WO2011069221A1 - Physical-chemical process for the recovery of metals contained steel industry residues - Google Patents

Physical-chemical process for the recovery of metals contained steel industry residues Download PDF

Info

Publication number
WO2011069221A1
WO2011069221A1 PCT/BR2010/000418 BR2010000418W WO2011069221A1 WO 2011069221 A1 WO2011069221 A1 WO 2011069221A1 BR 2010000418 W BR2010000418 W BR 2010000418W WO 2011069221 A1 WO2011069221 A1 WO 2011069221A1
Authority
WO
WIPO (PCT)
Prior art keywords
aciary
powder
metals contained
zinc
recovery
Prior art date
Application number
PCT/BR2010/000418
Other languages
French (fr)
Inventor
Antônio Luiz DE ALMEIDA
Wiliam Flissak
José Roberto DOS SANTOS
Original Assignee
Mineração Tabiporã Ltda.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mineração Tabiporã Ltda. filed Critical Mineração Tabiporã Ltda.
Publication of WO2011069221A1 publication Critical patent/WO2011069221A1/en

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
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/02—Working-up flue dust
    • 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
    • C22B19/00—Obtaining zinc or zinc oxide
    • C22B19/30—Obtaining zinc or zinc oxide from metallic residues or scraps
    • 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
    • C22B19/00—Obtaining zinc or zinc oxide
    • C22B19/34—Obtaining zinc oxide
    • 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
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • C22B7/007—Wet processes by acid leaching
    • 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

