AU2247400A - Method and production line for production of magnesium and chlorine - Google Patents

Description

-1-

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant/s: Actual Inventor/s: Address for Service: Russian National Aluminum and Magnesium Institute (VAMI) and Aluminium Alloies Metallurgical Processes Limited Alexander N. Tatakin and Vladimir I. Schyogolev and Alexander S.

Chesnokov and Gennady N. Svalov and Igor V. Zabelin and Vladimir N. Deviatkin BALDWIN SHELSTON WATERS MARGARET STREET SYDNEY NSW 2000 'METHOD AND PRODUCTION LINE FOR PRODUCTION OF MAGNESIUM AND CHLORINE' a a.

a. a t a.

a e@ Invention Title: The following statement is a full description of this invention, including the best method of performing it known to me/us:- File: 27574AUP00 la METHOD AND PRODUCTION LINE FOR PRODUCTION OF MAGNESIUM AND CHLORINE Field of the Invention This invention relates in general to production of non-ferrous metals and halogen gases, and in particular, to the production of magnesium and chlorine by electrolysis of molten salts.

Background of the Invention A method of electrolytic production of magnesium and chlorine from a melt of magnesium chloride or carnallite-type-raw material is widely known. The known method, in which the electrolysis of magnesiumchloride occurs under molten chlorides, is implemented both in individual electrolytic cells and in cells integrated into the production line in the form of the closed hydrodynamic cycle (See O.A. Lebedev, "Production of Magnesium by Electrolysis" Metallurgy Publishing House, pages 227-229, Moscow 1988).

One drawback of this method is the large amount of electrical energy used in melting the raw material. This step alone requires additional 2000 2500 kilowatt hours (kwh) of electrical energy per ton of S. 2 the produced magnesium. Another drawback is inefficient utilization of raw material in the melting units and initial electrolytic cells of the production line. This is attributable to large quantities of the raw material being evacuated along with the slime.

The step of loading solid dehydrated carnallite into an electrolytic cell is also known (see I.L. Reznikov et al., "Electrolytic Production of Magnesium from the Dehydrated in the Fluidized Bed Carnallite" Nonferrous Metals, 10, pages 52-56, 1969).

The loading of the solid dehydrated carnallite into the initial unit of the production line of electrolytic cells for production of magnesium is described in "Design and Development of a Production Line for Titanium -2and Magnesium" VAMI 72, Metallurgy, pages 48 55 (1972). Here, the efficiency of the loading of the solid chlorine-magnesium material into the electrolytic cell is enhanced by elimination of the melting phase in the special production units. It is known that such melting consumes a substantial quantity of electrical energy and requires special service.

Typically, solid dehydrated carnallite contains up to 1.5 percent of water and between 0.8 to 1.2 percent of magnesium oxide (MgO). When such raw materials are used in the individual electrolytic cells or in the initial or head unit of the production line of electrolytic cells, the service life S:i" o of the anodes in the cells is shortened considerably. Intense hydrolysis in ••othe cells leads to a high consumption of raw materials.

The above discussed drawbacks are partially eliminated in the production line disclosed by the Russian Patent No. 2,107,113. According to this patent, magnesium and chlorine are produced by electrolysis of 15 magnesium chloride in molten chlorides in a series of electrolytic cells.

The raw material in the form of solid carnallite is loaded into this production line which includes the electrolytic cells. The cells are formed with and without loading devices for handling the solid raw materials, and those cells having the loading devices also include melting units. The 2o disclosed production line alternates electrolytic cells having loading and melting devices with the cells without such devices. The speed of loading of a solid raw material into the electrolytic cells having loading and melting devices is adjusted, so that the differential temperature of the electrolyte between adjacent electrolytic cells does not exceed 20 C. The content of the magnesium chloride in the electrolyte is maintained to be at least 8 percent. During operation, the temperature in the melting devices of the electrolytic cells is between 4500 and 6000 C, and the content of MgCI 2 in the melting device is maintained between 15 and 35 percent. The electrical current load is regulated in accordance with average -3temperature of the electrolyte in all electrolytic cells of the production line.

