdal sulfur used at a particle size of less than 4 and there are no sulfur particles with a diameter greater than iSu.

 The mixture is then coated; during the coating, the powder is moistened by spraying 27 liters of water containing 2.7 kg of Na 2 O as NaOH.

 The 2.4 - 4 mm beads obtained are ripened 24 hours at 2G-30 C and then dried at 800C for 8h and at 1200C for 3h.

The specific surface of the beads obtained is 145 m 2 / g.

The grain-to-grain crush is 7kg and the total pore volume is 0.24cm3 / g including 0.04cm3 of porosity greater than 1 micron.

 The sulfur content of the mass B is 21%.

MASS C
80Kg of Secar 250 cement produced by the Company
Lafarge are carefully mixed with 20 kg of colloidal sulfur identical to that used to prepare mass B.

 The mixture is then sugar-coated with water spray.

 The resulting 2,4 - 4 mm beads are then matured for 24 hours at 20 ° C. and then dried at 800 ° C. for 8 hours and at 120 ° C. for 3 hours.

 The beads thus obtained have a specific surface area of 60 m 2 / g, a crush strength greater than 8 kg and a total pore volume of 0.21 cm / g, of which 3 cm 3 has a porosity greater than 1 micron.

 The sulfur content of the mass C is 20%.

B - TESTS
The effectiveness of the masses prepared and evaluated by passing a mercury-containing natural gas on 20cm3 of entrapment mass contained in a metal tube coated with 2cm diameter whose inactivity for mercury uptake was verified.

 The natural gas used has a composition in volume of 84% of methane and 0.3% of hydrocarbons in 5 or more carbon atoms.

 The initial efficiency of the masses is evaluated at ambient temperature and at various VVH with a natural gas having a mercury content of 1 mg / m3 for the atmospheric pressure tests and 1 mg / m3 for the 30 bar tests.

efficiency is defined for the report
Hg content at the inlet - Hg content at the outlet x 100
mercury content at the entrance
The results obtained are given in the following table
MASS VVH P PURIFICATION RATE
A 100 to 99.9
1000 1 99.5
2000 l 95.2
B 500 1 99.9
1000 l 99.9
2000 l 99.4
C 500 to 99.9
1000 1 99.7
2000 1 99.1
Pressure tests of 30 bar
MASS VVH P PURIFICATION RATE
A 10,000 to 99.9
15000 to 99.5
B 10,000 30 99.9
15000 to 99.9
C 10000 to 99.9
15000 to 99.7
In order to evaluate the absorption capacity of these masses, a volume of gas is passed over these masses at 30 bars, such that, at WH 5000, the amount of mercury fixed is 8 × of the total weight of these masses. .

An activity test is then carried out to evaluate the effectiveness of these masses under the same conditions as those defined for the test for 30 bars of pressure.
MASS VVH p PURIFICATION RATE
A 10000 to 99.7
15000 to 30 99.1
B 10060 30 99.9
15000 3Q 99.8
C 10000 to 99.8
15000 to 99.5

Claims (11)

 sulfur relative to the binder is between 1 and 90%.  between 10 and 250 m 2 / g, the proportion by weight of  greater than or equal to 0.110 cm 3 / g, its specific surface is  calcium sulphates, the total pore volume of the mass is  silica, silica-alumina, cements, silicates,  consisting of sulfur and a binder selected from:  in a gas or liquid characterized in that they are  1) absorption masses for the removal of mercury present 2) absorption masses according to claim 1 characterized in  that their total pore volume is between 0.20cm3 / g  and 0.70cm / g, their specific surface area is between 30  and 150m / g and the proportion by weight of sulfur with respect to  binder is between 5 and 60%. 3) Absorption masses according to any one of the claims  1 or 2 characterized in that the average diameter of  sulfur particles is less than 20 microns and  preferably between 0.01 and 10 microns. 4) Absorption masses according to any one of the claims  1, 2 or 3 characterized in that the binder is alumina and  in that the pore distribution of these masses is such that  - 0, Olem3 / g to 0,15cm3 / g of the porous feather is constituted by  pores with a diameter greater than 1 micron,  - 0.15 to 0.65 cm3 / g of the pore volume is constituted by  pores with a diameter greater than 0.1 micron, 5) Absorption masses according to any one of the claims  1, 2 or 3 characterized in that the cements are chosen  among: natural cement, portland cement, cements  Metallurgical, special cements, Ferrari cements,  pozzolana cements, aluminous cements. 6) Method of manufacturing the absorption masses according to one  any of the preceding claims characterized in that  it has the following steps  1500C.  retractable, either volative at a temperature below  c) and optionally a porosity adjuvant is  suspension, or in solution,  (b) sulfur in the native state, in flower, colloldal, in  cements, silicates, calcium sulphates,  rehydratable silica, silica-aluminas,  a) a binder chosen from: hydrated alumina or  10) Formatting a mixture comprising  at 1500C and preferably between 80 and 1200C.  20) Drying of the mass obtained at a lower temperature 7) - Method of manufacturing the absorption masses according to the  claim 6 characterized in that the shaping is  operated by extrusion, pelletizing, shaping at the bezel  turning, merumerization, dripping in oil. 8) Method according to any one of claims 6 or 7  characterized in that the average diameter of the particles of  sulfur is less than 20 microns and preferably included  between 0.01 and 10 microns. 9) Process according to revendicatton 6 characterized in that the  mixture also comprises, in a proportion by weight per  relative to the total weight of the mixture of 0.1 to 15%, a compound  selected from: starch, polyvinyl alcohol,  methylcellulose, micropolyethylene, epoxy resins,  polyester resins and phenolic resins.  10) Method according to claim 6 characterized in that  the porosity adjuvant is chosen from: naphthalene,  ammonium carbonate, ammonium hydrogencarbonate,  methylcellulose, ethylcellulose, carboxymethylcellulose,  sugars, gums, microcrystalline cellulose,  textile fibers, glass fibers, asbestos fibers,  alumina fibers. 11) Process for the removal of mercury present in a gas or  liquid characterized in that the gas or the liquid is  in contact with the absorption mass according to any one  Claims 1 to 5.