WO1999001182A1 - Equipment and method for self-contained chlorination and reduction - Google Patents

Abstract

The invention concerns materials for heating or cooling minerals, chemical or diverse products, and pyrolyzers for reduction and chlorination in reduced pressure. Said materials are also used for decontaminating soils and other inerts with elimination of organochlorine without emission into the environment and without risks of dioxin and furan formation. The heating or cooling or decontaminating materials are loaded in a rotating tank floating inside another tank by means of an alloy with low melting temperature using a heating medium. The pyrolyzers comprise a bottom-tank with an alloy bath. A bell covers the bottom and rests in a ring-shaped groove filled with an alloy ensuring tightness. These materials enable a 'self-contained' process.

Description

 MATERIALS AND METHODS OF CHLORINATION and REDUCTION IN A CLOSED VASE

The present invention relates to materials for heating or cooling chemicals or minerals, and reduction and chlorination pyrolysers at reduced pressure.

These materials allow to proceed "in a vacuum" in many ordinarily polluting processes such as for chlorination and reduction of metal oxides or metals.

These materials also allow "in situ" decontamination of soils and other inert materials with elimination of organochlorines without emission into the atmosphere and without the risk of the formation of dioxins and furans.

The invention also relates to processes using these materials for the coproduction of metals and chlorides, processes which can be combined with the elimination of products contaminated by PCBs, PCTs, etc., or even based on HCB Organochlorines, HCE,

HCBD, ... etc.

An installation composed of materials such as according to the invention allows the treatment of very diverse materials both in concentration and in consistency. The various components are preferably interchangeable, which facilitates operation and maintenance, and ensures high reliability during installation. This modularity makes it easy to double or triple the processing capacity.

The installation does not require heavy infrastructure and the assembly remains easily removable. It will therefore be put into operation on the very site of production of the ores, materials to be treated or waste to be eliminated, which avoids the transport and handling of these products which may present risks.

Currently, for the elimination of PCBs and PCTs, it is high temperature incineration which is the most commonly approved process. This specialized incineration is carried out at 1000 ° C in a rotary or fluidized bed oven. The gases are post-combusted at 1200 ° C and are dusted and washed. The chlorides are volatilized or fixed mainly in the effluents. If this specialized incineration does not provide an absolute guarantee with regard to the release of dioxins, this solution seems to give acceptable results for the elimination of concentrated and diluted PCBs and PCTs, but as soon as they are solvent-free.

Indeed, the Mid is Research Institute, under a contract funded by the EPA, has highlighted that the addition of 30% of TCB

(trichlorobenzene) promoted the formation of PCDF and PCDD. And that thus, TCBs, much more than PCBs and PCTs (Polychloro-biphenyls and polychloroterphenyls), were likely to generate PCDDs and PCDFs (PolyChloroDibenzo-Dioxins and Furans).

The optimal conditions for the formation of PCDD and PCDF from TCB being around 675 ° C. with an excess of oxygen of 8%. The formation process supposes the oxidation of TCB in an intermediate stage.

Certain processes for removing organochlorine solvents have therefore been directed towards hydrogenation techniques at low temperature. This requires very large quantities of hydrogen.

However, if it has been established that the destruction of the PCDD or PCDF molecules is ensured above 1000 ° C. , it has also been shown that at 750 ° C and in the absence of air, biphenylenes do not form (H.R. Buser - Environmental Health Perspective).

This is why, very differently from the preceding techniques, the process according to the present invention proceeds to cracking under reduced pressure and to the fixation of chlorine in the form of metal chlorides. The materials for its implementation allow operation "in a vacuum", which provides great security.

The cracking of organochlorines is an endothermic reaction. Chlorination of metals is a very exothermic reaction which therefore allows cracking and fixing of chlorine. However, depending on the metal, this latter reaction must be moderate in order to be able to be thermally controlled.

The process for removing organochlorines according to the present invention is therefore mainly based on a chlorination reaction under reduced pressure, in particular with magnesium, but, in a non- exclusive. Especially since the organochlorines to be destroyed are most often accompanied by hydrocarbons, and the process also includes the reduction of metal oxides by the hydrogen released during cracking.

