CLAIMS
1. A strake for heavy minerals concentrates precipitation from pulp having:
(a) at least one main flow-through gutter made from non-ferromagnetic material and meant to passage of a pulp stream containing a mix of heavy minerals' particles and arbitrary impurities, which, when operates, is inclined to the horizontal line and connected by upper end to a pulp source and by lower end to a means for dumping of enrichment's tails;
(b) a cellular carpet which is placed on the main flow-through gutter bottom and meant to catching and accumulation of heavy mineral's concentrate in the cells;
(c) at least one set of cinematically linked hard non-ferromagnetic stencils of shallow filling, each of which has longitudinal and transversal riffles, is placed between the sides of said main flow-through gutter above said carpet and is connected to at least one drive for its reciprocal motion along the flow-through gutter's sides and said carpet;
(d) at least one made from non-ferromagnetic material additional gutter which is inclined to the horizontal line too, is meant to discharging and separate withdrawal of ferromagnetic particles selected from the pulp stream in said main gutter, and, when it operates, is connected to a receptacle of ferromagnetic concentrate.
2. The strake according to claim 1 , which is equipped with at least one additional means for excitation of vertical vibrations in the pulp stream above the carpet's cells.
3. The strake according to claim 1 or claim 2, which comprises of located alongside practically even edgewise one main flow-through gutter and one additional gutter, and such magnetic separator that has an axle placed above conjunction zone of said gutters and mounted on said axle a bracket of crosswise allocated said controllable electromagnets.
4. The strake according to claim 1 or claim 2, which comprises of one relatively broad main flow-through gutter and two relatively narrow additional gutters located alongside of said main gutter, and such magnetic separator that has an axle placed above middle of said main gutter and mounted on said axle a bracket of crosswise allocated said controllable electromagnets.
5. The strake according to claim 1 or claim 2, which comprises of two relatively broad main flow-through gutters and one relatively narrow additional gutter located between said main gutters, and the has an axle placed above middle of said additional gutter and mounted on said axle a bracket of crosswise allocated said controllable electromagnets. |
STRAKE FOR EXTRACTION OF HEAVY MINERALS FROM PULP
Field of the Invention
The invention relates to structures of strakes those are meant - to extraction from pulp stream of fine-dispersed heavy minerals such as gold, mercury and so likes by their sedimentation under the Earth gravitation field action, and to by-extraction, using magnetic separators, of present in the same pulp ferromagnetic particles of magnetite, ilmenite, tailings of ferrous shot, hard steel grains, ferrous dross etc.
In particular, such strakes are most suitable for extraction of heavy minerals (as a target product) and ferromagnetic particles (as a by-product) from crushed dumps of some mining and/or metallurgical works and/or ashes of thermal power stations, which use hard fuel.
Background Art
Gravity separation of high-density heavy mineral particles from pulp stream is well known. It provides washing-off of obtained sediment of a target product from disperse impurities having lesser density and removing the most part of said impurities by said stream into enrichment's tails (UJOXMH B.H., JloπaτnH A. T. «rpaBHτau>iθHHbie MβTOflbi o6orameHMfl», MocKBa: HEflPA, 1993; In English: Shokhin V.N., Lopatin A.G. «Gravitation methods of enrichment)), Moscow: NEDRA Publishing House, 1993).
However, effectiveness of gravity separation decreases progressively as difference between density of the target product and density of the impurities diminishes and concentration of ferromagnetic particles in a pulp increases.
This disadvantage is especially evident when strakes of shallow filling equipped with monolithic cellular carpets and hard immobile stencils are used (KapMa3KH B.I/I, πpoueccbi and
MawnHbi Ann o6orau4eHκifl πoπe3Ht>ιx ncKonaeMbix. - Mociea: HEflPA, 1974, c. 115-188; In
English: Karmazin V.I. Processes and machines for enrichment of mineral wealths. - Moscow: NEDRA Publishing House, 1974, pp.115-188).
Cells of said carpets may be filled by sediment very quickly (for 1 ,5-2 hours of functioning) and tight. Therefore, heavy mineral particles skip together with pulp flow over arisen «bed» and take away into dump. Accordingly, proportion of target product in obtained concentrate decreases substantially. This disadvantage grows still more, if the pulp contains ferromagnetic and other particles having relatively high (more than 7,5 g/cm 3 ) density because these particles accumulate together with heavy mineral particles in carpet's cells. This side effect depletes obtained concentrate even greater and decreases advisability of the enrichment as a whole.