  • This invention relates to a physical-chemical process intended for the treatment of steel industry residues of electric arc furnaces (EAF), known as "aciary powder", for the recovery of metals of interest, such as zinc, iron and other ones contained therein through soluble sulphates in aqueous medium under specific conditions.
  • EAF electric arc furnaces
  • reagents are used in order to prevent the formation of pellets or lumps from part of the reaction mass, which decreases the efficacy of the open chemical reactions of the residues' metal constituents by the concentrated sulphuric acid.
  • the chemical reagent accepted as efficient for this use is potassium chloride (KC1), once it originates a large mass of hydrogen chloride in gaseous form (HC1). This gas is very reactive thus requiring special equipment in order to prevent rapid wear through corrosion from occurring.
  • the process requires subsequent treatment steps through hydrometallurgy.
  • the separation of metal constituents is conducted by controlling pH values, so that each metal can precipitate in the form of a specific compound.
  • the neutralizing agent should necessarily be potassium hydroxide (KOH) allowing thus the recovery of potassium sulphate (K 2 S0 4 ) at the end of the process.
  • the process proposed herein uses mechanic resources associated with the chemical process, able to avoid the formation of pellets or lumps. It relates to the adaptation of a milling device to the calcination reactor.
  • the reactor starts to operate as a mechanical stirrer which homogeneously stirs the steel industry residues with the concentrated acid.
  • This adequacy intends to grind the agglomerated material during the addition of sulphuric acid.
  • the same efficacy of the open chemical reactions of the several residue constituents' crystal networks is maintained when compared to the previously described process.
  • the Brazilian patent application PI 0801716-6 shows a chemical process for the treatment of "aciary powder", for the recovery of metals of interest contained therein by obtaining soluble sulphates in aqueous medium.
  • Such process uses reagents, notably potassium chloride ( C1) in order to prevent the formation of pellets or lumps, which decrease the efficacy of the open chemical reactions of the residues' metal constituents by the concentrated sulphuric acid.
  • the process proposed herein is presented as an upgrade of that process, once it eliminates the need of such reagents by including a new mechanical stirring and milling step in the calcination furnace.
  • Fig. 1 shows the general process flow chart, where the several single operations and the several products (9, 15, 18, 21 , 26 and 30) generated in the process through the calcination (3) of the raw material (EAF) in acid medium by adding sulphuric acid (H 2 S0 4 ), are noted.
  • the process can be described as the production of salts or sulphates from aciary powder (EAF) constituent metals using dry concentrated sulphuric acid, under normal pressure and moderate temperatures. It consists in promoting the direct reaction of concentrated sulphuric acid with the aciary powder (EAF), maintaining a homogeneous mixture without the presence of water avoiding the agglomeration of the particles by means of a grinder associated to the calcination reactor (3), which operates in parallel with a mechanical stirrer, eliminating the need to add potassium chloride as a dispersive agent and the use of potassium hydroxide for the neutralization of solutions in the hydrometallurgy steps.
  • EAF aciary powder
  • This mechanical adequacy allowed the neutralizing agent to be replaced by liquefied ammonia thus obtaining a significant decrease in weight and cost of reagents and eliminating the need of special equipment resistant to corrosion.
  • Another advantage relates to a decrease in mass, which can reach levels up to 95% when a second surfactant calcination (7) is performed.
  • EAF aciary powder
  • a lead concentrate (9) with a Pb content between 30% and 40% which can be recycled for the casthouses or transformed into chemical products such as acetate, nitrate, oxide or lead sulphate.
  • This technological innovation also allows the replacement of potassium hydroxide (KOH) in the neutralizing steps by liquefied ammonia gas (NH 3 ).
  • KOH potassium hydroxide
  • NH 3 liquefied ammonia gas
  • KOH potassium hydroxide
  • the process consists in the production of salts or sulphates from aciary powder (EAF) constituent metals using dry concentrated sulphuric acid, under normal pressure and moderate temperatures, where the direct reaction of concentrated sulphuric acid with aciary powder (EAF) is promoted, maintaining a homogeneous mixture without the presence of water, avoiding particle agglomeration by using a grinding device, coupled with the calcination reactor (3), operating in parallel with a mechanical stirrer.
  • EAF aciary powder
  • the calcinated material primarily composed by the sulphates of metals present in the original residue, is transferred to a reactor (4) for aqueous leaching, where all the metal sulphates are solubilized, except lead and calcium sulphates.
  • the pulp resulting from leaching is filtered in filter press (5a), while the filtrate is taken to a tank (10) of metal sulphates solution for treatment through hydrometallurgy, recovering iron in a precipitation tank (1 1 ) as paragoetite (13), which is subsequently dehydrated through drying (14), transforming into hematite ( 15) to be applied as pigment or recycled in blast furnaces of steel industries.
  • Manganese (21) is recovered as bioxide concentrate (Mn0 2 ) to be transformed into manganese sulphate monohydrate (MnS0 4 .H 2 0).
  • Zinc (30) is precipitated as a basic salt [ZnS0 4 .3Zn(OH) 2 .4H 2 0] for subsequent recovery as zinc oxide (ZnO) or crystallized zinc sulphate heptahydrate (ZnS0 4 .7H 2 0) and ammonia e recovered at the end of the process as crystallized ammonia sulphate [(NH 4 ) 2 S0 4 ] (26).
  • the cake (6) resulting from the first leaching (3) of the calcinated material represents 15% o the mass of aciary powder (EAF) residue fed to the process. It is directed to the second calcination step (7) in a furnace which is similar to the first one, but with lower size.