The reduction in pressure results first of all in the absence of air and therefore absence of oxygen, which reduces the risk of oxidation of benzenic nuclei. The vacuum or the low absolute pressure facilitates the vaporization of the organochlorines and promotes their cracking ing. By proceeding above 750 ° C the risk of dimerization of the benzenic nuclei is zero. And finally, the reaction of the cracking vapors makes it possible to proceed effectively "in a vacuum". This eliminates any emission into the atmosphere.

The cracking of organochlorines with reaction of chlorine on magnesium, leads to a mixture of carbon and magnesium chloride which can be taken continuously, according to the equilibria:

HCB => C6C16 + 3 Mg -> 3 MgC12 + 6 C

Or, for: 1 Kg of HCB and 0.250 KG of Magnesium, we collect: 1 Kg of MgC12 and 0.250 Kg of Carbon.

HCE = ≈> C2C16 + 3 Mg -> 3 MgC12 + 2 C Either, for: 1 Kg of HCE and 0.307 KG of Magnesium, we collect: 1.205 Kg of MgC12 and 0.102 Kg of Carbon.

HCBD ==> C3C16 + 3 Mg -> 3 MgC12 + 3 C Either, for: 1 Kg of HCBD and 0.292 KG of Magnesium, we collect: 1.146 Kg of MgC12 and 0.146 Kg of Carbon.

OCS => C8C18 + 4 Mg -> 4 MgC12 + 8 C

Or, for: 1 Kg of OCS and 0.255 KG of Magnesium, we collect: 1 Kg of MgC12 and 0.255 Kg of Carbon.

CTC => CC14 + 2 Mg -> 2 MgC12 + C

Or, for: 1 Kg of CTC and 0. 315 KG of Magnesium, we collect: 1,236 Kg of MgCl2 and 0 .079 Kg of Carbon.

PCE => C2C14 + 2 Mg -> 2 MgC12 + 2 C

Or, for: 1 Kg of PCE and 0. 292 KG of Magnesium, A we collect: 1,146 Kg of MgCl2 and 0.146 Kg of Carbon.

Thus, in the hypothesis where the theoretical waste is composed solely of HCB, HCE, HCBD, OCS, CTC, PCE of high purities, the magnesium chlorination reactions occur relatively simply, especially as the melting point of the chloride magnesium is normally 714 ° C, the treatment between 780 ° C and 800 ° C guarantees a total fixation of chlorine, but also the total elimination of dioxins and furans.

The mixture obtained is drawn off under vacuum at very high temperature and then cooled without intermediate exposure to the atmosphere, thus avoiding any formation of intermediate oxidized compounds which could then be emitted into the atmosphere.

The actual waste to be eliminated is rarely pure, and if the presence of parasitic elements in the form of "traces" (oxygen, nitrogen, hydrogen, sulfur, acid gases) but only traces, is acceptable, because these traces will be easily eliminated by magnesium, a presence in greater quantity must be avoided, and cannot be ignored in an industrial process. Evaporation "under vacuum" and more precisely without air or oxygen is the condition which secures the use of magnesium. Fortunately, under the conditions of vacuum and temperature of the process, the chlorine resulting from cracking cannot react with nitrogen to form NC13. Nitrogen will be fixed by magnesium in Mg3N2. Traces of sulfur will be easily fixed by magnesium.

Traces of hydrogen will be eliminated by the formation of MgH2, but the cracking of chlorinated hydrocarbons present with the organochlorines can release very large quantities of hydrogen. This is an almost constant circumstance which must not disturb the treatment, and, the hydrogen must be eliminated progressively, because: the hydrogen lowers the vacuum level in the pyrolyser, and above all, under pressure sufficient, its reaction with chlorine becomes brutal. Hence the interest of maintaining a preventive vacuum whatever the H2 / C12 ratio. This is why the elimination process according to the present invention does not only fix the chlorine, but also takes into account the presence of hydrogen. Which can become the main reaction in some applications.

