WO1991014010A1 - Procedimiento para la depuracion y recuperacion de mercurio en forma metalica a partir de gases de tostacion que lo contienen - Google Patents
Procedimiento para la depuracion y recuperacion de mercurio en forma metalica a partir de gases de tostacion que lo contienen Download PDFInfo
- Publication number
- WO1991014010A1 WO1991014010A1 PCT/ES1991/000012 ES9100012W WO9114010A1 WO 1991014010 A1 WO1991014010 A1 WO 1991014010A1 ES 9100012 W ES9100012 W ES 9100012W WO 9114010 A1 WO9114010 A1 WO 9114010A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- mercury
- solution
- roasting
- thiocyanate
- gas
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B43/00—Obtaining mercury
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/64—Heavy metals or compounds thereof, e.g. mercury
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- the object of this invention is a new process of purification of mercury in the treatment of raw materials that contain it, recovering it in metallic form without passing, in significant quantities, neither to the products obtained from those raw materials nor to the effluents from its manufacture
- Cinnabar has traditionally been the mineral from which mercury has been obtained. Although the concentration of this mineral is easy, due to the dispersion in which it is found in the ores, the whole one is usually treated with metal grades between 0.5 and 5% (equivalent to 5000 - 50,000 g / t) after crushing to adapt the material to the requirements of the oven.
- the cinnabar decomposes into S0 2 and Hg that pass with the gases to the later stage of cooling in which most of the mercury condenses. Normally, the rest of the elements that accompany the mercury remain in the residue, although in some cases it is necessary to take into account the presence of some elements such as Cl, Se and As that can be considered harmful for obtaining the metal.
- Chlorine is, among them, the most harmful, since it easily combines with mercury, forming volatile HgCl 2 first and then insoluble Hg 2 Cl 2 .
- Selenium has a sulfur-like behavior and, like it, it mostly goes to Se0 2 but it can also remain elementary, volatile and recombine with Hg giving insoluble HgSe.
- Arsenic during roasting is oxidized to As 2 ⁇ 5 and As 4 0 6 ; the first, acidic, is combined with metal oxides and is fixed as an arsenate in the residue, while the second passes to the gases and condenses, in the cooling, like mercury.
- mercury further increases the problem of pollution.
- the S0 2 of the gases is transformed into sulfuric acid, it fixes the mercury so that its content in this element reaches values between 10 and 60 ppm and even, in some cases, far exceeds 100 ppm, figures that most consumers do not want to admit to avoid contamination problems in their plants and / or their products.
- Spanish patent 556,731 introduces the novelty on the first of the addition of active carbon to the thiocyanate solution to increase the reaction rate.
- Figure 1 shows the scheme of a conventional plant to which the mercury purification system has been added.
- the process comprises the assembly formed by: a conventional gas cooling system (obtained in a roasting oven [1]) up to a temperature below 40 ° C (generally between 30 and 35 ° C) [2]; two conventional electroprecipitation systems [3] [4]; one or two towers irrigated, in closed circuit by a solution with sodium thiocyanate [5] [6]; a thickener [8] where, after degassing, the insoluble products captured in [2] and [3] are concentrated separating a clear aqueous solution that is partly used for the irrigation system of [2] and [3] and the The rest is sent to the conventional effluent treatment system [9] at the factory.
- a conventional gas cooling system obtained in a roasting oven [1] up to a temperature below 40 ° C (generally between 30 and 35 ° C) [2]
- two conventional electroprecipitation systems [3] [4] one or two towers irrigated, in closed circuit by a solution with
- the cooling system included in the block [3] usually consists of a first rain tower (empty) where the gases reach about 650 ° C after having passed through the heat recovery boilers and electrofilters (electrostatic precipitators ) dry; in it the gases cool to about 60-70 ° C, beginning, in some cases, the condensation of mercury, which occurs when the content of this element in the gas, in this temperature range, exceeds 300 to 550 mg / m 3 .
- the supersaturation phenomenon see A. Cuadra et. al, Rev. Metal.
- Waste storage falls on environmental rejection;
- the commercialization of waste means having to pay a heavy penalty and, above all, overcome the increasing obstacles that governments impose on their circulation.
- Processing at the plant itself requires facilities that are often disproportionate to the production of mercury expected from them.
- the present invention is based on a process of purification of known mercury, to treat with it gases with high mercury content, so that it can be collected by condensation during the cooling of the gas.
- the selected process must meet the condition of not introducing elements foreign to those carried by the mineral, or if these elements are harmful (chlorine case), not increase its presence, adding it; specifically, the one described in Spanish patent 411.067 (29-1-73), improved by 556.731, is considered more appropriate, with the modifications that will be set forth below for better adaptation to this particular process.
