Slurry density meter · PS7000

Leaching PLS · Raffinate · Catholyte Concentration On-Line Monitoring

Wet Metallurgy L-SX-EW

In the L-SX-EW hydrometallurgical process for copper, cobalt, and other metals, customers struggle to monitor the concentrations of the pregnant leaching solution (PLS), the raffinate, and the electrowinning cathode solution. Conventional differential‑pressure, tuning‑fork, or gamma‑ray instruments suffer from corrosion‑induced failures, solution contamination, electromagnetic interference, and restrictive radiation‑permit requirements. The PS7000 ultrasonic acoustic‑impedance slurry density meter, featuring a fully lined construction of Hastelloy, titanium, and PTFE paired with a non‑contact ceramic probe, delivers stable, online concentration measurements across the PLS, raffinate, and cathode solution streams, even in highly acidic, high‑chloride, and strongly electromagnetic environments, thereby supporting improved current efficiency and enhanced cathode‑product quality.

Applicable industries
Hydrometallurgy / Refining
Discuss this application View product PS7000
Leaching PLS · Raffinate · Catholyte Concentration On-Line Monitoring

PISONICS· Xi’an Pisonics

PS7000 Series

Ultrasonic Acoustic Impedance Slurry Density Meter

Application Case in the Hydrometallurgy / Refining Industry

—— Online Monitoring of Leaching Solution (PLS) Concentration, Raffinate, and Electrolyte ——

Resistant to Strong Acid and Chlorine Corrosion · Covers the Entire L‑SX‑EW Process · Enhances Metal Recovery Rates

Hydrometallurgy / Refining · PS7000 Application Solution

1. Process Background

Hydrometallurgy is the mainstream refining process for key metals such as copper, cobalt, nickel, lithium, and uranium, both domestically and internationally. The typical flow is “L‑SX‑EW”: leaching dissolves metals from ore into solution, producing a pregnant leach solution (PLS); solvent extraction selectively separates target metals using an organic phase, followed by stripping to yield a copper‑rich (or cobalt‑, nickel‑, or lithium‑rich) electrolyte; and electrowinning deposits high‑purity metal on stainless steel cathodes using lead‑silver anodes.

In all three stages, the core control parameter is solution concentration (density): the PLS concentration reflects leaching efficiency and endpoint; the raffinate concentration verifies SX extraction efficiency and recovery; and the Cu²⁺/H₂SO₄ concentration in the electrolyte directly determines current efficiency, energy consumption, and cathode quality. Any deviation in concentration at any stage will cascade through the process, severely impacting overall economics.

2. Pain Points of Traditional Density/Concentration Measurement Solutions

• Hydrometallurgical solutions feature a complex corrosive environment—high acid concentrations, high metal ion levels, and Cl⁻/F⁻—which drastically shortens the lifespan of conventional instruments;

• Contact-type instruments (differential pressure, tuning fork, rotary) can develop diaphragm perforations, contaminating solution batches and leading to downstream issues such as organic phase poisoning in SX and cathode nodules in electrowinning;

• The electrowinning workshop experiences severe electromagnetic interference, acid mist, and vibration, placing extremely high demands on instrument immunity;

• While gamma‑ray concentration meters can withstand corrosion, many hydrometallurgical sites are located in remote areas (South America, Africa, Qinghai, etc.), making it exceedingly difficult to obtain approvals for radiation sources, undergo annual inspections, and manage decommissioning.

3. PS7000 Solution

The PS7000 is deployed at critical points across the L‑SX‑EW process: at the leaching reactor outlet (PS7000 #1 · PLS concentration), along the SX raffinate line (PS7000 #2 · extraction efficiency monitoring), and in the electrolyte circulation loop (PS7000 #3 · key measurement point). Its all‑lining configuration—Hastelloy, titanium, and PTFE—ensures robust resistance to the highly corrosive conditions throughout the entire process.

Leaching PLS · Raffinate · Catholyte Concentration On-Line Monitoring

Figure 1 Schematic Layout of Online Density/Concentration Monitoring in the L‑SX‑EW Hydrometallurgical Process

Core Technical Advantages of the PS7000 in the Hydrometallurgy/Refining Industry

▶ Completely non-nuclear—aligning with global mining ESG trends and ensuring smooth environmental approvals for overseas projects;

▶ Optional materials including Hastelloy, titanium, tantalum, and PTFE—withstanding the combined corrosion of strong acids, high metal ion concentrations, and halogens throughout the entire process;

▶ Non-contact ceramic probe—ensuring contamination-free solution batches and protecting downstream SX organic phases from metal debris;

▶ Chirp acoustic impedance algorithm immune to the strong electromagnetic fields in electro-winning workshops, delivering stable outputs;

▶ High-temperature models up to 120°C (standard 80°C), suitable for heap leaching, pressure leaching, and other high-temperature processes;

▶ 4–20 mA + MODBUS-RTU + 4G—supporting centralized monitoring and remote diagnostics in large-scale hydrometallurgical plants.

