Tsarin Haɓakar Sharar Ruwa na Cyanide Zinare Tsari

A halin yanzu, da cyanide Hanyar hakar zinari na ɗaya daga cikin manyan hanyoyin da suka balaga don narkewar zinare a China. Yana amfani da maganin cyanide don cire zinari daga ma'adinai, yana nuna ƙimar farfadowa mai yawa, ƙarfin daidaitawa ga kaddarorin tama, da ikon samar da zinari a kan shafin. Tun lokacin da aka fara amfani da maganin cyanide don leach zinariya daga ores a cikin 1887. An yi amfani da wannan hanyar har zuwa yanzu. Duk da haka, hakar gwal na cyanide yana haifar da adadi mai yawa na abubuwa masu guba da cutarwa, yana haifar da babbar barazana ga yanayin da ke kewaye da mutane. Don haka, don rage cutarwa, ya zama dole a yi nazarin hanyoyin magance ruwan sharar zinare na cyanide. Yawancin masu bincike sun taƙaita hanyoyin jiyya, ka'idodin sinadarai, da ci gaban ci gaban cyanide - wanda ke ɗauke da ruwan sha, amma yawancinsu sun tattauna hanya ɗaya ko biyu kawai. Sabili da haka, wannan labarin yana gudanar da cikakken nazarin hanyoyin magani daban-daban don hakar gwal na cyanide a halin yanzu ana amfani da shi a cikin masana'antu, yana kwatanta fa'idodi, rashin amfani, da yanayin aikace-aikacen kowane hanya, wanda ke da takamaiman mahimmancin jagora ga aikace-aikace iri ɗaya a cikin ainihin samarwa.

I. Tufafi da Hatsari na Ruwan Cire Zinare na Cyanide

Babban ka'idar hakar gwal na cyanide shine cewa a cikin yanayin aerobic. sodium cyanide yana yin aiki da zinare don samar da hadaddun zinare, wanda daga baya ake narkar da shi. Bayan haka, ana iya fitar da zinare ta hanyar haɓaka ta hanyar kunnawa. Carbon sha ko kuma maye gurbinsa da foda zinc daga cyanide na zinariya. A lokaci guda, sauran ƙarfe masu nauyi kamar azurfa, jan ƙarfe, da zinc suma suna samar da hadaddun abubuwa kuma suna narkewa.

The cyanides da aka yi amfani da su a cikin martani da kuma hadaddun da aka samar duk abubuwa ne masu guba da cutarwa. Sodium cyanide yana da sauƙi don yin ruwa kuma abu ne na Class 1 mai guba sosai, tare da kashi mai mutuwa na 0.10g. Yaushe Cyanides zub da jini a cikin ruwa, yana da matukar illa ga halittun da ke cikin ruwa, kuma zai haifar da babbar barazana ga mutane da muhallin da ke kewaye. Don haka, kula da sharar ruwan zinare na cyanide yana da matukar muhimmanci.

II. Babban Hanyoyin Magani don Ruwan Ruwan Zinare na Cyanide

Hanyar chlorination na alkaline

Hanyar chlorination na alkaline a halin yanzu tana ɗaya daga cikin hanyoyin da aka fi amfani da su don magance cyanide - mai ɗauke da ruwan datti daga hakar gwal na cyanide. Yafi amfani da chlorine-based oxidants don oxidize da cyanides a cikin ruwan datti a karkashin yanayin alkaline, yana mai da su abubuwa marasa guba. Cyanide - karya tsari na alkaline chlorination ya kasu kashi biyu matakai:

Mataki na farko shine oxidize cyanide zuwa cyanate, wanda ake kira "incomplete oxidation" mataki. CN⁻ yana amsawa tare da OCl⁻ don fara samar da CNCl, sannan yana yin ruwa zuwa CNO⁻. Ya kamata a lura cewa CNCl yana da matukar damuwa kuma yana da guba a ƙarƙashin yanayin acidic. Sabili da haka, yayin aiki, ƙimar pH dole ne a sarrafa shi sosai don kasancewa cikin yanayin alkaline.

Mataki na biyu shine ƙara oxidize cyanate zuwa carbon dioxide da nitrogen, wanda ake kira "cikakken oxidation" mataki. A lokacin cyanide - karya tsari, ƙimar pH yana da tasiri mai girma akan halayen oxidation. Ya kamata a sarrafa darajar pH na farko - oxidation mataki a 10 - 11. kuma lokacin amsawa shine 10 - 15 mintuna. Ya kamata a sarrafa darajar pH na kashi na biyu - oxidation mataki a 6.5 - 7.0. kuma lokacin amsawa shine 10 - 15 mintuna.

