DE19600897C1 - Mobile preparation plant for wet classification of gravel and sand - Google Patents

Abstract

The plant runs on continuous tracks (9) and has a closed sieve water circuit with a fresh water tank for spraying sieve water on the double decker sieve. Sieve sprayers are provided for spraying the fractions. The third fraction comprising fine sand (24) is collected in a sieve underflow bath (30) together with the sieve water and a fourth fraction comprising floatable constituent parts (31) is accumulatable in a disposal bath. The fine sand collected in the sieve under flow bath is dewatered with a hydrocyclone. The separated sieve water is fed back into the sieve under flow bath and the circuit for sieve water.

Description

The invention relates to a self-propelled processing plant for the wet classification of gravel and Sand that is removed from the wall by a wheel loader in a dry open pit mine Feed bunkers plus upstream conveyor belts of a processing plant abandoned and dumped with downstream conveyor belts in classified fractions is stored.

The mobile processing plants currently known in practice with mechanical excited screening devices are based, for example, on road traffic approved trailer combination with pneumatic tires that can be linked to a truck Vehicle wheels built. Such processing plants are primarily for fast Suitable for moving between different deposits and different locations. For this reason, these processing plants are built to a lesser extent and not very suitable for wet classification of particularly large amounts of gravel and sand. Stationary processing plants that are stationary in one are particularly suitable for this Opencast mines are set up. The disadvantage of stationary systems generally has that with progressive dismantling the distance to be overcome by the wheel loader between the Deposit and the processing plant is getting bigger and more time consuming what the Economy of the processing plant negatively affected.

In US 5 234 564 is therefore showed a self-propelled processing plant, which a double-decker screen and arranged in pairs has hydraulic supports.

Furthermore, the stationary processing plants known in practice at Wet classification for spraying and rinsing the mechanically excited screens increased White water requirement with a correspondingly large and stable delivery line covered from more or less distant water or groundwater resources must become. As a result, when converting the processing plant are not too negligible expenses required when the heavy piping is repeated to be connected to the wet classification at a new location. Another The disadvantage of a stationary processing plant is that in the case of stock production the stockpile must be removed continuously when the fractions screened for stockpile the Have reached the discharge height of the downstream conveyor belt. At the latest on this At the time, the downstream conveyor belt must be extended or the stockpile must be moved, which is associated with a further increase in the cost of processing.  

These disadvantages shown in the known prior art can be avoided if the Water consumption for showering and rinsing the sieves is essential for wet classification lowered and the removal or repositioning of the stockpile can be avoided.

Consequently The invention aims at a processing plant for the wet classification of gravel and sand, the at intervals not very far apart, at the latest when reaching one maximum extendable stockpile height, can be quickly implemented. At the same time it has to be easy manageable service water pipe for the white water are provided, with the help of which Back of the processing plant can be simplified.

According to the invention, the task is performed on a crawler track self-propelled processing plant with the features of claim 1 solved.

With the help of the proposed treatment plant, a very inexpensive wet classification is possible of gravel and sand in the grain belts prescribed by the German industry standard enables. This is due, on the one hand, to the fact that the wheel loader advances as production continues no additional distance traveled between the feed bunker and the deposit must be when the self-propelled processing plant in the direction of Dismantling front is implemented again and again. The implementation of the processing plant will likewise conveyed through a flexible hose line, which is for the supply of the White water is equipped with a slim dimension. The prerequisite for this is a minimal white water requirement, which is closed within the treatment plant White water cycle with white water recovery can be realized through more than two thirds of the white water required compared to a conventional one Processing plant can be saved. As a result, the wet classification of Quality sand is also possible in cases where the usually high amount of white water cannot be covered from the naturally available resources. The application possibility the wet classification is thereby expanded.  

Finally, in the case of a more frequent back of the processing plant, inevitably each again a heap was created and the storage space available in the open space completely Deposited sand is used when immediate removal is not possible is guaranteed. Rather, when using the self-propelled processing plant a makeshift solution to move the processing plant whenever the stockpile is used Discharge height of the downstream conveyor belt has been reached. This eliminates the need for In contrast to a stationary processing plant, a quick removal or that Relocating the stockpile or creating an intermediate storage for the screened Sand.

In a special embodiment of the invention is between a movable on runners and with a wheel loader with raw gravel and sand feed hopper with a Discharge belt and a belt conveyor upstream of the processing system unconnected transfer point with an electrical sequence control of collaborating Conveyor belts are provided to enable the processing plant to be quickly assembled and disassembled Simplify back. Through a sequential control between the feed bunker and the Processing plant can malfunction if one or the other fails Conveyor belt can be avoided. It is also of particular advantage that the back of the entire system can be made possible without particular difficulties.