Accordingly, inventors keep on attempts to prevent quick compaction of the "bed" and sedimentation of relatively high dense mineral particles into carpet's cells. So, the strake disclosed in RU 2 095 147 C1 provides purposeful local loosening of concentrate that promote knockout of said relatively high dense mineral particles from said concentrate and deceleration of "bed" compaction. Said strake (see Fig.1 and respective parts of the patent specification) has:
(a) a flow-through gutter at least a bottom of which is made from non-ferromagnetic material and which, when operates, is inclined to the horizontal line and connected by upper end to a pulp source and by lower end to a means for dumping of enrichment's tails;
(b) a cellular catching carpet which is placed on the flow-through gutter bottom and equipped with permanent magnetic elements at (east under some cells;
(c) a set of cinematically linked hard stencils of shallow filling, each of which is connected to at least one drive for its reciprocal motion along the flow-through gutter's sides and said carpet and has: at least two longitudinal rows of lengthwise undulating riffles that are placed at one level above the catching carpet, and . transversal riffles that are placed in spaces between said rows of undulating riffles and between each extreme row of said riffles and the flow-through gutter's sides;
(d) a means for excitation of vertical vibrations within the pulp stream based on pulse alternating current generator and such solenoids, windings of which are connected to said pulse generator and upper ends of which are placed under those catching carpet's cells, which are equipped with said permanent magnetic elements.
In described strake, the undulating riffles and transversal riffles of oscillated stencils and skirting of catching carpet's cells decelerate the pulp stream and provide purposeful distortion of velocities' field of hard particles. Thus, "easy" particles move off from each bulge of each undulating riffle, which skirts pulp stream, and the heavy minerals' particles remain nearby or even approach to these bulges. Vertical vibrations of said carpet parts under pulse solenoids' and permanent magnets' action loose concentrate precipitated into the carpet's cells. As a result, repeated rearrangement of all hard particles in the velocities' field promotes enrichment of concentrate by target product. However, described above strake, which equipped with said carpet, catches practically all containing in pulp ferromagnetic particles together with heavy minerals' particles under action of magnetic field of permanent magnets. This effect decreases quality of obtained concentrate and hampers its processing into desirable target product.
WO 2006/085831 from 17.08.2006 (or RU 2 262 385 C1) discloses a more perfect strake. It comprises of:
(a) a flow-through gutter at least a bottom of which is made from non-ferromagnetic material and which, when operates, is inclined to the horizontal line and connected by upper end to a pulp source and by lower end to a means for dumping of enrichment's tails;
(b) a cellular catching carpet which is placed on the flow-through gutter bottom and equipped with permanent magnetic elements at least under some cells;
(c) a set of cinematically linked hard stencils of shallow filling, each of which is connected to at least one drive for its reciprocal motion along the flow-through gutter's sides and said
carpet and has: at least two longitudinal rows of lengthwise undulating riffles, which are placed at one level above the catching carpet and composed of alternated in series to bulge direction half-sinusoidal parts of which are connected by flat insertions, at that height of said half- sinusoidal parts and height of said flat insertions are practically equal, and transversal riffles, which are formed as set of separate rotatable plates and placed in spaces between said rows of undulating riffles and between each extreme row of said undulating riffles and the flow-through gutter's sides;
(d) a means for excitation of vertical vibrations in the pulp stream based on pulse alternating current generator and such solenoids, windings of which are connected to said pulse generator and upper ends of which are placed under those catching carpet's cells, which are equipped with said permanent magnetic elements,
(e) at least one magnetic separator, which has: a non-ferromagnetic box that is placed above at least one selected stencil and connected to reciprocal motion drive relative to this stencil, and a set of flat magnets, quantity and plane position of which correspond to the quantity and plane position of permanent magnetic elements under the catching carpet's cells and which are placed on pendants within said box and connected to drive of their synchronous swinging movement relative to the box bottom. Such strake, in comparison with earlier described analogue, allows to extract from a pulp stream even fine-dispersed and lamellar particles of heavy minerals if said stream contains ferromagnetic impurities. In fact, the magnetic separator used in said strake provides momentary catch of ferromagnetic particles at each local pulp splash and return of theirs into pulp stream above said stencils' transversal riffles at each moment of local lowering pulp level. It is clear that aforesaid transfer of ferromagnetic particles into dump is admissible if their content in the pulp is comparable with content of the target product (for example, in case when placer gold must be extracted from natural sands containing insignificant impurities of ilmenite or magnetite).
