ES2305571T3 - APPARATUS FOR MIXING FLUIDS. - Google Patents

Abstract

An apparatus (100) for mixing fluids within a container (102) having a contiguous side wall (104) centered around it and defining a longitudinal axis (AA), the mixing apparatus (100) comprising: a housing (138 ) located above said container (102); a mixing head (106) having a vane body (112) for immersion in the fluids, the vane body (112) having a first end (120), a second opposite end (122) arranged in spaced relationship with respect to to it along an axis (HH) of the vane body; a shaft (196) to support the mixing head (106) extending into the container (102); an actuator assembly with alternative movement (144) located substantially inside the housing (138), the actuator assembly with alternative movement (144) being operatively connected to the shaft (196) to impart alternative longitudinal movement to the mixing head (106); a linear bearing assembly (200) mounted in the housing (138) in surrounding relation with respect to the shaft (196), the mixing apparatus (100) comprising a passage (123) extending longitudinally between the first end (120) and the second end (122), conforming the passage (123) from the first end (120) to the second end (122), characterized in that the linear bearing assembly (200) includes upper (202) and lower (204) bearing subsets , the bearing (upper) (202) and lower (204) subsets being longitudinally spaced apart from each other, to engage the shaft (196) in the respective upper (206) and lower (208) positions, longitudinally spaced.

Description

Apparatus for mixing fluids.

Field of the Invention

The present invention is related in general with the field of ore ore processing and, more particularly, with a mixing apparatus and with its use in the mineral separation from ores carrying minerals

Background of the invention

In the state of the art the procedures that provide for the separation of minerals from of ore bearing ores.

For example, in the known procedures used for the separation of copper from minerals bearing copper, as schematically illustrated in Figure 1, the non-oxidized ores 20 (which could contain as little as 0.5% copper and which usually contain iron sulphides), are processed in a crusher 22, with water 24, to form a thick suspension 26. The thick suspension 26 is then transferred to a flotation tank 28 and subjected to a physical action, namely, air spray and mixing. As a result of the physical action, a substantial part of the copper content of the thick suspension 26 rises to the surface of the flotation tank 28 as a foam 30, the foam of which is removed by means of a vane mechanism 32, while the rest of the rock 33 ("bargain") remains in the dough, which is finally passed from the tank 28 to a dryer 34 and is discharged as tails 36. This "foam separation" procedure arises from the differences in the capacity of humidification of copper in comparison with other minerals, and is usually assisted by chemical foaming and collecting agents 38 added to the thick suspension 26, so that the foam 30 from said flotation contains 27 to 36% copper. Methylisobutylcarbonal (MIBC) is a typical foaming agent and, as usual collecting agents, sodium xanthate, flueloil and VS M8 (a formulation can be mentioned
registered).

The foam 30 is then fed to a smelter with oxygen 40 and copper and iron sulfides are oxidized to high temperature, resulting in impure molten metal 42 (97% -99%, copper, with significant amounts of iron oxide) and gaseous sulfur dioxide 44. Impure metal 42 is transferred then to an electrolytic purification unit 46, which separates impure metal 42 into copper material 48 with a purity of 99.99% and slag 50.

The sulfur dioxide gas 44 collects a reactor 52 where it is washed and mixed with water 24 to form acid sulfuric acid 54. sulfuric acid 54 is properly mixed with water 24 and is used to leach oxidized minerals, usually by "heap leaching" of a lot of ore 56. The resulting copper-bearing acid 58 is known as a "solution. of leaching mother. "The solution of leaching mother 58 is also obtained by mixing solutions of sulfuric acid 54, in vats 60, with tails 36 discharged from flotation operations, to dissolve trace amounts of copper there remain

Copper is "extracted" from the mother leachate 58 mixing with it, in a primary extraction stage 62, organic solvent 64 (often kerosene) where preferentially dissolves copper metal. Together with the solvent organic organic chemical chelators are also used 66, that bind solubilized copper but not the metals present as impurities, such as iron, to further activate migration of copper In this regard, as an example you can cite the hydroxy oxime.

In the primary extraction stage 62, copper it is preferentially extracted in the organic phase according to the formula:

[CuSO_4] aqueous} \ + \ [2HR] organic} [CuR 2] organic} + [H 2 SO 4] aqueous

where HR = extractant (chelator) of copper.

Separation of the mixed phases is allowed, to obtain an organic solvent charged with copper 68 and a leached out 70.

The leached spent 70 is contacted then with more organic solvent 72 in an extraction stage secondary 74, as indicated above, and left sediment, after which the phases are separated to obtain a phase lightly charged organic (which is recycled as solvent 64 to the primary extraction stage) and a sterile or refined leachate 76

Sterile leachate 76 is supplied to a coalescer 78 to separate organic compounds therefrom dragged 80, which are recycled to the system; the leachate so conditioning 82 is then suitable to be recycled to leaching system.

The mother 68 organic mixture (produced in the primary extraction stage 62) is separated from its copper content in a separation operation 84 by adding a Aqueous separating solution of higher acidity 86 (to reverse the previous equation); after phase separation, a charged electrolyte solution 88 ("rich electrolyte") as well as an organic solvent, the latter being recycled as solvent 72 in the secondary extraction stage 74.

The rich electrolyte 88 is sent to a unit of electro-recovery 90. The electro-recovery involves the deposition of copper solubilized on the cathode and oxygen evolution in the anode. The chemical reactions are shown below. involved with these procedures:

Cathode:

CuSO_ {4} \ + \ 2e ^ {1-} \ rightarrow \ Cu \ + \ SO_ {4} {} 2-

Anode:

H_ {2} O \ rightarrow 2H + \ \ \ 0.5 \ O_ {2} \ + \ 2e 1-

This procedure results in copper metal 92 and poor electrolyte (poor in copper), which is recycled as separating solution 86.

The leaching combination, along with extraction and electro-recovery, it is known usually in the art as extraction with solvent-electrorecovery, referred to here in later in this description and in the claims as "SXEW"

In the known application of the SXEW procedure described, both in the primary extraction stage 62 and in the secondary extraction stage 74, the organic and aqueous phases combined are supplied through a series of containers mixers (primary P, secondary S and tertiary T) and then at a ST settling tank, having the mixing vessel primary P a diameter of about 2.44 m (8 feet) and a height 3.66 m (12 ft), and being agitated by a mixer rotary driven by a 14,920 watt (20 horsepower) engine, and where each of the secondary mixing vessels S and Tertiary T have a diameter and a height of about 3.66 m (12 feet), and are agitated by a rotary mixer powered by a 5,595 watt (7.5 horsepower) engine. (The mixer system primary P, secondary S and tertiary T and sedimentation tank ST, is repeated to meet the needs of volume flow, processing each system around 0.63 m 3 per second (10,000 gpm)). This results in a mixing regime where Organic and aqueous phases are mixed intimately during a period of enough time to allow copper exchange (to achieve maximum copper recovery), at the same time as they separate substantially relatively quickly in phases Organic and aqueous

In a known application of the procedure of foam flotation, a plurality of vats of flotation 28, each of them around 1.52 m 2 (5 feet square) and 1.22 m (4 feet) high, sharing the pairs of tanks a 37,300 watt (50 horsepower) motor that drives the respective rotary mixers (not shown). This brings a sufficient mixing rate to allow air bubbles transport the copper content to the surface.