According to a preferred embodiment of the processing plant for the production of Quality sand due to wet classification of screen showers for screening and classifying gravel and Sand is provided in several fractions. By comparison, the gravel or sand at one The double-decker screen is structured in four fractions, the first being oversized showing fraction with the upper deck, the second fraction consisting of quality sand can be screened with the lower deck, the third fraction formed from the fine sand in one Sieve underflow pan can be collected together with the white water and essentially one the fourth fraction consisting of the washable components in a settling tank is accumulable. This creates a closed white water cycle for the white water enables, which allows the spraying of the screening device to be increased optimally can, without using the naturally available resources to an excessive extent to take. As a result, the extraction of gravel and sand is very economical. About that In addition, a particularly high yield of quality sand can be achieved.  

According to a further embodiment of the invention it is provided that the Fine sand trapped in the underflow pan with a drainage device, for example by means of hydrocyclone. The separated water is in the Sieve sub-vat and the water circuit for the white water returned. Through this Measure will be a very low water consumption for wet classification of gravel and sand achieved. The low water consumption in turn ensures that the treatment plant with a small dimensioned and very flexible hose line to a well system for the white water can be connected.

A further reduction of the white water requirement for wet classification is achieved that the screen underflow pan has an overflow pipe, the pipe outlet into a settling pan flows. The level of the water level is determined by the overflow pipe.

Furthermore, within the scope of the invention one of the settling trough in the Overflow pipe leading fresh water tank and closing the white water circuit provided with which the white water cleaned of the washable components in the White water cycle is returned. At the same time it is in the fresh water tank kicking flexible hose line with a float circuit adjustable so that only the loss of white water is compensated for by a fresh water inflow. Through both Measures are ensured that the settling process with the washable White water mixed with clay and clay is separated and recovered can be. Because of this, the loss of white water is essentially due to limits the part that capillates on the surface of the screened during discharge Components are liable. This is a comparatively very small amount, so that the White water requirements can be reduced by at least two thirds.

To ensure the trouble-free operation of the treatment plant and the white water recovery allow, is also connected on the suction side to the fresh water tank White water pump with one pressure line leading to the screen showers with several separate gate valves adjustable branches are provided, one of which is first Branch line into the screen underflow pan and a second parallel line into the Sieve distribution box opens. This ensures that for the ongoing operation of the  Hydrocyclones in the underflow pan have a sufficient amount of water available stands, which is adjustable by the gate valve in the first branch line.

Finally, with a sufficiently high water level in the screen underflow pan, one of branching off the pipeline of the hydrocyclone and leading directly into the settling tank Bypass line are provided to ensure optimal operation of the To ensure white water recovery, which is explained below using a Embodiment will be described in more detail.

In the drawing belonging to the embodiment shows

Fig. 1 shows the overview of the entire processing plant and

Fig. 2 shows a detail of the processing plant for gravel and sand shown in Fig. 1 in a schematic representation.

The processing of gravel or sand takes place depending on the deposit in an open pit with the help of a wheel loader, not shown, which moves back and forth between a mining front and a feed bunker 1 that is part of the processing system and is shown in a highly schematic manner in FIG . The raw gravel or sand that has been removed from the wall is filled into the feed hopper 1 . The feed hopper 1 is provided in a known manner with a hydraulically tiltable coarse grate 2 , with which the coarse grain can be separated from the raw gravel or sand. The feed hopper 1 is mounted on runners 3 and is designed in such a way that it can be moved separately with the aid of traction means, possibly with the wheel loader itself. The feed bunker 1 has a funnel-shaped bunker outlet 4 with a discharge belt 5 , via which the bunker contents are continuously drawn off. When moving the feed hopper 1 is positioned so that the extracted raw gravel or sand is thrown from the discharge belt 5 into an inlet box 6 of a belt conveyor belt 7 , which is connected upstream of the processing system.

So that trouble-free operation between the take-off belt 5 and the upstream belt conveyor belt 7 is made possible, both together form the unconnected transfer point 14 , an electrical sequence control is provided between the two belt drives, so that the take-off belt 5 can only be started when the processing system is used at the same time the belt conveyor 7 is put into operation in order to avoid the overflow of the inlet box 6 in the subsequent belt conveyor 7 . As a result, the assembly and disassembly of the processing system can be carried out separately and much faster and without effort when moving from the feed bunker 1 .

The processing plant is implemented in a self-propelled manner and independently of the feed hopper 1 . For this purpose, the processing system has a chassis frame 8 with two associated crawler tracks 9 , which are driven by separately controllable geared motors. On the outer areas 10 of the chassis frame 8 , which is extended on both sides beyond the width of the crawler chassis 9 , a total of four hydraulically actuated support cylinders 11 with base plates 12 are provided in pairs, in each case front and rear, with which the processing system can be adjusted between a lowered driving position and a raised working position is. If the support cylinders 11 assume the position shown in dash-dotted lines in the drawing, the crawler chassis 9 comes into engagement with the surface of the earth and the processing system can be moved in the direction of the dismantling front of the wheel loader following the progress of the wheel loader. As a result, the distance to be covered by the wheel loader between the deposit and the feed hopper 1 can always be kept short. After the processing plant has been implemented, the support cylinders 11 with the base plates 12 are extended again by hand, so that the processing plant is brought into a horizontal position which is indispensable for the wet classification of gravel and sand.

