DE2059580C - Process for cleaning pyrite and pyrrhotite burnouts from non-ferrous metals, arsenic and sulfur - Google Patents

Description

Burn-off temperature - mixed and then burned-offs converted into granules or pellets

are cured at temperatures above 1150 ° C. In the Italian patent 772287 is a method for cleaning pyrite burns from Non-ferrous metals such as Cu, Zn, Pb, Au, Ag, Ni, Co, Cd and Mn are described. This procedure includes the following stages:

a) pre-heating at temperatures between 600 and 800 ⁰ C and partial or complete reduction (20 to 100 ° / o) is carried out of hematite to magnetite This operation by canning a carbon-containing fuel in the fluidized bed reactor, together with air which is an absence of the total combustion.

b) chlorination and oxidation of the reduced at temperatures up to 650 ⁰ C and 950 burn-in a fluidized bed reactor. The gaseous mixture consisting of air and 1 to 20 ^e / ₀ chlorine flows in countercurrent to the burn-offs. The amount of chlorine used is that for the formation of non-ferrous chlorides erf orderlichestöchiometrische amount with an excess of 5 to 20 ° / _0th

c) washing or sprinkling the metal chloride vapors with water, whereby a solution is obtained, from which the metals are extracted by conventional hydrometallurgical processes.

The burns, which have been cleaned of non-ferrous metals, but still contain sulfur, are converted directly to the Granulating or pelletizing stage promoted if you

Iron content is sufficiently high, otherwise

they are first subjected to magnetic enrichment after a previous magnetization reduction.

The invention relates to a method for cleaning set. The sulfur is _{evaporated as SO 8} during the high of pyrite and pyrrhotite burns of non-ferrous 45 temperature hardening of the pellets, metals, arsenic and sulfur. If this procedure is modified according to a

are treated in a fluidized bed at 850 to 950 ⁰ C with a mixture of chlorine and oxygen-containing gases, in which the chlorine content K) 5 to 120 ° / _{0 of} the stoichiometric amount, based on the non-ferrous metals and the arsenic »5 in the burnups and in the admixed pyrite, the oxygen content in the gases flowing out being 0.5 to 5 percent by volume.

2. The method according to claim 1, characterized in that it is carried out in two stages, wherein in the first stage burn-offs, pyrite, air and the gases of the second stage are fed during in the second stage the burnup of the first stage, as containing pyrite, chlorine and oxygen Gases are supplied, the total amounts of pyrite, oxygen and chlorine containing gases the quantities of claim 1 are the same.

3. The method according to claim 1, characterized in that it is carried out in a single stage will.

4. The method according to any one of the preceding claims, characterized in that air is used as the oxygen-containing gas.

5. The method according to any one of the preceding claims, characterized in that the Oxygen content in the outflowing gases is 0.5 to 1 percent by volume.

35

So that pyrite and pyrrhotite burns or ashes can be used in the metallurgical industry, they must have a high iron content and be almost free of non-ferrous metals, such as. B. Copper, zinc, lead, arsenic and sulfur. The maximum permissible limits for these impurities are constantly falling. Currently should be a reasonably good commercial product no more than 0.03 to each Proposal that does not belong to the prior art, the reduction takes place at higher temperatures, for example 850 to 95O ° C., and with sufficiently long residence times, for example 30 to 90 minutes, in order to completely decompose the ferrous arsenate. The subsequent chlorination is carried out in such a way that an oxygen concentration greater than 3 ° / ₀ is maintained in the gases flowing out. Through this

0.05 ° / ₀ copper, zinc, lead, and not more than 0.01 to 55 still present after the chlorination 0.03% arsenic and sulfur (cf.. United arsenic in the form of a soluble arsenates, which by

States Steel, "The Making, Shaping and Treating of Steel", 1957).

The non-ferrous metals are by transfer. into soluble chlorides or sulfates and subsequent removal of the salts by acid extraction or leaching with acid or by converting the metals into chlorides with Cl ₂ , HCl, CaCl ₂ or the like and subsequent removal from the burn-offs or ashes by high-temperature volatilization - evaporation eliminated.

