use amass egr j l xd 'an - PROUJGTIOF IndEsto 7 In view of the h the Basalans ing and expanding the production of calcium metal at Bitterfeld and of the virtual certainty that this metal is intended for the reduction of uranium or thorium COmpounds to metal it has been thought advisable to make a general review of the situation the processes involved and the Production statistics up to December l9u7 A previous report from this office Calcium Production at Bitterfeld 27th May 19h gave the early history of the subject and estimated the total production to let May 19u7 as 160 tons In this report it is intended to deal in more detail With the processes and materials used in the production of the metal The production figures will be based more on definite information than on estimates of the rates of production only 5 - II Rm INITIAL PROCESSING N07 The primary raw materials used in the production of calcium are calcium carbonate in the form of limestone and hydrochloric said Both of these materials are normally available in adequate quantities although it may be noted that there are several demands for hydrogen which is used for making the acid Shortage of hydrosen has resulted in a temporary slowing down of another stage in the processiin which hydrOgen is used $1 The limestone is quarried at various places the chief of which are Ruebeland Elbingerode and Ruedersdorf From Ruebeland the Bitterfeld by rail via Halberstadt and Halle At Bitterfeld a dump of limestone located outside Building 169 is kept at approximately 2 000 tons Typical analyses of the Oa003 are said to be as follows Ruebeland Elbingerode 030 5u 8 - - 5h 6 Loss in heating h3 21 #3 5 3102 - 0 6 0 5 0 2 O 55 803 0 08 0 06 A1203 0 3 trace I The hydrochloric acid is made in the plant by burning the chlorine in hydrogen and absorbing the gaseous H01 in water The maximum capacity of this process is estimated at 65 tons daily of m31 of 20% strength The aw EC em LASSEFIFD A uthnritim 8 0 35% 1ng o 03% 810 0 05% max Fe 283 @1203 0 01490 An Tor seem DECLASSHWED 2 The limestone is converted into a 38% 3d312 liquor by solution in the acid and then dehydrated Briefly the' steps are as follows solution in Filtration I Neutralisation Dehydration to 90-95% Ca012 Nubilosa Dehydration to 99-100%i0a012 The limestone is treated in ton batches in percolators containing about 2 cubic metres the treatment being with a calcium chloride mother liquor to which con- centrated is added The maximum capacity of this process is estimated at 30 tons per day of 100% Ca012 80 tons of 38% lye corresponding to a requirement of 30 tons daily of limestone and 65 tons daily of 20% H01 The final lye is made a proximately neutral i by the addition of 8a0 or 2 Filtration is by means of conventions filter presses Analysis of the lye is given as - 35 1001 2 387355 while analysis here of a sample gave the figures 03012 36d6 311g 1 36 Dehydration to 90-95% is carried out by feeding the 38% liquor into a Nubilosa plant which is essentially a hot air Cyclone dryer running at a temperature of around The plant is made by Nubilosa Meissen A diagram of the plant yields the following figures - 30 tons per day of 92% chlorine together with 1150 cubic metres per hour of hydrogen give a 36% H01 WhiCh with 30 tons per day of 98% 08003 yield the 38% lye which is finally dehydrated to give 16 5 - 17 tons per day Of 91 95%a0a012 This finished material is in the form of a fine powder Average figures for the analysis of this material in documents received are - An analysis made here of a sample received gave 00012 91 22% H20 8 55% 0 55 ppm Fe Mn M3 on trace Final dehydration to 100% 051012 is achieved by melting this material in an electrically heated crucible is run at a temperature of approximately 1000 C The maximum capacity of this process is said to be 13 tons daily of OaCl2 of 99-99c5% strength The melting point of the material is stated to be and its electrical resistivity is 1 78 ohms cc at this temperature QLECTROLYSIS OF GJJBIUM CHLORIQE Two methods are used in the production of metallic calcium by the electrolysis of molten calcium chloride - They are the carrot process and the copper calcium process The Carrot Process This is the conventional process in which the cathode an iron rod possibly water cooled dips into the electrolyte contained in a carbon crucible which acts as the anode As the metal is deposited on the cathode the latter is slowly raised so that the calcium builds up in the form of a rod or carrot Considerable skill is required in the raising of the rod in order to maintain the reaction and at the same time avoid picking up too much chloride in the