- the overall process comprises, in addition to the conventional equipment described in Figure 1, a second (actually first) irrigation tower with thiocyanate solution [5] and what constitutes an essential part of the present invention, the treatment of the sludge obtained in the filters or thickeners of the system to recover the mercury in metallic form.
- the thick sludge obtained in [8] such as that from the electroprecipitator [4] is subjected to an ammonia treatment [10] to obtain metallic mercury (which after a purification treatment in [12] is packaged) and a mud that in a small thickener it leaves a thick pulp that is periodically recycled to the oven and a solution that goes to the conventional treatment [9] of factory effluent treatment.
- the solids that are periodically separated from the towers [5] and [6] in a filter [11] are also recycled to the oven.
- the first residue may contain in addition to S and Se (whose natural output is for [7] and [9] respectively) Cl which, preferably, tends to bind with the mercury forming Hg 2 Cl 2 and which, as has been proven, is one of the causes of the stability of the emulsion of mercury that appears in the sludge obtained from [8].
- the equipment represented in Figure 2 by block [10] has as its main mission the elimination of chlorine (chloride) thus achieving, on the one hand, avoiding the recycling of this element and, on the other, achieving that, breaking the emulsion when the conditions that will be seen later occur, the coalescence of the mercury is achieved, forming a liquid phase that is easy to separate from the aqueous pulp.
- the present invention contemplates the mercury enrichment of the raw material, so that the product that is fed to roasting has a content of that element of 500 ppm or more. Thus, during this period of time, the mercury content in the roasting gases reaches at least 200 mg / m 3 .
- the raw material has relatively high chlorine contents, it will be necessary to go to higher values, which is no more a problem than distancing more times in which the enriched charge is introduced.
- the enrichment is achieved by mixing to the own raw material, other products rich in mercury (obviously those with contents of harmful elements may not be used both for the final obtaining of the sulfuric acid and for the purpose to which the roasting residue is destined ) and / or recycling the mercury compounds produced in [10] and [11] as shown in Figure 2.
- Hg (aq) + Hg (SCN) 4 2 - Hg 2 (SCN) 2 + 2SCN " [3.1] 3Hg 2 (SCN) 2 + 4H 2 S0 3 + 18SCN " >> 6Hg (SCN) 4 2" + 4S 4 0 6 2 " + 12 H-0 [3,2]
- Maintaining a high concentration of mercury in solution is, in principle, related to the solubility of Hg (SCN) 2 in a thiocyanate solution.
- SCN Hg
- Sodium thiocyanate at 20 "C, this has been determined by AK Agrawal and RC Mehrotra [Z. Anorg. Allgem. Chem., 312, 230 (1961)], based on whose data Figure 3 has been drawn.
- the concentration of mercury in solution reaches a lower value than the solubility of Hg (SCN) 2 because before it begins to precipitate exponentially as sulfide (HgS), possibly by reaction of mercury with tetrathionate, reaching a limit value of about 30-35 g / 1 of mercury in solution, sufficient to have a high reaction rate with the sale that the mercury removed from the gas is transformed into a chemical compound that does not present any difficulty to be recycled Toasted oven.
- the mercury content which in the first few days after adding active carbon is practically zero ( ⁇ 0.05 mg / m 3 ) begins, after a very variable period of time, to give values greater than 0 * 1 mg / m 3 . From a certain value, different depending on whether it is the first or second tower, it is necessary to filter the solution, separating the carbon and the mercury sulphide, using the solution again after replacing the active carbon.
- an essential part of the The present invention is to have a simple and reliable method to predict when this loss of activity will take place.
- the method is to take a sample of the solution circulating through the tower to a washing bottle by bubbling air through it and measuring the mercury content in it at the exit. While the coal has enough activity, no mercury is detected at the exit. When it begins to lose activity, a content of O'l mg / m 3 is already detected; From this moment, a time of 24 to 48 hours is available to replace the deactivated coal with new activated carbon.
- the universally accepted solution consists in the use of two sets (in the industrial jargon there are two fields) of electrofilters or wet electrostatic precipitators which, when functioning correctly, have an efficiency of almost 100 %; Any failure in its operation, usually due to the breakage of any of the "threads", results in the appearance of the "feather" in the chimney.
- the mists are water and mercury, and in this case the absorption tower and electrofilter assembly form a strongly related set.
- the water has no harmful effect on the manufacture of the acid, since it is involved in obtaining it, the mercury must be practically eliminated before the gas enters the acid manufacturing process, where it would be completely fixed.
