SE202426C1

SE202426C1 -

Info

Publication number: SE202426C1
Authority: SE
Publication date: 1965-01-01

Description

Uppfinnare: K G Gorling Foreliggande uppfinning avser ett salt vid rostning av finkorniga ,arsenikhaltiga ,svavelmineral, sarskilt pyriter. Uppfinningen tar speciellt sikte pa det slag av pyriter, som erhallas vid flotation av svavelmineral. Inventor: K G Gorling The present invention relates to a salt for roasting fine-grained, arsenic-containing, sulfur minerals, especially pyrites. The invention is particularly directed to the kind of pyrites obtained from the flotation of sulfur minerals.

Del ãr kant, att rostning av :sarskilt finkorniga sulfidmineral, t. ex. flotationssvavelkis, enligt de moderna rostningsmetoderna, varvid materialet rostas i suspension med gasformigt medium, t. ex. antingen i NicholsFreeman-ugnar eller i virvelskiktsugnar, i vilka hada materialet medfoljer den bildade rostgasen ut ur ugnen, bereder aysevarda svitrigheter, om man viii erhalla ett rostgods, som är fritt frau arsenik. Narvaron av arsenik i rostgodset leder till nackdelar, can rostgodset shall bearbetas vidare, t. ex. genom. lakning f8r ntvinnande av vardefulla metaller, sasom guld, silver, koppar etc. eller, om rostgodset skall anvandas ,direkt for jarnframstallning, dã arsenik art& en icke ortskyard utreducerad bestandsdel i det fardiga j arnet. Part is edge, that roasting of: especially fine-grained sulphide minerals, e.g. flotation sulfur silica, according to the modern roasting methods, wherein the material is roasted in suspension with gaseous medium, e.g. either in NicholsFreeman furnaces or in fluidized bed furnaces, in which the material accompanying the formed rust gas out of the furnace prepares aysevarda sweats, if one viii to obtain a stainless steel which is free from arsenic. The presence of arsenic in the stainless steel leads to disadvantages, the stainless steel can be further processed, e.g. through. leaching for the extraction of precious metals, such as gold, silver, copper, etc. or, if the stainless steel is to be used, directly for iron production, then arsenic species & a non-orthopedic constituent component in the finished iron.

Svarigheten att ,avlagsna arseniken beror pa att jarnarsenater, i synnerhet av fern:yard arsenik, är mycket bestandiga fOreningar. De bildas relativt snabbt vid temperaturer, som aro normala for rostningen, om oxidationsforhallandena medgiva detta. The responsibility for removing arsenic is due to the fact that iron senates, especially fern: yard arsenic, are very persistent compounds. They are formed relatively quickly at temperatures which are normal for roasting, if the oxidation conditions allow it.