metal A small amount of 01 is added to facilitate the start up of the bath Electric power at 22 volts D C and between 800 and 1800 amps is provided for the electrolysis The power consumed per of metal produced is stated in one place to be 3 and in another 55 Kwh Approximately 10 tons of CaCl are required force yield of 0 u to 1 ton of calcium metal Other figures are that 8 tons of melted 0a012 '550 Kgs' of graphitd electrodes and 80 000 are required to produce 1 ton of metal Maximum capacity of the plant is around 1 ton metal per day The process is however highly dependent on the atmospheric conditions of temperature and humidity in the summer months the working of'the plant is difficult In addition a content of SiOo greater than 0 08% is said to be deleterious si ee it reduces the surface tension of the-melt Purity of the calcium produced by this process in the first place was on the average - Ca m r11 1 Idol- O Authority m 814002 1 DECLASSIFIED i u '3 I I @3333 hit Whilst0 01 0 015 0 15 - Mg 0 02 Mn 0 005 - 0 01 012 0 8 - 1 5 N2 1 0 1 5 The initial Russian specification for the metal was met by this analysis except for the Cl and Fe contents for which the Russians wanted 0 3 and 0 2 respectively The Fe content in the material produced fluctuates considerably Attempts were therefore-made to improve the metal by vacuum distillation This raised the calcium content to the order of 99% and decreased the Fe content but had little material effect on the chlorine Even a double distillation failed to effect any improvement The distillation processes will be discussed in more detail later About November 1946 the Russians issued a new speci fication as follows - Ca 97 98% minimum 31 a 0 01 Fe 0 005 Mn 0 0005 Ni 000005 N9 0 001 0 2 0 03 The average analysis after double distillation was given as Ga 99% Me 0 01 Si 0 01 Fe 0 001 A1 0 01 Mn 0 0005 Cu 0 0005 N2 0 001 0 002 012 0Ac 1 h Cd Gd I This shows that the required purity in respect of chlorine was completely unobtainable and that consideration had been given to B Cd Gd etc which are of fundamental significance in the materials for an at0mic pile The Germans therefore set out to improve their product and to this end develOped the copper calcium method of- electrolysis DECLASSHWEDJA 3 100 1 eGo opper Calcium Proc_s In this process the calcium is deposited in a molten cepper-calcium alloy in the bottom of the bath which forms the cathode the anodes being carbon blocks projecting into the tap of the electrolyte which is as before the molten dehydrated CaClg The baths are of cast iron 220 cm long 130 cm wide and 80 cm deep the walls being 3 5 cm thick Operation is at 7-11 volts and 13000 to 15000 amps A small amount of K01 of the order of 20% is again used in starting the bath Electrolysis is continued until the Cu Ca alloy has the proportions of no 60 A greater content of Ca lowers the density and allows the alloy to mix with the electrolyte The bath is tapped by pushing through the electrolyte a crucible which has a fusible plug of the same alloy By this means the crucible is filled with alloy uncontaminated EydiaClz Alloy is removed from the crucible by means of a a e Free metallic calcium is obtained by vacuum distillation of this alloy 'Distillation is continued until approximately half of the calcium in the alloy has been distilled off The residue a 40 30 Cu Ca alloy is then returned to the vets to act as cathode in further electrolysis It is thus apparent that impurities will build up in a cathode it is stated that the cathode material has to be replaced every three months on this account The requirements for this process are 3 tons of Gaol to produce one ton of Ga metal and between 15 and 30 ng per Lg Maximum capacity of the installed plant is given as 1 5 tons Ca metal per day This is however limited by the installed distillation plant which can only produce 0 5 tons per day from this alloy although it can handle 1 5 tons per day from the carrot process The melt in each bath is tested daily for 05012 and L31 contents while the alloy is tested twice a day for its Ca content The advantages of this method of electrolysis are - Ca012 requirement is some 50% less per ton of - Ga ii Energy requirement is lower by an appreciable - fraction Less man power needed iv Capital investment is less Baths have a much larger capacity of the order of 200 Kg MDDECLASSHWED Aut horitylAjNh81m-2 - IQ t3 ms-i3 - 6 - vi Improved purity - particularly in respect of 12 vii to atmospheric conditions 6 The principal disadvantages are 1 Distillation is essential ii Distillation rate is reduced due to large Cu content of the charge IV DISTILLATION PROCESS Distillation is carried out in a vacuum furnace at a temperature between 900 and 105000 The furnace iS a cylindrical structure 2500 mm high and 1350 mm in diameter It is electrically heatedxby means of three Sets of spirally wound resistance wires made of sicromal 12 a high temperature alloy-of Si Cr Fe Al 'The wires are mounted on the inner fire clay walls 'The retort within which distillation takes place is made of a nickel chromium steel VZA or welded sicromal and supported centrally inside the furnace The collector is a water-cooled tube projecting centrally downwards into the retort Both the furnace and the retort are separately evacuated The furnace operates at a pressure of 0 6 mm Hg and the retort at 0 2 mm Hg The three sets of windings are energised by voltages of 130-150 and currents between no and amps The voltages are so regulated that the temperatures are as follows 750 in the upper set 950 980q0 in the middle set a 1060 - in thoiiower set Pumps used in this plant are by the following makers - 1 Dehne Halle - 350 cb m p h 11 Pfeiffer Wetzlar 500 eb m p h Siemens I Much trouble is experienced with failures in the lower set of heating windings It is said that difficulty is - experienced in obtaining heater wire for which in addition to sieromala onc could use tungsram megapyr or kanthal they were available The main sources for theae are outside the Russian Zone Failure of the retorts due to long periods at llOOqG is another source of_trouble Maintenance of the pumps and vacuum Seals is also a source of considerable trouble The principal pumps are said to be those made by Pfeiffer who are located in the U S Zone The charge per oven is of the Order of 80 100 kg of Gu Ca from which it is possible to distil off same 25i3o kg'Ca while from a charge of 25 30 kg of carrot 1 DECLASSHFEED 2 Authoritme giq - if - w 31 #3733 Li Ldif ilna process calcium it is possible to distil off approxi - 8590 - - With this type of still it is possible to distil 70-80 kg of carrot process Ca in 8-9 hrs but only 30 kg is produced from the Gu Ca alloy in the same time In handling this latter material considerable splutter- ing is experienced so that a grid has to be introduced to catch the splashes This results in some lowering of the efficiency - It is stated that the efficiency of distillation of carrot Ca is 80-85% which qould possibly be increased to 90-92% by suitable modification while the corresponding figures for the Cu Ca process are 75 80% and 85 90% respectively A Reports have been received that consideration has been given to improving the efficiency by modifications to the retort and the condenser to allow a larger charge to be handled and a large distillate collected per cycle but no indication has been recechd that these proposals have been adepted A A source of delay in the distillation process is the period which has to be allowed for the retort to cool _beforc it can be Opened and the Ca billet removed The theoretical value of_the power consumed in distillation is given as 1 u Kwh kg of Ca but the figure obtained in practice is 12 Kwh kg V EEQDUCTION STATISTICS Up until l9u5 production of electrolytic Ca was only on a small scale with about 5-10 cells Operatingpin the cold season of the year only After commencing dismantling the plant the Russians reversed their decision and began to rehabilitate it By August 1945 between 10 and 5 cells were Operating in the North Works and producing 220 Kg crude calcium per day cJ v In of 19u6 a further 96 carrot process cells were planned for the South Works of which some were to be used as reserves The first of these worked by September l9u6 and all are said to have been in commission by October 1946 although another report suggests that 10 of the furnaces did not come into commission until a January l9h7 The planned capacity was 750 Kg per day Actually the plant was said to produce about 1000 Kg per day in winter and 200 per day in the summer of 1947 when only do baths were working due to the atmospheric conditions It was about October-November 19u6 that the Russians made the purity specification more rigorous and forced the Germans to adopt distillation and the Cu Ca process As has been mentioned these baths were much larger Approximatcly 2 imtyi hL Approximately 1h baths Were planned of which two were to be kept in reserve The set up was designed to produce 300 Kg Ca per bath per day in the form of alloy that is about 150 Kg of free Ca metal By the end of August l9h7 only a of these vats were in Operation although the successful trials were made in April May 19u7 In view of the success of the Cu Ca process Sit was reported that all