This process is suited for solid preprocessed carnallite raw material with water and magnesium oxide content in the range of 0.2 to 1.2 percent of each component and with a possible carbon content not exceeding 0.2 percent. According to this patent, the optimal content of water and magnesium oxide is within the range between 0.6 and 1.2 percent.

According to the above discussed method, fluidized bed dryers adapted for dehydration of carnallite in the flow of hydrogen-containing gases are provided the production line. The preprocessed, dehydrated 10 carnallite is dehydrated in the fluidized bed dryers until the water and .:••magnesium oxide content are in the range of 0.2 1.0 percent of each component. The production line also contains hydraulically connected electrolytic cells with loading devices which are alternated with the cells without such devices. There are also provided devices for neutralizing of exhaust gases from the fluidized bed dryers and devices for production of the artificial or preprocessed carnallite.

The major drawback of the above-discussed production line disclosed by the Russian Patent No. 2,107,113 is the substantial S..i consumption of anodic graphite of the electrolytic cells. This occurs because the graphite of the working part of the anode is typically immersed in the bath of the electrolytic cell and is consumed during the chemical reaction of the chlorination of oxygen bearing compounds. The reaction also produces the following gaseous products namely, carbon monoxide and carbon dioxide which contaminate chlorine gas produced at the anodes and inhibit the release of this gas from the melt in the vicinity of the anodes. Under such conditions the anode lifetime is reduced to between 7 to 10 months. The anode replacement operation requires substantial manual labor and is conducted at high temperatures in an environment polluted by chlorine. Such replacement is only feasible in the -4electrolytic cells in which the anodes are top mounted (top-input anodes).

The consumption of energy in such electrolytic cells is 8 to 10 percent higher than the consumption of energy in cells with bottom mounted (bottom-input) anodes.

A further drawback of the production line disclosed by the Russian Patent No. 2,107,113 is that the raw material can only be loaded into the limited number of electrolytic cells provided with special loading devices.

The service life of anodes in cells having loading devices decreases almost proportionately to the quantity of raw material fed into such cell.

10 On the other hand, the service life of anodes in electrolytic cells without oo loading devices decreases only insignificantly.

Furthermore, the melting devices installed within electrolytic cells often impede the movement of magnesium within the production line. This aspect is particularly significant when the system is processing a substantial quantity of magnesium.

Still further, when the temperature differential between adjacent electrolytic cells reaches 200 C, thermal stresses of the structural elements often results. This ultimately reduces the mean time between failures of .i the cells and required maintenance.

Technical problems such as anode wear, the impact of the carbon content on the anode functioning, presence of the melting devices impeding the process output, and the impact of temperature differentials between adjacent cells all impact the magnesium output represent important drawbacks of the prior art method.

Brief Descrition of the Drawing Figure 1 is a schematic diagram representing a production line for production of magnesium and chlorine according to the invention; Figure 2 shows a schematic section view of an electrolytic cell used in the production line of the invention; and Figure 3 shows a schematic section view of the separating unit utilized in the production line of the invention.

Description of the Preferred Embodiment A production line for production of magnesium and chlorine of the invention includes two essential areas: a preproduction area for preparation of chlorine-magnesium material, salts of chlorides of alkaline and alkaline-earth materials, and a production area for the electrolysis of the melt containing magnesium chloride.

The raw material processed in the preparation area can be in the io form of artificial carnallite KCI MgCI 2 6H 2 0 or magnesium chloride with six molecules of water. Such raw material is produced from the magnesium chloride bearing ores or from oxide bearing materials.