The removal of arsenic occurs either during the roasting of the pyrite or during the various Acid leaching of the cleaned burns is removable. However, in this case too, the residual sulfur becomes only completely removed during high temperature pelletization.

In a further modification of the method according to a proposal which is also not part of the state of the art, ^{reduction is carried out in the presence of HCl and at temperatures of 850 to 950 °} C. in order to achieve a high-grade removal of sulfur and arsenic. The subsequent chlorination takes place while maintaining the lowest possible oxygen concentration within the outflowing gases, see above

3 4

that together with the evaporation the non-ferrous content is low, an excellent raw material for

metal chlorides the removal of residual sulfur the production of pellets or tablets, iron-

_{A nd} arsenic is completed. Which eventually floated or rough for making fabrics

The burn-offs obtained do not require an additional high degree of conversion into metal iur Treatment, with the exception of a fortification for the iron industry.

in the event that the iron content is still low. The solutions obtained by this procedure

These burns are used in the iron industry and have a high content of non-ferrous metals

manure. i have low acidity and contain Fe and As,

From the German patent specification 970 903 it is possibly Cu in the form of a low valence, also already known, in the case of chlorinating roasting, this proves to be an economic advantage as a result

of Pyrite AbbräadcM at temperatures between about the decrease in the use of neutralizing agents

400 and 700 ° C fish to feed pyrite. and binding agents for the extraction of the ^ P ™haben ·

The above? The methods described have finally contained the gases after washing

however, the disadvantage that the chlorination phase always and the subsequent separation of the Metaueiüe partial reduction of the burn-offs of Hematite 15 chloride and the As compounds, that of the KeaKior

precedes to magnetite. The originally entrained fine powder, the Cl ₂ and one

The sulfur contained in the burn-up becomes the proportion of SO ₂ except for N ₂ and O ₂ SO _t in a nonen

mostly removed with the outflowing gases. Quantity and can therefore be used for the production of

The object of the invention is now to provide a method for sulfuric acid to be effectively used. Purification of Pjnt and Pyrrhotine burns from ao The two-stage process according to the invention can ioi-

Specify non-metals, aisene and sulfur, where the following are carried out in equal measure:

The cleaned pyrite burns that result from the ryrii-

tion to magnetite occurs. Roasting plant come to be at a temperature

The subject of the invention is a process for between 500 and 800 ° C in a ^ nReanonur Purification of Pfrit and Pyrrhotinabbrungen von as the chlorination introduced, which at 850 to vdu l.

Non-ferrous metals, arsenic and sulfur that works through it. In the reactor there is also pyrite in one

is characterized in that the pyrite burns, which consist of 25 to 200 kg FeS, per ton burned

come to the roasting oven at 500 to 800 ⁰ C, introduced with pyrite, the 200 kg of pyrite serving for this purpose

in quantities of 200 to 25 kg FeS ₂ per ton of burn-off from a temperature of 500 to yx u to burn - depending on the temperature of the burn-offs - while 25 kg of pyrite bring the temperature of

mixed and then allowed to rise ^{to 850 °} C. in a fluidized bed at 850 to 800. For the perfect

950 "C with a mixture of chlorine and oxygen combustion of the pyrite are from below 1um,

containing gases are treated, in which the approximately 3 Nm ⁸ air per 1 kg of pyrite, dn 75 to MW Nm / ι

Chlorine content 105 to 120% of the stoichiometric burnup, introduced together with the gas, aas of Amount, based on the non-ferrous metals and that comes to the second chlorination reactor, which

Arsenic in the burns and in the mixed chloride and the Cl ₂ , which does not yet contain

Pyrite, where the oxygen content in the has reacted. The effluent from the first reactor

outflowing Gaien is 0.5 to 5 percent by volume. Gases contain 0.5 to 5 percent by volume of oxygen

By adding pyrite according to the invention to the first reactor, the partial cleaning of the burn-offs takes place after the combustion, the ₄ o of the burn-offs and the combustion of the pyrite takes place

Temperature in the fluidized bed at the desired level of heat generation, which is the maintenance

