SU868492A1 - Device for atom-absorption determination of mercury in powder-like materials - Google Patents

Description

(54) DEVICE FOR NUCLEAR ABSORPTION DETERMINATION OF MERCURY IN POWDERED MATERIALS

The invention relates to devices for implementing physical methods of analyzing the chemical composition of substances-a and can be used in color metallurgy to determine mercury in ores, cinders, and other products of enterprises processing mercury-containing raw materials. Instruments are known for the atomic absorption determination of mercury, which is preliminarily transferred to the solution by chemical treatment of the powder materials under investigation. For atomic absorption analysis, the solutions are sprayed into the flame of burner atomizers or a flameless atomization method is used by introducing various fl reducing agents into the mercury-containing solution. Such devices are also complicated in order to achieve the required sensitivity (on the order of 10% Nd, in terms of the initial powder tests), additional nozzles are introduced into the design of the devices, which supply the solutions of reducing agents to the atomization zone simultaneously with the analyzed solutions. with considerable technological difficulties, and the data on atomic absorption determination of mercury is characterized by low accuracy. an ohm-absorption mercury determination in powdered materials consisting of an atomizer, a vibrating device for introducing powder into the atomization zone, a filter, an atomic absorption photometer and a backing pump. The atomizer is heated outside by an electric heater. analyzed material.

The resulting gas-air mixture is evacuated into the storage cylinder due to the pre-created vacuum (the air from the cylinder is pumped out to a pressure of the order of 1Spatm)

In the storage cylinder, the gas composition is averaged and the mixture with atomic mercury evenly distributed in it is directed to the analysis zone L2 J.

Thus, to prepare an air-gas mixture, the concentration of mercury in which is proportional to the concentration of mercury in the analyzed projection, a device made from a pen atomizer, storage tank, valve system and software analysis control unit is used. The valve system is often out of order and, together with the storage cylinder, is the most important link. Significant drawbacks also have an atomizer furnace and a device for introducing a sample into the atomization zone, the design features of which dictate the need to select a sample sample in order to form a gas-air mixture containing the mercury concentration corresponding to the atomization potential in this furnace after the heat treatment. -absorption photometer. When analyzing materials with a constant content of mercury, its determination on such an instrument is considerably more difficult, since it is necessary in each case to find the required weight by trial and error.

The purpose of the invention is to improve the accuracy and simplify the design of the device.

The goal is achieved by the fact that in the device containing an atomizer with .caps Filter, an atomic absorption photometer connected in series, and a vibrating dispenser for introducing powder into the atomization zone, the atomizer is formed in the form of a vertical cylinder, inside which is installed a conical distributor, under which the brake is placed Five inserts, a vibrating feeder for introducing powder into the atomization zone are installed above the top cover of the atomizer.

The braking inserts are made in vnde peripheral and central conical surfaces, the inner radius of the peripheral inserts is 0.25-0.35, the radius of the central inserts is 0.60-0.70 of the inner radius of the atomizer.

The inserts are located on a site equal to 0.3-0.5 lengths of the atomizer from its upper arch.

In this case, the central inserts are made gas-permeable.

The drawing shows the proposed device.

The device consists of an atomizer 1, made of stainless steel and made in the form of a vertical cylinder with a removable top and

bottom lids. External electric heater 2, designed for 220 V,

A power of 1.5 kW makes it possible to maintain a temperature of 700-900 ° C inside the atomizer.

A vibration absorber 3 of type ABP-2 is mounted above the hole in the top cover of the atomizer coaxially with the atomizer. 5 A cone distributor 4 is located inside the atomizer at the upper end of the end, and braking peripheral 5 and central 6 inserts are located on the section equal to 0, 5 lengths of the atomizer. The atomizer 1 is connected to the filter 7 for cleaning the gas-air mixture from mechanical impurities and then to the analytical cell atomic absorption photometer 8 and through the sanitary filter 9 to the backing pump 10.

The device works as follows.

Turning on the external heating 2 of the atomizer 1, the foreline pump and the atomic absorption photometer and the AC network with a voltage of 220 V, bring the temperature inside the atomizer to 800-900 ° C and set the air flow rate in the system to 1-5 l / min.

Claims (2)

After that, the analyzed material is poured into the hopper of the device for even waking and include a vibrating dispenser. In this case, the pororpous sample enters the atomizer 1 through the holes in the upper lid and, falling on the conical distributor 4, concentrates in the wall space and moves further in the heating zone under the influence of gravitational forces 5 along the walls of the atomizer. The free fall of the powder is interrupted by conical inhibitory inserts: peripheral 5 and central 6. 5 The system of inhibitory inserts increases the residence time of the material particles in the preheating zone by a factor of 2-3, and also preserves the redistribution of particles into the near-wall zone, which accelerates their heating the inner walls of the atomizer. The inner radius of the peripheral inserts (0.25–0.35) and the radius of the central inserts (0.6–0.75) from the inner radius of the atomizer ensures, with maximum particle braking, the exclusion of the possibility of material accumulating or lying on them equal to 0.3–0.5 of the length of the atomizer from its upper end (i.e., into zones, that is, the beginning of the heating of the particles of the material), eliminates the possibility of formation on the inserts of specs and overlays and, thus, difficulty in maintaining the device. This design of the atomizer allows to improve the heat exchange and increase the residence time of the pro in the heating zone, which leads, as established (by analyzing the mercury sample annealed in the atomizer, while it is free from mercury), to the complete evaporation of all mercury analyzed in the materials. The use of the proposed atom allows us to significantly simplify the design of the device, there is no valve system, a software control unit, a storage cylinder, which makes efo easier to manufacture and reliable in operation. The gas-air mixture formed through the filter 7 enters the analytical cell of the atomic absorption photometer 9, the scale of which is graduated in mercury concentrations. Thus, the design of the atomizer allows the process to be carried out in a dynamic mode, eliminating the addition of hinges, which improves the accuracy (determination of mercury and makes the analysis more rapid. 2 Claim 1. A device for the atomic absorption determination of mercury in powdered materials containing an atomizer with caps, a filter, an atomic absorption photometer connected in series, and a vibration meter for introducing powder into the atomization zone, characterized in that, in order to increase accuracy and simplify the design, the atom the isolator is made in the form of a vertical cylinder, a vibrating doser for introducing powder into the atomization zone is installed above the top cover of the atomizer, and a conical distributor is installed inside the latter, under which the braking inserts are placed, 2. The device according to claim 1, characterized in that braking inserts are complete in the form of peripheral and central conical surfaces, the inner radius from the peripheral inserts being 0.250, 35, and the radius from the central inserts being 0.60-0.75 from the inner radius of the atomizer. 3. The device according to paragraphs. 1 and 2, characterized in that the central inserts are gas-permeable. 4. Device on PP. 1-3, which is the fact that the braking branches are located on a site equal to 0.3-0.5 lengths of the atomizer from its upper end. Sources of information taken into account during the examination - 1. L Shchenko SD. et al. Flameless atomic absorption determination of mercury using sodium borohydrate as a reducing agent. ZAH, T. 41. vt. 2, 1976. 2. Kuznetsov Yu.N. and others. The method of atomic absorption analysis of mercury. Factory Laboratory, 1965, №31, p. 1085 (prototype) in TTGTD /; about