The hydrogen will be eliminated by reaction with an easily reducible metal oxide such as copper or nickel or cobalt or antimony oxide (and even molybdenum or tungsten) or a mixture of these oxides .

Thus, if we admit for 10 moles of HCB, the presence of I mole of hydrocarbon, (taking C6H12 to facilitate the calculation), it takes 6 moles of CuO to neutralize the hydrogen, and 30 moles of magnesium for neutralize chlorine.

That is to say, for 1 Ton, it is necessary:

165 Kg of Copper oxide (or 155 Kg of Nickel oxide), 248 Kg of magnesium,

We recover by by-products: 130 Kg of Copper, 1 Ton of magnesium chloride, 272 Kg of carbon, and, there are about 37 liters of water to condense,

Conversely, if we admit 1 mole of HCB per 10 moles of a hydrocarbon (using C6H12 for the calculation), 60 moles of CuO are needed to neutralize the hydrogen, and only 3 moles of magnesium to neutralize the chlorine . That is to say, for 1 Ton, it is necessary:

4280 Kg of Copper oxide (or 3400 Kg of Nickel oxide), 64 Kg of magnesium, We recover by by-products: 3400 Kg of Copper, 250 Kg of magnesium chloride,

705 kg of carbon, and there are approximately 963 liters of water to condense.

In this second case, the process becomes a "metal oxide reduction technique" with the capacity to eliminate organochlorines or chlorinated hydrocarbons. The materials of the invention are therefore suitable on the one hand for the elimination of highly concentrated organochlorines and on the other hand for the reduction of metal oxides with elimination of oils contaminated with PCBs or PCTs and of course, for all intermediate cases, especially when it is simply a question of decontaminating contaminated soil.

An installation according to the process is shown diagrammatically in Figure 1. It includes: three or four ACCUMULATORS-EVAPORATORS (1), an independent or clamped LOADER-SHREDDER (2), a CENTRAL MODULE (3), a base with two PYROLYSERS (4), three or four STORERS (5) of similar design to "EVAPORATORS".

The waste and products to be treated are loaded into an ACCUMULATOR-EVAPORATOR (1).

Charging can be done either directly in the clamping position for processing and via a calibration shredder charger which is then clamped with the central module, or: the accumulator can be previously charged from an independent charger. These previously charged accumulators are then mobile to move back and forth in the clamping position on the CENTRAL MODULE. This ACCUMULATOR-EVAPORATOR will consist of a "double wall" tank which may have an overall diameter of 2500 mm, with 2 elliptical bottoms, one of which with a flange and a centered cover with a diameter of 1100mm. This set will be mounted on two 2500 x 2500 frames (one at each end) to form the total overall gauge of 6.10 Meters or 20 feet. Thus, the whole is in the format of maritime containers fitted with standard locking systems for stacking and maritime transport or by flatbed truck. The payload is 10 to 15 tonnes.

Incidentally, the frames can be equipped with stabilizing jacks for stationing the assembly in the clamping position. They can also be fitted with hydraulically motorized handling wheels, and the assembly then constitutes a portable tank moving on site thanks to a hydraulic generator trolley.

These full or empty tanks are connected to the CENTRAL MODULE and are clamped by hydraulic cylinders so as to ensure perfect sealing for vacuuming or under slight overpressure. The operation of the cover (closure cap) of the accumulator can take place "under vacuum".

Each "double wall" tank contains an internal tank which will be rotated like "a rotary kiln" although the external tank remains fixed. For this rotation, an intermediate fluid is injected which, by hydrostatic thrust, acts as a "ball bearing". The flotation fluid used is a lead alloy which directly heats the internal tank, and indirectly the waste or products it contains. The rotation ensures efficient stirring and good temperature uniformity.

In order to limit the heat transfer from the inner wall to the outside, the space between the two walls is evacuated

(about 80 mBars). During the manufacture of these accumulators, an insulating coating may be provided to better protect the "double wall", and likewise the internal tank will be coated internally with an anticorrosion layer.