  • the second calcination (7) is performed under the same conditions as the first (3) one and the gases are also absorbed in a column (31) containing plastic spheres, with the circulation of a lime milk suspension (32).
  • this second calcinate is submitted to aqueous leaching (8) for the extraction of more soluble sulphates that have been formed.
  • the pulp is also filtered in filter press (5b).
  • the filtrate is directed to the tank (10) of sulphate solution; the cake is washed with water and directed to the tank of water from the various washings for a new leaching process.
  • Such cake resulting from the second aqueous leaching (8), represents only 5% of the initial residue mass which was fed to the first calcination furnace (3), allowing a total mass decrease of 95%, constituting a lead concentrate (9) with contents between 30 - 40%.
  • the solution from the first (4) and the second leaching (8) from the two calcinates, containing all the soluble sulfates from metals present in the original aciary powder (EAF) is oxidized with a small amount of hydrogen peroxide (H 2 0 2 ) for the transformation of ferrous sulphate (FeS0 4 ), eventually present, into ferric sulphate [Fe 2 (S0 4 ) 3 ].
  • the solution is fed into a reactor (1 1 ) in a point which is immediately below the stirrer helices, which is the region presenting the highest turbulence and which provides the rapid homogenization of the reagents with the entire reaction volume.
  • Oxidation can also be conducted by air bubbling close to the point at which the solution is added to the reactor (1 1 ).
  • the temperature inside the reactor ( 1 1 ) is maintained between 60° C to 70° C by means of a superheated vapor passage tubing. pH is maintained between 3.0 and 3.5 by ammonia gas (NH 3 ) bubbling. Under such conditions, the concentration of ferric irons (Fe 3+ ) inside the reactor ( 1 1 ) is null, once all these ions are instantaneously precipitated in the form of paragoetite (13) and the ammonia is transformed into ammonia sulphate according to the following chemical reaction:
  • Paragoetite ( 13) is a crystalline ferric oxide hydrate (Fe 2 0 3 .H 2 0) which easily flocculates and decants providing a good solid/liquid separation and with a high filtration rate.
  • the pulp is filtered in filter press (5c) and the solution ( 16) is directed to a cementation process (17) with zinc powder.
  • the cake is washed with hot water for the extraction of soluble sulphates, being directed to the tank containing water from the washings.
  • This cake is further washed with ammonia solution in order to decompose jarosite which, eventually, can be formed in paragoetite precipitation (13) reactor ( 1 1) and, also, in order to solubilize a small amount of basic zinc and copper sulphates which are formed in the working pH.
  • the cake is still submitted to a third wash with hot water for the extraction of all the soluble sulphates which can still be present.
  • the paragoetite cake (13) is calcinated at 180° C in a rotary furnace (14) for dehydration and transformation into hematite (15), which is a red pigment, according to the following reaction:
  • the solution (16) of the tank, free from iron, is continuously transferred to the reactor (17) for copper removal by cementation with zinc powder.
  • the copper cement ( 18) is filtered in a filter press producing a copper sponge concentrate which is directed to the copper sulphate pentahydrate production unit.
  • the filtrate (19), free from copper, is directed to another tank.
  • This solution, free from iron and copper, is fed into a rector (20) for manganese oxidation with potassium permanganate, or another appropriate-, oxidizing agent, and precipitation of manganese bioxide (21 ) through pH control between 3.5 and 4.5, also using liquefied ammonia (NH ).
  • the solution (22) obtained from the aforementioned operations is purified, particularly containing zinc sulphate and ammonia sulphate. It is transferred to a reactor (23) where zinc is precipitated as a basic salt (27), by controlling pH between 6.0 and 7.5 by adding liquefied ammonia (NH 3 ). The temperature is maintained between 70° C and 80° C. The basic zinc salt (27), precipitated under these conditions is easily decanted and has a good filtration rate.
  • the following chemical reaction illustrates this operation: 4ZnS0 4 + 6NH 3 + 10H 2 O + 3(NH 4 ) 2 S0 4
  • the pulp is filtered in filter press (5f) and the filtrate (24), containing just ammonia sulphate (26), is directed to a tank.
  • the basic salt cake (27) is washed in the filter with water which is directed to the tank containing water from the washings.
  • the resulting basic zinc salt (27) can be used as a raw material for the production of zinc sulphates, zinc oxide, metal zinc and other products.
  • the basic salt cake (27) is transferred to a reactor (28), repulped with a small volume of water and acidulated with sulphuric acid until pH between 4.0 - 4.5 to be transformed into a concentrated pure zinc sulphate solution, according to the following reaction:
  • This zinc sulphate concentrated solution is evaporated until the salt heptahydrate (ZnS0 .7H 2 0) is crystallized and cooled for subsequent centrifugation of such crystals (30) in a centrifuge (29) for separation.
  • the parent water returns to the evaporator and the crystals (30) are stored into appropriate silo for subsequent packaging into bags.
  • the basic salt cake (27) is calcinated at temperatures between 750° C and 1.000° C in a furnace (33), thus generating zinc oxide (34).
  • zinc oxide (34) Upon calcinations, dehydration and thermal decompositon of the basic salt compound occurs, generating zinc oxide (34), sulphur dioxide, oxygen and water vapor.
  • the sulphur dioxide is absorbed by a manganese bioxide pulp, generating manganese sulphate monohydrate (MnS0 4 .H 2 0).
  • the decomposition reaction is showed below: ZnS0 4 .3Zn(OH) 2 .4H 2 0 -> 4ZnO + S0 2 ⁇ + 0 2 T + ⁇ 2 ⁇ ⁇
  • the zinc basic salt filtration solution (24) containing the whole ammonia sulphate (26) is transferred to a tank where it is evaporated until ammonia sulphate [(NH 4 ) 2 S0 4 ] (26) is crystallized.
  • the crystals are separated by centrifugation in a centrifuge (25) and the parent water returns to the evaporators and the crystals (26) are stored in appropriates silos for subsequent packaging into bags.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