However, it is well known that dumps of many mining ad metallurgical works and ashes of coal thermal power stations contain such amount of ferromagnetic particles which exceeds considerably amounts of gold or other valuable heavy minerals.
Thus, momentary catch of ferromagnetic particles from pulp and return of theirs into pulp those repeat according to the frequency of action of the above described means for excitation of vertical vibrations do not provide infallible sedimentation of valuable heavy minerals particles into the catching carpet's cells. In fact, when the pulp, that flows under the bottom of said box where the said rotatable flat magnets are placed, contains significant amount of ferromagnetic particles, these particles may form such compact "bunches", which, for the most part, keep and grow within the pulp stream in consequence of irreversible magnetisation of said particles.
Further, magnetised ferromagnetic particles must easy settle and fast fix within the catching carpet's cells. And, finally, dumping of large quantity of ferromagnetic particles will be unprofitable.
Brief Description of the Invention The object of the invention is to create such strake, which could be substantially decrease risk of joint precipitation into concentrate both value heavy minerals' and ferromagnetic materials' particles and, hence, would be suitable for grubbing up of dumps of iron-ore mining and processing enterprises, ferrous metallurgy works and coal thermal power stations.
This object is provided by formation of separate tracts for removal of selected from the pulp stream ferro- and non-ferromagnetic products and by respective of a magnetic separator improvement. Accordingly, a strake for extraction of heavy minerals from pulp comprises of:
(a) at least one main flow-through gutter made from non-ferromagnetic material and meant to passage of a pulp stream containing a mix of heavy minerals' particles and arbitrary impurities, which, when operates, is inclined to the horizontal line and connected by upper end to a pulp source and by lower end to a means for dumping of enrichment's tails;
(b) a cellular carpet which is placed on the main flow-through gutter bottom and meant to catching and accumulation of heavy mineral's concentrate in the cells;
(c) at least one set of cinematically linked hard non-ferromagnetic stencils of shallow filling, each of which has longitudinal and transversal riffles, is placed between the sides of said main flow-through gutter above said carpet and is connected to at least one drive for its reciprocal motion along the flow-through gutter's sides and said carpet;
(d) at least one made from non-ferromagnetic material additional gutter which is inclined to the horizontal line too, is meant to discharging and separate withdrawal of ferromagnetic particles selected from the pulp stream in said main gutter, and, when it operates, is connected to a receptacle of ferromagnetic concentrate;
(e) at least one based on at least two controllable electromagnets magnetic separator which is mounted above said gutters, has possibility of step-wise rotation and vertical reciprocal motion, and is meant to ferromagnetic particles catching from the pulp stream in said main gutter and their transfer and discharging into said additional gutter. When this strake operates, the controllable electromagnets submerge in turn into the pulp stream flowing in said main gutter, collect up ferromagnetic particles and transfer these particles into said additional gutter for the purpose of further formation of ferromagnetic concentrate. Accordingly, precipitation of particles of value heavy minerals, e.g. gold, or environmental dangerous heavy minerals, e.g. mercury, from the depleted of ferromagnetic material pulp stream may be perfected substantially. Moreover, each switching-on of said electromagnets at their submergence into the pulp stream excites its vertical vibrations. These vibrations decelerate compaction of the "bed" within the carpet's cells and promote return into pulp of such natural or man-caused minerals' particles which no are target products of gravity enrichment.
First additional feature consists in that the strake is equipped with at least one additional means for excitation of vertical vibrations in the pulp stream above the carpet's cells. It is desirable if the pulp contains significant impurities of non-ferromagnetic particles of lead, copper, tungsten and other high-density metals or oxides or carbides of such metals. Second additional feature consists in that the strake comprises of located alongside practically even edgewise one main flow-through gutter and one additional gutter, and such magnetic separator that has an axle placed above conjunction zone of said gutters and mounted on said axle a bracket of crosswise allocated said controllable electromagnets. This simplest embodiment of the invention is suitable for extraction of heavy minerals and ferromagnetic materials from the most of crushed industrial wastes.