Wani ma'adanin yana amfani da hanyar chlorination na alkaline don kula da ma'auni na cyanide wutsiya slurry (tare da abun ciki na cyanide na 200mg/L) da ruwan da aka zubar daga tanki mai lalata (tare da abun ciki na cyanide na 5mg/L). Ana sarrafa ƙimar pH a 10 - 11. kuma ana ƙara bleaching foda a cikin rabo na 35 - 40 sau da abun ciki na cyanide don haɗuwa da motsawa. Bayan sedimentation a cikin thickener, jimlar abun ciki na cyanide za a iya rage zuwa 0.1mg/L.

Hanyar chlorination na alkaline ita ce hanyar da aka fi amfani da ita don magance cyanide - mai ɗauke da ruwa mai datti, kuma bleaching foda shine mafi yawan amfani da chlorine-based oxidant. Wannan hanya ta dace don magance ruwan sharar ruwan zinare na cyanide tare da babban ko ƙarancin ƙima. Yana kuma iya cire thiocyanate da cyanide - dauke da hadaddun (sai dai ferrocyanide complexes). Maganin yana samuwa a ko'ina, ragowar sharar da aka samar yana da sauƙi don tacewa, kuma aikin yana da sauƙi. Koyaya, yanayin aiki yana da ɗan tsauri yayin amfani da foda mai bleaching don kula da ruwan datti. Yanzu wasu kamfanoni suna amfani da ruwa mai bleaching ko chlorine dioxide maimakon, wanda ke inganta yanayin aiki zuwa wani matsayi. Amma ana haifar da iskar gas mai guba yayin aiwatar da aikin, kuma yana da ƙarancin lalata kayan aiki. Farashin magani da farashin kulawa suna da girma.

Hanyar Haɗin Gishiri

Hanyar hada gishirin tafsiri hanya ce ta magani don fitar da ruwan sharar zinare na cyanide wanda ya bayyana a cikin 'yan shekarun nan. Ta hanyar sarrafa ƙimar pH a 7 - 8. ions ferrous suna amsawa tare da cyanide kyauta da wasu rukunin cyanide a cikin ruwan sharar ruwan cyanide na hakar gwal don samar da hazo.

Gwaje-gwaje sun nuna cewa gabaɗaya, ƙara ferrous sulfate kawai don magance sharar ruwan zinare na cyanide ba zai iya sa ruwan dattin ya dace da matsayin fitarwa ba. Sabili da haka, ana buƙatar ƙara yawan oxidant a cikin ruwa mai tsabta don zurfin cirewar cyanide. Muddin yanayin yana da inganci, ana iya ƙara oxidant kai tsaye don magani ba tare da raba hazo ba, kuma ana iya cimma daidaitattun fitarwa. Wannan yana da ma'ana mai kyau idan aka kwatanta da hanyar gargajiya na rabuwa da farko sannan kuma magani.

Wani smelter na zinariya yana amfani da hanyar sodium sulfide - ferrous sulfate don magance cyanide - ruwa mara kyau. Tasiri yana da abun ciki na cyanide na 2500mg/l. Bayan jiyya, datti yana da abun ciki na cyanide kasa da 20mg/L, tare da adadin cirewa na 99.2%, yana nuna sakamako mai ban mamaki. Magani mai zurfi na gaba yana amfani da sodium metabisulfite - hanyar iska don rage jimlar cyanide zuwa ƙasa da 0.4mg/L.

Hanyar hadadden gishirin tafe wata sabuwar hanyar jiyya ce da ta kunno kai, akasari ana amfani da ita don magance babban - maida hankali cyanide - dauke da ruwan sha. Tsarinsa yana da sauƙi, ɗayan-lokacin saka hannun jari kaɗan ne, yana da sauƙin aiki, maganin (yafi ferrous sulfate) yana da yawa, mara tsada, kuma mai sauƙin amfani. Duk da haka, saboda maganin sulfate na ferrous yana da acidic, lokacin da aka haɗe shi da ruwa mai cirewa na cyanide zinariya, yankin ya zama acidic, kuma akwai yiwuwar samar da iskar hydrogen cyanide. Bugu da ƙari, ba zai iya cire thiocyanate ba, kuma ruwan da aka yi da shi har yanzu yana buƙatar magani mai zurfi don saduwa da matakan fitarwa.