Physical-chemical process intended for the treatment of steel industry residues of electric arc furnaces (EAF), known as "aciary powder", for the recovery of zinc, iron and other metals of interest contained therein through obtaining soluble sulphates in aqueous medium, with a mechanical step of disaglutination, using a grinder device to the calcination reactor intended to homogenize steel industry residues with concentrated acid and grinding the agglomerated material during the addition of acid.

Description

PHYSICAL-CHEMICAL PROCESS FOR THE RECOVERY OF METALS
CONTAINED STEEL INDUSTRY RESIDUES
Field of the invention
This invention relates to a physical-chemical process intended for the treatment of steel industry residues of electric arc furnaces (EAF), known as "aciary powder", for the recovery of metals of interest, such as zinc, iron and other ones contained therein through soluble sulphates in aqueous medium under specific conditions.
Background of the invention
In the current steel industry residues treatment process, called aciary electric arc furnace (EAF) powder, reagents are used in order to prevent the formation of pellets or lumps from part of the reaction mass, which decreases the efficacy of the open chemical reactions of the residues' metal constituents by the concentrated sulphuric acid. The chemical reagent accepted as efficient for this use is potassium chloride (KC1), once it originates a large mass of hydrogen chloride in gaseous form (HC1). This gas is very reactive thus requiring special equipment in order to prevent rapid wear through corrosion from occurring.
The process requires subsequent treatment steps through hydrometallurgy. The separation of metal constituents is conducted by controlling pH values, so that each metal can precipitate in the form of a specific compound. When potassium chloride is applied, the neutralizing agent should necessarily be potassium hydroxide (KOH) allowing thus the recovery of potassium sulphate (K2S04) at the end of the process.
The process proposed herein uses mechanic resources associated with the chemical process, able to avoid the formation of pellets or lumps. It relates to the adaptation of a milling device to the calcination reactor. Thus, the reactor starts to operate as a mechanical stirrer which homogeneously stirs the steel industry residues with the concentrated acid. This adequacy intends to grind the agglomerated material during the addition of sulphuric acid. In this system, the same efficacy of the open chemical reactions of the several residue constituents' crystal networks is maintained when compared to the previously described process.
Analysis of the state of arts
The Brazilian patent application PI 0801716-6, in the secrecy period, shows a chemical process for the treatment of "aciary powder", for the recovery of metals of interest contained therein by obtaining soluble sulphates in aqueous medium. Such process uses reagents, notably potassium chloride ( C1) in order to prevent the formation of pellets or lumps, which decrease the efficacy of the open chemical reactions of the residues' metal constituents by the concentrated sulphuric acid. The process proposed herein is presented as an upgrade of that process, once it eliminates the need of such reagents by including a new mechanical stirring and milling step in the calcination furnace.
Description of the drawings
Fig. 1 shows the general process flow chart, where the several single operations and the several products (9, 15, 18, 21 , 26 and 30) generated in the process through the calcination (3) of the raw material (EAF) in acid medium by adding sulphuric acid (H2S04), are noted.
Brief description of the invention
The process can be described as the production of salts or sulphates from aciary powder (EAF) constituent metals using dry concentrated sulphuric acid, under normal pressure and moderate temperatures. It consists in promoting the direct reaction of concentrated sulphuric acid with the aciary powder (EAF), maintaining a homogeneous mixture without the presence of water avoiding the agglomeration of the particles by means of a grinder associated to the calcination reactor (3), which operates in parallel with a mechanical stirrer, eliminating the need to add potassium chloride as a dispersive agent and the use of potassium hydroxide for the neutralization of solutions in the hydrometallurgy steps.
This mechanical adequacy allowed the neutralizing agent to be replaced by liquefied ammonia thus obtaining a significant decrease in weight and cost of reagents and eliminating the need of special equipment resistant to corrosion.
Another advantage relates to a decrease in mass, which can reach levels up to 95% when a second surfactant calcination (7) is performed. Thus, almost all the metals contained in the aciary powder (EAF) can be recycled, once the remaining mass, around 5%, refers to a lead concentrate (9) with a Pb content between 30% and 40% which can be recycled for the casthouses or transformed into chemical products such as acetate, nitrate, oxide or lead sulphate.
This technological innovation also allows the replacement of potassium hydroxide (KOH) in the neutralizing steps by liquefied ammonia gas (NH3). The mass reduction in the reagent consumption is approximately 3 fold, i.e., for each mol of neutralized sulphuric acid, two moles of potassium hydroxide are spent. In case of using liquefied ammonia, two moles are required, equivalent to just 34 g of NH3. Another benefit from the process development is related to the circuit dilution once potassium hydroxide (KOH) should be used in the form of a diluted aqueous solution, while ammonia is doses in the form of gas, without adding water to the circuit, being able to work with more concentrated solutions, thus saving energy in zinc and ammonia sulphates crystallization (29 and 25, respectively). The reagents costs, which represent a significant decrease, should further be considered.