Foraliggande uppfinning är baserad pa detta forhallande satillvida, att man genomfOr rostningen pa ett sadant satt, att man erhaller Atminstone en ,svag tsvavelsublimation, varvid arseniken kommer att foraligga i huvudsak sasom trevard sulfid. Delta kan man uppna genom att .anyanda lamplig rostningstemperatur, sasom Over 750° C, foretra.desvis Over 790° C, .oeh att instiila syrgaspartia:1- trycket i rostgasen, s att ej alit elementart svavel i sulfidmaterialet omvandlas till svaveldioxid. DA hummer aven den vid rostning,en lpildade gasblandningen att innehalla en del isvavelanga, forutom i angforan f5religgande arseniksulfider. I denna gasformiga blandning foreligger dessutom fast finkornigt material i form ay brander eller aska. Det vasentliga for uppfinningen ãi, att man avskiljer det fasta materialet fran den Yid mostningen erhallna rostgasen sued dari ingaende forangade arseniksulfider ,och svavel vid dtminstonc sh hog temperatur, att vasentligen endast det fasta materialet, som vasentligen halt utgores .av rostgods, avskiljes utan att sublimation av svavel och arseniksulfider konamer till stand. Denna avskiljning av fast material kan uppnas genom anvandande .av en intill ugnen belagen cyklon eller ekvivalent anordnbag, i vilken praktiskt taget alla brander avskilj as utan att fa Malta att i vasentlig grad reagera med famvarda arsenikforeningar under bildning av arsenater. Gaserna utsattas ,darefter for okat syrgaspartialtryck genom tillforsel av luft eller andra syrgashaltiga gaser i en lamplig kammare, t. ex. en ytterligare cykion nr 2, en special' .forbra.nningskammare eller halt enkelt i en gasled- varvid efterforbranning av elementart svavel, harrorande frau rostningen i det forsta ,steget, hemmer till stand. For efterforbranningsprocessen ar ,det onskyart men inte abs olut nodvandigt att den frau fast material befriade rostgasen har en sa. h5g temperatur, att forbranningen kan she direkt med mattligt .syreoverskott. Nodvandigt Mr processen ar emellertid, som namnts, att separeringen av rostgods—sker vid en sh hog temperatur, Dupl. kl. 40 a: 1/02 2 att flagon sublimation i separeranordningen av svavel ochteller arsenik ej intrader. Efterforhranningen ar &Avail:dig for att svavelforlusterna eljest bli for stora, i vissa fall ungefar 4 %, och utfores vid bibehallen hog temperatur, hl. a. aven for ,att undvika igensattning I tvattorn etc. av utfallande sublimerande svavel. Gamut denna uppdelning av rostningsprocessen kan man saledes uppna ett rostgads mad mycket lag halt av .arsenik. Det ar overraskande att man far sa lâ svavelhalt i branderna vid det laga syrepartialtrycket. The present invention is based on this ratio insofar as the roasting is carried out in such a way as to obtain at least one weak sulfur sublimation, the arsenic being present substantially as hardened sulphide. Delta can be achieved by using any suitable roasting temperature, such as above 750 ° C, preferably above 790 ° C, to adjust the oxygen portion: 1- the pressure in the roasting gas, so that not all elemental sulfur in the sulfide material is converted to sulfur dioxide. When roasting, it also loosens the gas mixture to contain some ice-sulfur long, in addition to the arsenic sulfides present. In addition, this gaseous mixture contains solid fine-grained material in the form of fire or ash. The essential thing for the invention is that the solid material is separated from the rust gas obtained by the Yid musting, which has no evaporated arsenic sulphides, and sulfur at a high temperature, that essentially only the solid material, which is essentially contained in the stainless steel, is separated without sublimation of sulfur and arsenic sulfides conamer to state. This separation of solids can be achieved by using a kiln-coated cyclone or equivalent device bag, in which virtually all fires are separated without causing Malta to react substantially with known arsenic compounds to form arsenates. The gases are exposed, then to increased oxygen partial pressure by supplying air or other oxygen-containing gases in a suitable chamber, e.g. an additional cyclone No. 2, a special combustion chamber or simply in a gas line, whereby post-combustion of elemental sulfur, which roars from the roasting in the first stage, inhibits the state. For the post-combustion process, it is unclear but not absolutely necessary that the fraus gas liberated from the solid material has such a. h5g temperature, that the combustion can she directly with moderate .acid excess. Necessary Mr process is, however, as mentioned, that the separation of stainless steel — takes place at a sh high temperature, Dupl. at 40 a: 1/02 2 that flake sublimation in the separating device of sulfur and / or arsenic does not enter. Efterforhranningen ar & Avail: dig for the sulfur losses otherwise become too large, in some cases about 4%, and is carried out at the maintenance of high temperature, hl. a. also for, to avoid clogging in the water tower etc. of precipitating subliming sulfur. Gamut this division of the roasting process, one can thus achieve a roasting food very low content of .arsenic. It is surprising that you get so low sulfur content in the fires at the low oxygen partial pressure.

Forstik ha utforts med arsenikhaltiga flotationskiser, innehallande 0,3 % arsenik. Barvid har arsenikhalten kunnat nedbringas med 92 %. Aft arseniken bortgar sasom sulfid, far anses bevisat darav, att stoft, som ,uppsamlats i ett provtvattorn, endigt analys innehailer % arsenik och 39 % svavel. Eventuedit bildad As203 simile ha last sig I vattnet. Forsticks have been made with arsenic-containing flotation kits, containing 0.3% arsenic. In addition, the arsenic content has been reduced by 92%. Since arsenic removes sulphide, it can be considered proven that dust collected in a sample water contains final analysis of% arsenic and 39% sulfur. Eventuedit formed As203 simile have loaded In the water.

