Descripcion de Control

7/28/2019 Descripcion de Control

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Tel: +44 2920 340 800 Maelgwyn Mineral Services Limited Registered and Business Office:

Fax: +44 2920 340 805 Registered in England and Wales Company No.3453319 1A Gower Street, Cathays

Email: [email protected] VAT No.s GB 701 0592 81 DE 812884045 Cardiff CF24 4PA UK

Q u o t a t i o n Nr.: CTN-IDMCHP1AJG-110512 Rev.0

Description of electrical and control delivery

Minera Valle de Aconcagua

Pneumatic Flotation Cells for MVA

Ingeniera de Minerales S.A.

Antofagasta, II region, Chile 16th of may 2012


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Filosofia de control INGENIERIA DE MINERALES S ACTN-IDMCHP1AJG-100512 Rev.0

Pg.

PLANTA DE FLOTACION DE FINOS Y

PLANTA DE MOLIBDENO2

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1. General

The pneumatic flotation design Imhoflot is a modern flotation technique that does not use

mechanical agitators to disperse the air in the flotation pulp. Pneumatic flotation is a fast and

intensive operating process that offers increased benefit due to lower capital and operating costs.

The design and the kinetics of pneumatic flotation are distinctly different from other flotation

techniques such as column flotation and flotation in mechanical cells.

The Imhoflot process has been proven in a range of different applications including;

coal, industrial minerals, ferrous and non-ferrous metal ores

roughing, scavenging and cleaning

both coarse and very fine particle sizes

primary raw materials or secondary materials

environment soil remediation and water treatment

The air is dispersed in a proprietary aeration device, operating without compressed air. In this

device, after conditioning with reagents, most of the hydrophobic particles adhere to the dispersed

extremely fine air bubbles. In the subsequent separating tank the mineralised air bubbles are

collected into the froth and discharged without the use of mechanical paddles or similar devices.

Wash water for froth cleaning is not normally needed, but can be used for special applications.

The aerating device is supplied with the flotation pulp by means of a centrifugal pump to produce

the necessary energy required for mixing pulp with air.

The specific power consumption is normally less than 60 % of conventional cells.

The cells are easily assembled.

The entire Imhoflot process can be automatically controlled at a remote location in the plant.

The process can easily handle changes in feed rate and mineral grade.

The flow sheet is simplified due to the improved selectivity in the process between mineral and

gangue.

Maintenance is reduced and is mostly constrained to the aeration device and the pump.


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2. Process and Design

Two different types of control loops are recommended:

Level control of the flotation cells

Air flow of aeration unit

High accuracy pressure sensors (for example the VEGA or Endress + Hauser brand) measure

levels in the cell. The method uses capacitance, not Piezo effects, whereby the sensor is

suspended in the pulp some 400 mm below the froth overflow rim. The bottom side of the sensor

incorporates a ceramic diaphragm which protects the capacitor. The electronic signal of the gauge

controls the speed of the discharge pump, which is feeding the next flotation cell. This method is

well proven at many plants. Subsequent cell levels are controlled in a same way.

In the air supply line of the aerator a similar pressure sensor (as used for the pulp level) is installed

to report the level of vacuum. This electronic signal controls the throttle valve (electro-pneumatic).

The first flotation pump feeding the cell from the conditioning tanks is also equipped with a

frequency inverter to modify pump speed and flow rate. The flow rate set point can be adjusted in

the control room. In the conditioning tank a level control valve adds process water and recycled

water. The dilution is therefore governed by the difference of the flow rate set point and the actual

feed flow rate to the conditioners.

Like the first flotation pump behind the conditioning tank the recycling pumps are also equipped

with frequency inverters to adjust the desired recycling flow. But this is only done manually. During

a number of cells in series operating the fresh flow (meaning the flow coming from the feed tank) is

reduced from cell to cell, because of the froth, which is separated. To allow to have the samepressures at the aerators from cell to cell, the speed of the recycling cells are increased from cell to

cell but this is adjusted by hand.


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Fig 1.- Control philosophy

3. Electrical cabinets for control of the plants

3.1 Switch board:

Two MCC- rooms build with two containers. This containers are isolated and air conditioned

There are two MCCs built with cabinets Rittal TS, the first cabinet of the MCC has a main switch

and the emergency relay. After the main switch the power supply for each drive is a busbar built in

all cabinets.


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There are 37 drives in the flowsheet MMS-IDM Proposal rev. J all drives are controlled by VFD this

VFDs are inside the cabinets and connected with the Profibus DP, all VFDs are ABB type 550 for

example.

There are two controls cabinet PLCs which will be located in the fines flotation plant the other one

in the Molybdenum flotation plant, in other words, the two cabinets for the remote I/O system will

be located in the field and to control locally the two flotation plants.

Inside the control cabinet is a power supply for 24 V DC, this power supply is for the PLC and the

measurement systems.

Inside the cabinet is the Siemens PLC, type Siematic S7.

PLC: CPU S7 318 2DP

Ethernet CP 343

Input and output cards SM 322, SM 321

Remote I/O Siemens DP

All analog inputs are isolated by an separate amplifier to protect the PLC.

Two Operator Panels Siemens MP 277 will be used to adjust and to operate the flotation.

Each of the plant are operated by its own Siematic PLC.

Instrumentation list

Circuit diagrams : MMS-IDM Proposal rev.M

Circuit diagrams control : MM-IDM Proposal rev. K

3.2 Views

Documentation 3-fold, DIN A4, and as DXF files on CD, operator program panel program WinnCC

Flex


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