FR2501721A1 - METHOD AND APPARATUS FOR CONCENTRATING NON-FERROUS METALS SUCH AS ANTIMONY AND TIN BY VOLATILIZATION FROM RESPECTIVE ORES OR BYPRODUCTS, AND PROCESS FOR OBTAINING ANTIMONY AND TIN IN THE METAL STATE - Google Patents

Abstract

THE PROCESS DESCRIBED IN THIS INVENTION IS CHARACTERIZED BY THE FACT THAT, IN A SINGLE STAGE, WE OBTAIN, WITH ETO AIR WITH OXYGEN AND CARBON COMPOUNDS, ALSO WITH LOWER QUALITY COAL, VOLAUSE OF SULPHIDES AND OR OXIDES, WHICH ARE THEN GRILLED IN THE GASEOUS PHASE, BY AIR AND OR BY OXYGEN. AN APPARATUS FOR CARRYING OUT THE PROCESS IS A REACTOR OF TRUNCONIC SHAPE, COMPOSED OF A METAL ENCLOSURE 2 LINED INTERNALLY WITH A REFRACTORY MATERIAL 3, THIS REACTOR CAN ROTATE AROUND ITS VERTICAL AXIS 1, AND IS MOUNTED AT THE BOTTOM OF A HOLE FLOW 5, SO THAT THE SOLID PRODUCT LOADED THEREIN ADHES UNDER THE EFFECT OF SEVERAL FORCES IN PLAY, TO THE INTERNAL WALLS OF THE REACTOR AND THAT THE LIQUID SUBSTANCES WHICH ARE OBTAINED CAN FLOW THROUGH THE DRAIN HOLE 5 USE OF THIS PROCESS TO OBTAIN A SINGLE SB OR SN OPERATION IN A METAL STATE.

Description

Process and apparatus for concentrating non-ferrous metals such as

  antimony and tin by volatilization to

  from the respective ores or by-products, and

  yielded to obtain antimony and tin in the metallic state.

  The present invention relates to a process which makes it possible to carry out oxidation enrichment processes.

  of antimony and tin, by volatilising at a suitable temperature

  products containing them, in a percentage which may be of any kind, in the form of oxides and sulphides, and

  the apparatus for performing such treatment.

  Usable products can be either primary raw materials (ores) or products

  secondary (mineral residues, slag, etc ...).

  The most important procedures will now be described as they are used today for the concentration of non-ferrous metals such as

than antimony and tin.

  In the processes generally adopted for antimony, three modes of operation are followed.

  commonly referred to as conventional procedures, that is,

  above: precipitation (wet process), roasting and

  volatilization, and roasting without volatilization.

  Volatile roasting is adopted whenever the starting material contains less than 40% antimony and other recoverable metals in a white phase, such as

  than copper and precious metals.

  Other processes, precipitation, and roasting

  without volatilisation, are used whenever

  Starting dults contain at least 40% antimony and not too much impurities. However, wet process installations, even if they require a single stage, are used, ultimately, for very rich concentrates and

  for small flows because their utlllsation is very expensive.

  Conventional roasting procedures are typically

  Problems arising from the particular physicochemical properties of trisulfate and antimony trioxide, that is: - high vapor pressure and low boiling points; - a low melting point;

  - instability in environments that are only slightly

oxidants.

  Therefore, these processes, because they take place in more than one stage, require slag recycling and

  recycling of white wines and produce large volumes of

  with performance falls associated with them, and they

  require the treatment of a certain number of

intermediates.

  One of the common behaviors of antimony and tin in volatilization is that the highest yields are obtained by the volatilization of their sulphides: it is therefore necessary that, in treatment, whatever is

  the process adopted, there are no oxidizing conditions.

  The process according to the present invention is represented by an alternative of conventional methods and

  is achieved in a single step with control of the medium, volati-

  sulphide and roasting, or post-combustion in the

  gas phase of said sulphides to obtain

  centered which are rich, as desired, in antimony and

in tin.

  In addition, the process suggested here allows considerable fuel savings, so even

  coal of lower quality may be used in the pulp

  checked, without having to use natural gas or coke. A first object of the present invention is a

  process for the concentration of oxides. First, we

  the volatiles of the sulphides and oxides contained in the starting materials are volatilised by exploiting the heat of reaction of a carbon product and a combustion auxiliary (air and / or oxygen), after which it is realized, in the vapor phase , roasting sulphides and oxides with air and / or with oxygen. The treatment temperatures must exceed by at least 50 ° C the boiling temperatures of the sulphides and / or oxides contained in the raw materials, so as to

  cause volatilization. (As a general rule, we start from

temperatures of 15001C and above).

  The non-volatile fraction of the load, yes will be found in scorles, will have concentrations in various

  components such that slag can melt at low temperatures

  erature and, at any rate, below 12000C. Therefore, suitable amounts of CaO, SiO 2 and other oxides will be added to the starting materials whenever

  such conditions will not be met in full.

  As another method, antimony or tin can be obtained in the metallic state. If so, the oxides and / or the suffixes are reduced to obtain the metal by means of

  carbon and carbon monoxide and the metals involved

tilisent.

  A second object of the present invention is the

to carry out the process.

  Reference is made to Figures 1 and 2 of the plates

  attached. The reactor has a cane trunk shape, and is

  composed of one or more trunks of cane, possibly replaced

  by their outer or inner enveloping surfaces, and arranged with their vertical geometric axis, said reactor

  being rotatable about said axis 1, and being formed of an enve-

  metal louvre 2, internally lined with refractory bricks

  3. The angular velocity of rotation and the angle 4, between the generatrices of the internal surfaces of the walls of the frustoconical bodies (or their enveloping surfaces) and the vertical

  such that the solid phase remains, from a dynamic point of view

  in equilibrium under the concurrent actions of weight, rotational inertia forces, and friction forces on the inner walls, while the liquid phase flows towards

  the reactor base which has a flow hole 5.