Several modifications can be made to the rotary mixers, in extractors and in tanks flotation of the previous procedure. However, it has been proven than the general settings indicated above they provide relatively cheap results and the fact making important variations of them can impact Adverse way about the economy. For example, an attempt to reduce energy costs decreasing the dimensions of the engines of the mixers would have the consequent impact on efficiency of copper recovery or over production rates available from the procedure. Specifically, the engines relatively large employees are needed to power the rotary mixers and sturdy (and therefore heavy) trees that are needed to support the motor pairs caused by the rotation; lower power engines would demand a slower pallet speed or use more pallets small, with the consequent impacts on the efficiency of mixing and transfer operations. In addition, in WO 02/083280 it is proposes an apparatus for mixing fluids inside a container that it has an adjacent side wall of entry around it and that defines a longitudinal axis, the mixing apparatus comprising: a housing that can be placed above said container; a mixer head that has a vane body for immersion in fluids, the pallet body having a first end, a second opposite end and arranged in spaced relationship with respect to it along a geometric axis of the body of the palette; a tree to support the mixer head that extends inside the container; a drive assembly of alternative movement located substantially within the housing, the drive assembly being in motion alternative operatively connected to the tree to impart alternative longitudinal movement in the mixing head. A linear bearing assembly arranged in the housing in relation surrounding with respect to the tree. However, the apparatus according to WO 08/023280 does not provide any positive response to above mentioned inconveniences. A solution in this regard is defined in the characterizing part of claim 1. According to another feature, the upper bearing subset is adapted and configured to engage slidably with the tree. According to one more characteristic, the bearing subset top includes a pair of matching bushing blocks that they surround the tree to slip slidingly with it. Each bushing block has a groove formed in it. to slider receive the tree. The grooves of the bush blocks are arranged in opposite relation to each other with the tree arranged between them when the blocks of Caps is made to match each other. In addition, the groove formed in each bushing block is lined with a liner manufactured from a material of self lubrication On the other hand, the lining presents Longitudinal nerves formed in it. According to one feature more, the groove formed in each block of Cap is generally semi-circular. In other feature, accommodation includes a base. The base supports one of the bushing blocks of the upper bearing subset. The tree is arranged to extend down through the base. On the other hand, the base has a groove formed in it along an edge of it to house the tree. Slot is configured to allow the tree to be received laterally in the groove and so that it can be separated laterally from said slot. The groove is substantially aligned with the groove of the bearing block supported on the base. According One more feature, the lower bearing subset is adapted and configured to rotatably engage with the tree. On the other hand, the accommodation includes a base. The set of Bottom bearing has at least two roller subsets arranged below the base in the lower position. In addition, the lower bearing assembly includes at least one element of assembly to operatively connect the roller assemblies well to the base or to the upper bearing assembly or to the base and to that set. According to another characteristic, the set of lower bearing has a first mounting element that joins the minus one of the roller assemblies to the base, and a second mounting element that joins at least one set of rollers to the upper bearing assembly. In another feature, the upper bearing subset includes a pair of blocks of matching bushings surrounding the tree to engage so sliding with it. The second mounting element is arranged in one of the bushing blocks and hangs down with respect to said bushing block. According to another feature, the lower bearing assembly has a first and a second roller assemblies supported by the first mounting element, and a third set of rollers supported by the second element mounting The first, second and third roller assemblies They are arranged in a surrounding relationship with respect to the tree.

In accordance with another aspect of the invention, provides an apparatus for mixing fluids inside a container which has an adjacent side wall centered around it and which defines a longitudinal axis. The mixing apparatus includes a mixing head, means for mounting the mixing head inside of the container and means for imparting longitudinal movement alternative to the mixing head. The mixing head has a paddle body to immerse in fluids. The body of paddle has a first end, a second opposite end and arranged in spaced relationship with respect to it along a geometric axis of the pallet body, and a step that extends to the along between the first and second ends. Step conifies from the first end to the second end. The body of the palette also has an inner surface and a surface Exterior. The outer surface of the pallet body defines a inner diameter of the ID vane at the second end, and a outer diameter of the OD vane at the first end. He alternative longitudinal movement imparted to the mixing head is defined by a stroke length S, with a duration T for each cycle The mixing apparatus can operate within a set of operating parameters defined by the equation:

80 \ 0.36 \ x \ (OD / 0.025) 2 / (ID / 0.025) 2 \ x \ (S / 0.025) / (T / 60) \ leq 550,

where OD, ID and S are expressed each in meters and T is expressed in seconds

(80 \ leq 0.36 \ x \ OD2 / ID2 \ x \ S / T \ leq 550,

where OD, ID and S are expressed each in inches and T is expressed in minutes. Under alternative longitudinal movement imparted to the mixing head, a part of the fluids is requested to flow through the step defined by the pallet body, to favor with it an efficient mixture of fluids in the container.

According to an additional feature, the length S stroke is between 0.05 m (2 inches) and 0.61 m (24 inches). Preferably, the stroke length S is between 0.10 m (4 inches) and 0.41 m (16 inches). Plus preferably, the stroke length S is between 0.20 m (8 inches) and 0.30 m (12 inches).

According to another characteristic, the relation OD: ID is greater than 1.0 and less than or equal to 1.7. Preferably, the relationship OD: ID is between 1.5 and 1.7. According to one characteristic more, the stroke length S is between 0.20 and 0.30 m (8 and 12 inches); and the OD: ID ratio is between 1.5 and 1.7.