production was being turned over to this method However distillation is the principal' bottleneck and although the cannity of this plant is theoretically of the order of 500 Kg Ga metal from Cu Ua daily production fell in September 19a to between 100 and 300 kg daily It has been stated that on account of this Moscow had ordered that crude calcium from the carrot process should again be made and sent The reason for the fall in production was partly the lack of vacuum pumps and partly the purity Specification - material although now satisfactory in Cl content had a nitrogen content greater than tge desired figure The reason for the increase in the nitregen had not been elucidated it was thought that it arose in the Ou Ca electrolysis The lack of vacuum pumps meant that several stills had to be connected to one pump so that failure of one pump caused stoppage of all stills One report states that the erection of 28 stills was planned for an output of 2 tons per day and begun in March 19u7 All were said to be in Operation by July l9u7 although this appears unlikely in view or the slow rate of production of distilled Ca in the latter part of'that year They cannot have all been Operating' at the same time The following statistics have been compiled from various sources-on the production of Gaol and metal The production of lye can be taken as starting in April 19nd the installed capacity_being 500 tons per month of 100% Ja012 1 0 1300 tons per month of 38% lye Actual production figures of lye are giving the lye both in tons of 38% liquormand in tons of contained CaCl2 - Period 38% LiQnor 0801 mow April 1946 - Maj 19u6 June 19u6 1 5 55 July l9u6 308 117 August l9u6 u36 166 September 19u6 721 27h October 19u6 2750 tons 1100 November 19h6 tons December 19M6 January l9u7 February 1947 March 19h April 19h7 May DECLASSHFIIED a - Authurinymn SST-1002 mi ago last I EJELZ - May 191 716 272 June 19h 7lu 271 July 1947 663 252 August 750 285 Septe ber l9u7 858 326 October l9h7 920 7 350 November 19h 806 307 December 19a 1100 MAD eqa 9277 tons 2603 tons or d- - - -- Of the total lye production a considerable proportion is used for other purposes A figure quoted for this is 500 tons per month of lye a definite shipment of 580 tons was made in early November while another of 225 tons lye later on in November and 68 tons in December The rate of production increased at the beginning of December to #5 tons lye pg day It is said to have stopped entirely about 27th Dccermer but to be going again on 8th January 19MB at the same rate AB tons per day The production of metal in the three plants is as follows in tons - Marie cues 213E anks anks i-d1a pril to Aug 'u6 - 20 - - Sept to ch 66 5 20 - Jan to bept 156 5 no 57 uzg 19 October 'n7 20 7 - 26 November 'h7 Estimated 20 7 - in December 'hj Estimated 20 7 - 9 Total 283 101 5 57 - 55 Actual content of Ca in u0360 Cu Ga undistilled a 337 tons Hence total Ca metal and total Ga metal distilled These figures are thought to be highly reliable being based on several reports which are in essential agreement both in quantities produced and in rates of production It will be seen that the production figures are in good agreement with the earlier and more tentative estimate made by this office It will be noticed also that distillation is now undertaken only for the material from the Cu 0a process and that some 112 tons of distilled calcium has this material is considered to be use ful for the production of uranium been produced Anthems W 8 me w I - w-Mm 1136 10 VI DESTINATIOH OF 4 ADI Reports on this subject have been varied Some say that the material is being flown to Russia others that it is going by rail A Russian order dated 2nd January 19h from the U S S R Abteilung fuer Reparationen und Lieferungen der S M A in to the Minister Praesident der Provinz Sachsen Halle demands 75 tons of Ca metal to be consigned to W70 Rasnoimport The specification of this material is interest- inw since this is almost the time when the Ou Ca process L was first being considered it is as written - ea 95% The folloring not to exceed Total Fe Al Si and Mg 0 u000@ 0 0100 N2 0 0300% 012 0 3000% an 0 01oo% As 0 0200% Ni 0 0200% Co 0 00u0% Ag 0 0020% Li 0 0000% ca 0 0000% 0 0000% Rare minerals 0 0000% Note the contents and other A rare minerals will be determined by spectrum Sic ' A full report of this method of analysis has been received This material had to be packed in hermetically sealed Pi This specification should put the intended use of this material beyond any shadow of a doubt - - Another report says that the material was packed in bags and then in boxes filled with or and consigned