As illustrated in Figure 1, in the preferred embodiment of the invention the production line includes thirteen electrolytic cells 3 15. It 15 should be noted, however, that a production line with any reasonable number of electrolytic cells is also contemplated.

oo ooS 00.As conventional in the present art, the magnesium metal is produced in electrolytic cells upon passing direct electric current between anodes and cathodes positioned in an electrolyte or a molten electrolytic bath containing magnesium chloride. In this arrangement, the bath is maintained at a temperature above the melting point of magnesium. Thus, the current heats the electrolyte or the bath and results in electrolysis of magnesium chloride contained therein. This causes molten magnesium metal to be released at the cathode surfaces. Since the metal is lighter than the bath it rises along the cathode surfaces. Simultaneously, the chlorine gas rises through the bath from each anode surface to be collected outside the electrolytic cell.

The fluidized bed dryer I is used for preparation of a raw material in the form of solid dehydrated carnallite. Although one fluidized bed dryer is -6shown in Fig. 1, production lines with multiple fluidized bed dryers form a part of the invention. A solid raw material containing chlorides is treated within the fluidized bed of the fluidized bed dryer 1 by a thermal medium containing hydrogen chloride. By processing in this manner, a deeply dehydrated carnallite with low magnesium oxide and water content is produced.

The direct electrical current is supplied to the production line by bus bars 27 which also connect the production line of the invention to other electrolytic cells. The bus bars 27 can also serve for the direct connection ee to the rectifiers. As illustrated in Fig. 1, the bus bars 27 are associated with the electrolytic cells 3 and 4 of the production line.

o.oo 0 As illustrated in Figure 2, the electrolytic cells utilized in the production line of the invention, typically consist of an electrolytic chamber 51 with cathodes 52 and anodes 53. A collecting chamber 54 is separated from the electrolytic chamber 51 by a partitioning wall 55 having openings 56 provided for circulation of electrolyte and removal of magnesium.

The construction of electrolytic cells 3-15 provides for installation of the anodes 53 from the top or bottom areas thereof. As shown in Fig. 1, *these electrolytic cells are integrated into the continuous production line by means of transportation channels 16. From the preparation area, a solid chlorine-magnesium material is supplied to the electrolytic cells. The chlorine gas generated at the anodes 53 during the process of electrolysis is collected and evacuated from the electrolytic cells 3-15 by means of a pipeline 17. After purification and separation from salt fumes, chlorine gas is partially delivered into the furnaces 2 of the fluidized bed dryer 1.

Magnesium metal produced at the cathodes 52 during the electrolytic process is ultimately accumulated along with the electrolyte in the separating unit 18.

-7- As conventional in the present art, the inner space of the separating unit 18 is divided by a partition wall 69 on two chambers (see Fig. The first chamber includes an accumulation area 61 formed with hermetically sealed outlets 65 adapted for discharging of magnesium metal and slime.

In operation, a mixture of electrolyte and magnesium metal is delivered from the electrolytic cells 3-15 to separating unit 18 at the inlet 62 of the first chamber. After separation from the electrolyte and removal of the impurities including oxides and chlorides, the magnesium metal is accumulated in the accumulation area 61. Through the channel 63, electrolyte separated from magnesium enters the second chamber equipped with pumping devices 19 and 20. By means of the pumping :device 19, the recycled electrolyte is delivered into the first electrolytic cell 3 of the production line. The pumping device 20 is adapted for feeding of the spent electrolyte to the unit 21. The magnesium metal through the outlets 65 is periodically removed from the separating unit 18. The electrolyte from the separating unit 18 is continuously delivered by means of the pumping device 19 through a transportation arrangement 35 into the first electrolytic cell 3 of the production line. The spent electrolyte is evacuated from the separating unit 18 by the pumping device 20 and i 20 through the transportation channel 31 is delivered to the unit 21. After dispersion and cooling in the unit 21, the spent electrolyte is partially returned into the production line and partially moved to the end product tank 22.

To reduce moisture content, the solid raw material is delivered to the electrolytic cells 3 15 by the system of hermetically sealed conveyors 23. By this transportation arrangement the raw material is initially supplied into the tanks 24 and subsequently fed through the loading devices 25 into the respective electrolytic cells.