This tank therefore allows evaporation "in situ", and under vacuum from the initial temperature of the waste, up to approximately 450 ° C. These conditions are sufficient to ensure the vaporization of all organochlorines and all dioxin and furan congeners that may be contained in the waste.

This tank ensures just as well: the evaporation of pure products or mixed with inert whatever the proportions, and also, the evaporation of traces that can impregnate large components such as capacitors or transformers with pyralene, to the floors or contaminated rubble.

After complete evaporation, the extraction being followed by a spectrometer probe, the decontaminated inert materials are removed by simple reversal of the direction of rotation in the manner of concrete mixers. The same double-walled tank assembly with internal tank will work not only as an accumulator-evaporator, but also as a storage or condenser-storage. In this case the double wall can be used for circulation of a cooling fluid, while the enclosure is under vacuum or under slight overpressure, but it is always in a controlled atmosphere during its filling.

It will be even more judicious to use the same lead alloy for rotating the inner tank as a cooling fluid for the crystallization of chlorides. Thus the energy recovered can be transferred to serve for evaporation in the accumulator-evaporators.

The transfer of calories will be much improved by adding molybdenum powder suspended in the lead alloy. Molybdenum, with a density close to that of lead, is neutral with lead, but it has thermal characteristics of capacity and conduction which are twice and four times those of lead.

A container "accumulator" or "store", can be sealed under vacuum, before unclamping, it therefore allows transport directly to the destination of use of the product, without any transfer.

For proper maintenance of these containers, each is "monitored" and at regular intervals, it can undergo an angular offset in rotation relative to the frames forming the template. An "empty run" allows the decontamination of the container itself.

An installation therefore appears in the form of several containers flanged together. It comprises: at least two accumulator-evaporators, and at least two storage units for evacuating the resulting products, and finally, it comprises various other containers during the transit of the products, whether they are upstream or downstream in the treatment. These modular containers facilitate simultaneous batch processing, even if the contents being processed are very different from one to the other. This technology therefore offers great flexibility or flexibility.

The products to be treated are evaporated under vacuum directly from the ACCUMULATORS-EVAPORATORS. The sucked vapors are analyzed continuously by mass spectrometry. These vapors are optionally treated on a condenser or a pretreatment device before being blown mainly into a pyrolyser-boiler for chlorination or reduction by hydrogen.

The two PYROLYSIS-BOILERS are united on a single BASE against which the STORERS of the by-products come to clamp themselves. This BASE of pyrolysers connects itself by clamping to the CENTRAL MODULE.

Each pyrolyser-boiler includes a cover bell, and a hearth which is directly integrated into the base.

The cover bell is composed of two concentric walls leaving between them a space for evacuation or for circulation of a cooling fluid. The interior wall is protected by a refractory and anticorrosive coating so as to resist partial pressures of chlorine and hydrogen chloride.

The bell caps the sole. The bell rests in a deep annular notch which is filled with a lead alloy with low melting point. This annular bath provides sealing and hydrostatic balancing between the interior of the bell and the atmosphere. This bath acts as a damper for sudden variations in the expansion of cracked gases. This bell is of a sufficiently large volume to also favor the damping of these variations and to offer a sufficient capacity of contact for the reactions.

The two bells of the pyrolyzers can be inscribed in a volume with the maritime gauge to facilitate their transport and a frame forming the frame with the gauge, can allow the lifting of the bells, to facilitate a complete visit of the bases of the pyrolyzers or to carry out the exchange. periodical of the bells.

The base, or sole, forms the reaction basin. The basin is partially filled with lead and zinc which separate by density. Zinc can be replaced by tin, but even better, by antimony.

The reactants and by-products of the reactions, float on the surface of the lead-zinc or lead-antimony bath, are: • magnesium and magnesium chloride in the case of chlorination

• copper or nickel oxides in the case of dehydrogenation.

