Industry Areas

Mining&Slurry

Copper Concentrates Production

Selecting the right valves for copper concentrates production, smelting and electrolysis processes

Each ore deposit is unique in its concentration and mineral composition. Therefore, the most economical plant flowsheet varies from site to site. Even though the unit processes might be site-specific, the principle for the processing of sulfide ore remains the same.

Copper processing plants turn to flow control experts to isolate and control various process flows. In the upstream processing, valves regulate, for example, flotation and dewatering. In the downstream smelting and electrolysis processes, valves control, gas, air and electrolyte solution flows.

Valves for froth flotation

Valves commonly control the slurry feed and discharge, reagent addition and water flows in flotation equipment. Knife gate valves are used extensively in this application.

Another typical valve type is rubber-lined butterfly valve. Segment valves are an excellent solution for the reagent feed and control.

Valves for dewatering

As particles become finer, the resistance against removing water increases. Dewatering can no longer be achieved by gravitation, so pressure must be utilized.

A mechanical filter press is one option for the dewatering service. The machine contains several valves: Pinch valves are typically used in the slurry inlet feed, while the rest of the valves for water and air service often consist of butterfly valves.

Valves for the smelting process

The smelting process is a complex, multi-stage process involving high temperatures and molten liquids. Oxygen and air control are key to a reliable and efficient process.

For these operations, valve materials need to be carefully selected, and cleanliness is of paramount importance due to the inherent danger of oxygen reacting with any grease, oil, or combustible material left in a piping system.

The evaluation of valves for an oxygen application requires an understanding of metallurgy as well as valve geometries.

Valves for electrolysis

The electrolyte solution is piped to the tank. As pressures are typically rather low, butterfly valves are a good choice and provide the lowest total cost of ownership.

Copper Leaching and Solvent Extraction

Optimally selected valves simplify copper leaching,
solvent extraction and electrowinning process controlValves play an important role in the LX-SX-EW process by ensuring that various liquid flows are kept within the optimum range. Because of the demanding requirements for some of the valve installations and the constant acidity, selecting the optimal valves can have a positive impact on the plant’s overall profitability.

Valves for the pregnant leach solution

The pregnant leach solution is the output product of leaching. It forms as sulfuric acid percolates through the ore pile while the copper content of the ore is introduced in the aqueous solution. At some sites, drainage systems move the solution to the next processing stage using gravity; other sites use pumps.

Butterfly and ball valves are good choices for PLS flow control. Chloride sometimes poses a challenge in PLS feed, in which case the valve material selection is an important factor to be considered. For instance, hastelloy steel is a typical choice, as it exhibits a very high resistance against corrosion.

Valves for the raffinate feed

Raffinate is a mild solution of sulfuric acid with a pH typically between 1.2-2.0. When choosing a valve, many of the choices are typically straightforward in terms of size and pressure class, but there are also factors that may need a proper evaluation to ensure the best possible outcome. In addition to material selection, the right body and seat designs ensure that the valves perform at their peak.

Valves for the rich electrolyte solution

In the stripping stage of the process, the copper in the organic solution transfers to an aqueous solution, resulting in a rich electrolyte solution. This solution is piped to the electrowinning stage. Pipe sizes vary from site to site and can be DN1000 or even bigger. As pressures are typically in the lower range, butterfly valves are a good choice and provide the lowest total cost of ownership.

Gold Autoclave Pressure Oxidation

Valves control various liquid and gaseous flows in gold autoclave pressure oxidation process

Autoclave POX operations include several different types of valves to control both liquid and gaseous flows.

Slurry feed and discharge valves, pump isolation valves, depressurization valves, steam supply and steam drum isolation valves, as well as oxygen feed valves, among others, make sure that the POX process works optimally and efficiently.

In the autoclave, valves are subjected to a high-temperature and an oxygen-rich environment, so the right selection of valves can potentially make a significant positive impact on the operation’s reliability.

Valves for slurry feed

The conditions that valves face in the POX process require the highest possible resistance against corrosion and erosion as well as against the deterioration caused by solids. The right material, seat and coating choices play an important role in maintaining the sealing abilities of slurry feed valves.

Valves for oxygen feed

Controlling oxygen feed is one of the essential jobs in the POX process.

In the event they are called upon, these valves need to provide absolute isolation. Valve materials need to be carefully selected, and cleanliness is of paramount importance because of the inherent danger of oxygen reacting with any grease, oil, or combustible material left in a piping system.