Detailed description of the invention
The process consists in the production of salts or sulphates from aciary powder (EAF) constituent metals using dry concentrated sulphuric acid, under normal pressure and moderate temperatures, where the direct reaction of concentrated sulphuric acid with aciary powder (EAF) is promoted, maintaining a homogeneous mixture without the presence of water, avoiding particle agglomeration by using a grinding device, coupled with the calcination reactor (3), operating in parallel with a mechanical stirrer.
It is necessary to dry the material in a drying furnace (2) until the humidity is lower than 2% in mass for subsequent milling in a mill (2) until a granulometry of 45 micra is reached. Following this preparation, the material is fed into the pre-heated calcination furnace (3) at a temperature of around 120° C. The stirrer and grinder are started and the concentrated sulphuric acid is continuously fed to the reactor (3) until a ratio of 1.1 kg of acid to 1 kg of residue is reached.
In this process, the reaction of opening the crystal networks of the constituents starts occurring as the acid is fed. For being exothermic reactions, the temperature of the reaction mass reaches values between 230° C and 250° C. Under these conditions, when the addition of acid is completed, almost all the residue constituents were transformed into their respective sulphates. The organic components, such as dioxins and furans are also chemically destroyed and transformed into carbon dioxide (C02), water vapor, molecular chlorine (Cl2) and/or hydrogen chloride (HC1), molecular fluorine (F2) and/or hydrogen fluoride (HF). All the produced gases are absorbed by a lime milk [Ca (OH)2] suspension (32), circulated in a column (31 ) containing plastic spheres. In the top of the column there is an exhauster which aspirates all the gases making them leach through the bed, in a counter flow against the lime milk (32). Only water vapor, free from components that are harmful to the environment, are released in the atmosphere.
The calcinated material, primarily composed by the sulphates of metals present in the original residue, is transferred to a reactor (4) for aqueous leaching, where all the metal sulphates are solubilized, except lead and calcium sulphates. The pulp resulting from leaching is filtered in filter press (5a), while the filtrate is taken to a tank (10) of metal sulphates solution for treatment through hydrometallurgy, recovering iron in a precipitation tank (1 1 ) as paragoetite (13), which is subsequently dehydrated through drying (14), transforming into hematite ( 15) to be applied as pigment or recycled in blast furnaces of steel industries.
Copper (1 8), in its turn, is recovered as copper sponge concentrate for subsequent transformation into copper pentahydrate (CuS04.5H20). Manganese (21) is recovered as bioxide concentrate (Mn02) to be transformed into manganese sulphate monohydrate (MnS04.H20). Zinc (30) is precipitated as a basic salt [ZnS04.3Zn(OH)2.4H20] for subsequent recovery as zinc oxide (ZnO) or crystallized zinc sulphate heptahydrate (ZnS04.7H20) and ammonia e recovered at the end of the process as crystallized ammonia sulphate [(NH4)2S04] (26).
The cake (6) resulting from the first leaching (3) of the calcinated material represents 15% o the mass of aciary powder (EAF) residue fed to the process. It is directed to the second calcination step (7) in a furnace which is similar to the first one, but with lower size. The second calcination (7) is performed under the same conditions as the first (3) one and the gases are also absorbed in a column (31) containing plastic spheres, with the circulation of a lime milk suspension (32).
Similarly, this second calcinate is submitted to aqueous leaching (8) for the extraction of more soluble sulphates that have been formed. The pulp is also filtered in filter press (5b). The filtrate is directed to the tank (10) of sulphate solution; the cake is washed with water and directed to the tank of water from the various washings for a new leaching process.
Such cake, resulting from the second aqueous leaching (8), represents only 5% of the initial residue mass which was fed to the first calcination furnace (3), allowing a total mass decrease of 95%, constituting a lead concentrate (9) with contents between 30 - 40%.
The solution from the first (4) and the second leaching (8) from the two calcinates, containing all the soluble sulfates from metals present in the original aciary powder (EAF) is oxidized with a small amount of hydrogen peroxide (H202) for the transformation of ferrous sulphate (FeS04), eventually present, into ferric sulphate [Fe2(S04)3]. Subsequently, the solution is fed into a reactor (1 1 ) in a point which is immediately below the stirrer helices, which is the region presenting the highest turbulence and which provides the rapid homogenization of the reagents with the entire reaction volume. Oxidation can also be conducted by air bubbling close to the point at which the solution is added to the reactor (1 1 ). The temperature inside the reactor ( 1 1 ) is maintained between 60° C to 70° C by means of a superheated vapor passage tubing. pH is maintained between 3.0 and 3.5 by ammonia gas (NH3) bubbling. Under such conditions, the concentration of ferric irons (Fe3+) inside the reactor ( 1 1 ) is null, once all these ions are instantaneously precipitated in the form of paragoetite (13) and the ammonia is transformed into ammonia sulphate according to the following chemical reaction:
Fe2(S04)3 + 6NH3 + 4H20 - 2F60.0H! + 3(NH4)2S04
Paragoetite ( 13) is a crystalline ferric oxide hydrate (Fe203.H20) which easily flocculates and decants providing a good solid/liquid separation and with a high filtration rate. The pulp is filtered in filter press (5c) and the solution ( 16) is directed to a cementation process (17) with zinc powder. The cake is washed with hot water for the extraction of soluble sulphates, being directed to the tank containing water from the washings. This cake is further washed with ammonia solution in order to decompose jarosite which, eventually, can be formed in paragoetite precipitation (13) reactor ( 1 1) and, also, in order to solubilize a small amount of basic zinc and copper sulphates which are formed in the working pH. The cake is still submitted to a third wash with hot water for the extraction of all the soluble sulphates which can still be present.
The following reactions provide a better idea of this double objective of the ammonia washing:
Jarosite decomposition
2NH4Fe3(S04)2(OH)6 + 6NH3 -» 3Fe203i + 4(NH4)2S04 + 3H20
Decomposition of basic zinc and copper salts
ZnS04.3Zn(OH)2.4H20 + 24NH3 Zn(NH3)6S04 + 3Zn(NH3)6(OH)2 + 4H20
CuS04.3Cu(OH)2.4H20 + 24NH3 -> Cu(NH3)6S04 + 3Cu(NH3)6(OH)3 + 4H20
Following these washings, the paragoetite cake (13) is calcinated at 180° C in a rotary furnace (14) for dehydration and transformation into hematite (15), which is a red pigment, according to the following reaction:
2FeO.OH - Fe203 + H20†
When paragoetite (13) is dehydrated at temperatures higher than 180° C, other pigments can be obtained such as brown and black.
The solution (16) of the tank, free from iron, is continuously transferred to the reactor (17) for copper removal by cementation with zinc powder. The copper cement ( 18) is filtered in a filter press producing a copper sponge concentrate which is directed to the copper sulphate pentahydrate production unit. The filtrate (19), free from copper, is directed to another tank. This solution, free from iron and copper, is fed into a rector (20) for manganese oxidation with potassium permanganate, or another appropriate-, oxidizing agent, and precipitation of manganese bioxide (21 ) through pH control between 3.5 and 4.5, also using liquefied ammonia (NH ). The chemical reaction below illustrates this operation: 3MnS04 + 2KMn04 + 4NH3 + 2H20 5Mn02i + 2(NH4)2S04 + K2S04 The pulp is filtered in filter press (5e), the washed cake and the resulting solution are directed to the tank containing water from the washings.
The solution (22) obtained from the aforementioned operations is purified, particularly containing zinc sulphate and ammonia sulphate. It is transferred to a reactor (23) where zinc is precipitated as a basic salt (27), by controlling pH between 6.0 and 7.5 by adding liquefied ammonia (NH3). The temperature is maintained between 70° C and 80° C. The basic zinc salt (27), precipitated under these conditions is easily decanted and has a good filtration rate. The following chemical reaction illustrates this operation: 4ZnS04 + 6NH3 + 10H2O
Figure imgf000009_0001
+ 3(NH4)2S04 The pulp is filtered in filter press (5f) and the filtrate (24), containing just ammonia sulphate (26), is directed to a tank. The basic salt cake (27) is washed in the filter with water which is directed to the tank containing water from the washings.
The resulting basic zinc salt (27) can be used as a raw material for the production of zinc sulphates, zinc oxide, metal zinc and other products. For the production of zinc sulphate (30), the basic salt cake (27) is transferred to a reactor (28), repulped with a small volume of water and acidulated with sulphuric acid until pH between 4.0 - 4.5 to be transformed into a concentrated pure zinc sulphate solution, according to the following reaction:
ZnS04.3Zn(OH)2.4H20 + 3H2S04 -» 4ZnS04 + 10H2O
This zinc sulphate concentrated solution is evaporated until the salt heptahydrate (ZnS0 .7H20) is crystallized and cooled for subsequent centrifugation of such crystals (30) in a centrifuge (29) for separation. The parent water returns to the evaporator and the crystals (30) are stored into appropriate silo for subsequent packaging into bags.
For the production of zinc oxide (34), the basic salt cake (27) is calcinated at temperatures between 750° C and 1.000° C in a furnace (33), thus generating zinc oxide (34). Upon calcinations, dehydration and thermal decompositon of the basic salt compound occurs, generating zinc oxide (34), sulphur dioxide, oxygen and water vapor. The sulphur dioxide is absorbed by a manganese bioxide pulp, generating manganese sulphate monohydrate (MnS04.H20). The decomposition reaction is showed below: ZnS04.3Zn(OH)2.4H20 -> 4ZnO + S02 † + 02 T + Η2Οτ
The zinc basic salt filtration solution (24) containing the whole ammonia sulphate (26) is transferred to a tank where it is evaporated until ammonia sulphate [(NH4)2S04] (26) is crystallized. The crystals are separated by centrifugation in a centrifuge (25) and the parent water returns to the evaporators and the crystals (26) are stored in appropriates silos for subsequent packaging into bags.
This invention is not limited to the representations commented or illustrated herein, and should be understood in its wide scope. A number of changes and other representations of the invention will come to mind of those who are familiar with the art to which this invention pertains, having the benefit of the teaching presented in the previous descriptions and attached drawings. In addition, it is to be understood that the invention is not limited to the specific disclosed form and that changes and other forms are understood as included in the scope of the attached claims. Although specific terms are employed here, they are use only in a generic and descriptive form and not for the purpose of limitation.

Claims

CLAIMS PH YSICAL-CHEMICAL PROCESS FOR THE RECOVERY OF METALS CONTAINED STEEL INDUSTRY RESIDUES
1. The process of recovering of metals contained in aciary powder characterized by promoting the homogeneous mixture of aciary powder (EAF) with concentrated sulphuric acid, using a grinder and a stirrer associated with the calcination furnace (3) in order to prevent the agglomeration of particles in the reaction mass.
2. The process of recovering metals contained in aciary powder, according to claim 1 , characterized by developing under normal atmospheric pressure.
3. The process of recovering metals contained in aciary powder, according to claim 1 , characterized by developing under temperatures between 150° C and 250° C.
4. The process of recovering metals contained in aciary powder, according to claim 1 , characterized by promoting the elimination of organic compounds containing halogens such as chlorine and fluorine.
5. The process of recovering metals contained in aciary powder, according to claim 1 , characterized by promoting zinc precipitation under the form of a basic salt cake (27) by adjusting pH and adding ammonia for a preferred range between 6.0 and 7.5, more preferably at a pH between 6.5 and 6.7 and exactly at a pH of 6.6.
6. The process of recovering metals contained in aciary powder, according to claim 1 , characterized by presenting a calcination step
(33) of zinc basic salt (27) for the production of zinc oxide (ZnO)
(34) , at a preferred temperature between 800° C and 1200° C, more preferably at temperatures between 900° C and 1 100° C and exactly at a temperature of 1000° C.
7. The process of recovering metals contained in aciary powder, according to claim 1 , characterized by presenting a basic salt solubilization step with sulphuric acid for the production of a concentrated zinc solution, followed by the recovery of zinc sulphate heptahydrate [ZnS04.7H20] (30) by crystallization.
PCT/BR2010/000418 2009-12-11 2010-12-10 Physical-chemical process for the recovery of metals contained steel industry residues WO2011069221A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BRPI0905473-1A BRPI0905473A2 (en) 2009-12-11 2009-12-11 physicochemical process for the recovery of metals contained in steel industry waste
BRPI0905473-1 2009-12-11

Publications (1)

Publication Number Publication Date
WO2011069221A1 true WO2011069221A1 (en) 2011-06-16

Family

ID=43567525

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/BR2010/000418 WO2011069221A1 (en) 2009-12-11 2010-12-10 Physical-chemical process for the recovery of metals contained steel industry residues

Country Status (2)

Country Link
BR (1) BRPI0905473A2 (en)
WO (1) WO2011069221A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104176757A (en) * 2014-08-08 2014-12-03 石棉县亿欣钙业有限责任公司 Light calcium carbonate suspension calcining process
EP3555327A4 (en) * 2016-12-15 2020-08-12 Teknologian Tutkimuskeskus VTT OY Processing of industrial metal-containing waste materials
IT202000016192A1 (en) * 2020-07-03 2022-01-03 Ecotec Gestione Impianti S R L PROCEDURE FOR THE SIMULTANEOUS TREATMENT OF RESIDUES FROM THE NON-FERROUS METALLURGICAL INDUSTRY, WITH THE OBTAINING OF PIGMENTS BASED ON IRON OXIDES AND OTHER PRODUCTS THAT CAN BE VALUED, IN ACCORDANCE WITH THE STRATEGIES OF THE CIRCULAR ECONOMY

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3691038A (en) * 1969-09-25 1972-09-12 Det Norske Zenkkompani As Process for the recovery of zinc from zinc- and iron-containing materials
US5431713A (en) * 1994-07-19 1995-07-11 Metals Recycling Technologies Crop. Method for the reclamation of metallic compounds from zinc and lead containing dust
KR100924296B1 (en) * 2009-03-31 2009-11-02 (주)한양미네랄 Process for preparing zinc sulfate from electric arc furnace dust, and an apparatus therefor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3691038A (en) * 1969-09-25 1972-09-12 Det Norske Zenkkompani As Process for the recovery of zinc from zinc- and iron-containing materials
US5431713A (en) * 1994-07-19 1995-07-11 Metals Recycling Technologies Crop. Method for the reclamation of metallic compounds from zinc and lead containing dust
KR100924296B1 (en) * 2009-03-31 2009-11-02 (주)한양미네랄 Process for preparing zinc sulfate from electric arc furnace dust, and an apparatus therefor