The supplies and withdrawals are made only by the sole. In addition to the holes for blowing the vapors into the molten bath, the sole also comprises:

• the lead bath circulation openings,

• the supply holes for consumables,

• the suction pipes for residual vapors, • the withdrawal pipes for the by-products formed,

The BASE of the Pyrolysers is connected with the CENTRAL MODULE. This CENTRAL MODULE brings together the additional functions and accessories to ensure the control, transfer and conditioning of fluids.

It includes in particular: vacuum pumps for accumulators, condenser for water vapor and organochlorines and others having a boiling point, lower than water, the water filter and the condensation water tank , the evaporation pump, the isolation valves, the three-way valve for chlorination / dehydrogenation modulation the suction pumps for the residual vapors of the pyrolyzers, the three-way valves for recycling the residual vapors, the condensers for chlorides and steam of water on the residual dehydrogenation or chlorination vapors, and again, the equipment: heating and pumping of alloys, conditioning and rotation of accumulators and storers, clamping and sealing cylinders, circulation pumps of alloys, the siphoning pump of magnesium chloride and carbon, the hydraulic device for introducing magnesium, the device for compressing carbonaceous residues, the THT heating duct for carbon residues, the hydraulic power unit, the power take-offs for: the shredder loader, the pyrolyzer base: the oxide extrusion screws, the clamping and sealing cylinders, the hydraulic motors of the storage units, etc.

Although a continuous treatment remains possible, several factors such as: the elimination of air from the dead volume of an accumulator, the humidity likely to impregnate the products to be treated, the content of CTC (carbon tetrachloride ) vaporizable before water, lead to a batch-by-batch or "batch" treatment. This “batch” treatment, far from being a drawback, is found to be in perfect harmony with the modular organization of the accumulators-evaporators of the products to be treated and of the storers of the by-products resulting from the treatment.

There are four phases for the treatment and evaporation of waste for each accumulator-evaporator:

1 ° - Vacuum without heating to eliminate air from the dead volume as much as possible. The extracted air is filtered on active carbon. These coals can be reprocessed by the installation.

2 ° - Vacuuming with start of heating, for selective evaporation-condensation of CTCs and water vapor. The water is filtered and stored.

3 ° - Evaporation of organochlorines and re-evaporation of CTC and other condensates.

It is from this phase that the vapors are directed to the PYROLYZER-BOILER. This is the phase of elimination of organochlorines. This is of course the longest phase.

4 ° - When, under the control of a mass spectrometry sensor, a temperature and a level of vacuum are reached and stabilized sufficient to guarantee that all of the organochlorines, and all the dioxin and furan congeners have been evaporated, it is then that the residue of the accumulator-evaporator can be:

• either, kept in the accumulator to be evacuated and transported directly by the accumulator, and it will be so when it is important inert or contaminated soil,

• either, it can be poured into the THT (Very High Temperature) treatment hopper by reversal of rotation, this will be the case for carbonaceous residues (EDC tars, Evaporator tanks, Effluent sludges, Carbon Adsorbent ... etc), " fly ash ", and other incineration residues.

The smooth running of the PYROLYSEUR-BOILER means planning at least two simultaneous "batches", which will be offset in time. This will improve the performance of the installation.

The chlorination PYROLYSER-BOILER is the main component in the cracking of organochlorine vapors, and in the chlorination of magnesium by the chlorine released.

The dehydrogenation or reduction PYROLYZER-BOILER is in this case the complementary and secondary component to the cracking of relatively pure organochlorine vapors, but it quickly becomes the main component with the increase in the hydrogen content, and in particular during the elimination of oils contaminated with PCBs or PCTs. In the latter case, it is the chlorination PYROLYZER which becomes secondary but remains essential for the fixation of chlorine.

In the evaporation phase for elimination of the organochlorine vapors, and according to the spectrometric analysis of these vapors, a "three-way" valve makes it possible to direct the vapors to one or other of these pyrolysers which are of the same design , but with very different functions. One can usefully refer to the diagram of the process in figure N ° 2.