to Moskau Eisenbahn Bezirk Kursk Postfach 3 The shipments are sometimes in the form of pellets or coarse granules and sometimes in the form of the original billets Experiments have been carried out to determine an efficient method of breaking up the billets into the small granules normally used in a uranium reduction process So far no satisfactory method has been dOVUlOdeo This is referred to as the shaving process DECLASSIIFHED Authoritym i $14002 VII wm wyv 0 4 E'r r quow-ve h If on - - - PUSSIBLE CALCIUM IN RUSSIA Much of the data in this re ort from plans drawn up by the Germa s fora to that at but to be located in Russia g intended location is not knOWn but among the pla gs 0 mentioned are hiev Dzorzhinsk and Samarov Two Germs technicians Drs Springmann and Krassel capable of supervising the erection of such a plant have written gettgr is located on the river ha 0 ween doscow and orki which in favour of that locality 9 weights the evidence It would however take a considerable time to such a plant into operation - 9 put Tho section of the scheme which deals With the naki of Ca012 is known as Research Project No 132 1 ng spiems'ggem CONCLUSIONS An attempt has been made to review the processes used for the production of calcium metal at on behalf of the Russians - It is concluded on the basis of the analytical specifications presented by the Russians to the German Directorate of the plant that the calcium is intended for an atomic energy project beyond any shadow of a doubt The best evidence available indicates that from April 19h6 to 31st 19h7 337 tons of undistilled calcium were made and 112 tons of distilled calcium of which approximately half came from the Gu Ca process and would have therefore a reasonably satisfactory purity In Appendix I to this report there is given a note on the organisation at and the personnel concerned with the process at some time in the last 20 months Appendix II contains some comments and deductions which can be made on the data presented in this report v unaunaw- Hem assume F9 F2 rung-1' Eh fgimqs r $391 hinge - APPENDIX 1 ORGANISATION PERSONNEL The former I G Farben Industrie at Bitterfeld has been recently renamed Abteilung der Sowjetischen Staatlich- previously en Aktien Kaustic in Deu called the Electrochemische Kombinat The factory has a Russian Direc Directorate Instructions are issued which the German Directorate are reSponsible for carr 1 out Only the German Directorate deals with the Germag ng staff Under the German Directorate is the German Management which is composed of German engineersrand chemists - Each German specialist however is surrounded 'by at least 2 or 3 Russian engineers who keep him under dlose surveillance and at the same time try to ick as much technical knowledge as possible up DIRECTORADE Dr Col vuv BELAJEFF Director General of Kombinat until late-July He repLaced a Col Margolin phonetic BELAJEFF is a chemist by profession and well versed in chemical matters He is about 50 years old 'He returned to Russia in August and has not been replaced ajgr JOFEE Second in command to Dr Belajeff takes a very close interest in the calcium production and in all development work at Bitterfeld Lt Col PROZBHKO Officer in charge of loading the finished haterial LJA ACHNASAROV Deputy to Belajeff at one time and chief engineer of the plant G M POLORZEFF Deputy of Managing Director S P STAROSTIN Head of Technical Production Department v 3 KORCLIOV A Chief Engineer of Technical Production Department Chief Engineer of Technical Production Department A Chief Engineer of Technical Production 1375 17136 L31 Head of Planning Department ZHead of Power Plant Chief Engineer of Power Plant and responsible for power supply to whole plant aw rm HQ gr 37ng 3 1 smemumw GERMAN DIRECTORAEE Dr Ing Adolf BEQH Director Genera 11 a Bigterfeld He was a leading ma years 1e is not a scientist but a 1 with highly developed skill in solution Regarded as a political chameleon and presently very pro Ruggian and is treated very well by the Russians He has re established his former wealth and advises members of his staff to go to Russia when they receiVe offers and has indicated his own readiness to go He is a member of SED and of all matters Russian a protagonist 4 Dr Second-in command to Dr Beck and head of the Works in'ETl chemical matters He is also the head of the South works He is prewRussian - Head of the distilling section in the South Works DevelOped 'Shaving' process and also the distillation process for the purification of calcium He Was trained at Freibnrg University is a chemist and is politically neutral Later stated that he has been made head