Third additional feature consists in that the strake comprises of one relatively broad main flow-through gutter and two relatively narrow additional gutters located alongside of said main gutter, and such magnetic separator that has an axle placed above middle of said main gutter and mounted on said axle a bracket of crosswise allocated said controllable electromagnets. This embodiment of the invention is desirable if the pulp is saturated with ferromagnetic particles, sizes of which exceed sizes of separating heavy mineral.
Fourth additional feature consists in that the strake comprises of two relatively broad main flow-through gutters and one relatively narrow additional gutter located between said main gutters, and the has an axle placed above middle of said additional gutter and mounted on said axle a bracket of crosswise allocated said controllable electromagnets. This embodiment of the invention is desirable if the pulp is saturated with ferromagnetic particles, sizes of which are near to the sizes of separating heavy mineral.
It is clear to each person skilled in art that arbitrary combinations of the basic invention and said additional features are possible. Thus, the described below preferable embodiments don't limit nowise the scope of rights.
Brief Description of the Drawings
The invention will now be explained by detailed description of proposed strake with references to the accompanying drawings, in which:
Fig.1 shows a simplest strake having two gutters for precipitation of heavy minerals from a pulp stream containing ferromagnetic particles (view from above);
Fig.2 shows an arrangement of a magnetic separator relative to the gutters of the strake shown in Fig.1;
Fig.3 shows an example of a strake having a central main gutter and two additional side gutters (view from above); Fig.4 shows an example of a strake having two side main gutters and one central additional gutter (view from above);
The Best Embodiments of the Invention In each embodiment of the invention (see Figs 1-4) the proposed strake has:
at least one non-ferromagnetic main flow-through gutter 1 which, when operates, is inclined to the horizontal line and connected by upper end to a not shown especially pulp source and by lower end to a not shown especially means for dumping of enrichment's tails; a cellular catching carpet 2 which is placed on the main flow-through gutter 1 bottom (as it is shown manifestly in Fig.2 and conditionally in "windows" in Figs 1 , 3 and 4) and meant to accumulation of heavy mineral's concentrate in the cells; at least one set of cinematically linked hard non-ferromagnetic stencils 3 of shallow filling, which is placed between the sides of said main flow-through gutter 1 above said carpet 2 and connected to at least one drive for its reciprocal motion along the flow-through gutter's 1 sides and said carpet 2; the each stencil 3 comprises of not shown especially longitudinal (in particular, straight or undulating in view from above) and flat transversal (usually straight in view from above) riffles; at least one preferably non-ferromagnetic additional gutter 4 which is inclined to the horizontal line too, meant to discharging and separate withdrawal of ferromagnetic particles selected from the pulp stream in said main gutter 1 and, when it operates, connected to a not shown especially receptacle of ferromagnetic concentrate; at least one based on at least two controllable electromagnets 5 magnetic separator which is mounted above said main 1 and additional 4 gutters; this separator is meant to ferromagnetic particles catching from the pulp stream in any said main gutter 1 and their transfer and discharging into any said additional gutter 4.
A drive of reciprocal motion of stencils 3 is shown conventionally by pairs of oppositely directed straight arrows in Figs 1 , 3 and 4.
As a rule, the magnetic separator (see Figs 1-4) has an axle 6 and mounted on this axle a bracket 7 of crosswise allocated said controllable electromagnets 5. A drive of step-wise rotation of the bracket 7 around the axle 6 is shown conditionally in Figs 1 , 3 and 4 by arc-like arrows. A drive of vertical reciprocal motion of the bracket 7 along the axle 6 (or together with said axle 6) is shown conditionally in Fig.2 by upper pairs of oppositely directed straight arrows. It is clear that above-mentioned drives may be usually connected to a not shown especially automatic control system of the strake. This system is required for switching on of the electromagnets 5 for a time of their submergence in the pulp stream flowing through the main gutter 1 and transfer of ferromagnetic particles to the additional gutter 4 and for switching off of the electromagnets 5 for a time of their stay above the additional gutter 4.
The simplest strake (see Fig.1) has located alongside practically even edgewise one main flow-through gutter 1 and one additional gutter 4, and magnetic separator's axle 6 is placed above conjunction zone of said gutters 1 and 4.
One of more complicated strake has one relatively broad main flow-through gutter 1 and two relatively narrow additional gutters 4 located alongside of said main gutter 1 , and magnetic separator's axle 6 is placed above middle of said main gutter 1.
Another more complicated strake has two relatively broad main flow-through gutters 1 and one relatively narrow additional gutter 4 located between said main gutters 1 , and magnetic separator's axle 6 is placed above middle of said additional gutter 4.
The strake can be equipped with at least one suitable additional means for excitation of vertical vibrations in the pulp stream above the 1 carpet's 2 cells (e.g., with usual mechanical or electromechanical pushers mounted under the main flow-through gutters' 1 bottom). This means is conventionally shown in Fig.2 by lower pairs of oppositely directed straight arrows.
The described strake operates as follows.
Maintenance staff installs the main flow-through gutter (or gutters) 1 and additional gutter (or gutters) 4 in operative position in which the bottom of any said gutter must be inclined to horizontal line at angle selected preferably in the range from 6° to 11°. Further, any main flow- through gutter 1 must be connected up by its upper end to a selected pulp source and by its lower end to a selected means for dumping of enrichment's tails, the catching carpet 2 must be laid on the bottom of any flow-through gutter 1 and the stencils 3 must be placed above said carpet 2 and connected to the drive of reciprocal motion.
This preliminary work would be completed when at least one group of the controllable electromagnets 5 of above-mentioned magnetic separator is placed nearly to stencils 3 across (see Figs 1 , 2 and 4) or along (see Fig.3) of the sides of any main flow-through gutter 1.
Then key worker or, preferably, automatic control system switches on said submersible electromagnets 5 and the drive of the stencils' 3 reciprocal motion, and starts with supply of the pulp contained non-ferromagnetic particles of extractable value heavy mineral, extractable ferromagnetic particles and non-ferromagnetic particles of useless impurities.
Said group of the electromagnets 5 would be submerged in the pulp stream until formation of compact "bunches" of ferromagnetic particles. Ad notam, the period, which is necessary for loading of submerged electromagnets 5 by sufficiently large compact "bunches" of ferromagnetic particles, may be stated experimentally by short-time test action of the strake using pulp of defined initial composition.
In steady-state regime, the bracket 7 periodically rises above the sides of respective gutters 1 and 4, turns on 90° around said axle 6 and anew goes down at lowering of loaded with said "bunches" electromagnets 5 into respective additional gutter 4 and at submergence of next group of unloaded electromagnets 5 into the pulp stream. At the end of said lowering the loaded electromagnets 5 must be switched off but the unloaded electromagnets 5 must be switched on.
Above described steps cause following effects.
Submergence of each next group of unloaded electromagnets 5 into the pulp stream and their removal from said stream after loading by said "bunches" cause local vertical oscillation of the pulp level (i.e. splashes of the pulp), which promote multiply repeated redistribution of hard particles having different density, sizes and magnetism between the catching carpet's 2 cells and said stream and decelerate substantially compaction of the "bed". Aforesaid "bunches" of
ferromagnetic particles fall into respective additional gutter 4 immediately after switching off of loaded electromagnets 5.
Then process of change of working position of groups of electromagnets 5 relative to said gutters 1 and 4 repeat as it described above until filling of carpet's 2 cells with concentrate of extracting heavy mineral. '
Further must be made following steps: cessation of the pulp supply into the strake, extraction of the loaded catching carpet 2 from any main flow-through gutter 1, removal of the concentrate of heavy mineral from carpet's 2 cells and its packing into containers to keeping and transportation to works, for refining of target product, laying of clean or new carpet 2 on the main through-flow gutter's 1 bottom, and repeating of all process as it described above.
Heaps of ferromagnetic particles on the bottom of any said additional gutter 4 must be washed or scraped off at least periodically into removable receptacles. Above-mentioned additional means for excitation of vertical vibrations in the pulp stream above the carpet's 2 cells (if this means is included in the strake) may be operated at the time of each submergence of electromagnets 5 in the pulp stream and/or at the time of each rotation step of the bracket 7.
Industrial applicability The any embodiment of the invention may be easy made from available materials and component by present machine works and used for effective - grubbing up of dump places of many iron-ore mining and processing enterprise, metallurgical works and ashes of thermal power stations.. separate extraction of gold (or other value or environmentally dangerous high-density substances) and various secondary ferromagnetic raw from said dump, and preparation of environmentally inert residues and clean territories for land reclamation.