- the present invention claims the use of two absorption towers irrigated with thiocyanate solution (as described in the previous section), and two electrofilter fields by arranging the assembly as follows (in the direction of the gas):
- the content of mercury in the gas that leaves the equipment is about 40-60 mg / m 3 in the form of steam and an indeterminate amount, but of the same order, in liquid form, due to the mechanical drag of the drops that have formed on the walls of the electrofilter tubes.
- mists have been transformed into droplets of mercury that are mostly collected at the base of the electrofilter or are captured in the first tower, at the exit of it, the gas carries, approximately, in addition to 3- 6 mg / m 3 of mercury vapor, 0 * 3-05 mg / m 3 of mercury as mist. Is Small amount of mercury needs to be captured or transformed into droplets in a second field of wet electrofilters.
- the active carbon maintains its activity and a drop separator of sufficient efficiency is placed in the design (avoiding the drag of solution), it is in a position to purify the mercury content in the gas at the outlet less than O'l mg / m 3 .
- both the waters that go to the treatment of effluents and the gases that go to the sulfuric acid plant can be considered free of mercury, it has no more outlet than with the sludge that is collected in it or the thickeners of the washing tower and refrigerants.
- FIG. 4 A schematic of the process is shown in Figure 4:
- the sludge from the thickener of the roasting plant [8 in Figure 2] arrives at the hopper 1, which discharges into a reactor 3 provided with a stirring system and a reflux and hydraulic seal 2 refrigerant to equalize the internal pressure with the atmospheric Then, a concentrated solution of ammonia (20 to 24 "Be aqueous solution) is added, which in some cases can be substituted by sodium hydroxide solution (commercial solution of NaOH 40-50% by weight) and zinc shot.
- sodium hydroxide solution commercial solution of NaOH 40-50% by weight
- the mixture is heated to 50-70 ° C and kept under stirring for 6 to 8 hours after which, normally, 80% of the mercury is collected at the bottom of the reactor from which it is removed, after stopping the stirring, siphoning it; the pulp, if it still contains significant amounts of mercury, passes by gravity, to a second reactor identical to the first one, to which zinc shot is added and continued, maintaining the temperature at 50-70 ⁇ C, stirring, during a time of at least 8 hours, while the upper reactor starts a new operation.
- the mercury collected in this second reactor is also siphoned, while the remaining pulp, which may still have mercury, passes into a solid separation system / liquid (filter, centrifuge or decanter) returning wet solids to the oven while the waters, practically free of mercury, go to the effluent treatment.
- the liquid mercury obtained in this way normally has an undesirable content of metal impurities, especially Pb and Zn, which are easily removed by an oxidation treatment in column 4, where by means of an alkaline solution and the passage of compressed air, which in turn it contributes to stirring the mixture, those elements are separated, by oxidation, from the mercury.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU73318/91A AU651812B2 (en) | 1990-03-05 | 1991-03-05 | Method for cleaning and recovering metal mercury from roasting gases containing it |
NO91914329A NO914329L (no) | 1990-03-05 | 1991-11-05 | Fremgangsmaate for rensing og gjenvinning av metallisk kvikksoelv fra roestegasser som inneholder dette |
FI915217A FI915217A0 (fi) | 1990-03-05 | 1991-11-05 | Foerfarande foer rengoering och tillvaratagning av metalliskt kvicksilver fraon rostgaser innehaollande detsamma. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ESP9000643 | 1990-03-05 | ||
ES9000643A ES2021960A6 (es) | 1990-03-05 | 1990-03-05 | Procedimiento para la depuracion y recuperacion de mercurio en forma metalica a partir de gases de tostacion que lo contienen. |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991014010A1 true WO1991014010A1 (es) | 1991-09-19 |
Family
ID=8266234
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/ES1991/000012 WO1991014010A1 (es) | 1990-03-05 | 1991-03-05 | Procedimiento para la depuracion y recuperacion de mercurio en forma metalica a partir de gases de tostacion que lo contienen |
