"Ten Questions and Answers on Handheld Soil Heavy Metal Detector"

With the introduction of the "Ten Measures for Soil", the soil remediation industry in China has developed rapidly. The demand for soil testing runs through the entire process of soil pollution remediation work, from the initial investigation of soil contaminated sites to the later assessment of soil remediation effects, all of which involve soil testing. Soil testing is the foundation for doing a good job in soil remediation. The handheld soil heavy metal detector can conduct on-site detection and rapid analysis of metal elements in the soil of contaminated sites. It is a very effective on-site soil heavy metal detection method. Currently, the handheld soil heavy metal detector has been increasingly applied in the soil remediation industry.

Question 1: What are the methods for on-site determination of heavy metals in soil?

Answer One: Currently, on-site determination of heavy metals in soil mainly employs handheld soil heavy metal detectors, which are commonly known as XRF soil analyzers. This technology can directly collect soil samples on site, achieving real-time on-site detection of heavy metals. Compared with previous laboratory tests, it saves a great deal of time and cost. This technical approach has been favored by the United States Environmental Protection Agency and other major regulatory agencies around the world.

XRF technology: that is, X-ray fluorescence spectrometry analysis technology, is a non-destructive testing method. It does not require sample digestion pretreatment, has a short testing time, high working efficiency, and can detect multiple elements simultaneously. The main method is to use primary X-ray photons or other microscopic ions to excite the atoms in the substance to be tested, causing them to produce fluorescence (secondary X-rays). The fluorescence produced varies depending on the type of heavy metal, thereby enabling qualitative and quantitative analysis of heavy metals.

Question 2: How many kinds of heavy metal elements in the soil can a handheld heavy metal detector generally measure?

Answer Two: Generally, more than 30 kinds of heavy metal elements can be determined, and the analysis range is usually from sulfur (S) to uranium (U). The main detectable elements are: K, Ca, S, P, Cl, Ti, Mn, Fe, Ni, Cu, Zn, Hg, As, Pb, Se, Rb, Sr, Y, Zr, Mo, Ag, Cd, Sn, Sb, V, Co, W, Bi, Th, U and 31 other elements.

Question 3: Are there any specific requirements for the types and shapes of the samples to be tested?

Answer Three: The form of the sample to be tested can be solid (block or powder), liquid or slurry, etc., as long as the concentration is higher than the detection limit of the equipment. The detection limits for different elements and matrices vary, generally ranging from 2 to 10ppm.

Question 4: How to use a handheld soil heavy metal detector?

Answer Four: Firstly, the detector needs to be calibrated with standard sample blocks to ensure its normal operation and reach the best usage condition. Handheld soil heavy metal detectors are generally calibrated once every 8 hours. During this period, even if the battery is replaced or the device is turned on or off, there is no need to recalibrate the equipment again. After calibration, set the test time according to the actual situation of the project and conduct soil sample determination. The operation of the instrument is very simple. Just pull the trigger once and the test will start. When the set test time is reached, the instrument will automatically stop.

Question 5: What issues should be noted during use?

Answer 5: The handheld soil heavy metal detector is easy to operate. Users do not need a professional background and can operate the instrument after simple training. But it should be noted that:

(1) Avoid high temperatures. The general operating temperature range is -10℃ to 50℃. Prolonged use of the instrument can also cause it to overheat. In such cases, it is necessary to take a short break before conducting the measurement to prevent the instrument from overheating and causing damage to the equipment. Currently in the market, the kMX-RAY K series products have made relevant improvements in this regard, paying more attention to the system improvement of heat dissipation of the equipment. Meanwhile, the instrument is equipped with an overheat protection function. When the instrument overheats, the system will give a reminder.

(2) Avoid dropping. Since the device contains X-ray light-emitting tubes, generally, when operating a handheld device, it is necessary to avoid subjiting it to violent impacts. How to prevent and resist drops is also the current research and improvement direction of handheld soil heavy metal detectors.

Question 6: How long does it usually take for a handheld soil heavy metal detector to test one sample?

Answer 6: Generally, it takes 60 seconds to 100 seconds to test a soil sample.

Question 7: How well-prepared and repeatable are the test samples?

Answer Seven: The accuracy and repeatability of the test samples are the points that everyone is most concerned about. Users usually compare the test results of handheld XRF analyzers with those of chemical methods. Due to different principles, test conditions, and the influence of various factors such as power after miniaturization, there will be certain deviations in the results, which is beyond doubt. By setting reasonable test conditions (such as test time, sample processing, etc.), the handheld XRF analyzer can obtain test results within the acceptable error range.

Question 8: What are the current brands of handheld soil heavy metal detectors?

Answer 8: The main imported brands of handheld soil heavy metal detectors are NITON and OLYMPUS, while domestic ones include KMX-RAY and SKYRAY. The KMX-RAY is simpler and more convenient to operate. The equipment is equipped with a gravity balance system, and the instrument has the best balance. During the test, it can stand on the workbench without the need for hand support. Moreover, during the test, only a gentle press of the trigger is required. There is no need for the operator to hold the trigger for a long time. Even after a long period of operation, the operator will not feel tired.

Question 9: How to solve the problem if the handheld soil heavy metal meter malfunctions?

Answer 9: When the instrument software malfunctions, the instrument can be connected to a computer, and the software and other components can be repaired through the computer. Meanwhile, the instrument engineer can also remotely diagnose and maintain the equipment.

Question 10: Can handheld soil heavy metal meters still be applied in other industry fields?

Answer 10: In fact, handheld heavy metal detectors are more widely used in the field of alloy detection. Through instrument measurement, the properties and specific component contents of alloys can be determined. At present, a handheld heavy metal detector can be loaded with multiple modules, namely soil, alloy, precious metal, ore, and ROHS. Among them, the ROHS module refers to the ability to determine the heavy metal content in children's toys or some substances closely related to life, thereby judging the harm of the substance to human health