NO883410L

NO883410L - SMOEREMIDDEL.

Info

Publication number: NO883410L
Application number: NO883410A
Authority: NO
Inventors: William Vilas Hanks; Charles Blighe Lindahl; Dayaldas Tanumai Jairam Meshri; James Ping King
Original assignee: Pennwalt Corp
Priority date: 1986-12-02
Filing date: 1988-08-01
Publication date: 1988-09-27
Also published as: NO883410D0

Description

Antimon-tio-antimonat, Sb(SbS4) er nyttig som et smøremiddel-additiv. Forbindelsen er i realiteten en "kompleks" for-bindelse i den betydning at hver av de to antimon-atomer trolig eksisterer i forskjellige valenstilstander, eksempelvis i +3 og +5 tilstandene. Antimony thioantimonate, Sb(SbS4) is useful as a lubricant additive. The compound is in reality a "complex" compound in the sense that each of the two antimony atoms probably exists in different valence states, for example in the +3 and +5 states.

Antimon-tio-antimonat (SbSbS4-produktet4) har vært fremstiltAntimony thio-antimonate (the SbSbS4 product4) has been prepared

å ved omsette antimon-oksyd (oppløst i konsentrert kalium-hydroksyd-oppløsning) med natrium-tio-antimonat (Na3SbS4) i et vandig medium etterfulgt av nøytalisering av den resulterende oppløsning med en syre, se eksempelvis J. P. King og Yayesh Asnerom, "Investigation of Extreme-Pressure and Antiwear Properties of Antimony Thioantimonat", ASLE Transaction, Vol. 24, 4, 497-504 (1981), og U.S. patent nr. 3.965.016. Den totale reaksjon kan skrives som følgende: by reacting antimony oxide (dissolved in concentrated potassium hydroxide solution) with sodium thio-antimonate (Na3SbS4) in an aqueous medium followed by neutralization of the resulting solution with an acid, see for example J.P. King and Yayesh Asnerom, "Investigation of Extreme-Pressure and Antiwear Properties of Antimony Thioantimonat", ASLE Transaction, Vol. 24, 4, 497-504 (1981), and U.S. patent No. 3,965,016. The total reaction can be written as follows:

Det er alvorlige begrensninger assossiert med den ovenfor viste reaksjon, eksempelvis (1) ko-utfelling av fritt svovel (6 %) med det endelige produkt og (2) generering av hydrogensulfid under nøytraliseringen. Etterfølgende studium har vist at en sidereaksjon finner sted samtidig med nøytraliserings-trinnet, som følger: There are serious limitations associated with the reaction shown above, for example (1) co-precipitation of free sulfur (6%) with the final product and (2) generation of hydrogen sulfide during the neutralization. Subsequent studies have shown that a side reaction takes place simultaneously with the neutralization step, as follows:

For store mengder (mere enn 1 %) fritt svovel i smøremiddel-additiver (slik som SbSbS4og andre) er meget uønsket på grunn av at fritt svovel fremmer korrosjon av kopperinneholdende metalldeler. Som følge av den ytterligere omkostning med hensyn til å fjerne fritt svovel fra det ferdige produkt og oppsamle H2S så er en forbedret og økonomiske fremstillings-prosess for fremstilling av SbSbS4meget ønskelig. Oppfinnelsen innbefatter en modifisert reaksjonsrute med enkle fremstillingsbetingelser for fremstilling av SbSbS4med et lavt svovel innhold. Med den nye fremgangsmåte kan fremstilles SbSbS4inneholdende fritt svovel i det mere aksepterbare nivå på under 1 % eller mindre. Ytterligere er generering av H2S og andre hydrolysespaltningsprodukter i det vesentlige eliminert. Ytterliger kan fremgangsmåten lett kontrolleres og kan drives som en kontinuerlig fremgangsmåte. Fremgangsmåten kan gjøres ennå mere økonomisk da den halogenid-stabiliserte antimon-tri-halogenid reaktanten kan fremstilles ved behandling av Sb203med konsentrert HCl og NaCl og deretter anvendes fortrinnsvis i form av NaSbCl4som en reaktant i form av en vandig oppløsning uten de alvorlige hydrolyse og spaltningsproblemer som vanligvis er assosiert med konvensjonelle antimon-trihalogenider. Excessive amounts (more than 1%) of free sulfur in lubricant additives (such as SbSbS4 and others) are highly undesirable because free sulfur promotes corrosion of copper-containing metal parts. As a result of the additional cost of removing free sulfur from the finished product and collecting H2S, an improved and economical production process for the production of SbSbS4 is highly desirable. The invention includes a modified reaction route with simple production conditions for the production of SbSbS4 with a low sulfur content. With the new method, SbSbS4 containing free sulfur can be produced at the more acceptable level of less than 1% or less. Furthermore, the generation of H2S and other hydrolysis cleavage products is essentially eliminated. Furthermore, the process can be easily controlled and can be operated as a continuous process. The process can be made even more economical as the halide-stabilized antimony trihalide reactant can be prepared by treating Sb2O3 with concentrated HCl and NaCl and then preferably used in the form of NaSbCl4 as a reactant in the form of an aqueous solution without the serious hydrolysis and decomposition problems that are usually associated with conventional antimony trihalides.

