SU1712435A1 - Flux for protection of zinc alloy melt surface - Google Patents

Abstract

The invention relates to metallurgy, in particular to the smelting and refining of molten zinc and its alloys, as well as to the application of zinc coatings by the hot method on steel products. The purpose of the invention is to reduce costs and reduce zinc losses. For this, the flux contains the following components, May. %: spent electrolyte of magnesium electrolyzers 45 - 60; sodium chloride 15 - 20, the rest of zinc chloride. The temperature of the flux preparation has been reduced, the formation of chlorides has been eliminated. 1 tab.

Description

The invention relates to metallurgy, in particular, to smelting and refining molten zinc and its alloys, as well as to applying Zinc coatings by the hot method. on steel products.

The purpose of the invention is to reduce costs and reduce zinc losses.

The proposed flux contains zinc chloride, sodium chloride and the spent electrolyte of magnesium electrolyzers in the following ratio of components, wt.%:

. Spent electrolyte of magnesium electrolyzers 45-60 Sodium chloride 15-20

Zinc chloride

The spent electrolyte of magnesium electrolyzers (mp. 680 - 690 ° С) when fed with carnallite contains, in wt.%: Magnesium chloride 4 - 6; potassium chloride 72 - 80; sodium chloride 8-18

After regular pouring out of the electrolyzer, cooling and grinding, the spent electrolyte is used only in agriculture as potassium fertilizer, but due to the high content of sodium chloride, it alkalizes.

At the same time, the composition of the spent electrolyte of magnesium electrolyzers includes the components necessary for producing a low-melting flux — potassium, sodium, and magnesium chlorides.

The inclusion of sodium chloride in the composition of the proposed flux in an amount of 15-20% by weight ensures a decrease in the melting point of the flux and an increase in its stability. The limits of the sodium chloride content range are due to the need to achieve an equimolar ratio

potassium chloride - sodium chloride 1: 1 (mol). Only such a ratio of these components in the composition of the flux leads to the maximum possible decrease in the melting point of the flux due to the formation of the most low-melting eutectic mixture.

The limitation in the composition of the flux of the content of the spent electrolyte of magnesium electrolyzers in the range of 45–60 wt.% Is explained by this. that an increase in its concentration of more than 60% increases the temperature of the melt: flux fluxes and reduces the erg refining properties. This also causes a sharp increase in zinc loss. A decrease in the concentration of the spent electrolyzer to less than 45 wt.% Leads to an increase in the content of zinc chloride, which causes a sharp increase in the vapor pressure of zinc chloride and loss of flux.

Only the proposed ratio of flux components ensures its high complex efficacy of the coating protection of zinc alloys against oxidation and the considerable stability of the flux composition in the belt, as well as sufficient overheating of the flux during hot galvanizing.

Depending on the ratio of intrinsic flux, the melting point of the flux is within 350 -, which allows the flux to overheat above the melting point of 100.- 200 ° C during smelting and casting of zinc alloys and hot-dip galvanizing. This makes it possible to minimize the volatilization of zinc chloride and increase the stability of the composition of the flux, which significantly improves the working conditions of the staff.

The costs of flux production are determined by the price of the flux components, as well as the technological costs of blending and melting the components.

The temperature of the spent electrolyte poured from the electrolyzer is 700-720 ° C and its enthalpy makes it possible to prepare the offered flux by mixing pre-warmed zinc chloride and sodium chloride with the spent electrolyte with an insignificant additional consumption of thermal energy. Such energy-saving technology intensifies and simplifies the process of flux preparation.

The electrolyte of magnesium baths is refined during the electrolyzer, therefore the component of the proposed composition

Foyus - the spent electrolyte does not contain electropositive impurities from traces of moisture.

Example. Preparation of fluxes according to

the prototype and the proposed method was carried out in an electric furnace with an upper limit of adjustable heating to 1100 ° C. The prepared mixture of a specific composition of the flux was kept for 1.0–1.5 hours at a temperature exceeding by 30–50 ° C the melting point of the most refractory component. The resulting molten flux was poured into heated crucibles. Mass of solidified salt blocks

did not exceed 1.5-2.0 kg. Then, these salt blocks were placed on the surface of a zinc bath with a surface temperature of 480 ° C, and the state of the metal surface and the presence of vaporization above the salt flux mirror were observed.

The results of the comparison of the preparation modes and some technological properties of the prototype flux and 4 compositions of the proposed flux are given in the table,

The technical advantages of the proposed method in comparison with the prototype are manifested in the use of spent electrolyte - electrolytic magnesium production waste, which leads to a reduction in material consumption and the achievement of a significant economic effect, a decrease in the preparation temperature of the proposed flux, which greatly simplifies the preparation process and reduces

heat consumption, in a significant improvement in the working conditions of personnel due to the virtually complete elimination of chloride formation in protecting the surface of molten zinc alloys with the proposed flux.

f o rm u l a and 3 o b rie n and Flux, to protect the surface of molten zinc alloys, containing zinc chloride and sodium chloride, which is a very tangible one. that, in order to reduce costs and reduce zinc losses, it additionally contains spent electrolyte of magnesium electrolysis cells in the following ratio of ingredients. wt.%:

Spent electrolysis: magnesium electrolyzers 45-60 Sodium chloride 15-20

Zinc chloride

Claims (1)

Claim Flux, to protect the surface of molten zinc alloys, containing zinc chloride and sodium chloride, with the fact that, in order to reduce costs and reduce zinc losses, it additionally contains spent electrolyte of magnesium electrolysis cells in the following ratio of ingredients, wt. %: Waste Electrolysis of Magnesium Electrolyzers Sodium Chloride Zinc Chloride I 45 - 60 15-20 Else 5 1712435 6 Composition The content of components, wt.% Flux preparation temperature, ° C The presence of vaporization at T 480 ° C Loss of zinc (ash, carbon monoxide), kg / t Potassium chloride Sodium chloride Zinc chloride Barium chloride Spent Electrolyte Prototype 15-30 11-22 36-50 12-24 990-1010 Inten- 6.61 Proposed 1 TO 10 55 35 800-820 sive Insignificantly 5.15 2 fifteen 40 45 830-850 exact same 4.86 3 - 20 20 - 60 830-850 No 4.63 4 25 5 70 850-870 blowing Inten- 6.20 V · ¹¹ ........ sive - Compiled by O. Golyzhnikoaaa Editor L. Pcholinskaya Tehred M. Morgenthal Corrector N. Revskaya Order 511 Circulation Subscription VNIIIPI of the State Committee for Inventions and Discoveries at the State Committee for Science and Technology 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Combine Patent, Uzhgorod, 101 Gagarin St.