Maintained value, oluie that doing so on external heat- the desired temperature and evaporation

sources must be used. or volatilization of the chlorides

The burn-ups are cleaned either in from the reaction of the non-ferrous metals with the

a single pin or in two stages. So 45 can form chlorine. . · ": _ ,."

for example the oxidation and chlorination in die partially purified in the first reactor

be carried out in a single fluidized bed, in burn-ups come into ^a second reactor

That at the same time fire-burning of pyrite, pyrite and the like from below also between 850 and 950 ° C, she won

Chlorine and air or any other oxygen with Cl ₂ in a maximum concentration of 105 to 120 "-containing gas are introduced. You can also use the stoichiometric amount, based on the not

in a first fluidized bed pyrite burns, fresh pyrite ferrous metals and the arsenic, which in the rym-

and from below air and the burn off from the second stage contain at the beginning and in the pyrite

Introduce originating Ga «. Are zusammenkom _men in the second stage. "That" d ^ J " ^A ^ edge

will then clean the pyrite burn-off of the first stage, we.terh.n, in a satisfactory manner

Tr shear pyrite and air and chlorine introduced from below. ₅₅ The gases abstaining from the second factor

Of course, the total amounts of must only be very small amounts of O ₂ less than

Pyrite, air and chlorine be the same as above. l »/“, included. In this way, ^ margins become

Also freed from sulfur and arsenic when cleaning the pyrite burns. Achieved this

According to the invention it is possible to free burn-ups by providing the second reactor in addition to ChIo

of non-ferrous metals, arsenic and sulfur to 60 air and pyrite are added instead of air

Reason of hydrochloric acid and sulfuric acid slightly acidic can also be a gas nut e.neni ^^ ^ J ¹ * 5

Solutions with a high content of non-ferrous oxygen are used ^b

^ £ ^ t: ^{chicken housing to GeS} ^^ ΖΐΤ

un _g the ^^ ΖΐΤ, ^^

^ f ^ U ^ g ^ ini ^ n burns have 65 pyrrhotite or the magnetic gravel or the elemen, tare a content of vfn ^ u, Zn ", Pb, S and As, of which sulfur serve besides Jur ^ d *« JideWj Wtane each less is than 0.03% .These burn-offs form the supply for the consumption of the oxygen, which is unwanted after a possible enrichment, if your iron.

The emitted, from the non-ferrous metals, as are brought to work at 900 to 950 ⁰ C

and S cleaned burns are then put on.

The following stages of work, namely the Magne- These burnouts contain apart from the iron and the

animal reduction, direct reduction, the pellet pigeons rock nor non-ferrous metals that are not

ization under the influence of heat or in a cold state. 5 have reacted practically all of the original ace

The gases are passed through the first chlorinator and all of the initial S that is sent as sulfate to the

(Chlorinator) and dust separators and contained alkaline earth metals CaO and BaO

finally washed with water. The one from which is bound. S as monosulfide and the pyritic

Separation column gases flowing off still contain sulfur are practically no longer available,

the majority of the SO ₂ that is from the combustion io in the reactor II are then for each ton

derives from the pyrite, and the sulfuric acid starting burnup A further 40 to 48 kg of pyrite B

production fed. (calculated on 100% FeS ₂ ) and from the bottom 100 to

If you are working with one stage, the 200 Nm ^{3 of} air E and a quantity of chlorine F must be supplied,

Operation at very low concentrations of O ₂ , which are 105 to 120% of the stoichiometric amount,

less than 1 ° / _0, take place in the flowing gases 15 with respect to the original in the burn-A

in order to achieve burn-ups to which the arsenic and the non-ferrous metals present and B are equivalent.