Oppfinnelsen innbefatter en ny fremgangsmåte ved fremstilling av antimon-tio-antimonat, SbSbS4ved kontinuerlig innmatning av to reaktanter til en reaktor og avtrekning av SbSbS4-produktet4derfra. Produktet blir deretter sentrifugert, vasket og tørket som en del av en kontinuerlig prosess. Anvendelse av ett vannoppløslig, halogenid-stabilisert antimon-tri-halogenidkompleks som en av utgangsmaterialene forbedrer prosessens økonomi betydelig og letter vesentlig den totale fremstillingsoperasjon, innbefattende høye utbytter og et lavt nivå av uønskede produkter som følge av spaltning og/eller sidereaksjoner. The invention includes a new method for the production of antimony thio-antimonate, SbSbS4 by continuously feeding two reactants into a reactor and withdrawing the SbSbS4 product from there. The product is then centrifuged, washed and dried as part of a continuous process. The use of a water-soluble, halide-stabilized antimony trihalide complex as one of the starting materials significantly improves the economics of the process and greatly facilitates the overall manufacturing operation, including high yields and a low level of undesired products resulting from cleavage and/or side reactions.

Foreliggende fremgangsmåte kan brett defineres som en fremgangsmåte ved fremstilling av et SbSbS4-produkt med et lavt innhold av forurensende fritt svovel hvilken fremgangsmåte omfatter å blande oppløsninger av ett alkalimetall-tio-antimonat og et halogenid-stabilisert antimon-tri-halogenid til å gi en reaksjonsblanding under bibeholdelse av en pH i reaksjonsblandingen på mindre enn 7, til å gi SbSbS4-produktet med et lavt innhold av forurensende fritt svovel. Fortrinnsvis er alkalimetall-tio-antimonatet natrium-tio-antimonat og tri-halogenid er antimon-tri-klorid og pH i reaksjonsblandingen holdes på mindre enn 7. The present process can be broadly defined as a process for producing a SbSbS4 product with a low content of contaminating free sulphur, which process comprises mixing solutions of an alkali metal thio-antimonate and a halide-stabilized antimony tri-halide to give a reaction mixture while maintaining a pH of the reaction mixture of less than 7, to give the SbSbS4 product with a low content of contaminating free sulfur. Preferably the alkali metal thioantimonate is sodium thioantimonate and the trihalide is antimony trichloride and the pH of the reaction mixture is maintained at less than 7.

Det er foretrukket at alkalimetall-tio-antimonat og tri-halogenid-oppløsningene blandes raskt og at tri-halogenid er tilstede i et molart overskudd for å tilveiebringe et lavt innhold forurensende fritt svovel. It is preferred that the alkali metal thio-antimonate and tri-halide solutions be mixed rapidly and that the tri-halide be present in a molar excess to provide a low contaminating free sulfur content.