The production efficiency of the system depends on the level of dehydration of carnallite. Such efficiency is maximal upon utilization of deeply dehydrated carnallite with the content of magnesium oxide and water not exceeding 0.3 percent of each component. An analysis of production efficiency for various temperatures at which the carnallite is delivered shows that when the temperature of carnallite is lower than 1500 C, a substantial reaction of carnallite with moisture laden air has takes place with a consequential lowering of efficiency. The reaction increases the content of oxygen-bearing impurities in the electrolytic cells and 0 causes the performance of the electrolytic cell to deteriorate. Thus, in the preferred embodiment of the invention, the solid dehydrated carnallite is o. aloaded into the electrolytic cells 3-15 at a minimum temperature of 1500C.

If necessary, salts of chlorides of alkaline and chlorides of alkalineearth metals undergo a preparatory procedure in the preparation area :5is including fragmentation and drying. After that, the salts are moved either by means of a designated transportation system 26 or moved concurrently with a raw material by means of the raw material conveyor system 23.

The influence of these salt additions on the chlorine-magnesium material .has been investigated. In this respect, two actions have been checked (a) "t0. 20 loading of the salts into the system immediately after the fluidized bed dryer 1 and loading of the independent supply of salts directly into the electrolytic cells 3 15. Since the salts are less hydroscopic than the chlorine-magnesium raw material, the requirement to hermetically seal the designated transportation system 26 is less stringent as compared to the raw material conveyor system 23.

From the separating unit 18, the recycled electrolyte is fed into the first electrolytic cell 3 of the continuous closed cycle production line of the invention. The quantity of such recycled electrolyte is sufficient to maintain a predetermined level of concentration and collection of metal in -9the separating unit 18. A solid raw material containing magnesium chloride is conveyed to each electrolytic cell of the closed cycle production line or into the majority of the cells. The raw material delivered to each individual electrolytic cell is of sufficient quantity to maintain the content of MgCI2 within the range of 7 to 11 percent. In this condition, the content of MgCI 2 in 30 to 50 percent of electrolytic cells situated at the beginning of the production line and located after the separating unit 18 and downstream of the electrolyte flow has increased from minimal to the maximal value of the above range. On the other hand, the content of MgCI 2 in 30 to 50 percent of electrolytic cells before the separating unit 18 C *and located at the end of the production line according to the direction of the electrolyte flow, has decreased from maximal to minimal of the above range. Such variation in the concentration of the main component (MgCI 2 has a positive effect on the efficient utilization of electricity. Furthermore, C. *e S• 15 such variation reduces the MgCI 2 losses with the spent electrolyte .C accompanied by reduction in consumption of raw material. The variation in Cthe concentration of MgCl 2 can also reduce the material flow when the C".**electrolyte is used in the production of the artificial or preprocessed carnallite.

The weight content of other components has changed as follows by mass): KCI, from 68 to 78 percent; NaCI, from 13 to 23 percent; CaCI 2 0 to 0.2 percent.

In addition to the above, temperature control of the electrolyte in the electrolytic cells is of key importance as, upon operating at too low a temperature, initial crystallization or crust formation occurs which disturbs the production process. In general terms, the initial crystallization temperature is, depending on the MgCl 2 concentration, within the range of 6000 to 6500 C. Lower MgCI 2 concentrations have initial crystallization temperatures near 6500 C; and, conversely, the higher MgCI 2 concentrations, near 6000 C. Thus, to avoid initial crystallization, the temperature of the electrolyte is maintained within the range of 6600 to 7200 C.

In the initial electrolytic cells where there is higher concentration of MgCI 2 the temperature is maintained at a lower level of the above temperature range. Simultaneously with lowering the content of MgCI 2 the temperature is increased at the end of the production stream of material.

This enables the invention to maintain a sufficient difference between the temperature of the electrolyte and the temperature of initial crystallization.