Sodium Metabisulfite - Hanyar iska

Sodium metabisulfite - hanyar iska an haɓaka ta daga sulfur dioxide - hanyar iska. Yafi amfani da tasirin synergistic na sodium metabisulfite da iska akan cyanides a cikin ruwan sharar gida a cikin wani yanki na pH, tare da tasirin tasirin jan ƙarfe, don oxidize CN⁻ zuwa CNO⁻.

Idan abun ciki na cyanide a cikin cyanide - wanda ke dauke da ruwa mai tsabta yana da girma, za a iya fara yin magani kafin a rage yawan ƙwayar cyanide zuwa kasa da 100mg/L. Sa'an nan, ana ƙara sodium metabisulfite da jan karfe sulfate, an shigar da isasshiyar iska, kuma ana sarrafa darajar pH (gaba ɗaya ana sarrafa shi a 7 - 8), don haka an sanya cyanide oxidized zuwa cyanate, wanda aka sanya shi hydrolyzed ya zama bicarbonate ions da ammonia.

Sodium metabisulfite - Hanyar iska ta dace don magance ƙananan ƙwayar cyanide zinare na hakar ruwan sharar gida. Matsakaicin maganin yana da ƙananan, ƙarfin aiki yana da ƙasa, amma zuba jari na gaba yana da girma, kuma kayan aiki irin su masu busawa yana buƙatar ƙarawa. Abubuwan buƙatun don alamun tsari suna da ɗan tsauri, kuma sarrafa ƙimar pH yana da mahimmanci. Copper sulfate kuma yana buƙatar ƙarawa azaman mai kara kuzari. Lokacin amsawa yana da tsawo. Idan maganin bai dace ba, za a samar da ions ammonium mai yawa, kuma slag da aka samar ba shi da sauƙi don tacewa. Akwai ƙaramin adadin iskar ammonia da aka samar akan rukunin yanar gizon, kuma ba shi da wani tasiri wajen cire thiocyanides.

Hanyar Oxidation Hydrogen Peroxide

Hanyar iskar oxygen ta hydrogen peroxide ita ce oxidize cyanides zuwa CNO⁻ a ƙarƙashin yanayin zafi na al'ada, yanayin alkaline (pH = 10 - 11), tare da Cu²⁺ azaman mai haɓakawa, sa'an nan kuma sanya su cikin abubuwan da ba masu guba ba. Complex cyanides (rikitattun Cu, Zn, Pb, Ni, Cd) suma sun rabu saboda lalatar cyanide a cikinsu. Ferrocyanide ions da sauran ions karfe masu nauyi suna samar da hadadden gishiri na ferrocyanide kuma ana cire su. A ƙarshe, jimlar cyanide a cikin ruwan da aka kula da shi za a iya ragewa zuwa ƙasa da 0.5mg/L.

Wannan hanya ta dace don magance ƙananan - maida hankali cyanide - dauke da ruwa mai tsabta. Kayan aikin maganin hydrogen peroxide yana da sauƙi kuma mai sauƙi don cimma iko ta atomatik. Koyaya, cyanate da aka samar yana buƙatar zama na ɗan lokaci don bazuwa zuwa CO₂ da NH₃. Rashin hasara shi ne cewa yin amfani da jan ƙarfe a matsayin mai haɓakawa na iya haifar da jan ƙarfe a cikin ruwan da aka fitar ya wuce misali, farashin albarkatun kasa yana da yawa, thiocyanides ba za a iya oxidized ba, kuma ana samar da ions ammonium. A gaskiya ma, ruwan sharar gida yana da wani guba. Haka kuma, tun da hydrogen peroxide iskar oxygen ne, yana da babban lalata, kuma akwai wasu matsaloli da haɗari a cikin sufuri da amfani.

Hanyar Acidification

Lokacin amfani da hanyar acidification don bi da cyanide - ruwa mara kyau, tsarin amsawa yana da rikitarwa, galibi ya haɗa da matakai guda uku: tsarin acidification na cyanide - wanda ya ƙunshi ruwa mai datti, tsarin tsiri da ɗaukar iskar gas na HCN, da tsarin neutralization na tsiri ruwa.