Ved utøvelse av fremgangsmåten som en satsmetode blir alkalimetall-tio-antimonatet tilsatt under blanding til tri-halogenid-oppløsningen. Som en kontinuerlig fremgangsmåte blir alkalimetall-tio-antimonatet og tri-halogenid-oppløsningene kontinuerlig innmålt i en blandesone hvor fra SbSbS4-produktet utføres som en oppslemning. Den foretrukne reaksjon-stemperatur er mindre enn ca. 30°C. Det halogenid-stabiliserte antimon-tri-halogenid underkastes en blanding av Sb203og konsentrert HX for reaksjonsbetingelser og tilveiebringe en vandig oppløsning av det halogenid-stabiliserte antimon-tri-halogenid. Det er antatt at tri-halogenid-komplekset er HSbX4hvor X er halogen og fortrinnsvis er Cl. Det er deretter foretrukket å tilsette overskudd av NaCl og noe ytterligere Sb203til oppløsningen, slik som vist i eksemplene. HC1 tilsettes fortrinnsvis i et lite overskudd (6 mol HC1 per mol Sb203er sterkometrisk.) Tri-halogenider kan også fremstilles på tilsvarende måte fra Sb-metall istedenfor Sb203, hvilket tilfelle det også er foretrukket og anvende et oksydasjons-middel så som H202. When carrying out the method as a batch method, the alkali metal thio-antimonate is added with mixing to the trihalide solution. As a continuous process, the alkali metal thioantimonate and trihalide solutions are continuously metered into a mixing zone from which the SbSbS4 product is produced as a slurry. The preferred reaction temperature is less than approx. 30°C. The halide-stabilized antimony trihalide is subjected to a mixture of Sb 2 O 3 and concentrated HX for reaction conditions and to provide an aqueous solution of the halide-stabilized antimony trihalide. It is believed that the tri-halide complex is HSbX 4 where X is halogen and preferably is Cl. It is then preferred to add excess NaCl and some additional Sb 2 O 3 to the solution, as shown in the examples. HC1 is preferably added in a small excess (6 mol of HC1 per mol of Sb203 is stochometric.) Tri-halides can also be prepared in a similar way from Sb metal instead of Sb203, in which case it is also preferred to use an oxidizing agent such as H202.

SbSbS4-produktet separeres fra reaksjonsblandingen og vaskes deretter for å nedsette kloridinnholdet i produktet til mindre enn 300 ppm. Ved den kontinuerlige fremstillingsmetode ved utførelse av foreliggende oppfinnelse er definert som fremgangsmåte ved fremstilling av SbSbS4-produkt med et lavt nivå av forurensende fritt svovel, og omfatter: (a) i kontrollerte hastigheter separate strømmer av vandige oppløsninger av et alkalimetall tio-antimonat og en vandig oppløsning av halogenid-stabilisert antimon-tri-halogenid til en blandesone til å gi en reaksjonsblanding, (b) bibeholde pH ved mindre enn 7 inne i reaksjonsblandingen, og deretter The SbSbS4 product is separated from the reaction mixture and then washed to reduce the chloride content of the product to less than 300 ppm. By the continuous production method in carrying out the present invention is defined as a process for the production of SbSbS4 product with a low level of contaminating free sulphur, and comprises: (a) at controlled rates, separate streams of aqueous solutions of an alkali metal thio-antimonate and a aqueous solution of halide-stabilized antimony trihalide to a mixing zone to provide a reaction mixture, (b) maintaining the pH at less than 7 within the reaction mixture, and then

(c) trekke av SbSbS4fra blandesonen.(c) subtracting SbSbS4 from the mixing zone.

Den mest foretrukne pH for reaksjonsblandingen er mindre enn 5. Ved den kontinuerlige fremgangsmåte blir pH bibeholdt ved å regulere forholdet mellom innmatningshastighetene av de separate strømninger. Anvendelse av NaSbCl4komplekset er også foretrukket. The most preferred pH for the reaction mixture is less than 5. In the continuous process, the pH is maintained by regulating the ratio between the feed rates of the separate streams. Use of the NaSbCl4 complex is also preferred.

SbSbS4-produktet vaskes for å nedsette kloridinnholdet i produktet til mindre enn 300 ppm basert på vekten av produktet . The SbSbS4 product is washed to reduce the chloride content of the product to less than 300 ppm based on the weight of the product.