According to one more aspect of the invention, provides a drive assembly with reciprocating motion for use in a fluid mixer and to impart alternative movement along a longitudinal axis to a tree It carries a mixing head for immersion in fluids. He drive assembly with reciprocating movement includes a housing, a steering wheel, a crankshaft element, a fork and a first and second fork sets. The steering wheel is arranged to rotate around an axis of rotation that extends substantially normal to the longitudinal axis. The crankshaft element projects from the steering wheel in a direction parallel to the axis of rotation. The fork is supported by the housing for move along a fork axis arranged substantially parallel to the longitudinal axis. The fork is releasably connected to the tree. The fork has a guide substantially linear rolling formed therein to receive the crankshaft element. The raceway guide is arranged inside from the fork substantially normal to both the axis of rotation as to the fork axis. The first and second guide sets are operatively connected to the housing and fork to slidably engage with such elements along of a pair of guide shafts that extend in one way substantially parallel to the fork axis. The first and second guide assemblies are laterally separated from each other with the fork arranged substantially between them. When he flywheel is rotatably driven, the crankshaft element is forced to move linearly within the rolling guide, thereby requesting the fork to fit so slide with the guide assemblies and move along the axis of the fork to make the longitudinal movement alternative of the shaft and the mixing head.

According to one more characteristic, each of the first and second guide sets consist of sets of linear slide According to another characteristic, each set of Linear slide include an associated guide rail element with at least the corresponding guide rail of the other element. Each guide rail element is fixedly arranged in the accommodation coinciding with one of the guide axes. Each one of the guide rail elements is rigidly connected to the fork and can be slidably moved with respect to its corresponding guide rail element. In addition, each element of guide rail has rear guide rail elements upper and lower, separated from each other, associated with it.

Brief description of the drawings

The new aspects that are believed are characteristics of the present invention, in terms of its structure,  organization, use and method of operation, along with others objectives and advantages thereof, can be better understood from of the following drawings where it will be illustrated now, only by way for example, a presently preferred embodiment of the invention. However, it should be understood that the drawings are offered only for illustrative and descriptive purposes and should not be considered as a definition of the limits of the invention. In the drawings attachments:

Figure 1 is a schematic representation of A conventional SXEW procedure APRA copper extraction.

Figure 2 is a front view, from the part upper and from the right side, in perspective, of an apparatus fluid mixer according to a preferred embodiment of the present invention, operatively arranged on a container.

Figure 3 is a cross-sectional view. from the right side of the fluid mixing device and container shown in figure 2.

Figure 4 is a front view, from the top and left side, in perspective, of the fluid mixing apparatus of Figure 2, showing, inter alia , a drive assembly with alternative movement and mounting means.

Figure 5 is a perspective view and in Exploded view of a part of the structure shown in Figure 4.

Figure 6A is a front elevation view of the structure of figure 4, having been deleted, for greater clarity, the mixer shaft and the clamping means of the tree.

Figure 6B is a view similar to Figure 6A with, inter alia , the steering wheel moved 90 ° to the left with respect to its position in Figure 6A.

Figure 6C is a view similar to Figure 6A with, inter alia , the steering wheel moved 90 ° to the left with respect to its position in Figure 6B.

Figure 6D is a view similar to Figure 6A with, inter alia , the steering wheel moved 90 ° to the left with respect to its position in Figure 6C.

Figure 7 is a front view, from the part upper and right side, in perspective, of the mixing head of the fluid mixing apparatus shown in figure 2.

Figure 8 is a view from the part posterior, from below, from the left side and in perspective of the  mixing head of the fluid mixing apparatus shown in the figure 2.

Figure 9 is a plan view from below. of the mixing head of the fluid mixing apparatus shown in Figure 2

Figure 10 is an elevation view from the right side of the mixing head of the fluid mixing apparatus shown in figure 2.

Figure 11 is a detailed, enlarged view, of an alternative modality of support bands such as those shown in figure 7, whose view corresponds to the area circumscribed by circle 11 in figure 7.

Figure 12 is a detailed and enlarged view of an alternative modality of the pallet body shown in the Figure 7, whose view corresponds to the area circumscribed by the circle 12 in figure 7.

Figure 13 is a view similar to that of the Figure 12, showing another alternative modality of the body of the palette.

Figure 14 is a front view, from the top and left side, in perspective, of an apparatus fluid mixer according to a preferred embodiment of the invention in its use in a foaming flotation tank.

Figure 15 is a cross-sectional view. left side of the structure of figure 14.

Figure 16a is a sectional view. transverse side of an alternative fluid mixing apparatus to that illustrated in figure 3, showing the mixing apparatus of fluids arranged inside a container that has baffles arranged in it.

Figure 16b is a view from the part top and left, in perspective, of the mixing head alternative shown in figure 16a.

Figure 16c is a plan view from below. of the alternative mixing head shown in Figure 16a.

Figure 17 is a partial exploded view which shows an alternative mounting means and a clamping means alternative of the tree, with respect to those illustrated in the figure Four.

Figure 18 is a sectional view, along of line 18-18 of figure 17, showing the fully assembled device.

Figure 19 is a perspective view of another alternative mounting means and other drive assembly with alternative movement, with respect to those shown in the figure 4.

Figure 20 is a perspective view and in partial exploded view of the mounting means and the assembly of alternative motion drive of figure 19.

Figure 21 is a view from the part top and right, in perspective, of a drive assembly with alternative movement different from the one shown in the figure 19.

Figure 22 is a perspective view and in partial exploded view of the drive assembly with movement alternative of figure 21.

Figure 23 is a view from the part top and right, in perspective, of a drive assembly with alternative movement different from the one shown in the figure 19.

Figure 24 is a perspective view and in partial exploded view of the drive assembly with movement alternative of figure 3.

Detailed description of a preferred mode

With reference now to figure 2 of the drawings, a fluid mixing apparatus according to a preferred embodiment of the present invention and represented in general by reference number 100, in use with a container containing fluids 102 having a side wall contiguous 104 centered around it and defining an axis longitudinal A-A. The fluid mixing apparatus 100 is mounted on a frame 140 extending from one side to another of the container 102.

The fluid mixing apparatus 100 includes a mixer head 106, for immersion in the fluids to be be mixed; means 108 for mounting the mixing head 106 inside the container 102; and means of alternative movement 110 to impart an alternative longitudinal movement (i.e. vertical) on mixer head 106.

With reference to figure 7, the head mixer 106 includes: a vane body 112 formed around of an H-H axis of the head; a cube element generally tubular 114; and a plurality of support bands 116 for connecting the body of the vane 112 with the hub element 114

As shown in Figure 8, the body of the vane 112 has a first end 120, a second opposite end 122 and arranged in spaced relationship with respect to it length of the H-H axis of the head, and a step 123 that extends longitudinally between the first and second ends 120 and 122. In the preferred embodiment, step 123 unifies uniformly from the first end 120 to the second end 122, to impart a substantially trunk-conical configuration in pallet body 112.