-o:00 io The process efficiently uses electrical power and retains a flow undisturbed by "crusting". However, upon the temperature being at the level in excess of 7200 C, the electrical current efficiency of the Oil• 00. magnesium production is substantially reduced.

By using additives to the raw material mixture, the electrolyte is 5is maintainable at the required level of concentration for the given temperature. Such additives include chlorides of the alkaline and alkalineearth metals, which are components of the electrolyte; sodium chloride or its mixture with solid electrolyte.

In the production line of the invention, loading of the chlorinemagnesium raw material is alternated with loading of chlorides of alkaline and alkaline earth metals into the groups of neighboring electrolytic cells.

Each such group consists of at least two individual electrolytic cells.

The loading of NaCI compensates the electrolyte for the loss of NaCI resulted from the removal of this component with the removed electrolyte. The addition of a quantity of NaCI maintains the concentration of this component in the electrolyte, increases the conductivity of the electrolyte, reduces the voltage within the electrolytic cells, and also reduces the initial temperature of crystallization. As the solid salts require energy for heating and fusion, constant loading of the solid salts into the -11system required increase of the direct current amperage. This leads to an increase of productivity of the electrolytic cells.

Sodium chloride and/or solid spent electrolyte from the electrolytic cells can be used as components of the solid salts which are added to the chlorine-magnesium material or loaded directly into the electrolytic cells.

As discussed hereinabove in the closed hydrodynamic cycle or hydrodynamic loop of the production line of the invention, the temperature of electrolyte is maintained within the range of 660 7200 C. This occurs :00 in such a manner that the temperature of electrolyte is maintained at the io upper limit of the above-mentioned temperature range in 10 30% of the electrolytic cells located before the separating unit 18 and in the direction of downstream flow of the electrolyte-magnesium mixture. On the other hand, the temperature is maintained at the lower limit of the above mentioned temperature range in 10 30% of the electrolytic cells located 15 after the separating unit 18. The temperature range is maintained at the a lower limit of the above temperature range by changing the quantity of loaded raw material and/or salt mixture.

For optimal productivity, the maintenance of a stable average temperature throughout all electrolytic cells 3 15 of the production line is essential. This is accomplished by changing the current amperage, which is increased upon decreasing the average temperature and decreased upon increasing the average temperature. To avoid the increase in the temperature beyond the predetermined limits in the individual cells, the feeding rate of the solid materials (raw materials and/or salt additives) is controlled. In this respect, the feeding rate was maintained between 3 and percent by comparing the feeding rate in the individual cell to the overall average feeding rate in all electrolytic cells of the system per each degree of temperature change per hour.

12- Typically, the process of electrolysis is maintained at a relatively low speed of movement of the recycled electrolyte, i.e. at the speed of 20 to ton per/hour. Simultaneously, a small difference between the electrolyte levels in the first 3 and last 15 cells of the closed hydrodynamic cycle or loop is maintained.

It has been determined that in the electrolytic cell the optimal condition for removal of the magnesium metal from the electrolytic chamber 51 into the collecting chamber 54 is to position the upper region of the openings 56 at the depth of 50 150 mm below the level 57 of io electrolyte (See Fig. In this instance, the speed of circulation of the recycled electrolyte is not significant, for example, such speed is about ton per hour.

Upon increasing the speed of circulation of the recycled electrolyte in the production line in the ratio 1.5 3, the difference between the level of electrolyte in the first electrolytic cell 3 and the last electrolytic cell situated respectively after and before the separating unit 18, is increased :up to 350 mm (see item 58 in Figure This condition results in the deterioration of the transfer of magnesium metal from the electrolytic chamber into the collecting chamber. In view of the above, a short duration of this condition (for about 30 60 minutes) is maintained before removal of the magnesium metal from the separating unit 18.