Ved den kontinuerlig metode er foretrukket å avtrekke produktet og gjenværende reaksjonsblanding som må overføres til mottakningskaret under kontinuerlig omrøring. Produktet er erholdt i henhold til oppfinnelsen kan beskrives som SbSbS4-produktet erholdt ved de ovenfor nevnte fremgangsmåter, eller alternativt som en blanding bestående av SbSbS4og et halogenid-stabilisert antimon-tri-halogenid (fortrinsvis SBCI3i en konsentrasjon på mindre enn 3 00 ppm). With the continuous method, it is preferred to draw off the product and remaining reaction mixture, which must be transferred to the receiving vessel under continuous stirring. The product obtained according to the invention can be described as the SbSbS4 product obtained by the above-mentioned methods, or alternatively as a mixture consisting of SbSbS4 and a halide-stabilized antimony trihalide (preferably SBCI3 in a concentration of less than 300 ppm).

Den foretrukne utførelsesform innbefatter en proposjonal blanding av 2 vandige oppløsninger av råmaterialene (Na3SbS4og SbCl3kompleks) igjennom målepumper av rørtypen inn i en sentrifugalblandepumpe som utfører SbSbS4-oppslemning til en holdetank (fortrinnsvis ett omrørt mottakende par). Det proposjonale forhold mellom de to råmaterialer blir først etablert ved titrering og målepumpene innstilt i henhold til dette. Den ønskelige pH av reaksjonsblandingen er 3 og kontrolleres ved å variere forholdet mellom innmatningshastighetene av reaktantene. SbSbS4-oppslemning pumpes fra holdetanken til en annen mattank anordnet direkte over en 60 cm senterslyngesentrifuge. Materialet falltilføres til sentri-fugen inntil en passende kake er dannet. Kaken skjæres ut og transporteres ved hjelp av en beltemater til en rørekjele for vasking for å nedsette kloridnivået til akseptable grenser, eksempelvis mindre enn 30ppm. The preferred embodiment involves a proportional mixing of 2 aqueous solutions of the raw materials (Na3SbS4 and SbCl3 complex) through tube-type metering pumps into a centrifugal mixing pump which performs SbSbS4 slurrying to a holding tank (preferably one stirred receiving pair). The proportional relationship between the two raw materials is first established by titration and the metering pumps are adjusted accordingly. The desired pH of the reaction mixture is 3 and is controlled by varying the ratio between the feed rates of the reactants. SbSbS4 slurry is pumped from the holding tank to another feed tank arranged directly above a 60 cm center scroll centrifuge. The material is dropped into the centri-joint until a suitable cake is formed. The cake is cut out and transported by means of a belt feeder to a stirrer for washing to reduce the chloride level to acceptable limits, for example less than 30ppm.

Oppfinnelsen tilveiebringer mange fordeler fremfor de eksisterende metoder, innbefattende: (a) anvendelse av et mindre kostbart og mere stabilt utgangsmateriale (et halogenid-stabilisert antimon-tri-halogenidkompleks), (b) eliminering eller drastisk nedsettelse av både fritt svovel og hydrogensulfid biprodukter, (c) kontinuerlig fremstilling, (d) dannelse av lett fjernbare biprodukter og (e) høye utbytter. The invention provides many advantages over existing methods, including: (a) use of a less expensive and more stable starting material (a halide-stabilized antimony trihalide complex), (b) elimination or drastic reduction of both free sulfur and hydrogen sulfide byproducts, (c) continuous production, (d) formation of easily removable by-products and (e) high yields.

Oppfinnelsen innbefatter omvendelse av en vandig oppløsning av et halogenid-stabilisert antimon-tri-klorid-kompleks dannet ved omsetning av Sb203med konsentrert saltsyre og NaCl (overskudd) . Dette kompleks er stabilt i det lave pH området og utviser god holdbarhet. Formelen for ioner i dette kompleks er antatt å være (SbCl4)~ og komplekset er fortrinnsvis NaSbCl4. The invention involves the conversion of an aqueous solution of a halide-stabilized antimony trichloride complex formed by reacting Sb 2 O 3 with concentrated hydrochloric acid and NaCl (excess). This complex is stable in the low pH range and exhibits good durability. The formula for ions in this complex is assumed to be (SbCl4)~ and the complex is preferably NaSbCl4.

Det er antatt at de mest kritiske særtrekk ved oppfinnelsen er: (i) bibeholdelse av pH i reaksjonsmediet ved pH mindre enn 7 og (ii) anvendelse av det halogenid-stabiliserte antimon-tio-antimonat . It is believed that the most critical features of the invention are: (i) maintenance of pH in the reaction medium at pH less than 7 and (ii) use of the halide-stabilized antimony thioantimonate.