  The inside diameter of the largest base of the reactor can be chosen between 1 and 10 meters, the preferable dimension being between 2 and 6 meters, while the diameter

  Inside the smaller base varies from 0.2 to 1 meter.

  The diameter of the drainage hole should be between 5 and 301 of the largest inside diameter. Even up to 100% of the inside diameter

  the smallest base according to the potential flow rate of the

tallation.

  The angle 4 between the generator of the cone and the

  tical can range from 10 to 60, with values higher than being pre- 'In the case of an apparatus consisting of more than one truncated cone, or an enveloping curved surface, generators and their tangents shall not have the

  against each other an inclination greater than 30).

  The rotational speed of the conical body must remain between

and 80 rpm.

  There are, in addition, 2 to 4 pipes (nozzles) (6,7) whose end opening into the reactor is tilted properly, and which can be moved along a vertical axis and are used both to load the

  feedstock and fuel.

  In addition, through one or more pipes 8, (up to 4 pipes, maximum) which are necessarily parallel to the generatrices of the inner surface and, more exactly, through the perforations 9 made all along the pipe and if possible regularly spaced apart from one another,

  continuously infuse air and / or preheating oxygen

  Fez. The flow velocity of the combustion auxiliary has a radial centrifugal component and a tangential component with respect to the trajectory of the point where the current strikes the reactor wall and in a direction consistent with the movement so as not to interfere with the conditions dynamic

  of the charge that is kept in the reactor, that is, the

liquid state is the solid charge.

  Finally, there is a central pipe (10) for charging a combustion aid, which is also used for

  burn the resulting carbon monoxide.

  The filler may be a primary raw material and / or a secondary raw material that contains

  sulphides and oxides of antimony and tin with a

  grain thickness between 0.01 mm and 5 mm.

  Products can be introduced to the party

  reactor, possibly already mixed with the

  the latter also having a fine grain size, or they may be introduced discontinuously through the appropriate pipes (6, 7) while the product containing the coal is added by one of the pipes which does not have still served, so as to provide the desired thermal conditions

for the process.

  As a combustion aid, it is possible to use air, optionally preheated to 600 ° C. and enriched with oxygen.

  gene, or pure oxygen, possibly preheated to 200 C.

  The reaction rate of the process is very high because of the very large contact area between the phases,

  which is a direct consequence of both fine granulation

  the charged product and the rotational movement of the reaction

  tor. The present invention is illustrated by the example

  descriptive and not limiting thereafter.

  From a sulfide, a concentrated product having an antimony content of 50 to 60%, a product having an oxide content of 80% with yields of 95% or more and a flow rate of 10 kg / ml is obtained. using a frustoconical reactor made of metal plate lined internally with refractory bricks, and having the following specifications: - diameter of the largest base 1600 mm - diameter of the smallest base 400 mm - height of the trunk 1000 mm - angle of the Generator of cone with vertical approx.

The values of the characteristic quantities of the treatment are presented below: Cone speed of rotation 350 rpm flow rate of the air flow 4 m 3 normal per min. - Charcoal feed rate 3 kg per min. feed rate of the feed mixed with 0.05 kg of coal per kg of feed 15 kg per min.

Claims (7)

  1. Process for the concentration of oxides   of antimony or tin from ores or   respective by-products containing sulphides and oxides, characterized in that, in a single stage, with air and / or oxygen and carbon compounds are obtained,   even with lower quality coal, volatilization   sulphides and oxides, followed by roasting in the vapor phase by air and / or oxygen of the sulphides to oxides, at an appropriate temperature, having appropriate granulation.   2. Method according to claim 1, characterized in that the temperatures must exceed by at least C the boiling point temperature of the oxide or sulphide to be volatilized.   3. Process according to claims 1 and 2, characterized   the fact that the granulation of the charged product must   be between 0.01 mm and 5 mm.   4. Process according to any one of the claims   1 to 3, characterized in that the auxiliary of   combustion, air and / or oxygen, is preheated to a   temperature between 200 C and 600 C.   5. Apparatus for carrying out the process according to   claim 1, characterized in that it is truncated   of one or more trunks of the cone, possibly   replaced by their enveloping curved surface,   or internal and composed of a casing (2) of metal lined with a refractory product (3), and rotatable about its geometric axis (1) arranged vertically and provided at the bottom with a flow hole (5). ), so that the charged solid products, under the effect of several forces in play adhere to the inner walls of the reactor and that the liquid substances formed can flow to said flow hole (5), the inner diameter of the the largest base being chosen between 1 and 10 meters, the inner diameter of the smaller base between 0.2 and 1 meter, the diameter of the flow hole (5) between 5 and 100% of the diameter of the smallest base, the angle (4) of the generators of the   between 10 and 600 and the rotation speed   the reactor is between 10 and 80 rpm.   6. Apparatus according to claim 5, characterized in that the generatrices surfaces must not have relative to each other a higher inclination at 300.   7. Process for obtaining antimony and tin at   the metallic state from the primary or secondary products   characterized in that a reduction reaction of the oxides and / or sulphides in the charge, in the metallic state by the carbon or the oxide of the oxide, is obtained in a single step.   carbon and volatilization of the metals concerned, which flowing.