Country Status (8)
Country | Link |
---|---|
US (1) | US5232488A (es) |
EP (1) | EP0476079A1 (es) |
AU (1) | AU651812B2 (es) |
CA (1) | CA2054744A1 (es) |
ES (1) | ES2021960A6 (es) |
FI (1) | FI915217A0 (es) |
NO (1) | NO914329L (es) |
WO (1) | WO1991014010A1 (es) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5744109A (en) * | 1994-10-26 | 1998-04-28 | Asturiana De Zinc, S.A. | Continuous procedure for the simultaneous collection and precipitation of mercury in gases containing it |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE9303905L (sv) * | 1993-11-25 | 1995-05-26 | Boliden Mineral Ab | Förfarande och anordning för destruktion av kvicksilverhaltigt avfall |
DE4415947C2 (de) * | 1994-03-25 | 1999-04-22 | Thermoselect Ag | Verfahren zur Aufbereitung und Verwertung metallhaltiger Abscheidungen aus der Gasreinigung bei der thermischen Abfallbehandlung |
ES2098181B1 (es) * | 1994-10-26 | 1997-12-01 | Asturiana De Zinc Sa | Procedimiento para la obtencion de mercurio metal a partir de productos que contienen cloruro mercurioso. |
WO2009017736A1 (en) * | 2007-07-30 | 2009-02-05 | University Of Georgia Research Foundation Inc. | Diagnostic assay for trypanosoma cruzi infection |
CN110819815A (zh) * | 2019-12-03 | 2020-02-21 | 山东国大黄金股份有限公司 | 一种废酸净化方法 |
CN114082291A (zh) * | 2021-11-18 | 2022-02-25 | 郑晓峰 | 一种金属冶炼产生的废气中汞回收的设备及回收方法 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2324579A1 (fr) * | 1975-09-16 | 1977-04-15 | Boliden Ab | Procede d'extraction et de recuperation de mercure se trouvant dans des gaz |
EP0001456A1 (en) * | 1977-09-29 | 1979-04-18 | Akzo N.V. | Process for removing mercury from mercury vapour-containing gases |
EP0064962A1 (en) * | 1981-05-08 | 1982-11-17 | Boliden Aktiebolag | A method for separating gaseous, elementary mercury and gaseous halogenides of mercury and other heavy metals from a gas |
EP0208490A1 (en) * | 1985-07-01 | 1987-01-14 | A/S Niro Atomizer | A process for removal of mercury vapor and vapor of chlorodibenzodioxins and -furans from a stream of hot flue gas |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2453143C3 (de) * | 1973-11-09 | 1979-09-13 | Nippon Mining Co., Ltd., Tokio | Verfahren zum Entfernen von Quecksilber aus einem Schwefeldioxyd enthaltenden Gas |
SE455767B (sv) * | 1986-06-02 | 1988-08-08 | Erik Lindahl | Forfarande och anordning for avskiljning av kvicksilver fran rok- eller processgaser innehallande vattenanga |
-
1990
- 1990-03-05 ES ES9000643A patent/ES2021960A6/es not_active Expired - Lifetime
-
1991
- 1991-03-05 WO PCT/ES1991/000012 patent/WO1991014010A1/es not_active Application Discontinuation
- 1991-03-05 AU AU73318/91A patent/AU651812B2/en not_active Ceased
- 1991-03-05 EP EP19910904775 patent/EP0476079A1/en not_active Withdrawn
- 1991-03-05 CA CA 2054744 patent/CA2054744A1/en not_active Abandoned
- 1991-11-05 US US07/800,477 patent/US5232488A/en not_active Expired - Fee Related
- 1991-11-05 NO NO91914329A patent/NO914329L/no unknown
- 1991-11-05 FI FI915217A patent/FI915217A0/fi not_active Application Discontinuation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2324579A1 (fr) * | 1975-09-16 | 1977-04-15 | Boliden Ab | Procede d'extraction et de recuperation de mercure se trouvant dans des gaz |
EP0001456A1 (en) * | 1977-09-29 | 1979-04-18 | Akzo N.V. | Process for removing mercury from mercury vapour-containing gases |
EP0064962A1 (en) * | 1981-05-08 | 1982-11-17 | Boliden Aktiebolag | A method for separating gaseous, elementary mercury and gaseous halogenides of mercury and other heavy metals from a gas |
EP0208490A1 (en) * | 1985-07-01 | 1987-01-14 | A/S Niro Atomizer | A process for removal of mercury vapor and vapor of chlorodibenzodioxins and -furans from a stream of hot flue gas |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5744109A (en) * | 1994-10-26 | 1998-04-28 | Asturiana De Zinc, S.A. | Continuous procedure for the simultaneous collection and precipitation of mercury in gases containing it |
Also Published As
Publication number | Publication date |
---|---|
CA2054744A1 (en) | 1991-09-06 |
NO914329L (no) | 1992-01-03 |
ES2021960A6 (es) | 1991-11-16 |
AU7331891A (en) | 1991-10-10 |
FI915217A0 (fi) | 1991-11-05 |
US5232488A (en) | 1993-08-03 |
NO914329D0 (no) | 1991-11-05 |
AU651812B2 (en) | 1994-08-04 |
EP0476079A1 (en) | 1992-03-25 |
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