4. Customer Value

Comparison Dimensions

Original γ-ray/differential pressure solution

PS7000 Solution

Radiation Safety

Overseas approvals are restricted

Non-nuclear source · Globally deployable

Corrosion-resistant

Membrane pore fouling

Hastelloy / titanium / PTFE ≥ 5 years

Solution Purity

Contact-type devices carry a risk of contamination

Non-contact · Zero contamination

Electromagnetic Interference Resistance

EW section output drift

Chirp algorithm · Stable output

Full Process Coverage

Multiple models are required

One model covers L-SX-EW

At a large overseas copper hydrometallurgical project (50,000 tons of cathode copper per year), three identical PS7000 units were installed at the leaching, raffinate, and electrolyte measurement points. After one year of operation, feedback indicated that the fluctuation in Cu²⁺ concentration in the electrolyte narrowed from ±3 g/L to ±0.8 g/L, current efficiency improved by approximately 1.5%, and the pass rate of cathode copper grades increased significantly. This solution has since been extended to numerous domestic cobalt hydrometallurgical refineries, nickel laterite heap leaching operations, and salt‑lake lithium extraction projects.

Selection Supplementary Notes

▶ Note: Hydrometallurgical solutions are clean, homogeneous liquids. If higher accuracy is required (on the order of ±0.0005 g/cm³), the PS7020 sound-velocity‑based solution can also be selected, which is particularly well suited for the separate measurement of the two parameters—Cu²⁺ and H2SO4—in electrodeposition catholyte.

Conclusion

Xi’an Pisonics, based on the four ultrasonic measurement principles of the PS70 series (acoustic impedance, acoustic attenuation, sound velocity, and sonar frequency modulation), covers the full range of online density/concentration measurement needs—from two‑phase slurries containing solids to clean, homogeneous liquids. Tailored to the process characteristics of the hydrometallurgy and refining industries, the PS7000 series ultrasonic acoustic impedance slurry density meters provide end‑to‑end technical support, from instrument selection and installation/commissioning to long‑term maintenance.

For an in‑depth discussion of your project’s specific operating conditions, customized selection guidance, or on‑site technical consultation, please feel free to contact the Xi’an Pisonics engineering team at any time.

More applications for Slurry density meter

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Online Measurement of Gypsum Slurry Density in Absorption Towers

In the wet flue-gas desulfurization process, real-time monitoring of gypsum slurry concentration is crucial for ensuring the quality of the by-product gypsum and the proper operation of equipment. However, conventional concentration meters—such as mass flow meters, tuning fork sensors, and differential pressure concentration meters—suffer from issues like radiation safety concerns, bubble interference, and scaling. Pisonics’ PS7000 employs ultrasonic technology for non-contact measurement, can penetrate bubble layers to deliver stable and reliable concentration data, and requires no maintenance, with a service life exceeding five years.

Online Density Measurement for Limestone Slurry Preparation

During the preparation of limestone slurry, conventional density-measurement solutions suffer from issues such as wear and scaling, leading to inaccurate data and compromising flue-gas desulfurization efficiency. The PS7000 acoustic impedance concentration meter overcomes these challenges through non-contact ultrasonic measurement, delivering stable, high-precision online density monitoring and ensuring consistent control of slurry concentration.

Online Measurement of Desulfurization Wastewater Density

In the flue-gas desulfurization process at power plants, online monitoring of the slurry density in the underflow from the thickener is critical. Conventional contact-type instruments are prone to scaling and corrosion, making it difficult to meet the demands of long-term, stable operation. Pisonics’ PS7000 acoustic impedance concentration meter employs a non-contact ceramic probe and a corrosion-resistant lining, effectively addressing severe corrosion and fouling while ensuring the accuracy and stability of the measurement data.

Online Density Measurement for the AFT Tower (High-Concentration Desulfurization Slurry Processing Tower)

In the AFT tower, measuring the density of high-concentration, high-viscosity, and easily crystallizing slurries has long been a challenge. The PS7000 acoustic impedance concentration meter, employing non-contact measurement, overcomes the failures of conventional instruments caused by clogging, wear, and crystallization, enabling real-time, continuous monitoring of slurry density and automated control of the discharge process, thereby ensuring stable system operation.

