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November 2, 1956
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For S. Bulfltiwn Co)pi-C icnl T,..i L +, P. Planhla+r ~1mQ D~lo, Vol n. No 2, Sofia, Mar-1}.r 1956, pp 16-21. Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 Coke was obtained in all these experiments. Hoowever, its quality does not permit its use in high and average furnaces. It can only be used in low-pit furnaces, as an addition (up to 30%) to ordinary coal. The results achieved in the German Democratic Republic, showing that the production of coke with rather good mechanical qualities is possible, are most encouraging. This coke, however, has a very low degree of porosity (26 to 30%; while for normal coke, it is over 50%). The German specialists have observed that this coke can be added to ordinary coke in amounts up to 30%. Taking into account that a great deal of work has been done on methods of coking brown coal during the past decades, and that coking techniques are still being perfected, it can be expected that brown coal will widely be used for making coke in the very near future. Even at present, the German Democratic Republic uses coke produced from brown coal in ferrous metallurgy (despite the fact that the classical high furnaces are not employed). The results of research carried out so tar on coal for cok- in: give us the opportunity for evaluating the Bulgarian raw-mate- rial resources for the production of coke. The most important thing is that we have coal including all the technological grades necessary for coking. However, it has a .:other high percentage of ash and sulphur. In general, its eonce^- is a difficult process, and obtaining the necessary concen- trate for coking (having a low percentage of ash and sulphur) re- quires t:;e utilization of a considerable tonnage of the geological .:Uerves krv,n. The reserves of coal for coking now known still do nut permit - 8 - the establishment of a cokoproducing industry on a large scale. Furthermore, lean caking and noncaking coals predominate in the deposits so far tested, which limita the possibilities of using all tfie deposits of hard coal so far discovered for coking. The quantities of coal of the "Gas, " "Fet, " and "Coke" .grades which would be added to the batch with the "lean" and "lean caking" coals are insufficient. The technical possibility, in the future, of using brown coal as well for coking widens the raw material resources for coke production. This problem, i,owover, is now under research. The use of brown coal is still limited. In this connection, there are also other obstacles: the Bulgarian brown coal pits (we have in mind those in Dimitrovo, Bobov Dol, and Pirin) have small reserves of I gh quality coal, and the coal with high ash content is difficult to concentrate and reduce its ash content to 6-:%, which is re- quired for coking. Under such circumstances, the problem of the development of the coke-chemical industry in Bulgaria must be analyzed in the fol- lowing manner. The research and studies made on the coal reserves in the Balkan basin and in certain other places justify a serious consid- eration of the problems concerning the construction of a coke- chem-ical plant. It is necessary, of course, to know in advance that from .is coal we will produce coke only under rather difficult conditions -- chiefly due to the difficulties involved in concen- trating, and to the lack of sufficient "gas" and "fat" coal. The site of this plant will have to be determined on the basis of ex- isting reserves as well as the prospects for the discovery of new reserves of coal for coking. Meanwhile, until the necessary re- serves of "gas" and "fat" coal have been discovered in Bulgaria, coal can be imported from abroad. The construction of a coke-chemical industry on a wider scale, calls for several undertakings to be carried out in the shortest possible time, the most important of these, in our opinion, are the foll6wing.'- 1. Still wider geological research must be cc o? Ln the Balkan basin for locating further reserves of hard coal, with special attention to prospecting for reserves of "gas" and "fat" coal. Research in other regions containing hard coal, particularly in northwestern Bulgaria, must also be undertaken. 2. Systematic chemical and technological research on coal must be carried out, along with geological research, in order tr determine the suitability of the coal for making metallurgical coke. Particular efforts are required in choosing the proper met?ods of concentration suitable for Bulgarian coals, and for in- suring the production of a concentrate having a low ash and sulfur ccwtent. Systematic research and seaiindustrial and industrir.l tests with a view to discovering the most suitable method of mix- ing the coal dust be carried out, in favor of making coke wits high physical, mechanical, and chemical qualities, and to achieve bo':tar utilization of existing hard coal reserves. 