Sulfur are withdrawn. The amount of air and pyrite can also be less

Regardless of whether you are now in two-stage or as the above values when setting

also works in one-step mode, the amount of is done in such a way that an oxygen analyzer is on

added pyrite significantly reduced, which shows 0.2 to 0.3 percent by volume of the gas line Ig,

Depends on the amount of unused sulfides that are still used when working at 900 ° C, or 0.7 to 0.8 vol-

are present in the burns to be treated. lumprozent, when operating at 950 ⁰ C. This

The total residence time changes in general, the latter temperature can easily be due to the considerable

depending on the level of impurities and borrowed from the burn-off heat and

of the temperatures used in the process 25 reached as a result of the heat of reaction generated by

wenJeii. Kit licgi at 30 to 120 minutes. the reaction between the pyrite and the supplied

In Fig. 1 is schematically a possible practical air is created.

Embodiment of a two-stage process shown. Besides the combustion of the pyrite takes place in this

represents. Stage also a chlorination

The burns A, which with an average temperature of 30.,.,.,. ",,

of 800 ° C come from a pyrite roasting plant, ^the non-ferrous metals become according to the reaction

fed into the fluidized bed reactor I through la , MO 4 Cl ₂ -► MCl ₂ + V ₂ O ₂

while in the same reactor through \ b too. .

Pyrite B is supplied, which also from the pyrite for ^a g ^hen ß ^en amount of hematite

the roasting plant can distinguish. The feed 35 Fe ₂ O ₃ + 3 Cl ₂ -> ■ 2 FeCI ₁ + ^s / s O «

amount is 60 to 70 kg FeS ₂ (calculated at 100%).

per 1000 kg of burns. At the bottom of the reactor ^of ^ ^vnt

"is supplied via Ie air E in such quantities, FeS ₈ 4 Cl ₂ + 2 O ₂ -> FeCl ₂ + 2 SO ₂
that on the O ₂ analyzer the gases H, which from IV

flow off, 3 to 5 percent by volume are displayed. 40 ^of trdalkali sulfates

This is done with air volumes between 150 and 300 Nm ³ MSO ₄ 4 Cl ₂ -> MCl ₂ 4 SO ₂ + O ₁

per ton of burn-up compared to 180 to 220 Nm ⁸ . ",,

reached, the ^{v n} ° arsenals and their decomposition products are calculated theoretically for FeS ₂ by

be able. ^Warmth

The amount of air can, of course, dependent on the 45 2 FeAsO ₁ 4 3 Cl ₂ - »- Fe ₂ O ₁ 4 2 AsCl, + _^6/2 O ₂ content is reduced to Nichteisenmetalloxyden, 2 FeAsO ₄ -" ■ Fe ₂ O ₃ 4 As _x O, 4 G ₁
which are released by reaction with Cl ₂ O ₂ . In the opposite direction, that is, where the use of all these reactions are necessitated by the low large amounts of air, act other O ₂ content of the gases promotes Almost all of these parameters, such as the amount of the dihydric 50 reactions set O ₂ free and allow Ver -Iron and S as monosulphide and in sulphide in the reduction of the amount of air supplied via Ie.
Initial burn-off, as well as the dilution effect, the cleaned burn- offs D flow out of the reactor through the gas tor II coming from the reactor II over 2 d and stand for the subsequent one which contains less than 1% oxygen. Treatments available, ie, a heat-recovery-At the bottom of the reactor I is züge- by Ig gas extraction 55 which Magnetisierreduktion, the reduction leads coming from the reactor II and not converted to sponge iron, etc.

converted Cl ₂ , N ₂ , O ₂ (0.2 to 0.8 percent by volume), The hot gases G that come from I are,

SO ₂ , As ₂ O ₃ and AsCI ₁ as well as the chlorides of the non- after they have passed through the cyclone ΠΙ in

ferrous metal and iron contains IV washed. The metal chlorides and the As

Complete combustion takes place in reactor I. 60 bonds are separated quantitatively. When

of pyrite B, as a result of which the temperature is worked at about 900 ^° C. according to the invention, is the ratio

increases, as well as the partial conversion of the non-SO ₂ / C1, in the gases G so high that the quantitative

iron metal oxides, which are contained in A , in chlorides, separation in IV also of Cl ₁ after the reaction, all of which is at the expense of Cl ₂ and the iron chlorides,

coming from reactor II. That of the gases 65 Cl ₂ 4 SO ₂ 4 2 H ₂ O - »- 2 Ha 4 H ₂ SO ₄
entrained fine powder are in the cyclone III,

the dust collector, trapped and the bed is guaranteed. After washing, the contain

burn-off admixed, the gases through la in the reactor II // in this way only SO "namely 13 to