Here, the raw gravel or sand with the aid of the belt conveyor belt 7 first reaches a sieve distributor box 15 which is intended for the uniform distribution of the sieved material on the sieve system consisting, for example, of a double-decker sieve 16 . In the double-decker sieve 16 selected in the exemplary embodiment, the raw gravel or sand in the processing plant is first comparatively divided into three fractions. The double-decker screen 16 has an upper deck 17 , with the aid of which the oversize grain 18 can be separated from the remaining screenings. The first fraction separated as oversize grain 18 passes via a grain slide 19 to a first conveyor belt 20 downstream of the processing plant, by means of which the oversize grain 18 is thrown onto an oversize grain pile 21 .

From the sieve passage from the upper deck 17 , the second fraction consisting of quality sand 22 is classified on the lower deck 23 by appropriately screening the third fraction formed from the fine sand 24 . The product quality sand 22 , for example concrete sand or mason sand, passes from the lower deck 23 to an indicated sand slide 25 and from there to a second downstream conveyor belt 26 with which the quality sand 22 is thrown onto a sand pile 27 . When one of the two aforementioned heaps 21 , 27 has reached the discharge height of the conveyor belt 20 , 26 in its vertical extension, the processing plant can be moved. For this reason, it is appropriate if the length and the inclination of the conveyor belts 20 , 26 are chosen so that the resulting stockpile is adapted to the progress of the wheel loader. If, for example, a daily production is set for an average stockpile, there is not only a small dimension of a conveyor belt 20 , 26 , but also a very economical operation of the processing plant. After commissioning, this can then work without interruption for a shift or continuously for a certain period of time.

The fine sand 24 separated in the lower deck 23 arrives as a third fraction in a sieve underflow trough 30 and is collected there together with the white water and a fourth fraction, which mainly consists of the washable constituents 31 of clay and clay.

It is much more effective if the gravel and sand are classified by wet classification. For this purpose, a flexible hose line 32 is provided according to FIG. 2, with the aid of which fresh white water is pumped from a naturally existing hot water source, a well system or the like to a fresh water tank 33 . The water level in the fresh water tank 33 is regulated by a float circuit 34 and kept at a constant level, so that a sufficient amount of white water can be made available at all times. A white water pump 35 is connected on the suction side to the fresh water tank 33 , which pumps the fresh water on the pressure side into a pressure line 37 leading to the screen showers 36 . The brewing of the double-decker screen 16 can be adjusted with a special gate valve 38 between the white water pump 35 and the screen showers 36 . A second separate gate valve 38 is located in a branch which, referred to as a parallel line 39 , opens into the screen distributor box 15 . The wet classification on the double-decker screen 16 can thus be optimally adjusted if the gravel and sand from different deposits are composed differently.

Finally, a further branching of the pressure line 37 , which can be regulated with a separate gate valve 38, is provided, which leads to the screen underflow trough 30 with a branch line 40 . Their function will be described below.

As already mentioned, the white water conveyed by the white water pump 35 to the double-decker screen 16 is collected with the fine sand 24 and the components 31 that can be washed off in the screen underflow trough 30 . Only an insignificant proportion of white water reaches the stockpiles 21 , 27 with the oversize grain 13 and the quality sand 22 . The loss of white water can be reduced even further if the fine sand 24 is dewatered in the screen sub-tub 30 and the components 31 that can be washed off are separated from the white water in order to return the white water into the fresh water tank 33 in a closed water circuit.

For this purpose, an overflow pipe 42 for the washable components 31 is provided in the sieve underflow trough 30 , which otherwise determines the level of the water level. The overflow pipe 42 ends with a pipe outlet 43 in a settling trough 44 , in which the components 31 which can be washed off are accumulated in a conical lower part 45 . The suction nozzle 46 of a sludge pump 47 is located near the bottom of the settling trough 44 , with which the components 31 which can be washed off are deposited on a waste dump 49 . The white water which has been completely cleaned of the settable constituents 31 can flow back into the fresh water tank 33 through an overflow line 48 . At the same time, this creates a closed white water cycle.

In the closed white water circuit there is also fine sand 24 in the lower sieve trough 30 , which is also to be dewatered without a great loss of white water. For this purpose, a hydrocyclone 50 is provided, with which the fine sand 24 is separated from the white water and is deposited on a fine sand stockpile 51 in FIG. 1.

