Method for preparing fine platinum powder used for negative electrode fine platinum wire in intensified thermocouple wires

Abstract

The invention discloses a method for preparing fine platinum powder used for a negative electrode fine platinum wire in intensified thermocouple wires. According to the method, waste material of Pt-based material thermocouple wires PtRh or Pt is adopted, dissolution, impurity removal through sedimentation, revivification and other methods are carried out on the waste material to obtain the fine platinum powder, and the fine platinum powder prepared through the method is machined to be the fine platinum wire. The fine platinum powder is machined to be the Pt wire, therefore, tensile strength and elongation of the platinum wire can be increased, creep resistance of the platinum wire is improved, service life is prolonged, and the platinum wire is made to be easy to micronize.

Description

technical field [0001] The invention relates to a method for preparing metal materials, in particular to a method for preparing fine platinum powder used for negative electrode fine platinum wires in reinforced thermocouple wires. Background technique [0002] Pt cluster metal has good thermoelectric and processing properties, good oxidation resistance and corrosion resistance and high melting point at high temperature, and is a good material for making thermocouples. [0003] With the widespread use of precious metals, the scarcity of resources, and their high prices, new requirements are put forward for the use of precious metal thermocouple wires: on the basis of ensuring the thermoelectric performance of the thermocouple wires, the thinner the wires used, the better it is good. [0004] At present, Pt-based material thermocouples in precious metals mainly include Pt-Pt10Rh (S type), Pt-Pt13Rh (R type), Pt6Rh-Pt30Rh (B type), etc. Pt-based material thermocouples are the ...

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Problems solved by technology

[0005] At present, Pt-based material thermocouples use sponge platinum. In the traditional production process of sponge platinum, since the solution needs to be concentrated when converting sodium chloroplatinate into chloroplatinic acid, ammonium chloride is added to the acidic solution to precipitate platinum, and chloroplatinum Ammonium acid is decomposed at high temperature to obtain sponge platinum, and its reaction formula is (NH 4 ) 2 PtCl 6 =Pt+2NH 4 Cl+2Cl 2 ; Therefore in this preparation process mainly have following shortcoming: 1. remove the platinum solution of impurity and need consume a large amount of electric energy just can be converted into chloroplatinic acid; 2. ammonium chloride precipitation platinum can produce a large amount of waste water containing ammonium chloride; 3. The decomposition of ammonium chloroplatinate produces a large amount of toxic gas Cl 2 and NH 4 Cl; 4. During the concentration and evaporation process, platinum will volatilize with the water atmosphere and when ammonium chloroplatinate is decomposed, the gas volatilization will take away platinum, resulting in the loss of platinum. Therefore, this method has the advantages of long preparation process cycle, high energy consumption, and platinum Disadvantages of high loss and large environmental pollution

[0006] In addition, the sponge Pt wire has the following disadvantages in the process of micro-filament processing: 1. The low tensile strength and elongation are the bottlenecks of miniaturization, which limits the process of miniaturization; Poor creep performance also limits the long-term use of S-type and R-type thermocouples at high temperatures

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