FR2561257A1 - PROCESS FOR HOT AGGLOMERATION OF FINE GRAIN SUBSTANCES, AND FOR SUBSEQUENT TREATMENT OF HOT AGGLOMERS - Google Patents

Abstract

THE INVENTION RELATES TO A HOT AGGLOMERATION PROCESS OF FINE GRAIN SUBSTANCES, WITH THE USE OF AGGLOMERATED FATTY COAL AS A BINDER, AND OF SUBSEQUENT TREATMENT OF HOT AGGLOMERS. THIS PROCESS CONSISTS OF HEATING, ALONE OR MIXED WITH OTHER SOLID CARBON SUBSTRATES, IN A DRIVE CURRENT, METAL OXIDES CHARGED WITH SOLID AND LIQUID CARBON SUBSTRATES, TO A TEMPERATURE OF APPROXIMATELY 600C, TO MIX THE SAID OXIDES TO FAT AGGLOMERANT COAL PREHEATED TO A MAXIMUM OF 360C, TO DEPUT AND BRICKET THE RESULTING MIXTURE AT A TEMPERATURE OF 500C 40C, AND TO SUBJECT THE AGGLOMERES THUS OBTAINED TO A PYROMETALLURGIC REDUCTION TREATMENT IN THE CONCERNED METALS WITH A VIEW OF AGGLOMERATION. APPLICATION TO THE METALLURGIC TREATMENT OF SLUDGE AND DUST CONTAINING IRON, ZINC AND LEAD OXIDES.

Description

/ D-1 2561257

  METHOD FOR HOT AGGLOMERATION OF FINE GRAIN SUBSTANCES,

  AND FURTHER TREATMENT OF HOT AGGLOMERES

  The present invention relates to a process for the hot agglomeration of fine-grained substances, using agglomerating fatty

  binder, and subsequent treatment of hot agglomerates.

  The so-called "ANCIT" process is known in which at least two carbonaceous components, one of which constitutes a non-agglomerating component containing only a small proportion of volatile constituents, and the other component of which is formed of sticky or sticky coal, are substantially mixed with the softening temperature of the clumping coal, after which the mixture is subjected to agglomeration at

  (see Stahl und Eisen 92 (1972), issue 21, pages 1039 to 1044).

  In the iron and steel industry, some residual products of metal oxides with carbon carriers are obtained

solid and / or liquid.

  Thus, the rolling mills (scale) which are formed in the mills contain oily impurities; especially

  the rolling mills present in the form of relative fractions

  The finer amounts of oil contain relatively higher proportions of oil.

  Vees. In order to be able to subject the rolling mills to a

  In metallurgical applications, sintering must be provided. Since oils and their cracking products cause disturbances in the electrostatic precipitators, it is not recommended to sinter the mills without first burning the oil. But since adequate facilities are needed for the burning of the oil and such facilities are expensive in investment and maintenance, in most cases the scale is stored, so that the oxide as well as the fuel remain

  unused. These stored products pose a significant problem of environ-

  ment. The oil could be separated from the scale by extraction with organic solvents. But this process is also very

  expensive and does not prove profitable. -

  Other substances of the present invention are sludges and dusts containing iron, zinc and lead oxides which are formed during the purification of blast furnace gases and which contain finely divided carbon carriers. When it is desired to work by a wet chemical separation process, the so-called "top sludge" sludge must generally be dried with filters; during this treatment, they block very quickly. Because of these difficulties, in most cases, these sludges are also deposited on slag heaps. Similar considerations apply to dusts with zinc oxide and lead content

  is not high enough to warrant metallurgical treatment.

  cal. As a result, the fuel content, sometimes quite high,

  this mud and dust is, of course, also lost.

  At present, manganese and carbon-containing dust, which is obtained during the manufacture of ferromanganese, either at the top of the furnace or at the electric furnace, are generally also deposited on slag heaps, because they can not be used for make

  ferromanganese, because of their fine grain size.

  The deposit of all these products mentioned above, on

  crassiers or similar, raises environmental protection problems.

  extremely serious and a threat to human health

  for example in the case of heavy metals, such as zinc and lead.

  The object of the present invention is to create a process making it possible to make the substances described above accessible to metallurgical treatments, without it being necessary to separate the fuels contained in these substances beforehand. The invention also aims to protect the environment against the deposit or storage of these

harmful substances.

  For this purpose, according to the invntion, the method consists in heating,

  alone or mixed with other non-agglomerated solid carbon

  in a driving stream, metal oxides filled with solid and / or liquid carbon carriers, at a temperature of

  600 C, mixing said metal oxides with agglomerated fatty

  preheated to 360 C at the most, to puddle and brick the mixture

  resulting in a temperature of 500 C + 40 C, and subjecting the agglomerates

  thus obtained to a pyrometallurgical reduction

  recovering the metals contained in said agglomerates.

  The proportion of fine-grained metal oxides filled with solid and / or liquid carbon supports in hot agglomerates is preferably 20 to 80% by weight, especially 25 to 60% by weight, and the total carbon content. finished agglomerates is 30 to 70% in

weight of the dry substance.