Arsenikavdrivningen genomfores saledes enligt uppfinningen under ,sadana betingelser, vilka aven ,ge .svavelsublimation. Hur rostningsbetingelserna skola atvaljas, for att arsenik skald sublimera sasom arsenik-IIIsulfid och nagot ,svavel samtidigt skald overgd angform, kan fackmannen latt avgara, synnerhet om man samlidigt .studerar farsoksresultaten I bifogade tabell — de faktorer, som vasentligen kunna anvandas for att installa de betingelser, .som aro nodvandiga enligt uppfinningen, Oro, sorn namnts, rostningstenaperaturen och forhallandet mellan syrgashaltig gas och far rosining avsett gads. Var!den runt liar dot for rostning av har avsedda material foreslagits idel tvastegsforfaranden ailed partial! avrostning °eh slutrostning. Enligt var uppfinning kan arseniken avdrivas kontinuerligt samtidigt som man uppnar en tolerabel svavelavrostning. The arsenic evaporation is thus carried out according to the invention under such conditions, which also give sulfur sublimation. How the roasting conditions should be chosen, in order for arsenic to sublimate as well as arsenic-III sulphide and something, sulfur at the same time to be given an angular form, the person skilled in the art can easily determine, especially if one studies the farcical results in the attached table - the factors that can be used. conditions which are necessary in accordance with the invention; The! Around the liar dot for roasting of has intended materials have been proposed idel two-step procedures ailed partial! defrosting ° eh final roasting. According to each invention, the arsenic can be evaporated continuously while achieving a tolerable sulfur defrosting.

Uppfinningen genomfores, sasom torde 'framga av ovanstaende, heist sa gott s-om alltid kontinuerligt. The invention is carried out, as will be apparent from the above, almost always continuously.

Sasom en sarskild forded vid fOrfarandet andigt uppfinningen kan namnas, att till foljd av rostningsbetingelserna kommer en ,stor del av jarnet i branderna ,att fOreligga sasom Fe304, vilket innebar akat varde och fordelar vid vidare behandling. As a special advantage of the process according to the invention, it can be mentioned that, as a result of the roasting conditions, a large part of the iron in the fires will be present as Fe3 O4, which meant value and benefits in further treatment.

Nagra forsoksresultat Iran svavelsublimation. Some test results Iran sulfur sublimation.

Material Rostn. SO2 As-avdriv- As i bran- Ingaende S i kisel- S I tvatt- temp. c.c % ning der % As % brander % vattenstoft of Svavelkis flan 800 14 81,0,12 0,39 1,4 10,7 Bolidens gruv- 800 14 71,3 0,07 0,0,67 10,7 aktiebolag 900 80,9 0,03 0,19 0,21 10,8 8714,84,2 0,08 0,34 0,stark subl. 8714.92 0,04 0,31 2,3 41,3 8714.79,9 0,11 0,34 0.06 1,Material Rostn. SO2 As-stripping- As in bran- Incoming S in silicon- S In wash- temp. cc% ning der% As% brander% vandstoft of Svavelkis flan 800 14 81,0,12 0,39 1,4 10,7 Bolidens gruv- 800 14 71.3 0.07 0,0,67 10,7 aktiebolag 900 80.9 0.03 0.19 0.21 10.8 8714.84.2 0.08 0.34 0, strong subl. 8714.92 0.04 0.31 2.3 41.3 8714.79.9 0.11 0.34 0.06 1,

Claims

1. Patent claim: Intended to produce an arsenic-poor rust material when roasting arsenic-containing, also containing sulfur mineral, preferably pyrite, wherein the sulfur mineral is roasted in suspension with an oxygen-containing gas and formed fires are separated from the rust gas, which can be Essentially all arsenic contained in the pyrite In vapor form as sulphides and at the same time a small amount of sulfur is phased in elemental form, and thereafter, after the fires are separated from the rust gas with diene, arsenic sulphides and evaporated evaporated sulfur, the oxygen partial pressure in the still hot rust increases , st that a complete combustion of present arsenic and sulfur takes place In the rust gas in the absence of the fires. Request publications: