Online Slurry Density Measurement in Nonferrous Metallurgical Concentrating Plants
■ Project Snapshot / Process Overview
Customer Industry | Nonferrous / Ferrous Mineral Processing |
Application Area | Xinjiang / Qinghai / Inner Mongolia (multiple projects) |
Measured Medium | Metal slurry (mill discharge / hydrocyclone feed / thickener underflow) |
Operating Temperature | Ambient temperature 15–40°C |
Pipe Diameter / Installation | DN50–DN1000 main pipe, flanged direct insertion (non-contact) |
Commissioning Time | Long-term stable operation (now standard equipment at the plant) |
Comparison Method | Alternative to differential pressure / gamma-ray density meters |
Problems Before the Retrofit | Post-modification Data (PS7000) |
Differential pressure diaphragms suffer from wear, fouling, and zero drift; gamma-ray instruments require a Radiation Safety License, and several major mining provinces have already been placed on restriction lists | Ultrasonic, non-contact, zero wear and zero fouling; multiple on-site comparisons have shown that the output is fully consistent with manual sampling and laboratory analysis, with long-term measurement accuracy remaining stable |
I. Process Background
The core wet-process operations of nonferrous mineral processing plants (copper, lead, zinc, nickel, molybdenum, tungsten, etc.) primarily include crushing, grinding, classification, flotation, thickening, and filtration. In each stage, slurry density (or solid–liquid ratio) is a critical process-control variable: the discharge density from the mill determines the grinding circuit load, directly affecting mill energy consumption and liner life; the feed density to hydrocyclones influences classification particle size, thereby impacting subsequent flotation efficiency; the feed concentration to flotation cells governs reagent effectiveness, directly influencing metal recovery rates; and the underflow density from thickeners dictates the concentrate/tailings discharge consistency, which in turn stabilizes filtration, press filtration, and tailings conveyance.
According to many years of statistics from China’s mineral-processing industry, for every 1 percentage point deviation of slurry concentration from the setpoint, metal recovery can drop by 0.3% to 0.5%, while grinding energy consumption may increase by 1% to 3%. For a large concentrator handling 5 million tons of raw ore annually, the cumulative economic losses from concentration fluctuations over a year can amount to several million yuan or more.
II. Pain Points of Traditional Density-Measurement Solutions
• Gamma-ray concentration meters: While highly accurate, they are radiation-based instruments requiring a Radiation Safety License, annual inspections, training for radiological personnel, and costly source decommissioning. Several major mining provinces have already placed them on restricted-use lists, making environmental approval increasingly difficult for new projects.
• Differential-pressure or diaphragm-type concentration meters: Directly exposed to highly abrasive metallic slurries—especially those containing high-density minerals like iron ore and copper ore—the diaphragms suffer severe wear, exhibiting noticeable zero-point drift after just 3 to 6 months of operation and necessitating frequent shutdowns for calibration. Scale buildup on the diaphragm surface further amplifies measurement errors.
• Tuning-fork or vibration-based concentration meters: In flotation-feed lines, surfactants generate abundant fine froth, severely disrupting the fork’s vibration frequency, causing erratic, fluctuating readings and precluding stable control.
• The underflow from thickeners often reaches concentrations of 50% to 70% and frequently contains coarse particles, leading to frequent clogging of conventional insertion-type instruments, high maintenance demands, and low availability.
III. The PS7000 Solution
In concentrating plants, the PS7000 is typically deployed at three key measurement points: mill discharge/hydrocyclone feed (controlling the grinding circuit), flotation-cell feed (stabilizing flotation concentration), and thickener underflow (regulating discharge concentration). The instrument is installed via flanged direct insertion, with ultrasonic waves transmitted from outside the pipe and echo signals analyzed to extract acoustic-impedance features—ensuring no contact with the slurry and eliminating wear and fouling concerns.
Figure 1: Schematic Layout of Three Slurry-Density Measurement Points in a Nonferrous Mineral Processing Plant
Figure 2: Comparison of Key Indicators Before and After Retrofit (Trend Illustration · Based on Public Data from This Case)
Core Value of the PS7000 in the Nonferrous Metallurgy Industry ▸ The Chirp algorithm’s broadband analysis ensures stable measurement even for flotation feed containing fine bubbles, eliminating the “jumping” issue common with tuning fork–type instruments; ▸ A 316L stainless steel plus ceramic probe configuration (with a 2205 duplex steel option) delivers exceptional resistance to highly abrasive metal slurries, offering a service life of ≥ 5 years; ▸ Flange-mounted direct‑insertion installation covers all pipe diameters from DN50 to DN1000, providing a one‑stop solution for grinding, flotation, and thickener piping requirements; ▸ Completely non‑nuclear—zero radiation—no radiation permit required, ensuring smooth environmental compliance approvals; ▸ Dual 4–20 mA outputs plus MODBUS‑RTU protocol enable seamless integration with the plant’s DCS/PLC automation platform. |
IV. Customer Value
Comparison Dimensions | Original gamma-ray / differential pressure solution | PS7000 Solution |
Operational Safety | Radiation source control faces significant pressure | Intrinsically safe · Radiation-free |
Instrument service life | The diaphragm wears out and requires maintenance every 3 to 6 months | Ceramic probe with ≥ 5 years of maintenance-free operation |
Stability of Flotation Feed Measurement | Foam interference · Data jumps | Chirp anti-bubble · Stable output |
Risk of underflow blockage | Insertion-type instruments frequently experience pipe blockages | Non-contact · Completely no blockage |
Metal recovery rate | Concentration fluctuations lead to a decline in the recovery rate | Precision concentration control · Steady improvement in recovery rate |
At a large iron-ore concentrator in Xinjiang, the PS7000 replaced the original differential-pressure concentration meter on the mill-discharge line. Multiple on-site comparisons confirmed that its output fully matched results from manual sampling and laboratory analysis, with stable long-term accuracy, and it has since become standard equipment at the plant. Similar applications have been successfully extended to a nonferrous-mineral concentrator in Qinghai and a copper–molybdenum mine in Inner Mongolia, among other projects.