The evaluation of valves for an oxygen application requires an understanding of metallurgy as well as valve geometries.

Valves for depressurization

In an operational disturbance, emergency or maintenance event, autoclave processes are sometimes depressurized. During depressurization, a vent line is used to reduce the pressure and temperature inside the autoclave.

When selecting the right valve for this service, Neles combines the knowledge of experts in process technology, metallurgy and field service to deliver the most reliable and economical solution.

Gold Production in CIL, CIP or CIC circuits

Valves control various liquid and gaseous flows in gold autoclave pressure oxidation process

Autoclave POX operations include several different types of valves to control both liquid and gaseous flows.

Slurry feed and discharge valves, pump isolation valves, depressurization valves, steam supply and steam drum isolation valves, as well as oxygen feed valves, among others, make sure that the POX process works optimally and efficiently.

In the autoclave, valves are subjected to a high-temperature and an oxygen-rich environment, so the right selection of valves can potentially make a significant positive impact on the operation’s reliability.

Valves for slurry feed

The conditions that valves face in the POX process require the highest possible resistance against corrosion and erosion as well as against the deterioration caused by solids. The right material, seat and coating choices play an important role in maintaining the sealing abilities of slurry feed valves.

Valves for oxygen feed

Controlling oxygen feed is one of the essential jobs in the POX process.

In the event they are called upon, these valves need to provide absolute isolation. Valve materials need to be carefully selected, and cleanliness is of paramount importance because of the inherent danger of oxygen reacting with any grease, oil, or combustible material left in a piping system.

The evaluation of valves for an oxygen application requires an understanding of metallurgy as well as valve geometries.

Valves for depressurization

In an operational disturbance, emergency or maintenance event, autoclave processes are sometimes depressurized. During depressurization, a vent line is used to reduce the pressure and temperature inside the autoclave.

When selecting the right valve for this service, Neles combines the knowledge of experts in process technology, metallurgy and field service to deliver the most reliable and economical solution.

Nickel Autoclave High Pressure Acid Leaching

Improving reliability with optimal valves for nickel autoclave high-pressure acid leaching

Autoclave HPAL is a challenging process requiring the toughest flow control solutions. Temperatures and pressures are extremely high, and acidic media and abrasive solids increase the wear and tear of the equipment. An optimal HPAL operation generally uses several different types of valves, such as slurry feed and discharge valves, pump isolation valves, depressurization valves, steam supply and steam drum isolation valves, as well as acid injection valves.

Valves for slurry feed

The conditions that valves face in the HPAL process require the highest possible resistance against corrosion and erosion as well as against deterioration caused by solids. Selecting the right material, seat and coating is vital in maintaining the sealing abilities of slurry feed valves.

Valves for acid feed

Controlling the acid feed is essential in the HPAL process. Valves must provide absolute isolation. If unstable situations occur, the valves and other process equipment in the acid feed line must be able to resist very high concentrations of acid.

Valves for depressurization

Autoclave processes are occasionally depressurized as a result of operational disturbances, emergency situations or maintenance. During depressurization, a vent line is used to reduce pressure and temperature inside the autoclave. Careful consideration of valve materials and coatings are among the top priorities when selecting the valves for this service.

 Valve Selection Principles
  • The model and performance of the selected valve can achieve the requirements of process parameters such as flow rate, pressure, working temperature, medium going through pipe etc

  • Corrugated pipe sealing design or leak-free valves are required for valves that transport flammable, explosive, toxic or valuable media,
  • Corrosive materials such as teflon are required for flow passage components for valves that transport corrosive media,

  • For valves containing solid particulate media, it is required that the flow passage component have to be made of wear-resistant material, and if necessary, the shaft seal should be flushed with a cleaning liquid.

  • When valve going through highly corrosive media (such as concentrated sulfuric acid, concentrated nitric acid), flammable and explosive media, and environment must not have any pollution, you can use a resilent valves.

  • Choosing the proper valve is crucial for you as it not only saving the cost, but the valve can work in a long service life.

Experience and Cases
Wetlap Machine #3,TNPL,India

Wetlap Machine|TNPL

PM 7 project| ITC

Rayagada |JK PAPER

Pulp Making|CMPC

Pulp Making|Suzano

Paperboard Making|Visy Paper

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