Selection support

Guides

Comparisons

Voices from users of this product

"Our original tuning fork and differential pressure meters on the absorber gypsum discharge main had recurring problems with bubbles and scaling — we had to shut down weekly to clean them. After switching to PS7000, both problems disappeared. Basically maintenance-free now, accuracy is stable, and it fully meets our FGD process control needs."

Thermal Control Foreman Wang
Thermal Control Specialist
A certain thermal power plant in Inner Mongolia

"After switching to the PS7000, our overflow density readings finally stabilized — we stopped tuning reagent dosing by feel. The unexpected win was not having to clean the sensor weekly; our previous radiometric meter needed window-wiping almost daily in the scaling slurry."

Director Li
Mineral Processing Workshop Director
A certain copper mining enterprise

"Our potash blending tank is a harsh environment — KCl near saturation, 30~40% crystal content, temperature swinging 5~20°C. Traditional density meters can't hold up here. After two weeks of PS7000 service, the deviation from manual lab samples stayed in the 0.5~0.8% range, even during concentration peaks. No anomalies."

Director Xie
Process Engineer
A potash fertilizer plant in Qinghai

FAQ

Is the PS7000 ultrasonic density meter a radiometric device? Does it need a radiation license?

The PS7000 is an acoustic-impedance ultrasonic density meter with no radioactive source whatsoever. No radiation license is required. It uses only piezoelectric transducers to send and receive ultrasonic signals — the same physical principle as medical and NDT ultrasound.

If you're currently using a Cs-137 / Co-60 source-based meter and want to remove the regulatory burden, PS7000 is a drop-in alternative. We also offer the PS7500 gamma meter, which uses an exempt-activity Na-22 source (< 1000 KBq) — also requires no radiation license.

Can PS7000 really measure stably in bubbly mining slurries?

Yes.

The PS7000 employs a linear frequency-modulated (Chirp) acoustic impedance algorithm—after transmitting a broadband ultrasonic pulse, the host unit analyzes the echo signal in the frequency domain, and multiple-reflection interference caused by bubbles is identified and eliminated by the algorithm. This is the core difference between the PS7000 and conventional reflective ultrasonic density meters: traditional single-frequency reflection is highly sensitive to bubbles, whereas the PS7000’s Chirp algorithm is virtually immune to them.

At the gypsum discharge line of an absorption tower in a thermal power plant in Inner Mongolia (under conditions of continuous air oxidation that generate dense bubbles), the PS7000 has been operating stably for several years after replacing the original tuning fork concentration meter.

What installation requirements does the PS7000 have?

The installation requirements for the PS7000 flanged direct-insertion type are as follows:

  1. Straight-run pipe sections: ≥5D (upstream) + 2D (downstream), where D is the nominal pipe diameter;
  2. The installation point must operate with a full pipe to avoid stratification of gas and liquid phases;
  3. The applicable pipe sizes range from DN50 to DN1000 (larger sizes can be customized);
  4. The flanges are compatible with ANSI/DIN/JIS standards;
  5. In highly abrasive conditions, it is recommended to use a 316L probe with special ceramics or a 2205 duplex stainless steel probe;
  6. In strongly corrosive environments, a PTFE-lined option is available.

If the pipeline does not allow for tapping, please consider the PS7010 clamp-on type instead.

PS7000 vs nuclear density gauges: which costs less over the life cycle?

On purchase price alone, ultrasonic and nuclear gauges sit in a similar bracket. The gap opens over 5 to 10 years of ownership.

Hidden cost list of a Cs-137 / Co-60 nuclear gauge:

  • Radiation safety licensing and annual reviews, plus operator training and certification;
  • Licensed transport and installation filing for the source;
  • Dose monitoring and record keeping during service;
  • Source replacement as activity decays (purchase, transport, commissioning, return of the old source);
  • End-of-life disposal of the spent source — often the single largest bill.

PS7000 acoustic-impedance ultrasonic gauge: no radioactive source and no permits of any kind; non-contact sensor with zero wear and zero clogging, sensor life of 5 years or more, virtually maintenance free with no consumables. Power plant, potash and iron ore sites have run 2+ years at near zero maintenance.

Bottom line: on a 5-year basis the total cost of ownership of the PS7000 is typically far below a nuclear gauge. Where a nuclear principle is genuinely required (such as dense-medium coal washing), the PS7500 with an exempt-activity Na-22 source needs no license, though the roughly 2.6-year half-life still implies periodic source renewal.