3, Research on the use of brown coal for coking -- mainly fo:? adding to other types of coals used for coking, ang also as au independent raw material -- must be carried out in Bulgaria. - lu - Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 4. Work on drafting ylsas for pits must be completed on schedule, then the construction of theme pits must begin immedi- ately to insure the supply of coal necessary for the operation of the coke-chemical plant. 5. It is necessary to pay attention to the problem of lim- iting the current exploitation of the valuable kinds of coal ("gaa," "fat," and "coke") in the Balkan basin, and to reserve these types for the projected coke plant. These tasks call for the mobilization of some considerable forces -- material and manual. So far, technological research on coal for coking has been carried out almost exclusively by the NIITIG. Even at the Institute only 3 or 4 persons, who are inad- equately trained and poorly equipped, are engaged in research on tine problems of coke production. The number of specialists en- gaged in research on coal for coking must be increased as quickly as possible, and the basic material necessary for carrying out qualitative and fruitful research work must be created. Further- more, specialists must be sent abroad for training, where they can become acquainted with the methods and techniques necessary for carrying out the necessary research. The specialists of the BAN (Bulgariaa aksdeaiya na naukite, Bulgarian Academy of Sciences) and the VtM (Visshi uchelni r_aveden- iya, Higher Educational Institutions) must participate more actively in the implementation of this task, by taking over part of the re- search work related to the establishment of the coke-chemical in- dustry in Bulgaria. The planning and the building of a coke-chemical plant will - 11 - Sanitized Cdr Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 .WV& a aw aiw sass swap w avawafa. aapavaeaaas-a.. aa.aa waaa prob- As far as preliminary research is concerned, including the choice of the most likely and favorable mixture for coking, this can be carried out entirely in Bulgaria. It is wrong to consider that such research must be carried out abroad. It is difficult to send all the samples necessary for research out of the country. The location of the various deposits and the variety in the kinds of coal make numerous combinations and tests impossible if they were to be conducted abroad. Also we must pay for such tests per- haps even more than it would take to eouip a research center locally and to train local personnel. The time is already ripe for a serious discussion of the problems of establishing a Bulgarian coke-chemical industry. We must devote the efforts required and invest the funds necessary for the final solution of this problem. Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-00280R001300190013-5 I^08 A BQLOARIAN CM-C EIIICAL IXDUSTRY Mine delo [Mining), P. Plachkov Vol XI, No 3, (Director of Niitig) March-April 1956, . Sofia, Pages 16-21 the industrial development of wiy country depends on numer- ous :actors. One of the principal factors'is the metal industry, particularly, t,e production of pig*iron and steel. e}lgaria is pursuing a?course of speedy industrialization. The mr,1nr efforts of the party and the government have been di- rected 'toward the building up of heavy industry, which. is the b tts Jor.transformirs the country from an agrarian country into an iulvstrial-agrarian one. However,. it is difficult to build up heavy industry without domestic production of pig iron and steel. That is how the building of the "Stalin" DILL (Durzhaven Mashin- ostroltelen. Zavod, State Machine-building Plant) was one of the first large !tanstruction projects in Bulgaria. This plant is now being expandtd, and' the first blast Iurt.?kee for the production of pig iron is currently being added to it. Along with this, in the. past few years research has been carried out on a large scale with a V AI*' to locating iron ore deposits, whi4t are necessary for pig .? in production. In this connection,`c~julgarian geological reseaicn organizations have achieved considerable success, and it can said that iron ore reserves sufficient to last several consecutive decades are as- sured. leserves of manganese ore, equally necessary for the for- foul industry, have also been.insured. Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 coke, for the blast furnaces. In order to insure the supply of coke, the directives of the Sixth Party Congress have called for sufficient geological research for the discovery of more hard coal reserves which is the basic raw material for coke production. The plan calls for an increase of 38 times in the. known reserves. by the and of the current Five-Year Plan. During the past few ;gars, large scale geological'researcla with a view to the discovery of new hard coal reserves for coking have been carried out in Bul- garia. At the same time, considerable technological research for the purpose of determining the possibility of the production of coke from one or another kind of coal has-been conducted in Bul- garia and abroad. In the present article, we wish to provide a short summary of the research carried out so far on the'problem of the production of coke in Bulgaria and to attempt to point out some of the further messuros necessary for the final solution of this problem. Attempts to-organize a Bulgarian coke-chemical industry data back to the bourgeois capitalist period. The Bulgarian capitalists who owned the deposits of hard coal, good for coking, in the Balkan basin, thought of instituting such production, and, as . result, the coke factory at the P achkovtsi railroad station, consisting of only a few furnaces, was built. The lack of proper dev:r.apment in industry at that time, the contradictory interests of tn& mine owners, the lack of interest on the part of the bourgeois fascist state in the development of the coke-chemical ind"utcy, and the influence exerted by other capitalist countries, made it impossible in practice to solve the problem of the oruani- Lath. of coke production in Bulgaria. Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 Th;n for the first time in Bulgarian history this question was paste for complete solution, by the People's Regime. The pro- duction o.:' coke is linked with the problem of the development of the Bulgarian entire indcustry, particularly ferrous and nonferrous metal- lurgy, the chemical industry, and the machine-building industry. Brown coal was sent to France in 1949 for research work on the possibility of producing coke by now methods. Inter, brown coal was also sent to the German Democratic Republic and the Hungarian People's Republic, for the same purpose. tY2 ehs11 re- view the revults achieved after we have analyzed the research on hard Balkan coal in greater detail; the latter still represents the aost feasible raw material basis for the production of coke. General Administration of Geological and Mining.Rasoarch has since 1953 been carrying out a detailed study of the Balkan coal basin, With a view to locating reserves of coal suitable for industrial coking. The reserves in the active pits and those of the new sectors are being studied in detail. Technological research is be- ing carried along with geological research, with a view to determin- ing the suitability of the coal for the production of metallurgical The technological tests were carried out by NIITIG (Nauch- noisaledovatelski institut as takhnoloahki issledvaniya na gori- vats, Scientific and Research Institute for Technological Research on Fuels) on samples of coal, 30-50 t each, submitted by the ge- ological research groups. The tests included: (1) chemical anal- ysis; (2) sifting operations to establish granulation; (3) frac- tional analysis to determine concentration capacity; (4) industrial Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 ooawsatntios test to obtain eeaseotratlda tadieoew tot seal wi?r industrial ooditioms, and saialy to ebtala larver asastit:ve @I concentrated coal necessary let the ether t"10, Gets 12) jas (sanduchno j and ooepar ta?a t oci 1 ag of the oeseea t r"a t++ coal -- separately or is a mixture with other coal -- to onset tc elatervr inc the coking capacity. Rooeatly, sines rseniviah Um ltapowari- kov apparatus, it ha. been poesibld to deternirw th., plastscity indexes of a larbe part of the tested coal as well. These tests leave many gaps to bo filled. still no ca.plcte research on petrography, tendency to cake, plasticity, -wellin,r pressure, etc has been carried. lloreovar. the industrial coacentrs- Lion testing has been conducted at the 'Lev' DIJI installations a: the Plachkovtsi railroad station, which are still not fully rauippe.:. and the resulting data cannot really be used in tnw :iral plaar.ias of installations for the industrial concentration of ..url. the coke testing was carried out in the coke compartment k:las of ins above mentioned onterpriso, in which work is done without heat ro,enera- Lion, at relatively low temperatures. It is well k:wwn, tanswer, that modern furnaces are built mainly foe high temperature hoattu4. Despite these gaps in the research, the results achieved rake it possible to evaluate the coking capacity of the coal and to deter- mine the possibility of its use as raw material in coke production. The Institute for Technological Research on yuals an so tar carried out more detailed research on the coal obtained from the following regions: Kachulka, Chumerna ('thumerna" pit, "bivina" pit, 'Yoke" pit, and the "Kichesta" and "Sheshkingrad" sites), Trurditas, and Butura. A certain amount of research has bean carried out by Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 the institute, and by other organisations and individuals, an