of the electrolytic section also Deputy to Dr Seliger in the distilling section the South Works Left the works in October to take an appointment with some chemical firm Now in Stuttgart Dr JABNQEHEE Head of the electrolytic sections in the Sonth Works Deputy to Dr Jaenekner in the electrolytic section of the South Works He is a chemist and originally from Mainz He was a Nazi but is now a political convert Reaponsible for calcium production Dip Ing Minus Head of the calcium electrolysissectidn in the North Works I 0 Deputy to Dr Winkler in calcium electrolysis section in the North Works Is head of the copperhcalcium electrolysis section in the No th Works 1 Head of the engineering department of Bitterfeld Directly concerned with installation of the new calcium section in the South Works Installation started in January 19h7 Director MAINZER Head of the electro technical department and associated with Rdcke an installation of aalcium section in South Works - Dr Chemist and engineer specialist for the erection and Operation of equipment Ex Nazi party member Lived- many years in Manchester E gr SEDLACEK Head of the cepper calcium electrolysis section in the South Works He is a Sudeten German and Was with the Skoda-WOrks Plzen Czechoslovakia during the war a n-a m IFD- a wg hCLASSnnEn AutMrityNN it gime mam 2 itff i it-HV ea mawaid n i - 3 - Fug EHRLICH Expert on develOpment of distillation equip menu LOP the purification of calcium Reported to have left Rus31an Zone and returned to Hannover udi l Former director of Light Metal Foundry at Bitterfeld Dr HACHTIGALL A chemist formerly at the Bitterf ld works and involved in the production and testing of the calcium New at metallwerk Plansee Reutte 23- SPRINGEMANN or A technician formerly at Bitterfeld and part author of a report on the production of 0401 from limestone Now believed to be at Dzerzhinsk nr Gorci Technician formerly at Bitterfeld and now believed to be at Dzerzhinsk Dr MIDmmonr A phosphorus expert at Bitterfe'ld and anxious to escape to the Western Zone Technician at Bitterfeld and part author of the report on CaClg production Technician at Bitterfeld and author of a report on an undervater burner used in the process for concentration of Cn012 liquor German responsible for administration and sales of light metals - Chemist now believed to be in charge of the nnalytical section - Analyst previously under Nachtigall and now under Sehiehtel DECLASSHHED Author 5 3 59 11 JUMS 11 PURITY CONSIDERATIONS 1- sew It is not clear to us why the specification insisted on low chlorine content other than a tentative suggestion that the presence of chlorine would interfere with the keeping preperties of the metal in storage Chlorine does not affect the conversiOn process 2 Low Nitrogen Content The increased rigors of the Russian specification for nitrogen content may have been due to a lucky guess on their part or a knowledge of other countries' work or fairly advanced experiment we can form no judgement between these possibilities ' In the British process at least the presence of nitrogen interferes seriously with the uranium reaction and nitrogen must be kept low The reason for the-comparatively high nitrogen content in the Bitterfeld distillation is0 thought to be that the oven is Opened which temperature nitrogen reacts with the calcium both in the koenig and in the bath That in the koenig is only a surface reaction and does not matter very much but that in the bath is cumulative and passes over in distillation so that the whole koenig has an over high content and becomes progressively worse as the process is speeded up I in an attempt to increase production Another source of trouble in the German distillation process incidentally is that the flow of coolant inside the condensing rod is insufficient to lower the surface temperature of the koenig while_it is being formed below M50 C At this temperature the aipha form of as is produced while at a lower temperature gamma-Ca is formed Gamma Ga is friable and is therefore easy to break into pellets as required in the U crucible while the alpha form is malleable and must be shaved or cut resulting in a loss of several per cent 3 Elements of High Capture Cross section The significance of the zero figures in the Jan'h Specification Quoted for Li B Cd ani TR 18 obv1ous but it is less obvious that the other allowed values are in prepcrtion to their capture cross-section 9 me I This document is from the holdings of The National Security Archive Suite 701 Gelman Library The George Washington University 2130 H Street NW Washington D C 20037 Phone 202 994-7000 Fax 202 994-7005 nsarchiv@gwu edu