Avoid an overly brutal reaction by blowing the organochlorine vapors into the magnesium chloride bath rather than directly into the magnesium which monkfish on the chlorides bath. This is why it is necessary to maintain a sufficient level of magnesium chlorides so as to breathe in these vapors which are then cracked, and the chlorine released reacts with the magnesium while the carbon mixes with the magnesium chloride.

Because of the high reactivity of magnesium, the process must exclude the presence of oxygen. In fact, there remains traces of oxygen only at the beginning of the cycle. Indeed, after filling the accumulator, the presence of oxygen remains essentially limited to the partial pressure in the residual volume during the clamping or closing of this accumulator. This residual volume is pumped cold. The air is filtered over activated carbon before being returned to the atmosphere. More than 75% of the air is removed safely, since this is done under the control of a spectrometer sensor. The residual oxygen can be evaluated as the quantity of about twenty mole-grams which will react with less than 1 Kg of magnesium to produce approximately 1.5 Kg of magnesia, while 2500 Kg of magnesium are theoretically necessary to fix the chlorine of 10 Tons of HCB that can be contained in an accumulator.

Traces of nitrogen will be fixed by magnesium in the form of Mg3N2. The maximum amount of magnesium required to transform all of the nitrogen is still less than 6 kg.

Because of this high reactivity and high exothermicity, magnesium is introduced only as it is consumed. It is introduced from the outside, and through the lead bath. This bath acts as a "fluid airlock". It balances atmospheric pressure and incidentally, it allows the drying of traces of moisture and the preheating of magnesium. This bath also contributes to heat transfers to stabilize the reaction.

Magnesium is an expensive metal, but its very reducing and very exothermic properties guarantee the stability of chlorine fixation and reduce energy requirements. Magnesium is used, either in the form of a billet which sinks to the bottom of the lead bath. The billet advances as needed. Magnesium can also be used in ingots with an automatic feeding device.

By substitution, the magnesium displaces the other metal chlorides and in particular the chlorides which may be present. The neutral A ton of pure organochlorines consumes around 250 to 300 kg of magnesium. However, for very high chlorine concentrations, the reaction should be moderate by adding metals which burn easily in chlorine, but giving less exothermic reactions than magnesium.

This will be the case for antimony which has the advantage of being tri and pentavalent in its chlorides, which, if they are not reduced by magnesium, will be easily condensed.

Aluminum can also be added to lead to the formation of chlorides which are of great industrial interest.

This will reduce the theoretical consumption of magnesium by more than half.

However, the magnesia which is already present in the refractory coatings of pyrolyzer bells will be the first element of moderation and stabilization, and it can be added with magnesium. Other oxides can be added, in particular those of titanium or zirconium.

The action of chlorine on magnesia in the presence of the pyrolysis carbon of the organochlorines causes the formation of carbon oxides which will intervene in the second pyrolyzer, just like the hydrogen which results from the cracking of chlorinated hydrocarbons.

The vapor cracking carbon remains in suspension in magnesium chloride which is a liquid salt at the reaction temperature. Indeed, carbon (density = 2.23) has a density very close to that of magnesium chloride (density = 2.32). The mixture is extracted by siphoning, which means that this mixture is relatively pure from all other components. The magnesium chloride is then easily crystallized since its transformation temperature is 714 ° C (at normal pressure).

Insufflation of organochlorine vapors in the lead-zinc or lead-antimony bath should be avoided, as chlorides would be suspended in the magnesium chloride bath.

Lead has a low melting point (327 ° C) and a very wide range before boiling (1740 ° C). It is not very sensitive to chloru- ration. It is neutral with regard to steel. It can therefore be used as a heat transfer fluid, especially as its characteristics will be significantly improved by adding molybdenum powder.

Molten zinc is aggressive towards steel, so it could not be used as a heat transfer fluid. It is much more sensitive to chlorination, but its chloride is easily reduced by magnesium. Zinc dissolves easily with lead, but it separates by density, and its presence makes it possible to stop the scent of lead and therefore to limit the dissemination of lead in the by-products. Its intermediate density gives it a role of separator between lead and the products to be extracted.