Det er antatt at den raske blanding av reaktantene fremmer bibeholdelse av pH under 7 innen alle områder av blandesonen til alle tider (HSbCl4og NaSbCl4oppløsning er meget sur, mens Na3SbS4er meget basisk med en pH som typisk er over 11). It is believed that the rapid mixing of the reactants promotes the maintenance of pH below 7 within all areas of the mixing zone at all times (HSbCl4 and NaSbCl4 solution is very acidic, while Na3SbS4 is very basic with a pH typically above 11).

Det er også ønskelig å anvende et molart overskudd av tri-halogenid-komplekset typisk 2-20 % overskudd (fortrinnsvis 2-10 %) . It is also desirable to use a molar excess of the trihalide complex, typically 2-20% excess (preferably 2-10%).

Eksempel 1-10Example 1-10

Eksemplene 1-10 (vist i tabell I) viser visse reaksjonspara-metere for prosessen som påvirker totalutbyttet, innehold av fritt svovel, hydrogensulfidfrigjøring og kloridinnhold. Reaksjonssekvensen, utgangsmaterialet og biprodukter dannet ved foreliggende fremgangsmåter er vist i de følgende trinn: Examples 1-10 (shown in Table I) show certain reaction parameters for the process which affect the total yield, free sulfur content, hydrogen sulphide release and chloride content. The reaction sequence, the starting material and by-products formed by the present methods are shown in the following steps:

Resultatene ifølge eksemplene 1 - 10 er vist i tabell I. The results according to Examples 1 - 10 are shown in Table I.

Fremstillingen av Na3SbS4(reaksjon I) er beskrevet i U.S. patent nr. 3.965.016. The preparation of Na3SbS4 (reaction I) is described in U.S. Pat. patent No. 3,965,016.

Fremstilling av HSbCl4(reaksjon II) utføres under omrøring og oppvarmning av 70 - 75°C av en blanding av hvit Sb2C>3 og 37 - 99% HC1 til å gi en klar oppløsning. Detaljer ved fremstilling av sluttproduktet (reaksjon III), nemlig SbSbS4, innbefatter reaksjonstempeatur, tilsetningstid, omrøringshastighet, etc. er vist i tabell I. Reaksjon III kan tilveiebringe kloridion-ene (resirkulert) nødvendig i reaksjon II. Sluttproduktet vaskes enten med destilert vann eller 1 %ig NaHC03eller begge deler. Preparation of HSbCl4 (reaction II) is carried out with stirring and heating to 70 - 75°C of a mixture of white Sb2C>3 and 37 - 99% HCl to give a clear solution. Details of preparation of the final product (reaction III), namely SbSbS4, including reaction temperature, addition time, stirring rate, etc. are shown in Table I. Reaction III can provide the chloride ions (recycled) needed in reaction II. The end product is washed either with distilled water or 1% NaHCO3 or both.

Molprosentverdiene (H2S/ SbSbS4) som er et mål på frigitt H2S erholdt ved å felle H2S med blyacetat. Dette ble oppnådd ved å føre avløpsgasser fra SbSbS4igjennom en Pb(0AC)2oppløsning. Utviklet H2S felles ut som PbS som blir oppsamlet, tørket og veiet. Fra vekten av PbS og de aktuelle utbytter av SbSbS4ble molprosenten av H2S over SbSbS4beregnet (eksempelvis (mol H2S / mol SbSbS4) X 100). The mole percentage values (H2S/ SbSbS4) which are a measure of released H2S obtained by precipitating H2S with lead acetate. This was achieved by passing waste gases from SbSbS4 through a Pb(0AC)2 solution. Developed H2S is precipitated as PbS which is collected, dried and weighed. From the weight of PbS and the relevant yields of SbSbS4, the mole percentage of H2S over SbSbS4 was calculated (for example (mol H2S / mol SbSbS4) X 100).

Eksempel 11Example 11

Dette eksempel viser kontinuerlige fremstillingsbetingelser This example shows continuous manufacturing conditions

for storskalafremstilling av SbSbS4.for large-scale production of SbSbS4.

Fremstilling av natrium- tio- antimonat oppløsning ( reaksjon I). Preparation of sodium thioantimonate solution (reaction I).

I en typisk reaksjon for fremstilling av en Na3SbS4ble anvendt en 795 1 reaktor foret med "Kynar" (polyvinyliden fluorid film). Reaktoren ble først fylt med en 530 1 varmt vann (82°C), etterfulgt av 72,6 kg natriumsulfid (Na2S'3H20), 62.1 kg antimon-sulfid (Sb2Sb3) og 11,3 kg svovelpulver. Denne blandingen ble oppvarmet til 93°C og holdt ved denne temperatur i 4 timer. Deretter ble 227 1 kaldt vann tilsatt for å forhindre utkrystallisering av Na3SbS4og oppløsningen ble avkjølt med saltlake til 0"C. Hele innholdet ble deretter filtrert igjenom en filterpose (5/6m porestørrelse) inn i et lagringskar. In a typical reaction for producing a Na3SbS4, a 795 1 reactor lined with "Kynar" (polyvinylidene fluoride film) was used. The reactor was first filled with 530 L of hot water (82°C), followed by 72.6 kg of sodium sulphide (Na 2 S 3 H 2 O), 62.1 kg of antimony sulphide (Sb 2 Sb 3 ) and 11.3 kg of sulfur powder. This mixture was heated to 93°C and held at this temperature for 4 hours. Then 227 L of cold water was added to prevent crystallization of Na3SbS4 and the solution was cooled with brine to 0"C. The entire contents were then filtered again through a filter bag (5/6m pore size) into a storage vessel.

I henhold til et annet eksempel ble materialet filtrert igjennom et karbonfilter. According to another example, the material was filtered through a carbon filter.

I et annet eksempel fikk oppløsningen henstå og den klare oppløsning ble dekantert. In another example, the solution was allowed to stand and the clear solution was decanted.

Fremstilling av halogenidstabilisert antimon- klorid- oppløsning ( reaksjon II) . 1 en typisk reaksjon for fremstilling av halogenidstabilisert SbCl3oppløsning ble en omrørt "Hastalloy C" kjele anvendt. 2 61 1 (147 kg) 2 0° Baume saltsyre ble tilsatt til reaktoren etterfulgt av 3 0,8 g antimon-oksyd SB203. Blandingen ble omrørt inntil en oppløsning ble erholdt. Deretter ble tilsatt 32.2 kg natriumklorid. Deretter ble ytterligere 3 0,8 kg antimonoksyd tilsatt langsomt under kontinuerlig omrøring. Oppløsningen ble deretter filtrert igjennom et karbonfilter til en lagerbeholder. Preparation of halide stabilized antimony chloride solution (reaction II). In a typical reaction for the preparation of halide-stabilized SbCl3 solution, a stirred "Hastalloy C" boiler was used. 2 61 1 (147 kg) of 20° Baume hydrochloric acid was added to the reactor followed by 3 0.8 g of antimony oxide SB203. The mixture was stirred until a solution was obtained. 32.2 kg of sodium chloride were then added. Then a further 30.8 kg of antimony oxide was added slowly with continuous stirring. The solution was then filtered through a carbon filter into a storage container.

Den balanserte ligning for denne reaksjon er antatt å være: Sb203+ 6HC1 + 2NaCl>2NaSbCl4+ 3H20 med overskudd av NaCl. The balanced equation for this reaction is assumed to be: Sb203+ 6HC1 + 2NaCl>2NaSbCl4+ 3H20 with an excess of NaCl.

Således er 6 mol HCl krevet for hver mol Sb203og NaCl er tilstede i overskudd. Thus, 6 moles of HCl are required for each mole of Sb2O3 and NaCl is present in excess.

Sb203tilsettes i to deler for å fremme oppløslighet av Sb203. Prosessen kunne utføres med en en-trinnstilsetning av Sb203etter en forutgående tilsetning av NaCl. Sb203 is added in two parts to promote solubility of Sb203. The process could be carried out with a one-step addition of Sb2O3 after a prior addition of NaCl.

Fremstilling av natrium- klorid- oppløsning.Preparation of sodium chloride solution.

416 1 vann ble tilsatt til en omrørt reaktor etterfulgt av 118 kg natrium-klorid og omrørt inntil saltet var oppløst. 416 1 of water was added to a stirred reactor followed by 118 kg of sodium chloride and stirred until the salt was dissolved.