(1) Acidification dauki: The cyanide - matalauta ruwa ne acidified da kuma tsarkake da acid. Cyanide mai rikitarwa a cikin ruwa mara kyau zai haifar da hazo maras narkewa kamar CuCN, CuSCN, da Zn₂ Fe (CN)₆ kuma a cire su, kuma a lokaci guda, ana samar da hydrogen cyanide.

(2) Volatilization da ɗaukar halayen: Rashin ruwa mara kyau shine pre-mai tsanani zuwa kusan 30 ℃ kafin acidification. Tun da tafasar batu na HCN ne kawai 26.5 ℃, shi ne musamman maras tabbas. Sabili da haka, ana amfani da hasumiya mai cike da kayan aiki a matsayin taro - kayan aiki na canja wuri don hulɗar tsakanin gas - ruwa biyu - lokaci a cikin hanyar acidification, wanda yake da sauƙi don cimma raguwa da sha na HCN.

(3) Halin tsaka-tsaki: Ana amfani da lemun tsami ko alkali ruwa don kawar da ruwa mai tsiro. Ragowar kwayoyin HCN a cikin maganin za a canza su zuwa sigar CN⁻. Hanyar acidification na iya dawowa sodium Cyanide daga cyanide - dauke da sharar gida da kuma gane albarkatun dawo da. Koyaya, yana da manyan buƙatu don hatimin kayan aiki, babban saka hannun jari na gaba, yana buƙatar ƙwarewar aiki mai girma, kuma kulawar kayan aiki yana da wahala. Hakanan akwai wasu haɗarin aminci. Ruwan sharar da aka samar bayan murmurewa har yanzu yana buƙatar kulawa mai zurfi don saduwa da ƙa'idodin fitarwa.

Hanyar Electrolysis

Hanyar electrolysis tana amfani da halayen redox na electrochemical don lalata cyanides a cikin ruwan datti. A lokacin ion electrolysis, cyanides sun rasa electrons a anode kuma suna oxidized zuwa cyanate, carbonate, nitrogen, ko ammonium. Cyanate an ƙara oxidized zuwa CO₂ da H₂O. Babban halayen sune:

CN⁻ + 2OH⁻ - 2e → CNO⁻ + H₂O (24)

2CN⁻ + 4OH⁻ - 6e → 2CO₂ + N₂ + 2H₂O (25)

Gwaje-gwajen Electrolysis ta hanyar amfani da yumbu mai tushe da sandar gubar carbon dioxide da bakin karfe cathode farantin karfe sun tabbatar da cewa ta hanyar amfani da hanyar electrolysis don magance cyanide - dauke da ruwa mai datti, bayan sa'o'i 2 na electrolysis, ana iya rage yawan CN⁻ daga 385mg/L zuwa 58mg/L, kuma Cu²⁺ daga 450mg/L48 zai iya rage yawan maida hankali. Bugu da kari, Hunan Zhongnan Gold Smelter yana amfani da hanyar kimiyyar lantarki don magance sharar ruwan zinare na cyanide, wanda zai iya rage jimillar cyanide daga 4g/L zuwa 0.8g/L. Bambanci daga na sama shi ne cewa duka anode da cathode faranti an yi su ne da faranti na ƙarfe. A lokacin aikin aiki, ba kawai wutar lantarki ke cinyewa ba, har ma da faranti na ƙarfe suna cinyewa.

Ana amfani da hanyar electrolysis musamman don magance babban - maida hankali cyanide - dauke da ruwan sha. Kayan aiki sun mamaye ƙananan yanki, tsarin yana da sauƙi kuma mai sauƙi don sarrafawa, amma yana cinye yawan adadin makamashin lantarki, kuma farashin aiki ya fi na hanyar chlorination alkaline. Yawan cire cyanide matsakaita ne, kuma ba shi da wani tasiri kan cire hadadden cyanide.

A halin yanzu, daga cikin hanyoyin magani don cire ruwan zinari na cyanide, hanyar alkaline chlorination, hanyar acidification, da sodium metabisulfite - hanyar iska ana amfani da su sosai. Hanyar electrolysis da ferrous gishiri hanyoyin sababbin hanyoyin da aka samu nasarar amfani da su a cikin maganin masana'antu. Hanyar oxidation na hydrogen peroxide shine galibi hanyar maganin gaggawa. Akwai wasu hanyoyin magani da yawa don magance ruwan sharar ruwan zinari na cyanide, kamar hanyar tsarkakewa ta halitta, hanyar nazarin halittu, hanyar rabuwa ta membrane, ion - hanyar musayar, da sauransu.