Zinc could be replaced by tin. This solution is more expensive, but allows a greater amplitude of temperature regulation of the baths.

Preferably, the zinc will be replaced in whole or in part by antimony which, better still will ensure the separation, and its more volatile chlorides will be easily aspirated and condensed during the extraction of the magnesium chloride.

The residual vapors from the chlorination pyrolyzer are continuously sucked so that the absolute pressure in the pyrolyzer is as low as possible and always remains below 300 mBars. These vapors are analyzed continuously, and by a "three-way valve", they are re-blown in chlorination or directed to the pyrolyser for reduction of oxides (dehydrogenation).

The reduction pyrolyzer is quite similar to the chlorination pyrolyzer. It also has a bell resting in a deep notch filled with a low-melting point alloy and its sole forms a basin with a lead-zinc or lead-antimony bath.

This pyrolyzer can become the essential element of a process for the reduction of metal oxides which jointly authorizes the removal of oils contaminated with PCBs and PCTs.

Like magnesium and magnesia, the oxides are introduced through the lead bath. They are continuously pushed towards the bottom of the bath by a mechanical device such as an extrusion screw. sion and, they go up to the surface of the bath, but inside the pyrolyzer. It will be advisable to pre-load and pre-heat them in a "storage device" from which they are gradually extracted by rotation of the internal tank of the storage device.

The hydrocarbon vapors are blown into the lead bath to be cracked. The cracked hydrogen reacts with the metal oxides (Copper, Nickel, Cobalt) which are reducible by hydrogen from the temperature of 300 ° C, but which will be brought to more than 800 ° C by their transfer through the bath of lead. These oxides are therefore reduced to metal in the form of powder (copper or nickel or cobalt). This powder is precipitated in the molten bath while the oxides normally float on the bath.

Depending on the temperature, and in the case of a lead-zinc bath, part of the copper dissolves in the bath, because, for a high concentration of zinc, the temperature of the brass liquidus is around 900 ° C. . The partial dissolution of copper therefore makes it possible to increase (if necessary) the temperature of the bath.

The replacement of zinc with antimony will allow a better separation as much as the antimony will be easily introduced in the form of oxide in mixture with copper oxide and it will be reduced at the same time as copper oxide.

By segregation, copper is concentrated at the level of the lead-antimony separation surface. Indeed the density of copper is 8.94 while that of antimony is 6.7 and that of lead is 11.34. The same would be true for nickel or cobalt with a density of 8.9.

The bath is pumped regularly at the lead-antimony separation surface and directed to a concentration basin, in which the lead is withdrawn, while the upper level of lower copper concentration is recycled to the sole basin . The part of the bath concentrated in copper is regularly siphoned off and is poured into ingots.

Under similar conditions, and depending on the nature of the oxides, an alloy or pseudo-alloy of nickel or cobalt would be obtained. It will be easy to process antimony oxide directly and you can consider reducing oxides of molybdenum or tungsten, which this time will be recovered from lead.

Reduction of oxides will result in water vapor which will be easily condensed. Residual vapors can be treated in the chlorination pyrolyzer.

Carbon dioxide from the carbon monoxide formed during the chlorination of the oxides in the presence of carbon will be fixed on lime contained in a flanged storage tank on the installation. Thus, the treatment can be maintained in a "vacuum".

To improve the chlorination or dehydrogenation yield, and also the maintenance of the pyrolyzers and therefore the quality of the by-products, a second base with two pyrolyzers can be clamped at the first. And it will be interesting to combine the treatment of highly exothermic batches (pure organochlorines) with less exothermic batches such as those of soils to be decontaminated.

The continuous spectrometric analysis of the vapors makes it possible to regulate the installations and to predict the carbon / magnesium chloride ratios that will result. Thus, this ratio, which ranges from 10 to 25% depending on the organochlorine pure or as a mixture, is completely reversed in the presence of hydrocarbons which also generate other by-products such as alloys and other chlorides which can constitute the main production goal. We can therefore consider adding hydrocarbons to regulate the production of alloys.