Fremstilling av antimon- tio- antimonat.Preparation of antimony antimonate.

De tre tidligere fremstilte oppløsninger (Na3SbS4, SbCl3, NaCl) ble innført ved hjelp av "Randolph" rør (slange) pumper for innmatning til reaktoren ("Kenic" blander). Produktet ble pumpet ut av "Kenic" blander inn i en omrørt mottaker. I laboratoriet ble prøver av Na3Sb4og SbCl3kompleks opp-løsningene først omsatt for å gi et tilnærmet forhold mellom volumene for å oppnå den ønskede pH på 3 + 2 reaktoren. Denne informasjon ble anvendt for å innstille de initiale inn-matningshatigheter for pumpene for SbCl3og Na3SbS4opp-løsningene. SbSbS4-produktoppslemningen ble sentrifugert og vasket for å fjerne HCl og natrium-klorid. Produktet ble deretter tørket og avstøvet. The three previously prepared solutions (Na3SbS4, SbCl3, NaCl) were introduced by means of "Randolph" tube (hose) pumps for feed to the reactor ("Kenic" mixer). The product was pumped out of the "Kenic" mixer into an agitated receiver. In the laboratory, samples of the Na3Sb4 and SbCl3 complex solutions were first reacted to give an approximate ratio between the volumes to achieve the desired pH in the 3 + 2 reactor. This information was used to set the initial feed rates for the pumps for the SbCl3 and Na3SbS4 solutions. The SbSbS4 product slurry was centrifuged and washed to remove HCl and sodium chloride. The product was then dried and dusted.

Natriumkloridoppløsningen ble innmatet i det omrørte SbSbS4mottakerkar (mottatte produkt fra "Kenix" blander) inntil oppløsningen dekket blanderbladene. Pumpene for halogenid-stabilisert SbCl3og Na3SbS4oppløsningene ble oppstartet for å påbegynne fremstillingen. PH av produktutløpet til mot-takerkaret ble overvåket. Hvis pH falt utenfor området 2-4 ble målepumpene justert. The sodium chloride solution was fed into the stirred SbSbS4 receiver vessel (received product from "Kenix" mixer) until the solution covered the mixer blades. The pumps for the halide-stabilized SbCl3 and Na3SbS4 solutions were started to begin production. The pH of the product outlet to the receiving vessel was monitored. If the pH fell outside the range 2-4, the measuring pumps were adjusted.

Claims

1. Process for the production of SbSbS4 product with a low content of contaminating free sulfur, characterized by mixing aqueous solutions of an alkali metal thio-antimonate and a halide-stabilized antimony tri-halide to give a reaction mixture, which is retained at a pH less than 7 to give the SbSbS4 product with a low level of contaminating free sulphur.

2. Process according to claim 1, characterized in that the alkali metal thioantimonate is sodium thioantimonate and the trihalide is antimony trichloride.

3. Method according to claim 1, characterized in that the pH is less than 4.

4. Process according to 1, 2 or 3, characterized in that the alkali metal thioantimonate and the trihalide solutions are mixed quickly.

5. Method according to claim 4, characterized in that tri-halides are present in one molar excess to give a low content of polluting free sulphur.

6. Method according to claim 4, characterized in that the preparation takes place in batches and that the alkali metal thio-antimonate is added while stirring to the trihalide solution.

7. Method according to claim 4, characterized in that during continuous production, the alkali metal thioantimonate and the trihalide solution are continuously metered into a mixing zone from which the SbSbS4 products are produced as a slurry.

8. Method according to claim 4, characterized in that the reaction mixture is kept at a temperature which is less than approx. 30°C.

9. Method according to claim 4, characterized in that the halide-stabilized antimony trihalide is prepared by subjecting a mixture comprising Sb2 03 and concentrated HCl to reaction conditions to give an aqueous solution of halide-stabilized antimony trihalides.

10. Method according to claim 9, characterized in that the mixture includes an excess of NaCl to give NaSbCl4.

11. Method according to claim 9, characterized in that the mixture includes antimony metal.

12. Method according to claim 11, characterized in that the mixture includes an excess of NaCl to give NaSbCl4.

13. Method as defined in claim 4, characterized in that the halide-stabilized antimony trihalide is formed by subjecting a mixture including antimony metal and concentrated HCl to reaction conditions to give an aqueous solution of the halide-stabilized antimony trihalide -halide.