The body of the vane 112 also has a inner surface 126 and outer surface 128. The surface  outer 128 defines an inner diameter ID of the vane in the second end 122 of the vane body 112, and a diameter outer OD of the pallet at the first end 120 thereof. He OD outer diameter can be between 25 and 40% of the inner diameter D of the container.

The taper in step 123 can be expressed as an angle? where the angle? is the angle formed between a pair of X, X and Y, Y axes defined by, and coinciding with, the intersections of the outer surface 128 of the body of paddle 112 and a P-P plane coinciding with the axis H-H of the head, as shown and indicated in Figures 9 and 10. The angle α is greater than or equal to 90 ° and less than 180º. Preferably, the angle α is comprised between 90º and 120º.

While in the preferred mode, step 123 unifies evenly along its length from the first end 120 to the second end 122 to define a body of the substantially trunk-conical trowel 112, the passage it can be configured to define other body shapes of the palette. For example, the step can be configured to have different degrees of conicity throughout it. In a Alternative mode shown in Figures 16a, 16b and 16c, is shows a mixer head 400 that has a vane body 402. The body of the vane 402 includes a first end 404, a second end 406 and a step 408 defined therebetween. He step 408 conifies in a non-uniform manner between the first end 404 and the second end 406. More specifically, the body of the vane 402 is formed with an inflection point 410 located between the first end 404 and the second end 406. Step 408 consists of a first grade from the first end 404 to the point of inflection 410, and in a second degree from the inflection point 410 to the second end 406. In the alternative mode shown, the first degree of conicity is less than the second degree of conicity However, this may not be the case in all cases. In certain applications, it may be convenient that the first degree of conicity is greater than the second degree of conicity.

In the preferred embodiment, the body of the palette 112 is constructed from six arched segments 118 arranged end to end. The segments are secured between yes by bolts (not shown) fastened through beams 124 provided at the ends of each segment 118 for this purpose (see figures 7, 8 and 9).

The hub element 114 is arranged generally coinciding with the H-H axis of head, chief, engine head. Extending substantially radially and in a descending oblique manner from the hub element 114, it find the plurality of support bands 116. The bands of support 116 connect the arcuate segments 118 of the body of the palette 112 with the hub element 114. Said connection is made by means of rivets or bolts (not shown).

While in the preferred mode, the body of vane 112 and support bands 116 are substantially uniforms, in an alternative mode, the body of the pallet or the support bands, or both the pallet body and the support bands could be formed with perforations or dimples For example, with reference to Figure 12, a body of the alternative vane 412 where a plurality of perforations 414 each of which extends between an inner surface 416 and an outer surface 418 of the same.

Figure 13 shows a portion of the palette 420 provided with a plurality of 422 dimples that are projected outward from the outer surface 424 of the portion of the vane 420 and inwards from the inner surface 426 of the portion of the vane 420. This allows a precise tuning of the mixing device in a way that does not It has been described in the state of the art.

In another alternative mode shown in the Figure 11, a support band 430 is provided with a plurality of perforations 432, as well as a plurality of lugs 434 each of which resides substantially above the respective perforation 432. The lugs 434 are connected to the support band 430 at one of the edges of said respective 432 drilling to form a gill. In this way, the characteristics of the mixing streams produced by the Paddle body in motion, can be tuned in shape very precise to control the size of the droplets of the dispersion and, therefore, the efficiency of the device mixing operation it is a feature not available in the mixers of the state of the art

With reference now to Figure 3, you can appreciate that the preferred mounting means 108 includes a shaft 130 of the mixer to carry the mixing head 106 and a bearing linear 132 adapted to engage slidably with the shaft 130 of the mixer.

The shaft 130 of the mixer has one end lower 134 releasably mounted on the mixing head 106, and an upper end 136 operatively connected to the means of alternative movement 110. The releasable connection of shaft 130 of the mixer to mixer head 106 can be done by threaded coupling of lower end 134 of shaft 130 mixer through the threaded inside of the hub element 114. When is installed in the mixer head 106, the shaft 130 of the mixer extends substantially coincident with the axis H-H of the head.

In the preferred embodiment illustrated in the Figures 2 and 3, the mixing head 106 is mounted on the shaft 130 of the mixer with the second end 122 of the vane body 112 disposed below the first end 120 thereof. In a alternative mode, the orientation of the mixer head could invert, so that the first end of the pallet body is arranged below the second end of it.

As best seen in Figure 5, the tree 130 of the mixer is preferably hollow and is constructed of a plurality of tubular segments 170, threaded at their ends and linked together in an end-to-end relationship by thread couplings 172, so that segments 170 can be added or deleted, as desired, to accommodate Different depths of the container. The use of a hollow tree of the mixer leads to lower energy consumption by the apparatus fluid mixer during use. In contrast, the mixers Conventional rotary type use solid, heavy trees that require a greater income of energy.

Linear bearing 132 is a type bearing sleeve mounted in a surrounding relationship with respect to the tree 130 of the mixer to slidably engage with it during its alternative longitudinal movement. Linear bearing 130 is securely attached to a housing 138 that supports the alternative movement means 110.

As best illustrated in Figure 4, the medium of alternative movement 110 includes a clamping means 142 of the shaft to hold the shaft 130 of the mixer in an adjacent position to its upper end 136 and a drive assembly with alternative movement 144 operatively connected with shaft 130 of the mixer to impart alternative longitudinal movement in the mixing head 106.

With reference to figures 4 and 5, the means of shaft fastener 142 preferably includes a jaw 163 formed by a pair of matching clamping blocks 164a and 164b. Each holding block 164a, 164b has a groove 166 formed in it and that is sized and adapted to receive the shaft 130 of the mixer in a narrow adjustment ratio. In the preferred embodiment, groove 166 is generally concave and It has a semi-circular cross section. When the clamping blocks 164a and 164b coincide, their grooves 166  are arranged in an opposite relationship to each other to receive with grab mixer shaft 130 and retain tree 130 captive of the mixer between them. Bolts 168 hold so rigid the clamping blocks 164a and 164b with each other and the assembly of alternative motion drive 144. The blocks of subject 164a and 164b thus held, transfer the movement longitudinal alternative of the drive assembly by alternative movement 144 to the shaft 130 of the mixer when the fluid mixing apparatus 100 is being used.

This clamping arrangement allows adjustment from above conveniently the relative depth of the head mixer 106 in the container 102; it is only necessary to release the jaw 163 decoupling associated bolts 168, after which the Mixer shaft 130 can be raised or lowered as desired, and the 168 bolts can be reattached.

As shown in Figures 4 and 5, the drive assembly with reciprocating movement 144 includes: a steering wheel 146; a drive 148 to drive the rotation of the flywheel 146; a crankshaft element 150 that projects from the steering wheel; a fork 152 adapted and configured to receive the crankshaft element 150; and guide means 156 to guide the fork 152 along an axis 153 of the fork to assume alternative longitudinal movement. The steering wheel 146, the drive 148, crankshaft element 150, fork 152 and the guide means 156 are operatively connected to each other and they also cooperate with each other, to form a fork assembly Scottish 143.

The steering wheel 146 is arranged in the housing 138 to rotate around an axis of rotation R-R which is substantially normal to the longitudinal axis A-A The drive 148, with the nature of a electric motor, is operatively connected by its shaft drive (not shown) at steering wheel 146 to drive rotation.

Projecting from the steering wheel in one direction parallel to the axis of rotation, is the crankshaft element 150. The crankshaft element 150 is releasably attached to the flywheel 146 to turn with it. In order to reduce to minimum friction, the crankshaft element 150 includes a part of inner shaft 182 that is fixedly connected to steering wheel 146 and an outer roller part 184 that is rotatably mounted by bearings (not shown) on the inner shaft portion 182 (see figure 5).

The fork 152 is arranged inside the housing 138 to move along axis 153 of the fork disposed substantially parallel to the longitudinal axis A-A The fork 152 is offset from the flywheel 146 in the direction of the crankshaft element 150 and has formed therein a substantially linear rolling guide 154 to receive the crankshaft element 150. The raceway guide 154 it is arranged inside the fork 152, substantially normal both the axis of rotation R-R and axis 153 of the fork. Tread guide 154 is adapted and configured to allow the translational movement of the crankshaft element 150 with  with respect to the fork 152 as the steering wheel 146 rotates.

Guide means 156 includes guide trees upper and lower threads 158a and 158b that are received in threaded coaxial bore 156 arranged on upper surfaces and lower fork 152. The corresponding bearings of upper and lower guide 160a and 160b are provided in the housing 138 for slidingly coupling the trees of upper and lower guide 158a and 158b, respectively. During the alternative longitudinal movement, the upper guide shaft 158a extends to protrude through an opening (not shown) formed in the housing around which the upper guide bearing 160a.

To counteract the tensions created over the fork 152 by virtue of the support it makes of the means of fastening 142 of the tree, the guide means 156 further includes a tree compensator or stabilizer 174 and a pair of bearing blocks linear lines 176a and 176b fixed on the fork for slidably engage with stabilizer shaft 174. The stabilizer shaft 174 is rigidly connected to the housing 138 and extends substantially parallel to axis 153 of the fork. Each linear bearing block 176a and 176b has a groove 178 semi-circular cross section formed in them that is lined with a material self-lubricating such as polytetrafluoroethylene. When linear bearing blocks 176a and 176b are made coincide, its grooves 178 are arranged in relation opposite each other, extending the stabilizing shaft 174 longitudinally between them. Bolts 180 hold the linear bearing blocks 176a and 176b on fork 152.

The work of the drive assembly with alternative movement 144 is explained in greater detail below. With the fork 152 operatively arranged with the upper and lower guide shafts 158a and 158b disposed within the guide bearings 160a and 160b, the fork 152 remains disposed in the housing 138 so as to limit the movement of the fork 152 that is not along the axis 153 of the fork and normal to the axis of rotation RR. When the flywheel is rotatably driven by the drive 148, the crankshaft element 150 is forced to move linearly inside the raceway guide 154, thereby requesting the fork 152 to move along the axis 153 of the fork for effect the alternative longitudinal movement of the shaft 130 of the mixer, as indicated by the sequence of Figures 6A-6D. As a result, the mixing head 106 carried by the mixer shaft 130 is displaced longitudinally through a stroke length "S" with a duration "T" for each cycle (where "S" is expressed in meters (inches) and "T" is expressed in seconds (minutes)). For clarity, a cycle consists of the upward and downward movement of the mixing head 106. In Figure 3, the mixing head 106 is shown in thick lines in a starting position and, in hidden lines, in a longitudinally position. shifted from the starting position through the stroke length
"S".

The length of the resulting run can be select by appropriate adjustment with respect to position radial of the crankshaft element 150 (i.e. the distance between the crankshaft element 150 and the rotation axis R-R). Therefore, the steering wheel 146 is provided with a plurality of threaded bushings 162 arranged in a radial arrangement in the flywheel face 146 (see figure 5). Each threaded bushing 162 It is sized and adapted to receive the crankshaft element 150 in it. Each crankshaft element combination and bushing corresponds to a stroke length "S" default The "T" duration of each cycle can be select by adjusting the rotation speed properly of drive 148.

Under the longitudinal movement alternative imparted to mixer head 106, a part of the fluids from container 102 is requested to flow through of step 123 defined in the body of the palette 112, favoring thereby the efficient mixing of the fluids in the container 102. It has proven that mixing operation efficiencies tend to be improved when the fluid mixing apparatus 100 is driven within a set of operational parameters defined by the equation:

80 \ leq 0.36 \ x \ (OD / 0.025) 2 / (ID / 0.025) 2 \ x \ (S / 0.025) / (T / 60) \ leq 550,

in where:

OD is the outer diameter of the body of the paddle 112 at the first end 120 thereof, measured in meters;

ID is the inside diameter of the body of the paddle 112 at the second end 122 thereof, measured in meters;

S is the stroke length measured in meters; Y

T is the duration of each cycle, measured in seconds

(80 \ leq 0.36 \ x \ OD2 / ID2 \ x \ S / T \ leq 550,

in where:

OD is the outer diameter of the body of the paddle 112 at the first end 120 thereof, measured in inches;

ID is the inside diameter of the body of the paddle 112 at the second end 122 thereof, measured in inches;

S is the stroke length measured in inches; Y

T is the duration of each cycle, measured in minutes

While the stroke length "S" can be measuring between 0.05 m (2 inches) and 0.61 m (24 inches), is it is preferable that the stroke length "S" is comprised between 0.10 m (4 inches) and 0.41 m (16 inches). Plus preferably, the stroke length "S" is comprised between 0.20 m (8 inches) and 0.30 m (12 inches).

In addition, although it has been proven that they can be obtain improved mixing efficiencies when the value of the OD: ID ratio is greater than 1.0 and less than or equal to 1.7, preferably the value of the relation OD: ID resides between 1.5 and 1.7.

When operating within the set of operating parameters defined above, it has been verified that The present invention can be used with great advantage as a mixer for a container in an extractor unit with solvent, as shown in Figures 2 and 3 and illustrated in the following examples 1 and 2.

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Example one

In the known application of the SXEW procedure previously described, samples were taken from the output of discharge of each from the primary container; secondary vessel; tertiary vessel and sedimentation tank of the respective secondary extraction unit (A), and allowed separation.

In a parallel secondary extraction unit (B) (ie, processing of a leachate mother of composition substantially identical), instead of the rotary mixer of the secondary mixing vessel, a mixing apparatus of according to the present invention (OD = 1.52 meters (60 inches); ID = 1.02 meters (40 inches); α = 120; S = 0.25 meters (10 inches); T = 1,998 seconds (0.0333 minutes), triggered by a 1,492 watt motor (2 horses) and again samples were taken from the discharge discharge of each of the mixing vessels primary, secondary and tertiary, and also the tank of sedimentation, and separation was allowed.

Copper concentration was measured (gram / liter) in the organic component of each sample, as follows:

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one

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As expected, the concentration of copper of the primary mixing vessel in each of lines A and B it is similar (because at that point in the procedure, the mixing operation is provided by rotary mixers identical). However, surprisingly, the concentrations copper in the outlet discharge of the secondary mixers it also remained identical, and the concentration of copper in the discharge discharge from the sedimentation tanks remained very similar, despite the almost 70% reduction in the entry of energy (932.5 watts (1.25 horsepower)) extracted from a motor 1,492 watt (2 horse) drive for the mixer alternative movement, compared to 3,730 watts (5.0 horses) extracted from the 5,595 watt (7.5 drive motor) horses) for the rotary mixer.

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Example 2

In a second trial, line B of the example 1 altering the mixer motor speed of the present invention, so that it will work at 0.75 cycles / second, that is T = 1,333 seconds (45 cycles / minute (T = 0.0222 minutes)).

Copper concentration was measured again (g / l) as follows:

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2

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Again, as expected, the concentration copper from the primary mixing vessel in line B remained similar to that obtained on line A (because at that point of procedure, mixing is provided by rotary mixers identical). However, surprisingly, the concentrations copper in the discharge outlet of the sedimentation tank of the modified B line showed a significant improvement over Line A results (copper recovery was improved by 2.14 g / l at 2.16 g / l).

Without this implying a theoretical limitation, believes that the fluid mixing apparatus of the present invention provides mixing streams that [at least in the context of liquids used in SXEW copper extraction] create a dispersion characterized by droplets of consistent size, evenly distributed throughout the mixing vessel, while in a rotary mixer there is a wide variation in the sizes of the droplets, and in the distribution of said droplets (perhaps due to the fact that the blade of a rotary mixer is moves at different speeds along its length). It is believed that this uniform dispersion provides a prone environment to a efficient mass transfer between phases, providing the at the same time a substantial disunity of the phases mixed in a relatively short time frame.

Although the illustrations show a modality preferred of the present invention, several are contemplated Modifications as described below.

In the preferred embodiment, the clamping means 142 of the tree is adapted to allow the blocks of clamp 164a and 164b disengage from each other and disengage from the fork 152 by simply removing bolts 168. Without However, it may be appreciated that in some cases it may not be convenient to disengage the fork jaw completely when the mixer shaft is released. In such cases, it would be preferable decouple the clamping blocks while maintaining still a rigid connection between one of the clamping blocks and The fork. In the alternative mode shown in figures 17 and 18, this is achieved by replacing jaw 163 with a jaw modified 186. Although jaw 186 is generally similar to jaw 163 as it has a pair of matching clamp blocks 188a and 188b formed with concave grooves 190 therein, it differs in a material aspect, that is, the block of fastener 188a is fastened on fork 152 by bolts 192, independently of the holding block 186. By means of the clamping bolts 194 it is achieved that clamping blocks 188a and 188b match.

While in the preferred mode, the means of Assembly 108 includes a single linear bearing 132 that engages in Sliding way with the mixer shaft 130 at a single point, in an alternative mode a set of linear bearing for sliding coupling with the Mixer tree in more than one point. One such modality alternatives are shown in figures 17 and 18, where the tree of the mixer is designated with reference number 196 and the linear bearing assembly is designated with the number of reference 200. The linear bearing assembly 200 includes a upper bearing subset 202 and a bearing subset bottom 204 for coupling with the mixer shaft 196 in upper and lower positions, longitudinally separated, 206 and 208, respectively.

The upper bearing subset 202 is adapted and configured to engage slidably with the 196 mixer shaft. More specifically, it comprises a cap 210 formed by blocks of matching bushings 212a and 212b arranged in surrounding relationship with respect to tree 196 of the mixer. Each block of bushings 212a, 212b has a concave groove 214 cross section semi-circular formed in them to receive the 196 mixer shaft. Each groove 214 is coated with a arched lining 216 of self-lubricating material such as polytetrafluoroethylene. Preferably, each liner 216 is veined When the bushing blocks 212a and 212b are made coincide, its grooves 214 are arranged in relation opposite each other, extending the mixer shaft 196 longitudinally between them. 212a bushing blocks and 212b bind securely to each other through bolts 218. Bushing 210 is operatively connected with bushing 138 safely mounting the bushing block 212a in a base 207 of accommodation 138.

The lower bearing subset 204 is adapted and configured to be rotatably coupled with the 196 mixer shaft. The lower bearing subset 204 includes at least two sets of rollers identified in general by 220, arranged below base 207 of housing 138 in position 208. However, preferably, the subset of lower bearing 204 comprises a first, second and third roller assemblies respectively, 222, 224 and 226, arranged in surrounding relationship with respect to shaft 196 of the mixer. A first mounting element in the form of a tubular support 228 joins the first and second roller assemblies 222 and 224 to base 207 of housing 138. Tubular support 228 hangs down from base 207 and ends, at its distal end, with an element flange 230. Flange element 230 has a pair of brackets vertical 232 in which the first and second are fastened roller assemblies 222 and 224 by means of bolts 234.

The lower bearing subset 204 includes also a second mounting element in the form of a pair of separable supports 236. Separable supports 236 are connected together securely to bushing block 212a and hang down with respect thereto to a terminal point 238. The terminal point it has a bracket 240 that extends downwardly from the same. The third set of rollers is secured to the bracket 240 by means of bolts 242.

In the preferred mode, each set of rollers 222, 224 and 226 includes a single roller 239 arranged rotatably in a roller housing 241. It will be appreciated that, in alternative modalities, multiple rollers

When the bushing blocks 212a and 212b are operatively secure each other, the first, second and third roller assemblies 222, 224 and 226 circumferentially surround the Mixer shaft 196, as illustrated in Figure 18, in a position below bushing 210 and longitudinally separated of the bushing 210. The support provided by the first, second and third roller assemblies 222, 224 and 226 in position lower 208 tends to limit the flexion of tree 196 of the mixer, while allowing longitudinal movement alternative of it.

As best seen in Figure 17, the tree 196 of the mixer can be removed from housing 138 for service, maintenance, repair or replacement, disassembling in first place the upper bearing subset 202 and disassembling then jaw 186. The removal of bolts 218 from the bushing 210 allows the bushing block 212b and the third set of roller 226 attached to it, are removed from the sliding coupling with the 196 shaft of the mixer. Bolts 194 can be removed then from jaw 186 thereby releasing tree 196 from mixer. A recess or groove open at the ends 244, formed along the outermost edge of the base 207, it allows to move laterally the mixer shaft 196 with respect to the base for facilitate its separation. To further facilitate the handling of tree 196 of the mixer once released, tree 196 of the mixer is formed with an enlarged upper end portion 246, in which a threaded bore 248 is provided, to receive a threaded stud or protrusion (not shown).

With reference to figures 19 and 20, it is shown an alternative mounting means 250 and a drive assembly with alternative movement 252 different. The mounting means 250 is generally resembles mounting medium 108 as it includes a shaft 254 of the mixer and a linear bearing 256. Tree 254 of the mixer is generally similar to tree 130 of the mixer, but differs in that it has an enlarged head 258 of the intended tree with a support flange 259. When it is operatively connected to the clamping jaw 260 of the shaft, the support flange 259 of the 254 shaft of the mixer butt is attached to the clamping blocks 262 and 264, thereby providing an additional mechanical connection to the friction connection made by clamping blocks 262 and 264

The linear bearing assembly 256 includes a sleek type linear bearing 266 mounted in relation surrounding with respect to shaft 254 of the mixer. Plain bearing 266 is secured in base 207 of accommodation 138 by means of catches 268. A keyhole groove 270 formed at length of the outermost edge of the base 207, allows the tree 254 of the mixer moves laterally with respect to the base 207 during their separation. Under the use of plain bearing 266, it will be evident, however, that in order to remove the tree 244 of the mixer, the plain bearing 266 must first detach from the housing 138, removing the fasteners 268.

The drive assembly with movement Alternative 252 is generally similar to the drive assembly with alternative movement 144 described above, since it has a flywheel 272, a drive 274, a crankshaft element 276, a fork 278 and a guide means 280 operatively connected to form a set of Scottish fork 282. However, while the guide means 156 of the drive assembly with Alternative movement 144 includes upper guide shafts and lower 158a and 158b, the corresponding guide bearings upper and lower 160a and 160b and a single stabilizing shaft 174 with matching linear bearing blocks 176a and 176b, the guide means 280 uses a pair of parallel guide assemblies, left and right, in the form of a first and second sets of linear slide 284 and 286. The first and second sets of linear slide 284 and 286 are operatively connected to the housing 138 and fork 278 to engage so sliding with it along a pair of guide shafts 288 and 290 that extend substantially parallel to the axis of the fork designated by 292. The first and second sets of linear slider 284 and 286 are laterally separated from each other, the fork 278 being substantially disposed between the same.

Each linear slide set 284, 286 includes a guide rail element in the form of a track 294 associated with at least one of the corresponding elements of rear guide rail in the form of an element configured as a saddle 296. Each track 194 is fixedly secured to a support element 298 of the housing 238 coinciding with the respective guide shaft 288 or 290, as the case may be. Each element Shaped saddle 296 is adapted and configured to move slider along its corresponding track 294

Linear slide assemblies 284 and 286 they are also provided with mounting elements in the form of a chair assemble 300 to join saddle-shaped elements 296 with fork 278. The saddle-shaped mounting elements of assemble 300 are generally T-shaped members arranged between a pair of transverse fork beams 301 and 303 to define a rolling guide 306 formed in the fork 278. The elements Shaped saddle 296 are arranged in turn in the back of the chair-shaped mounting elements of mount 300 in opposite relation to runway 294. United in this way, saddle-shaped elements 296 united in any side of the raceway guide 306. Looking in the direction of the arrow 307 (as shown in figure 19), it can be seen that linear bearing assemblies 284 and 286 are located towards behind the fork 278.

In the alternative mode shown and described above, each linear slide assembly 284, 286 is provided with two saddle-shaped elements 296, longitudinally separated, to achieve stability improved; an upper saddle shaped element 308 and a lower saddle-shaped element 310.

It will be appreciated that other alternative arrangements of tracks and saddle-shaped elements can be constructed. With reference to FIGS. 21 and 22, a drive assembly with alternative movement 350 is shown generally similar to the drive assembly with alternative movement 252. The drive assembly with alternative movement 350 has, inter alia , a fork 352 and assemblies of linear slide of track-and-saddle type 354 and 356. Linear slide assemblies 354 and 356 are generally similar to linear slide assemblies 284 and 286 since each assembly 354, 356 includes a track 358 associated with at least one of the corresponding saddle-shaped elements 360. However, the assemblies 354 and 356 differ in that they are manufactured with saddle-shaped elements 360 already held captively on tracks 358 to engage. in a sliding way with them. The fork 352 differs from the fork 278 shown in Figures 19 and 20 in that it is of a unitary construction and has, incorporated therein, mounting portions 362 in the form of a saddle.

Different configurations are also possible. of a drive assembly with reciprocating motion that It has double sets of linear slide. With reference now to Figures 23 and 24, a drive assembly with alternative movement 312 generally similar to the set of 252 reciprocating drive described previously. The drive assembly with movement Alternative 312 includes a handwheel 314, a drive 316, a crankshaft element 318, a fork 320 and a guide means 322 operatively connected to form a fork assembly Scottish 324. Guide means 322 is similar to guide means 280 since it also uses a pair of left guide sets and right, parallel, extending longitudinally. Without However, while guide means 280 uses a couple of tracks 294 each associated with at least one element in the form of saddle 296, guide means 322 uses an arrangement of Thompson tree, that is, a pair of guide struts 326 associated each of them with at least one sliding block linear 328.

Each guide strut 326 is disposed within of housing 138 extending upwardly between base 207 and an upper plate 332 thereof. Guide struts 326 are secured to base 207 by means of collar elements 330 and sureties (not shown). Each linear slide block 328 is mounted in surrounding relation to its guide strut associated 326 to slidably engage with it. How in the case of linear sets 284 and 286, the elements of assembly 333 join the linear slide blocks 328 with the fork 320. However, in this mode, the sets of linear slide (consisting of guide struts 326 and blocks of linear slide 328) are located in front of the fork 320.

While the drive assembly with alternative movement 318 works in a generally similar way to the drive assembly with reciprocating motion 252, is different the way in which the steering wheel 314, the element of crankshaft 318 and fork 320 cooperate with each other. Unlike the crankshaft element 276, the crankshaft element 318 does not have an inner shaft fixedly connected to the steering wheel with the portion of external roller rotatably mounted therein. The element of crankshaft 318 is incorporated in a cam pusher block 334 adapted and configured to move slidingly within the rolling guide 335 defined in the fork 320. The block Cam pusher 334 is preferably made of steel and houses therein a roller bearing 336 and a shaft 338 mounted rotatably in roller bearing 336. Shaft 338 is left received in a socket 340 formed on the handwheel 314. Plates of Brass wear 342 are fastened on the upper surfaces and bottom of cam pusher block 334 to achieve a improved wear resistance. When cam pusher 334 is disposes of the wear plates within the rolling guide 336 Brass 342 lean against hard steel wear plates (no shown) covering the raceway guide 335.

Although in the preferred mode, a Scottish fork device to provide movement linear alternative, it will be evident that as possible substituents other mechanisms, such as crankshafts, cams and cam thrusters, as well as plates motor.

Of course, although the detailed description offered here refers specifically to the recovery of copper to from copper bearing ores, it may also be understood that the The present invention can be used in other applications where SXEW procedures are used, such as, for example, in the recovery of zinc, nickel, platinum, uranium and gold.

Furthermore, it will be apparent that the invention can have an advantageous utility even outside the procedure SXEW, in other mixing applications, such as in the context of a foaming flotation tank illustrated in Figures 14 and 15, wherein the fluid mixing apparatus is used to stir a thick suspension and form a foam, and a vane mechanism 32 is operatively arranged in the container 102 to clean the foams so produced.

As shown in Figure 16a, the apparatus fluid mixer can also be used in a container that It has 500 baffles arranged in it.

Claims (16)

1. An apparatus (100) for mixing fluids within a container (102) having a contiguous side wall (104) centered around it and defining a longitudinal axis (AA), the mixing apparatus comprising
(100):

accommodation (138) located above said container (102);

a head mixer (106) that has a vane body (112) for its immersion in the fluids, the paddle body (112) having a first end (120), a second opposite end (122) arranged in spaced relationship with respect to it along an axis (H-H) of the pallet body;

a tree (196) to support the mixing head (106) that extends inside of the container (102);

a set of drive with reciprocating motion (144) located substantially inside the housing (138), the assembly being drive with reciprocating motion (144) connected operatively to the tree (196) to impart longitudinal movement alternative to the mixing head (106);

a set of linear bearing (200) mounted on housing (138) in relation surrounding with respect to the tree (196),

understanding the mixing apparatus (100) one step (123) extending longitudinally between the first end (120) and the second end (122), conforming step (123) from the first end (120) to the second end (122),

characterized in that the linear bearing assembly (200) includes upper (202) and lower (204) bearing subsets, the (upper) (202) and lower (204) bearing subsets being longitudinally spaced apart from each other, to engage with the shaft (196) in the respective upper (206) and lower (208) positions, longitudinally
spaced out 2. A mixing apparatus (100) according to claim 1, characterized in that the upper bearing subset (202) is adapted and configured to engage slidably with the shaft (196). 3. A mixing apparatus (100) according to claim 2, characterized in that the upper bearing subset (202) includes a pair of matching bushing blocks (212a), (212b) that surround the shaft (196) for sliding engagement with it, each bush block (212a), (212b) having a groove (214) formed therein to slidably receive the shaft (196), the grooves (214) of the bush blocks (212a) being arranged ), (212b) in spaced relation to each other with the shaft (196) arranged between them when the bushing blocks (212a), (212b) are made to coincide with each other. 4. A mixing apparatus (100) according to claim 3, characterized in that the groove (214) formed in each bushing block (212a), (212b) is lined with a liner (216) made from a self-lubricating material ). 5. A mixing apparatus (100) according to claim 4, characterized in that the liner has longitudinal ribs formed therein. A mixing apparatus (100) according to claim 3, characterized in that the groove (214) formed in each bushing block (212a), (212b) is generally semi-circular. A mixing apparatus (100) according to claim 3, characterized in that the housing (138) includes a base (207), supporting the base (207) to one of the bearing blocks (212a), (212b) of the assembly upper bearing (202); and because the tree (196) is arranged to extend downwardly through the base (207). A mixing apparatus (100) according to claim 7, characterized in that the base (207) has a groove (244) formed therein along an edge thereof to accommodate the shaft (196), the configuration being configured slot (244) to allow the shaft (196) to be received laterally therein and can be removed laterally from the slot (244); the groove (244) being substantially aligned with the groove (214) of the bearing block (212a) supported on the base (207). A mixing apparatus (100) according to claim 1, characterized in that the lower bearing subset (204) is adapted and configured to engage in a rolling manner with the shaft (196). 10. A mixing apparatus (100) according to claim 9, characterized in that the housing (138) includes a base (207); and the lower bearing assembly (204) has at least two roller assemblies (220) disposed below the base (207) in the lower position (208). 11. A mixing apparatus (100) according to claim 10, characterized in that the lower bearing subset (204) includes at least one mounting element (228), (236) for operatively connecting the roller assemblies (220) to less an element chosen between the base (207) and the upper bearing assembly (202). 12. A mixing apparatus (100) according to claim 11, characterized in that the lower bearing assembly (204) has a first mounting element (228) joining at least one of the roller assemblies (222), (224) a the base (207), and a second mounting element (236) that joins at least one of the roller assemblies (226) to the upper bearing assembly (202). 13. A mixing apparatus (100) according to claim 12, characterized in that the first mounting element (228) is arranged in the base (207) and hangs down from the latter. 14. A mixing apparatus (100) according to claim 12, characterized in that the upper bearing subset (202) includes a pair of matching bushing blocks (212a), (212b) that surround the shaft (196) for sliding engagement with the same; and because the second mounting element (236) is arranged in one (212b) of the bushing blocks (212a), (212b) and descends downwardly from said bushing block (212b). 15. A mixing apparatus (100) according to claim 14, characterized in that the lower bearing assembly (204) has a first (222) and a second (224) roller assemblies supported by the first mounting element (228), and a third roller assembly (226) supported by the second mounting element (236); the first (222), the second (224) and the third (226) roller assemblies being arranged in a surrounding relationship with respect to the shaft (196). 16. A mixing apparatus (100) according to claim 9, characterized in that the lower bearing assembly (204) has a first (222), a second (224) and a third (226) roller assemblies arranged in a surrounding relationship with regarding the tree (196).