  Fine-grained substances consisting of metal oxides

  solid and / or liquid carbon carriers are, in particular,

  rolling mills containing impurities in the form of

  of oil and, in this case, these metal oxides are reduced after agglomeration.

  hot maceration to produce iron.

  Fine-grained substances consisting of metal oxides

  loaded with solid and / or liquid carbon carriers may be sludge and / or dust containing zinc oxide and lead, which are obtained during the purification of blast furnace gases, and these are then reduced. metal oxides, after hot agglomeration,

  to recover zinc and lead.

  According to another embodiment, the fine-grained substances constituted by metal oxides filled with solid and / or liquid carbon supports are manganese dusts obtained during the manufacture of ferromanganese, and these ocides are reduced.

  after hot agglomeration, in order to produce ferromagnes-

  ganèse. Preferably, fine-grained substances with a high water content,

  sludge, are subjected to a pre-drying before their introduction

  in the cyclone of the hot agglomeration step, or are mixed with other dry fillers in order to be made fluid. According to yet another embodiment, the hot agglomerates are maintained substantially at the pressing temperature, for at least 30 minutes after hot agglomeration, for the purpose of eliminating the

Residual tar.

  Thanks to the use, in accordance with the invention, of metal oxides filled with carbon supports, during hot agglomeration, the liquid carbon supports are burned in large proportion and therefore used as a source of heat, while most of the solid carbon supports are not burnt but briquetted. After hot agglomeration, the agglomerates present themselves

  in the form that can be used in various pyrometallic processes.

  lurgical reduction. They are used, for example, in

  furnaces or electric ovens in combination with conventional

  such as coke and calibrated ores. In these furnaces, the metal oxides are reduced by means of the carbon content of the agglomerates,

  including carbon from waste products used in accordance with

  in accordance with the invention. The excess carbon present in the agglomerates, which is not used for the reduction of the metal oxides contained in the agglomerates, constitutes an additional reducing agent, which leads to a decrease in the consumption of coke compared to that

that we should expect otherwise.

  Depending on the nature of the waste products used and / or the metal oxides they contain, according to the invention,

  hot agglomerates to produce or recover the corresponding metals

dent.

  Since the additive substances targeted by the present invention are not in a fluid particulate form, it is recommended that these substances be pre-dried to

  fluidify, before their introduction into the cyclone of the agglomeration stage.

  hot maceration. It is also possible, according to the invention, to mix these substances, according to their degree of humidity, with appropriate proportions of corresponding dry substances, in such a way that the desired degree of fluidity is obtained. For example, high-water sludge from blast furnace gas washing plants can be mixed with dust.

  from the dry purification filters of the high-pressure gases

  furnace, until the desired state is obtained.

Claims (9)

  1. A process for the hot agglomeration of fine-grained substances, with the use of fatty carbon agglomerating as a binder, and for the subsequent treatment of hot agglomerates, characterized in that it consists in heating, alone or mixed with other non-agglomerating solid carbon carriers, in a driving stream, metal oxides loaded with solid and / or liquid carbon carriers, at a temperature of about 600 ° C, mixing said metal oxides with preheated agglomerating fatty coal at 360 C at most, to puddle and briquet the resulting mixture at a temperature of 500 C + 40 C, and subjecting the agglomerates thus obtained to a pyrometallurgical reduction treatment for recovering the metals contained in said agglomerates.  2. A process according to claim 1, characterized in that the proportion of fine-grained metal oxides filled with solid and / or liquid carbon supports in hot agglomerates is from 20 to   % by weight, especially 25 to 60% by weight.   3. A process according to claim 1 or 2, characterized in that the total carbon content of the finished agglomerates is 30 to 70% by weight. weight of the dry substance.   4. A process according to any one of claims 1 to 3, characterized   characterized in that the fine-grained substances consisting of metal oxides filled with solid and / or liquid carbon carriers are rolling mills containing impurities in the form of an oil, and in that these metal oxides are reduced after hot agglomeration to produce iron.   5. A process according to any one of claims 1 to 3, characterized   characterized in that the fine-grained substances consisting of metal oxides filled with solid and / or liquid carbon supports are sludges and / or dusts containing zinc oxide and lead, which are obtained during the purification of the blast furnace gas, and in that these metal oxides are reduced, after agglomeration to   hot, in order to recover-zinc and lead.   6. A process according to any one of claims 1 to 3, characterized   characterized in that the fine-grained substances consisting of metal oxides loaded with solid and / or liquid carbon carriers are manganese-based dusts obtained in the manufacture of ferromanganese, and in that these metal oxides are reduced, after   hot agglomeration to produce ferromanganese.   7. A process according to any one of claims 1 to 6,   characterized in that fine-grained substances with a high water content,   sludge, are subjected to a pre-drying before their introduction   in the cyclone of the hot agglomeration step, in order to make fluids.   8. A process according to any one of claims 1 to 7, characterized   in fine-grained substances with a high water content,   sludge, are mixed with other dry fillers, to be made fluids.   9. A process according to any one of claims 1 to 8, characterized   characterized in that the hot agglomerates are maintained substantially at the pressing temperature, for at least 30 minutes after agglomeration   hot, for the purpose of removing residual tar.