7 8

15 percent by volume, Ο _{ί (} namely 3 to 5 percent by volume, example 1

N ₂ and H ₂ O and are therefore used for the production of

H ₂ SO ₄ suitable, for example in that they come from a fluidized bed roasting system 1000 kg / h

Circuit of the roasting plant either upstream or from burning a Spanish pyrite with a

downstream of the point where the sulfur-containing gases 5 mean temperature of 80O ⁰ C, with the burnups

washed with water, introduced, the following chemical composition in weight

what depends on whether you have acid mist or not percent:

contain. Total Fe 60.15

As a result of the procedure according to the invention, _Fe , ₊ 545

the solution holds K Fe and As ions as well as partially 10 total S 1.17

Cu ions in a reduced form. In addition, _As 0.32

it has a free acidity that is less than _{Cu 091}

the one that is used in a system for a conventional _Zn 2.47

Borrowed or conventional chlorination evaporation or _{pb 0.98}

Volatilization plant, which gives 15 _BaQ , 0.32

by the fact that the amount of the gas G in _Ca0 0.16

contained free Cl _{2 is} lower if one invents _Mg0 0.09

duly works, assuming that there is _Alt O ₃ 0.58

_Reacts with the pyrite in the upper regions of the SiOl 4.25

The furnace in which the pyrite is placed tends to be ao _K ,, - _{AA A} ■ ■ _c , _A.

The solution K accordingly shows a content of these burns A will .η a fluid or

FeCl which is larger and a content of HCl and fluidized bed reactor I introduced, which at the same time 73 kg / h

H SO which is less than those obtained from Spanish Pyrite B of the following composition

would? when working in the absence of FeS ₂ . to be admitted:

These three facts, namely, lower acidity, Ab- as _{Fe 42j} 36

Essence of Fe ⁺⁺⁺ and a moderate presence _{s 48j51}

of Cu ⁴⁺ , lead to considerable savings in _As 0.43

Reactants, namely lime for the neutral _Cu 0.77

ization, scrap iron for the binding or cement _Zn ^ g ₂

tation, etc., in the subsequent hydrometallur- 30 _pb 1.04

gical work stages for the extraction of the valuable _BaO 0.22

Metals out of solution. CaO 0.12

_{The basic advantages} with the inventive Mg0 0.07

Working method can be achieved, fol- _AlsOj 0.41

can be summarized as follows: 35 SiO ₂ 3.05

The preheating phase and the magnetization reduction

-, or burn-ups upstream of the cleaning stage then go through the bottom of the reactor

The 274 Nm '/ h air for maintaining the temperature and that from reactor II are omitted

of the chlorination reactor supplied to the desired value coming gas. The heat required for operating conditions is supplied by the pyrite, 40 are: temperature 900 ^° C., residence time in the fluidized bed

which is preferably the same pyrite from which the 60 min, O ₂ in the exhaust gases G 3.3 to 3.5 volume

Burn-offs of the roasting plant are produced. percent.

The S originally present in the pyrite becomes The fine powder C is captured by cyclones

completely with recovery of SO ₂ both in the gene and together with those of the fluidized bed to the roasting process and in the chlorination and oxidation 45 reactor IT for the chlorination. This

process utilized. The feed mix has the following composition:

The result is burns that are not only free of non-total Fe 64.08

ferrous metals, but also of arsenic and sulfur _{total s 0 100}

are. This allows the residues to be used directly for the _{s jn} ψ _{οπη of} monosulfide traces

Manufacture of, for example, sponge iron or ₅ o _{M 0140}

for pelletizing at low temperature, use _{Cu 0} 030

be turned. . . Zn 0.090

When cleaning non-ferrous metals with a _{pb 0 030}

limited consumption of Cl ₂ results in high

Yields since no hydrogen-containing fuel ₅₅ In the same reactor are then 78 kg / h

Substances are used that form the same pyrite B that was used in the first stage I.