Positioning of the separating unit 18 between the first electrolytic cell 3 and the last electrolytic cell 15 of the production line facilitates separation of the electrolyte and accumulation of substantially all magnesium metal generated by the production line in the separation unit 18. The electrolyte passing through the channel between the electrolytic cells 3 and 4 contains the magnesium metal in the form of small droplets.

This enables the invention to reduce the leakage to a level below 0.2 -13percent. Simultaneously, the productivity is increased to 1.8 percent compared to the prior art.

In the system of the present invention there is centralized control over the movement of the spent materials and distribution thereof into the s electrolytic cells and the feeding rate and the temperature of the electrolyte in the specific cells. Through the above analytic criteria for changes in the electrical current are determinable.

A comparison in the performances of the production lines of the prior art and the present invention is illustrated in the attached Table. The io Table illustrates application of various types of electrolytic cells to the production lines and usage of several types of raw materials with different content of magnesium oxide and water.

The data disclosed by the Table corresponds to the operation utilizing a raw material of optimized composition according to the prior art S* 1is when half of the material is fed into the electrolytic cells with top input of anodes (TIA) (See example According to Example 2, a raw material :with decreased content of impurities was loaded into all TIA-type electrolytic cells of the production line of the invention. In Example 3, a raw material with decreased content of impurities was loaded into the electrolytic cells with bottom input of anodes (BIA) integrated into the production line of the invention. Example 4 relates to the operation of the production line of the invention equipped with BIA cells which receive solid deeply dehydrated carnallite and 25 percent of additions in the form of various combinations of the mixture of sodium chloride and solid electrolyte. Such operation resulted in 6.5 percent increase in the productivity of the cells and the electrical current load. The increase caused the respective reduction of the specific consumption of graphite at the insignificant increase of the energy consumption. In the production line of the invention maintenance of the BIA-type of electrolytic cells -14completely excluded the anode replacement operations. In the prior art such replacement was carried out typically twice during the service life of the cell. In the production line of the Example 2 the anodes were replaced once during the service life of the cell.

Thus, the method and the apparatus of the invention including the production line, enables a user to reduce the cost of material and the required labor, as well as to decrease the consumption of energy. The invention also increases the productivity of the equipment, and improves V the techno-economic characteristics of the production facilities.

a a.

*go* 15

TABLE

Characteristics of the Production Line Utilizing Carnallite Having Various Content of Magnesium Oxide and Water.

EXAM

PLE

*5

S

S. S

S

S.

*5*S

S

S

S

S S. S

S*

CONTENT OF

CARNALLITE

N) mass

ELECTRO

-LYTIC

SELL

LIFE OF

ANODES

(months)

CONSUMPTION

(kg /t Mg)

CONSUMPTION

(kwh kg Mg)

PRO-DUC-

TIVITY OF

PRODUCTION

LINE

MgO 0.6 0.3 TIA 10 33~ 15.3 f 100 0.25 0.25- 20 30 30 14.9 13.7 13.9 105 100 106.5 0.25 I L

Claims (9)

1. A method of producing magnesium and chlorine in a production line having at least a plurality of electrolytic cells and separating unit interconnected by transportation channels into a closed hydrodynamic cycle, said production line being adapted for the electrolysis of magnesium chloride in the melt of chlorides, said method comprising the following steps: a. preparing an electrolyte from a chlorine-magnesium raw material and a mixture thereof with chlorides of alkaline and alkaline-earth metals :i :o in the electrolytic cells of the production line, said chlorine-magnesium raw material and/or said mixture thereof with chlorides of alkaline and alkaline-earth metals being loaded into said electrolytic cells in a solid condition; .i b. introducing in and circulation of said electrolyte in said s15 hydrodynamic cycle of said production line; and c. maintaining the MgCI 2 content of the electrolyte within the range of 7 to 11 percent in such a manner that in 30 to 50 percent of the electrolytic cells located after the separating unit and downstream of the electrolyte flow, the content of MgCI 2 being increased from the minimum to the maximum value of said range; and, in 30 to 50 percent of the electrolytic cells located before the separating unit, the content of MgCI 2 being decreased from the maximum to the minimum value of said range.

