{"id":34541,"date":"2022-02-07T12:50:55","date_gmt":"2022-02-07T12:50:55","guid":{"rendered":"https:\/\/mineralmilling.com\/?page_id=34541"},"modified":"2022-03-28T08:23:02","modified_gmt":"2022-03-28T08:23:02","slug":"po-de-carvao","status":"publish","type":"page","link":"https:\/\/mineralmilling.com\/pt\/po-de-carvao\/","title":{"rendered":"P\u00f3 de Carv\u00e3o"},"content":{"rendered":"\n\n\t<h1>P\u00f3 de <strong>Carv\u00e3o<\/strong><\/h1>\n<h5>Iron Casting Application<\/h5>\n<p>This fine, powdered coal has been used to improve the surface finish of iron and copper castings since the 1870s. Used in greensand and dry sand moulding, coal dust protects the mould surface against the action of molten metal. When the metal comes into contact with a mould surface containing coal dust, a gaseous envelope is formed, which resists the fusion of sand to metal. Additives like pitch, cellulose, and silica flour are used, depending on the metal cast.<\/p>\n<ul>\n<li>Castings cool more slowly, preventing cracking<\/li>\n<li>Coal dust increases both greensand and dry sand strength<\/li>\n<li>Reduces expansion, scabbing, and metal penetration<\/li>\n<li>Prevents sand burn<\/li>\n<li>Imparts a cleaner finish<\/li>\n<li>Aids in separation at knockout<\/li>\n<li>Lessens rat tailing and other expansion defects<\/li>\n<li>Coal dust contains low concentrations of trace metals, PAH, and sulphates.<\/li>\n<li>Standard and Low-Ash formulations suitable for foundry use<\/li>\n<\/ul>\n<h3>Specifications<\/h3>\n<p>African Pegmatite has two grades of Coal Dust available.<\/p>\n<p>Standard<\/p>\n<ul>\n<li>100 Micron<\/li>\n<li>23%-25% Volatile Matter<\/li>\n<li>14%-20% Ash<\/li>\n<li>5% Moisture<\/li>\n<\/ul>\n<p>Low-Ash<\/p>\n<ul>\n<li>100 Microns<\/li>\n<li>34%-40% Volatile Matter<\/li>\n<li>10%-11% Ash<\/li>\n<li>5% Moisture<\/li>\n<li>6%-1% Sulphur<\/li>\n<\/ul>\n<h1>\n\tFolha de <strong> Dados<\/strong>\n\t<\/h1>\n\t<h4>Refractory Grade<\/h4>\n\t<a href=\"\" target=\"_self\" role=\"button\" rel=\"noopener\">\n\t\t\t\t\tVer Folha de Dados\n\t<\/a>\n\t<a href=\"https:\/\/mineralmilling.com\/wp-content\/uploads\/2022\/03\/DS-039-Coal-Dust-Standard-Grade-PT.pdf\" target=\"_self\" role=\"button\" rel=\"noopener\">\n\t\t\t\t\tVer Producto\n\t<\/a>\n\t<h4>Foundry- Low Ash Grade<a target=\"_self\" href=\"\/foundry\/coal-dust\/\" rel=\"noopener\"><\/a><\/h4>\n\t<a href=\"\" target=\"_self\" role=\"button\" rel=\"noopener\">\n\t\t\t\t\tVer Producto\n\t<\/a>\n\t<a href=\"https:\/\/mineralmilling.com\/wp-content\/uploads\/2022\/03\/DS-039-Coal-Dust-Standard-Grade-PT.pdf\" target=\"_self\" role=\"button\" rel=\"noopener\">\n\t\t\t\t\tVer Folha de Dados\n\t<\/a>\n\t<h4>Foundry- Standard Grade<\/h4>\n\t<a href=\"\" target=\"_self\" role=\"button\" rel=\"noopener\">\n\t\t\t\t\tVer Producto\n\t<\/a>\n\t<a href=\"https:\/\/mineralmilling.com\/wp-content\/uploads\/2022\/03\/DS-039-Coal-Dust-Standard-Grade-PT.pdf\" target=\"_self\" role=\"button\" rel=\"noopener\">\n\t\t\t\t\tVer Folha de Dados\n\t<\/a>\n\t<h3>General Information<\/h3>\n<p>The quality of coal dust that&#8217;s suitable for foundry use should consist of finely crushed bituminous coal that&#8217;s free of foreign material.<\/p>\n<p>Contamination of sulphur by the metal at the mould face can cause defects. Sulphur content of foundry coal dust should never be more than 10%.