The arrangements and devices for analysis, control and recording of physical parameters will guarantee the total elimination of organochlorine compounds without the formation of dioxin or furan congeners. All this will allow the recycling of by-products and mainly of the mixture of carbon and magnesium chloride.

Several possibilities of recycling or use are possible for this mixture of magnesium and carbon, in particular:

1 ° - In the manufacture of refractory materials. For example: if we add to magnesia baked to death at 1750 ° C, a proportion of 10% of a magnesia which has not been calcined at 1000 ° C, we obtain a mixture which added chloride of magnesium, can be poured into molds with controlled humidity, or pressed under 1000 Kg / cm2, then kept for several days in an atmosphere saturated with water. Under these conditions, Sorel cement (magnesium oxychloride) is formed without the products cracking and, the addition of carbon provides greater mechanical strength and greater resistance to corrosion by acids and slag.

Carbon also helps reduce shrinkage when bricks are first fired. Thus, large parts can be manufactured such as: the coating of the bells of pyrolyzers.

Other compositions based on chromite, mullite, zircon ... etc. are also possible.

2 ° - The mixture of magnesium chloride and carbon can also intervene directly in the process of elaboration of magnesium and indirectly in that of certain metals such as titanium, zirconium, etc ...

3 ° - We can proceed to the separation of carbon and magnesium chloride. Since magnesium chloride is soluble, separation by dissolution with filtration is the most common method. The carbon which is retained as filtrate is then dried and pyrolysed under vacuum at very high temperature.

The simultaneous conduct of different batches, the interpretation of the spectrometric analysis of the extracted vapors and residual vapors, the supervision of the physical parameters (temperatures and pressures) as well as the various alarms on the components, will be under the control of a system computerized. This system can integrate several levels of redundancy, with "atch-dogs", multiple access, including by modem for remote maintenance, as well as very advanced access key control possibilities.

Although the installation can be stopped at any time, it remains preferable to operate it "continuously", even if it is in reduced operation at night under the supervision of an operator.

Claims

1. Physico-chemical treatment process which can be applied to the elimination of organochlorines, to the treatment of soils or various materials and equipment contaminated by hydrocarbons or by organochlorines, or which can also be applied to the reduction of ores or to the chlorination of metals and allowing the co-production of alloys and chlorides, characterized as associating at least one reaction enclosure and at least one evaporation or cooling enclosure, and which, put under reduced pressure compared to atmospheric pressure, operate in a closed vessel or closed circuit, the vapors sucked into the chambers being blown into the bottom bath of the reaction chamber. 2. Method according to claim 1 characterized by several reaction chambers, the vapors sucked from one being blown to react in the bath of the reaction sole of another chamber. 3. Method according to the preceding claim characterized as using at least two enclosures of conjugate reactions and such as one of chlorination and the other of reduction or fixing of hydrogen, the residual vapors of one being re-blown into the other after elimination of the condensable vapors. 4. Method according to one of the preceding claims, characterized in that the reaction chamber consists of a hearth and a bell, the hearth being filled with molten metals of different densities, and on the surface of which the products to chlorinate or reduce float, and where the chlorinating or reducing vapors are blown into it, while the bell caps the sole and rests in a deep annular notch which is filled with a metal with low melting point which ensures sealing by simple hydrostatic balancing. 5. Method according to claim 4, characterized in that the bath of molten metals is composed of lead and at least one other metal with a density between 6 and 8. 6. Method according to claim 4 characterized by the introduction of the reaction products through the bath of molten metals, this bath acting as a fluid lock. 7. Method according to claim 1, characterized in that an evaporation enclosure under reduced pressure or an enclosure for cooling in a controlled atmosphere, is constituted by an external tank and another internal tank with interposition between them of a alloy with low melting point which is used both for flotation for the rotation of the internal tank and as a heat transfer fluid so as to heat or cool the products contained in the internal tank. 8. Method according to claim 7, characterized in that the heat transfer fluid is an alloy with low melting point to which is added molybdenum powder.