14. Method according to claim 13, characterized in that the mixture includes NaCl.

15. Method according to claim 1, 2 or 5, characterized in that the trihalide complex includes the (SbCl4 )~ ion.

16. Method according to claim 15, characterized in that the trihalide complex is selected from the group essentially consisting of HSbCl4, NaSbCl4, HSbCl4 hydrates, NaSbCl4 hydrates and mixtures thereof.

17. Method according to claim 15, characterized in that the alkali metal thio-antimonate and tri-halide solutions are mixed quickly.

18. Method according to claim 15, characterized in that tri-halides are present in molar excess to give a low content of polluting free sulphur.

19. Method according to claim 15, characterized in that, in a batch method, the alkali metal thio-antimonate is added while mixing to the trihalide solution.

20. Method according to claim 15, characterized in that during continuous production, the alkali metal thio-antimonate and tri-halide solutions are continuously metered into a mixing zone from which the SbSbS4 product is produced as a slurry.

21. Method according to claim 15, characterized in that the mixture is maintained at a temperature less than approx. 30°C.

22. Method according to claim 4, characterized in that the SbSbS4 product is separated from the reaction mixture and washed to reduce the chlorine content in the product to less than 300 ppm.

23. The SbSbS4 product produced by the method according to claim 4.

24. Procedure for the production of SbSbS4 product with a low level of polluting free sulphur, characterized by (a) metering controlled amounts of separate streams of aqueous solutions of an alkali metal thio-antimonate and a halide-stabilized tri-halide into a mixing zone to provide a reaction zone; (b) maintaining a pH of less than 7 in the reaction mixture, and then (c) extracting the SbSbS4 product from the mixing zone.

25. Method according to claim 24, characterized in that the alkali metal thioantimonate is sodium thioantimonate and trihalides are antimony trichloride.

26. Method according to claim 25, characterized in that the pH is less than 4.

27. Method according to claims 24, 25 or 26, characterized in that the alkali metal thioantimonate and the trihalide solutions are mixed rapidly.

28. Method according to claim 27, characterized in that the pH of the reaction mixture is maintained by regulating the ratios between the input amounts of the separate streams.

29. Method according to claim 27, characterized in that the method is a continuous method.

30. Method according to claim 27, characterized in that reaction mixtures are maintained at a temperature less than approx. 30°C.

31. Method according to claim 27, characterized in that the halide-stabilized antimony trihalide is the reaction product of a mixture including Sb 2 0 3 and concentrated HCl.

32. Method according to claim 31, characterized in that the mixture includes NaCl.

33. Method according to claim 31, characterized in that the mixture includes antimony metal.

34. Method according to claim 33, characterized in that the mixture includes NaCl.

35. Method according to claim 27, characterized in that the halide-stabilized antimony trihalide is the reaction product of reactants that include antimony metal and concentrated HCl.

36. Method according to claim 35, characterized in that the mixture includes an excess of NaCl.

37. Method according to claims 24, 25, 26, 28, 29 or 31, characterized in that trihalides are a complex which includes the (SbCl4 )~ ion.

38. Method according to claim 37, characterized in that the trihalide complex is selected from the group consisting mainly of HSbCl4, NaSbCl4, NaSbCl4 hydrates, NaSbCl4 hydrates and mixtures thereof.

39. Method according to claim 27, characterized in that the extracted SbSbS4 product is washed to reduce the chloride content in the product to less than 300 ppm, calculated on the weight of the product.

40. Method according to claim 27, characterized in that the extracted product and remaining reaction mixture are transferred with continuous stirring to a receiving vessel containing aqueous NaCl.

41. Mixture comprising SbSbS4 and a halide-stabilized antimony trihalide.

42. Mixture according to claim 41, characterized in that the halide-stabilized antimony trihalide is present in an amount in the range 1-300 ppm, calculated on the weight of SbSbS4.

43. The mixture according to claim 41 or 42, characterized in that antimony trihalides are antimony trichloride.

44. Mixture according to claim 41 or 42, characterized in that trihalides are a complex which includes the (SbCl4 )~ ion.