If necessary, the fine sand 24 according to FIG. 2 can be deposited together with the components 31 that can be washed off on a common landfill in order to limit the storage area.

As is generally known, a considerable amount of water is required for the correct operation of the hydrocyclone 50 , which can be substantially larger than the amount of water required for the wet sieve device to operate properly. For this reason, the dewatering of the fine sand 24 by means of hydrocyclone 50 can only be achieved if a correspondingly large proportion of white water is continuously pumped into the screen underflow trough 30 by the screen water pump 35 . For this purpose, the branch line 40 is provided with the gate valve 38 , through which primarily the amount of water required for the hydrocyclone 50 can be adjusted accordingly.

The fine sand 24 is pumped together with the white water from the sieve underflow trough 30 to the hydrocyclone 50 with the aid of a thick matter pump 52 . The grains of sand lose their kinetic energy in a cylindrical vortex space 53 and fall into the conical collecting container 54 . The white water separated from the fine sand 24 is returned through a pipeline 55 into the sieve underflow trough 30 and again pumped together with further constituents of fine sand 24 through the thick matter pump 52 into the hydrocyclone 50 .

The outlet of the pipeline 55 into the sieve underflow trough 30 is controlled by a level controller 56 . So that a safe operation of the hydrocyclone 50 is nevertheless ensured when the water level in the screen underflow trough 30 is blocked and when the level controller 56 is closed, a bypass line 57 which branches off and leads directly into the settling trough 44 is provided in the pipeline 55 leading to the screen underflow trough 30 .

This bypass line 57 is preferably designed in terms of flow technology so that the screen sub-trough 30 can be supplied primarily with the white water. This guarantees in any case that a disturbance in the drainage of the fine sand 24 cannot occur.

As a result, this almost completely enables the sand and gravel processing plant to operate independently, with which an excellent quality sand 22 can be produced with a very low fresh water requirement. This is primarily due to the fact that the spraying for the double-decker screen 16 can be set as optimally as possible without regard to existing resources. By recovering white water in a closed white water cycle, disadvantages for the environment are excluded.

Claims (7)

1. Self-propelled processing plant for wet classification of gravel and sand, which is adjustable by means of paired hydraulic support cylinders ( 11 ) with base plates ( 12 ) between a lowered driving position and a raised working position on both sides of a chassis frame ( 8 ) and comprises a double-decker screen ( 16 ) , characterized in that it has a crawler track ( 9 ) and a closed white water circuit with a fresh water tank ( 33 ) for the white water for brewing the double-decker screen ( 16 ) with fresh water. 2. Self-propelled processing plant for wet classification of gravel and sand according to claim 1, characterized in that screen showers ( 36 ) are provided for showering the fractions, the third fraction formed from the fine sand ( 24 ) in a screen underflow pan ( 30 ) together with the white water can be collected and a fourth fraction consisting essentially of the components ( 31 ) that can be washed off can be accumulated in a settling tank ( 44 ). 3. Self-propelled processing plant for wet classification of gravel and sand according to claim 2, characterized in that the fine sand ( 24 ) collected in the sieve underflow trough ( 30 ) can be dewatered with a dewatering device, for example by means of hydrocyclone ( 50 ), and the separated white water into the sieve underflow trough ( 30 ) and the water cycle for the white water is recyclable. 4. Self-propelled processing plant for wet classification of gravel and sand according to claim 2 to 3, characterized in that an overflow pipe ( 42 ) determining the level of the water level is arranged in the screen underflow trough ( 30 ), the pipe outlet ( 43 ) into the settling trough ( 44 ) flows. 5. Self-propelled treatment plant for wet grading of gravel and sand according to one of claims 2 to 4, characterized in that an overflow line ( 48 ) closing the white water circuit is provided, which leads from the settling trough ( 44 ) into the fresh water tank ( 33 ), one flexible hose line ( 32 ) opening into the fresh water tank ( 33 ) can be regulated with a float circuit ( 34 ). 6. Self-propelled processing plant for wet classifying gravel and sand according to one or more of claims 1 to 5, characterized in that a white water pump ( 35 ) connected on the suction side to the fresh water tank ( 33 ) with a pressure line ( 37 ) leading to the screen showers ( 36 ). with a plurality of branches which can be set by separate gate valves ( 38 ), of which a first branch line ( 40 ) opens into the sieve underflow trough ( 30 ) and a second parallel line ( 39 ) opens into the sieve distributor box ( 15 ). 7. Self-propelled processing plant for wet classification of gravel and sand according to one or more of claims 1 to 6, characterized in that a bypass line ( 57 ) branching off from the pipeline ( 55 ) of the hydrocyclone ( 50 ) and leading openly into the settling trough ( 44 ) ) is provided.