the coals obtained from Placxhkovtsi and other regions of the Balkan basin, and also from some other northwestern Bulgarian sites. Coal from some sites has been tested in the USSR as well. With few exceptions, the regular coal frow the sites studied appears to have a high ash content. In general, the ash content varies from 10% to 60%, mainly between 20% and 45%. The sulfur c" tent varies between U.85% and 5%. and in some sites in northwestern Bulgaria (Gorno Orzirovo) the sulfur content has been over 10% in certain tests. Because of this, the coal from all these sites must be concentrated before it is used for coking. Some of the coal layers at numerous sites could not be used for coking in any case, because after concentration this coal still retains high ash or sulfur content. This further reduces the quantities of coal suitable for coking, on the basis of the re- serves of hard coal which have been studied. In general, ailicium and aluminum oxides predominate in the ash content of the coal and its concentrates. These contents make the coal further unsuitable for coking. In terms of sire as indicated by siftiag, the finer grades of coal predominate. There is an average of 40% to 60%, mostly 50%, of coal of the 0 to 3 n grade, chile the percentage of large- sine grade of coal decreases as the grade rises. Thus only a small percentage, rarely even 10% to 15%, falls in the over 50-mm grade category. In general, the ash content is low in the finer grades, Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-00280R001300190013-5 and the sulfur content is high in the middle grades. However, there is no sharp differentiation. Coal lends itself to concentration in varying degrees, but usually with difficulty. The concentrates which can be produced from various coals vary between 30% and 70% -- mainly ?&i%. The ash content of the concentrates is between 6% to 15-20%. Coal which has been subjected to stronger metamorphoses (belonging to the group of thin-caking coal) concentrates better, while coke and fat coals of the Kachulka and other regions concentrate with greater difficulty. For coals of the finer grades, concentration has to be carried out at installations equipped for finer grades, while the finest grades and residue will have to be enriched by flotation. The technological classification of the coal tested is de- termined on the basis of the data provided by the research so far conducted on the coal (production of volatile substances, kind of coke residue, plasticity indexes, petrographic composition, and coking capacity) in the compartments of the Plachkovtsi coke kilus, to the Donets coal for grade classification of the Bulgarian coals, we have: "Gas" (g) -- at some sites in Plachkovtsi region (Lev and others); "Fat" (PO) -- at some sites in Plachkovtsi region and in northwestern Bulgaria (Como Osirovo, Zelenigrad, etc); "Coke" to "Fat" (K to PO) -- Xacbulka, Tantra-Iavor, etc; "Coke" -- (shesh- kingrad, etc); "4MLn caking" (PS), with varying degrees of caking - from rather high, close to that of coke, .o poor (Koko, Kichesta, Tivina, Chumerna, Butura, and Tvurditsa); "Thin noncaking" (T) -- Sanitized Copy Approved for Release 2011/06/04: CIA-RDP81-0028OR001300190013-5 roes sites in Tvurditsa region (Nadeahda), xarabair, etc. Further research will be necessary to assess more accurate technical grad- ing of the above. The data available at present indicates that some of these types of coal fall into categories intermediate to those described.above. Thin calls for more exhaustive testing of tins coal from each site, as wall as a more fle.-.ible system of grading. The present classification, even though only preliminary, shows that, in Bulgaria, we have all the technological grades (in- cluding the basic grades, "coke" esd "fat") necessary for the com- pilation of a proper mixture for the production of zaotallurgical coke. We mentioned earlier that experiments for coking Bulgarian brown coal have been carried out in the German Democratic Republic, France, and the Hungarian People's Republic. All of these experi- ments were carried out in large laboratories. The coal was sub- jected to various tests, particularly thorough experiments being carried out on the so-called 2-step method of producing briquettes. Basically, the method consists of the following operations: pre- liminary low-temperature carbonization of the coal at temperatures from 4300 to 650? C (to varying degrees according to the tempera- ture). The low-temperature carbonization tar thus obtained helps to make briquettes of the asmicoke of the coal, after which the briquettes are coked. In some of the experiments, tests were also made with the process of adding certain quantities of Bulgarian hard "gas" coal. The coke thus obtained retained the briquette fora and acquired various physical, chemical, and mechanical qualities depending on the conditions maintained and the compon- ents used.