Sampling of solution during heap leaching

Sampling of the solution is relatively simple compared to ore sampling. This is because the leachate and various tail liquids in the heap leaching field are all clear liquid. Although the content of the component to be tested in the solution varies with time, the difference is very different, but it can be characterized by the aggregate sample and the transient sample, and the solution is easy to mix evenly, so the solution sampling problem is rarely reported.

First, the transient sample

Refers to a sample that represents the nature of the solution at a given moment. The transient sample is generally a sample taken by a research or production personnel to observe and judge the process state at a certain time. The purpose is to grasp whether the process is in normal operation, whether the operating parameters are improper, such as the concentration of the leaching agent, the pH value of the solution, etc., so as to adjust in time. Sometimes it is to know how far a certain process has been carried out, such as whether the adsorption process is saturated, whether the rinsing is complete, and whether the replacement is thorough. In general, the transient samples are timed and fixed-point sampling, and a certain amount of solution sample is randomly taken at a certain time and at a certain time. Of course, some processes, such as the neutralization and precipitation process, do not use timed sampling in order to check whether the precipitation is complete. In order to improve the process and develop new technologies, the researchers need to constantly observe the change of the process and the instantaneous samples are not likely to be fixed and timed. .

It is very simple to take a transient sample. Use a designated sampling container to quickly take a volume of solution from the process line or the inlet and outlet of the equipment. It is worth pointing out that the sampling container must be cleaned before sampling and then rinsed with the sample for 2 to 3 times before it can be formally sampled. After sampling, the container mouth should be covered to prevent debris from being dropped, the sample evaporated, and the low-priced elements (such as Fe ^{2 +} ) to be tested are oxidized by air.

Second, the assembly sample

Refers to a sample of all the properties of a solution that represents a process over a period of time, or a device that has flowed in (in). The purpose of taking the sample is not only to investigate the operation of the process or a certain equipment; but also to calculate the important technical and economic indicators such as material balance, leaching rate and recovery rate for scientific research or production. It is an essential foundation work in the heap leaching process. The fundamental difference between it and the transient sample is that the aggregate sample is related to the volume of the solution it represents, so the volume of the solution it represents must be measured while sampling the sample.

The collection of the heap leaching field can be generally divided into two types: the leaching solution collection sample and the collection process of each recycling process or equipment.

(1) Leachate collection

Generally, the rich liquid pool is a collection of the leaching liquid, that is, the leaching liquid is continuously flowed into the slag-rich pool. After a certain period of time (for example, 24 hours), the volume of the leaching liquid is recorded, and the mixture is uniformly mixed, and a certain volume of the sample is taken for analysis. . It is also possible to take the leachate into the specified volume (for example, 50 m ³ ) without time, mix it evenly, and take the sample. The collection of leachate can also be sampled by a collection device on the inlet line such as adsorption and extraction.

(2) Collection of recycling processes (equipment)

A collection of sample devices is specifically installed on the inlet and outlet lines of the process or equipment to perform collective sampling. Now adsorption (uranium leaching solution ion-exchange, activated carbon adsorption leachate gold ore) step, for example, be described. At present, the device shown in Fig. 1 is used in China. That is, a small hole is drilled in the liquid inlet pipe between the flow meter and the adsorption tower, and another small short tube with a diameter of 3 to 5 mm is welded at the small hole, and the small short tube jacket has a spiral water stop clamp. For the thick-walled latex tube, place the liquid collector under the latex tube for sampling.

Figure 8-2 Schematic diagram of the sample sampling device

1-pump; 2-flow meter; 3-adsorption tower; 4-valve;

5-rotation (or water stop clip); 6-breast tube; 7-collector

It can be seen from Fig. 1 that the adsorbed stock solution (ie, the leachate) is metered into the adsorption tower through the flow meter, and when it passes through the sample collection device, it enters the container containing the sample through the small hole, the small short tube and the latex tube in the form of droplets. The speed of dripping is controlled by a spiral water stop clamp. After the adsorption is stopped, or the solution in the container is mixed regularly (for example, 24h), and all the solutions in the container are released, and a certain volume of the solution is taken from the sample for analysis.