DE2253591A1 - PROCESS FOR THE PURIFICATION AND RECOVERY OF INGREDIENTS OF EXHAUST GASES FROM METALLURGICAL MELTING PROCESSES - Google Patents

Description

Slkem A / S, Oslo 3, Majorstua.

Methods for cleaning up and recovering the ingredients of exhaust gases from metallurgical smelting processes o

The invention relates to a method for cleaning and recovering the constituents of metallurgical exhaust gases Melting processes in which the exhaust gases with the solids they contain are introduced into water and a Form sludge-containing washing water that is processed.

The gases leaving furnaces for metallurgical smelting processes carry solid particles with them, some of them from dust consist of the raw materials and partly of substances that precipitate from the furnace gases. The dust can in barrel washers conventional type, and the effluents from these scrubbers are usually discharged into bodies of water. Immediate discharge of gases or runoff water leads to contamination of air or water, and in addition still comes the loss of valuable raw materials and degraded ones Output of the process.

In some melting processes, e.g. B. in the production of manganese alloys, such as ferromanganese, silicon manganese contains the dust contained significant amounts of manganese in the form of both entrained and precipitated particles. Example

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Weise developed a furnace for the production of high-carbon FeMn about 85o Hm "gas per ton of produced alloy, the grasses contain about 25 g of dust per Nm. The dust in turn contains 30 - 40 wt. "$ Manganese". Thus, large amounts of valuable manganese are lost with the dust or sludge.

There have been several attempts to the metal content of the sludge from cleaning plants for gases of metallurgical melting processes recover, wherein wet plants were operated "It has u. A _o the sludge into briquettes or pellets agglomerated ₉ which were then returned to the furnace. Such agglomeration processes are not only complicated, but also expensive, because they include both the precipitation of the sludge and the drying and agglomeration, or possibly the hardening of the agglomerates o

It has now become a simple and effective method of collecting and recycling the metal content in the sludge Found around the furnace.

The method of the invention for purifying and recovering the constituents of exhaust gases from metallurgical smelting processes by introducing the solid-containing exhaust gases into water is characterized in that the sludge-containing Wash water is passed through at least one filter made of carbonaceous material, such as coal or coke, whereupon the so cleaned washing water is drained or further used for washing the exhaust gases and the carbon-containing material is fed to a metallurgical melting process together with the constituents retained by it

According to one embodiment of the invention, for recovery of manganese, the pH of the washing water is set to:; values suitable for optimal precipitation.

By setting to optimal pH word,:;. B. Manganese

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almost quantitatively precipitated “In the course of precipitation the pH of manganese should be greater than 7 »through adjustment The pH value and the eventual addition of alkalis to the water before filtering can cause precipitation of dissolved water Metal compounds etc. are brought about, which are then taken up by the filters after the precipitation.

When filtering, the drainage water can also be freed of harmful substances, such as cyanides, as cyanides Oxidation due to the catalytic effect of the carbon material to be increased by air in the filter,

Continuous purification of the wastewater will require the use of two or more filter systems one filter set can be removed while the other or the other sets are in operation o Each filter system would then of course have to be equipped with devices for quick switching on and off »

example

The wastewater from a purification plant to remove the gases from a furnace for the production of FeMn was filtered through coke filters iJs were the water before and after the filters Samples taken. The samples were tested for the turbidity given in Jackson Trubidity Units (J.ToUo) as well as for the sludge and Analyzed manganese content

Gate to the filtering brook to the filtering

Turbidity (J.ToU.) 1ooo 3-5

Sludge content (mg / l water) I800 5

Mn content (mg / l water) 265 1 1

The turbidity is accordingly reduced to o _s 5 fo of the original value, while 99 _S 7 ^c ß> of the sludge and 99? 6 $ of the manganese could be recovered "

jjio CarbonfiJ.tcr you can use the melting furnace ».Ι« ifod uktionuinat ο rial been supplied »thereby becomes

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the lethal yield of the process is also increased. The Garbonfilter may optionally also another Sci'unelzprozess be fed, wherein the carbon material as the reducing agent and the precipitated sludge can be used as additive material ₀

In the method of the invention, the construction of filling pits or jellying oil is saved. A considerable saving in space is thus achieved in addition to the technical _{and economic advantages}

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Claims (3)

Claims 1) Methods for cleaning up and recovering the ingredients of exhaust gases from metallurgical smelting processes by introducing the Exhaust gases containing solids in water, characterized in that the sludge-containing washing water by at least one Filters made of carbonaceous material such as coal or coke »passed through is, whereupon the so purified washing water is drained or further used for washing the exhaust gases and the carbon-containing Material is fed to a metallurgical melting process together with the constituents it has retained. 2) The method according to claim 1, characterized in that for the recovery of manganese, the pH of the washing water to suitable values are set for optimal precipitation. 3) Method according to claim 1, characterized in that for increased oxidation of cyanides during their catalytic oxidation through the carbon material it is ventilated.