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
HAVLIK T ET AL: "Atmospheric leaching of EAF dust with diluted sulphuric acid", HYDROMETALLURGY, ELSEVIER SCIENTIFIC PUBLISHING CY. AMSTERDAM, NL, vol. 77, no. 1-2, 1 April 2005 (2005-04-01), pages 41 - 50, XP004777572, ISSN: 0304-386X, DOI: DOI:10.1016/J.HYDROMET.2004.10.008 *
HAVLIK T ET AL: "PRESSURE LEACHING OF EAF DUST WITH SULPHURIC ACID//SCHWEFELSAURE DRUCKLAUGUNG VON ELEKTROLICHTBOGENOFENSTAUB//LA LIXIVIATION A L'ACIDE SULFURIQUE ET SOUS PRESSION DES POUSSIERES DE FOUR A ARC", WORLD OF METALLURGY - ERZMETALL, GDMB - MEDIENVERLAG, CLAUSTHAL-ZELLERFELD, DE, vol. 57, no. 2, 1 March 2004 (2004-03-01), pages 83 - 90, XP001200022, ISSN: 1613-2394 *
JHA M K ET AL: "Review of hydrometallurgical recovery of zinc from industrial wastes", RESOURCES CONSERVATION AND RECYCLING, ELSEVIER SCIENCE PUBLISHER, AMSTERDAM, NL, vol. 33, no. 1, 1 August 2001 (2001-08-01), pages 1 - 22, XP004246483, ISSN: 0921-3449, DOI: DOI:10.1016/S0921-3449(00)00095-1 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104176757A (en) * 2014-08-08 2014-12-03 石棉县亿欣钙业有限责任公司 Light calcium carbonate suspension calcining process
EP3555327A4 (en) * 2016-12-15 2020-08-12 Teknologian Tutkimuskeskus VTT OY Processing of industrial metal-containing waste materials
IT202000016192A1 (en) * 2020-07-03 2022-01-03 Ecotec Gestione Impianti S R L PROCEDURE FOR THE SIMULTANEOUS TREATMENT OF RESIDUES FROM THE NON-FERROUS METALLURGICAL INDUSTRY, WITH THE OBTAINING OF PIGMENTS BASED ON IRON OXIDES AND OTHER PRODUCTS THAT CAN BE VALUED, IN ACCORDANCE WITH THE STRATEGIES OF THE CIRCULAR ECONOMY
WO2022003747A1 (en) * 2020-07-03 2022-01-06 Ecotec Gestione Impianti S.R.L. Process for the simultaneous treatment of residues of the non-ferrous metallurgical industry to produce pigments based on iron oxides and other valued products, in accordance with circular economy strategies

Also Published As

Publication number Publication date
BRPI0905473A2 (en) 2011-08-02

Similar Documents

Publication Publication Date Title
Binnemans et al. Hydrometallurgical processes for the recovery of metals from steel industry by-products: a critical review
Liu et al. A novel method to extract vanadium and chromium from vanadium slag using molten NaOH‐NaNO 3 binary system
AU2011334600B2 (en) Process for recovering zinc and/or zinc oxide II
EP3169817B1 (en) Hydrometallurgical process to produce pure magnesium metal and various by-products
US11912582B2 (en) Systems and methods to recover value-added materials from gypsum
US20230220516A1 (en) Process for recovering titanium dioxide
CN115427593A (en) Vanadium recovery from basic slag materials
WO2011069221A1 (en) Physical-chemical process for the recovery of metals contained steel industry residues
BRPI0801716A2 (en) chemical process for the recovery of metals contained in steel industry waste
AU2013389686B2 (en) Method and plant for processing roasted pyrites
US20230312364A1 (en) Processing of titaniferous ores and minerals
AU2010217184A1 (en) Zinc oxide purification
CN112442591B (en) Copper-nickel leaching and iron separation method for copper-nickel sulfide ore
AU2013220926B2 (en) Process for zinc oxide production from ore
JP7280573B2 (en) Method for producing precursor of lithium adsorbent
US2424351A (en) Process for the treatment of marmatitic zinc ores with hci
JP2021008385A (en) Method for producing zinc carbonate
CN104386754B (en) A kind of technique for preparing ammonium tungstate solution
US2363572A (en) Treatment of zinc carbonate ores
WO2023218288A1 (en) Beneficiation of manganese-bearing ore
CA3218330A1 (en) Systems and methods to recover value-added materials from gypsum
WO2024149937A1 (en) A method for separating manganese in leaching of cobalt and/or nickel from delithiated solid raw material and use of delithiated solid raw material comprising cathode material
CN117843029A (en) Method for realizing metal step separation in metallurgical slag based on silicate regulation and control

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10803337

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10803337

Country of ref document: EP

Kind code of ref document: A1