Water the hydrolysis of the metal chlorides and one becomes, and through the soil 145 Nm ³ / h air and * ■

consequently would cause decreased yield. 50 kg / h Cl ₂ supplied, which is about 110% of the stoichio-

There are great savings in the raw metric amount equivalent to the total amount

stoff JΓ the ffli-the extraction of the valuable metals 60 of Cu, Zn and Pb, which in the reactor with the

from the Äsungen containing the chlorides, required burn-off and the pyrite was introduced when

These solutions eventually have a chloride to eliminate. In continuous operation have themselves

low 'acidity and en (hold cations with the following operating conditions result: temperature

the nSrtetCT degree of vSence 950 ° C, residence time in the fluidized bed about 60 min, O.

With reference to the following examples, the pre-S ₅ is illustrated in more detail in the gases after the reaction 0.5 to 0.8 Volumliegende invention, wherein the P ^ro f ^ent \ "

Percentages by weight, unless overall The discharged burn-D following Zusondert have listed are made. composition:

Total Fe 64.92 brought. Burn-offs and pyrite are the same

Total S 0.025 Composition as in Example 1.

^{Monosulfide S traces 300 Nm 3} / h of air are at the bottom of the reactor

As 0.025 and 51 kg / Cl ₂ introduced, which is 115% of the stoichio-

Cu 0.008 5 metric amount equivalent to the formation of

Zn 0.015 Cu, Zn and Pb chlorides is required. in the

Pb 0.015 continuous operation, the operating conditions are: temperature 950 ⁰ C, residence time in the fluidized bed 90 min,

The gas G flowing from the reactor I after the dedusting O ₁ in the gases G after the reaction is 0.5 to 0.8 lum percent in an aqueous solution. The discharged burns show consequent washed. Under continuous operating conditions, the following composition is drawn off: 500 l / h of solution K are withdrawn from the circuit, total Fe 64.78 has the following composition in g / l: Total S 0030

_n ", C λ _n monosulfide S traces

Total Fe 4.0, ₅ ¹ L

£ 5 EE ι, Cu o.oio

^S ] '1 Zn 0.040

Cu ⁺ 8.2 _ao 500 l / h of solution K are obtained from the precipitation cycle

Zn 54.4 subtracted with the following composition in g / I:

^Pb ° ' ⁷ Total Fe .: 11.7

p _e ++ \\ 5

The loss of iron through evaporation or total As 67

Volatilization as FeCl ₁ is up to 0.3%, while as As +++ .//^ .................. 67

the corresponding consumption of Cl ₁ 2.54kg / h from total Cu 198

power. Cu ⁺ 101

The gas H coming from the wax phase has ^ _n 530

an average composition in percent by volume of p ^ _o 'g

N 82 7 ³ °

Jj * V ₀ The loss of iron by volatilization as

"*, Vi sClg is up to 0.8 ° / _0, the corresponding amount

^bUl 'on CU is around 6.5 kg / h. That from the washing phase

Example 2 incoming gas H has an average composition

^p 35 kg in volume percent of the coming of a Wirbelbettröstanlage with a temperature of 800 ⁰ C 1000 / h of exhaust N ₁ 83.2

Branden A from Spanish pyrite are together O ₁ 0.6

with 120 kg / h of pyrite in a fluidized bed reactor SO ₁ 16.2

1 sheet of drawings

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Claims (1)

Patent claims: 1. A method for cleaning pyrite and pyrrhotite burns of non-ferrous metals, arsenic and sulfur, characterized in that the pyrite burns that come from the roasting furnace at 500 to 800 ⁰ C, with pyrite in amounts of 200 to 25 kg FeS ₁ per ton of burnup - depending on Purification steps, for example during the Magnetisierredaktion, Djer ^ chlorination, the - magnetic enrichment of leaching or Pelletisieruag under the influence of heat. The removal of sulfur from the burns occurs in part during the various stages of purification mentioned above. Generally have At the end of such a process the burn-up still has too high a content of sulfur, with the exception of the