2. The method of claim 1, further comprising the steps of: d. accumulating magnesium in the separating unit upon the forced movement of electrolyte-magnesium mixture through said hydrodynamic cycle; and -17- e. periodically evacuating magnesium and spent electrolyte from said separating unit.

3. The method of claim 1, wherein the chlorine-magnesium raw material is dehydrated carnallite with a content of magnesium oxide and a water being less than 0.3 percent of each said element.

4. The method of claim 1, wherein said solid carnallite is loaded into said electrolytic cells at a minimum temperature of 1500 C. S:I' 5. The method of claim 1, wherein the chlorine-magnesium raw material is fed into the transportation channels interconnecting said electrolytic cells.

6. The method of claim 1, wherein loading the chlorine-magnesium raw material is alternated by loading of chlorides of the alkaline and alkaline earth metals into groups of neighboring electrolytic cells, each said group consisting of at least two individual electrolytic cells.

7. The method of claims 1, wherein sodium chloride and/or solid spent electrolyte from the electrolytic cells are used as components of said solid salts being added to the chlorine-magnesium material or loaded directly S. into the electrolytic cells.

8. The method of claim 1, wherein in said hydrodynamic cycle the temperature of electrolyte is maintained within the range of 660 720 C, in such a manner that the temperature of electrolyte being maintained at the upper limit of said range in 10 30 percent of the electrolytic cells located before the separating unit and downstream flow of the electrolyte- magnesium mixture, whereas the temperature electrolyte being maintained at the lower limit of said range in 10 30 percent of the electrolytic cells located after the separating unit, said temperature range being maintained at the lower limit of said range by changing the quantity of loaded raw material and/or salt mixture.

9. The method of claim 1, wherein the predetermined temperature is maintained in the individual electrolytic cell by changing the quantity of

18- loaded solid raw material and/or added salts by 3 30 percent regarding the average loaded quantity per each one degree of the electrolyte temperature change per hour. The method of claim 1, wherein the average predetermined temperature of electrolyte is maintained within the production line by changing the electrical current amperage. 11. The method of claim 2, wherein the flow rate of electrolyte in the production line is increased within the ratio 1.5 3 before evacuation of 000* magnesium from the separating unit. 10 12. A production line for production of magnesium and chlorine, said .i production line including a plurality of electrolytic cells, a separating unit for separation of magnesium from an electrolyte received from said .goe ***.electrolytic cells, a plurality of loading devices for loading of a raw material 0o00 and salt mixture into said plurality of electrolytic cells and bus S: is arrangements for supplying electrical current to the electrolytic cells, characterized in that said production line further including a :transportation arrangement for transporting of the raw material and/or salt mixture to said loading devices and a device for evacuation of spent electrolyte from said separating unit. 13. The production line of claim 12, further comprising a unit for dispersion and cooling of said spent electrolyte, said dispersion and cooling unit being associated with a transportation system for transporting said spent electrolyte in a solid state into the loading devices of said electrolytic cells and/or for transporting of said solid spent electrolyte to an end product unit. 14. The production line of claim 13, wherein said transportation system is adapted for transporting of said solid spent electrolyte to a transportation system for transporting of said raw material, said separating unit is located -19- downstream of the electrolyte flow in the production line and before one of the electrolytic cell connected to said bus arrangements. A method of producing magnesium and chlorine substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. 16. A production line for production of magnesium and chlorine substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. 10 DATED this 22nd Day of March, 2000 RUSSIAN NATIONAL ALUMINUM AND MAGNESIUM INSTITUTE (VAMI) and ALUMINIUM ALLOIES METALLURGICAL PROCESSES LIMITED O Attorney: PAUL G. HARRISON Fellow Institute of Patent Attorneys of Australia 15 of BALDWIN SHELSTON WATERS S