DE2134101A1 - Electron conducting glass - contg oxides of silicon iron,sodium and lithium,for use in glass electrodes - Google Patents

Abstract

Glass electrode for measuring oxidation potential of liquid media consists of (in wt.%) SiO2, 45-65, Fe2O3 25-50, Na2O 4-15, and Si2O 2-10. The electrode is stable not susceptible to poisoning and inert with respect to liquid media. The electron exchange at the liquid-glass boundary proceeds rapidly. Wide potential range is covered (from -200 to +1200 MV).

Description

1. B @ ris @ etrovi # Nikol @ skij, Leningrad / USSR 2. Michail Michajlovi # Sul'c, "3. Aleksandr Moiseevi # Pisarevskij," 4. Anatolij Aleksandrovi # Beljustin, "5. Sof'ja Konstantinovna Bolchonceva," 6. Vladimir Aleksandrovi # Dolidze, Tbilisi / USSR 7. Valentina Michajlovna Tarasova, "8. Julija Michajlovna Kara # eneeva, "9. Liana Iosifovna Dolmazova," ELECTRONIC GLASS AND GLASS ELECTRODE FOR MEASURING THE OXYDATION POTENTIAIS OF LIQUID MEDIA The invention relates to Perfecting of means for a potentiometer analysis of liquid media, in particular of electron-conducting glass, which is used to manufacture a sensing element can be used for glass electrodes that lead to a potentiometer measurement of the Oxidation potential of liquid media are provided.

The electrodes are widely used in transmitters of steady effective monitoring and control systems for technological processes in chemical, Pulp, <and> paper, textile, <> pharmaceutical industry and in the Hydrometallurgy.

The electrodes en fill a hollow glass tube Chen with current discharge, at one end of which a Fuhielement is soldered.

A design of the sensing element made of glass on lithium silicate is known and sodium aluminosilicate base, which have ionic conduction. Such electrodes do not allow the oxidation potential (eH) of control media to be measured.

Usually the sensing element is turned off to measure the oxidation potential EReltl7e & A1eß7, for example made of gold, platinum.

Except. The electrodes @ with such Feeler elements also have the following disadvantages.

The sensing elements made of precious metals are damaged by catalyst poisons (for example poisoned by H2S and other sulfur compounds). The opening act @@ be <in the control medium> one gaseous oxygen or hydrogen <> acts on the electrode @ poten @@@@ on, which increases the accuracy of the measurement. @@@ via @@@ from can the precious metals the dismantling of some Redersystems (for example from Wasserst @ ffporoxyd) katalys @@@@@.

Electrodes with a sensing element made of @@@ chl @@@@ off @@@@@@@@@ are usually cheaper. Mat @ rial @@@@ @@@ ensure @ber k @@@@ @@ he @@ ßgen @@@ gk @@@ @@ @ xyd @ tion potentials at having a small buffering capacity with respect to oxidation-reduction Redox systems.

The known alkali silicate glass only has an electron conduction at a very high concentration of iron oxide on what the manufacturing properties and chemical resistance of the former is impaired.

In addition, the sensing element made of such a glass enables the measurement of the oxidation potential only in an extremely limited concentration range of the redox systems.

The purpose of the invention is to create an electron-conducting glass, that is chemically resistant and has good production-related behavior and it allows the measuring range for the concentration of the redox systems to be expanded.

In order to achieve the stated and other goals, the task is to To choose a composition of iron silicate glass, the significant currents as a result an electron exchange at the boundary between the glass and the control solution is secure and indifferent is against the control solution.

The object is achieved by using an electron-conducting glass according to the invention in percent by weight SiO2 contains 45 to 65; Fe2O3 25 to 50; Na2O 4 to 15; LiO 2 to 10.

That. Presence in the inventory of the glass is such a significant one The amount of iron ensures high exchange currents when this glass is used as a sensing element at the limit glass solution. At the same time suppresses the presence of two alkaline Oxhden the ionic conduction and ensures good operating properties and high Chemical resistance.

A sensing element with the best properties can contain the following components The following are obtained in percent by weight: SiO2 55; Fe2O3 37; Li2O 4; Na2O @ or SiO2 50; Fe2O3 39; Na2O 7; Li2O 4.

The invention is intended below with the aid of a description and will be explained in more detail by examples of the invention and a drawing showing a glass electrode.

t) as. proposed glass is. from chemically pure powder form, previously up to Weight of dried oxides In the table below, the amounts of components contained in the batch formulation for the production of an electron-conducting glass are given in percent by weight.

Example no.

Oxyde '1 2 3 4 5 6 7 8 Li2 ° 4 4 2 2 10 3 2 6 Na2O 7 4 15 4 4 8 4 Fe2O3 39 37 38 33 40 50 42 25 SiO2 50 55 45 61 46 43 48 65 The of glass is done as follows.

The crucible with a carefully mixed batch recipe is placed in a previously used in an oven heated to 11000C. In four hours the temperature will be Brought in the oven to 13500C, and at this temperature the glass mass becomes one and a half Hours held. During the melt, the melt is mixed periodically, and after melting the glass is poured into a mold.

In the following, this glass becomes the sensor element in the drawing electrode shown.

The glass obtained in the manner described is in the flame melted a burner, transferred to the end of a glass tube 1, carefully warmed through and blown until a ball is formed.

Before filling the cavity of the tube 1 will from the outer and inner surface of the sphere serving as sensing element 2 a thin one Glass layer removed, the composition and structure change when the Have changed the sensing element2 to the tube1.

The electrode for measuring the oxidation potential contains a tube, at one end of which a sensing element 2 made of glass of the stated composition is soldered. The cavity of the tube 1 is filled with an electrically conductive material 3 in which a current conductor 4 is accommodated. The top of the tube list with a cap 5 covered, An electrode with the sensing element made of the present glass allows the oxidation potential to be measured within the limits of -200 to +1200 mV in a measuring range of 3 to 9 pH.

The temperature range of the work of the electrode is 0 to 90 ° C. The electrical resistance is Another advantage of the proposed glass is the fact that the presence <in the solution> of a catalyst poison> has no effect on the speed of the electron exchange between the glass and the solution .;

Claims (1)

PATENT CLAIMS: 1. Electron-conductive glass made of SiO2, Fe2O3, Li2O, Na2O, not indicated by 45 to 65 wt.% SiO2; 25 to 50% by weight Fe2O3; 4 to 15% by weight Na2O and 2 to 10% by weight Li2O. 9 2. Glass according to claim 1, d a d u r c h g e k e n n n n z e i c h n e t that it consists of 55 wt .-% SiO2.37 wt .-% Fe2O3, 4% by weight Na2O; 4% by weight Li2O. 3t glass according to claim 1, characterized in that it consists of 50% by weight SiO2; 39 wt% Fe2O3; 7 wt% Na2O; 4% by weight Li2O. > t3 \ 4. Reading electrode for measuring the Oxydatsonsp4 so en u kedi «Xs the one tube of 54 A «ve3g, 42.% gen t Y gen glass rt tt ia its hollow space > + ç the end of the tube A 2 electrode taktier ß head beteatigg t5tX / \ / 1 a 1 urchekenazej 0 net * th «,% I}" w v hlel t from Emea; iP "ts glass after a vitality zgBg: |> i8t * X .: lyLAIN, Lr vl. EtbrL iat ;, zrk. t Patent claim 4. Use of the glass according to one of the preceding claims as a sensing element in a glass electrode for measuring the oxidation potential of liquid media.