<\/p>\n<p>Optimum levels of Coal Dust should be established by trial and always weighed and metered.<\/p>\n<p>Appropriate proportion by weight of Coal Dust in greensand varies from 2%-3% for small castings and from 7%-8% for heavy work. Higher levels are sometimes used in special cases.<\/p>\n<p>Effects of too much Coal Dust:<\/p>\n<ul>\n<li>Grazed surfaces<\/li>\n<li>Gas holes<\/li>\n<li>Rounded edges<\/li>\n<li>Misruns<\/li>\n<\/ul>\n<p>A build-up of coal dust in sand can cause a blue skin on the casting, a decrease in permeability, and an increase in moisture requirement of the sand.<\/p>\n<h3>Fundi\u00e7\u00e3o de ferro<\/h3>\n<p>A poeira de carv\u00e3o \u00e9 um componente essencial da fundi\u00e7\u00e3o de ferro. Simplificando, a fundi\u00e7\u00e3o de ferro envolve derreter o ferro at\u00e9 que atinja um estado l\u00edquido, para depois o despejar sobre um molde. O molde \u00e9 removido quando o metal solidifica na forma desejada. Outros metais empregam p\u00f3 de carv\u00e3o nos seus processos de fabrico, mas esta p\u00e1gina concentra-se na aplica\u00e7\u00e3o nas fundi\u00e7\u00f5es ferro.<\/p>\n<p>[LEIA MAIS SOBRE AS V\u00c1RIAS APLICA\u00c7\u00d5ES DO P\u00d3 DE CARV\u00c3O]<\/p>\n<h3>O Processo<\/h3>\n<p>Uma vez fundido o ferro, s\u00e3o utilizados desgaseificadores para eliminar contaminantes que podem causar v\u00e1rios defeitos durante o processo de fundi\u00e7\u00e3o. O mon\u00f3xido de carbono \u00e9 um desgaseificador comum para fundi\u00e7\u00e3o de ferro. Se a desgaseifica\u00e7\u00e3o n\u00e3o eliminar a porosidade do ferro o suficiente, a impregna\u00e7\u00e3o a v\u00e1cuo pode ser usada para selar poros e fluxos de vazamento.<\/p>\n<p>Podem ser definidos padr\u00f5es para moldes de madeira, pl\u00e1stico, metal ou cera. Quando o molde est\u00e1 pronto e o metal derretido, o ferro l\u00edquido \u00e9 despejado sobre o molde. Hoje, o vazamento \u00e9 geralmente feito por rob\u00f4s e m\u00e1quinas de vazamento, mas alguns moldes podem exigir o uso de v\u00e1cuo ou gases pressurizados.<\/p>\n<p>Depois, \u00e9 permitido que o ferro solidifique no interior do molde para reter a forma da cavidade deste. A figura s\u00f3lida \u00e9 depois removida do molde recorrendo a t\u00e9cnicas conhecidas, como a sacudidela e o tombamento. Uma vez que a pe\u00e7a fundida seja removida do molde, as cabe\u00e7as, canais, port\u00f5es e risers s\u00e3o removidos da fundi\u00e7\u00e3o usando tochas, l\u00e2minas de corte de cer\u00e2mica ou serras de fita.<\/p>\n<h3>O papel do p\u00f3 de carv\u00e3o na fundi\u00e7\u00e3o de ferro<\/h3>\n<p>Areia verde contendo p\u00f3 de carv\u00e3o \u00e9 usada para fundi\u00e7\u00e3o em areia de materiais ferrosos como o ferro e o a\u00e7o. Nunca deve existir mais de 5% de p\u00f3 de carv\u00e3o na areia verde, dado que o p\u00f3 de carv\u00e3o passa pela combust\u00e3o quando exposto ao metal fundido e liberta um vapor de g\u00e1s. A areia verde nunca deve ser usada na fundi\u00e7\u00e3o de metais n\u00e3o ferrosos porque o p\u00f3 de carv\u00e3o liberta mon\u00f3xido de carbono, causando a oxida\u00e7\u00e3o dos metais n\u00e3o ferrosos.<\/p>\n<p>O p\u00f3 de carv\u00e3o aumenta a refractariedade da areia verde para que esta possa suportar as altas temperaturas exigidas durante a fundi\u00e7\u00e3o do ferro. A temperatura de fus\u00e3o do p\u00f3 de carv\u00e3o \u00e9 superior a 1600\u00b0 C. O tamanho de part\u00edcula fina do p\u00f3 de carv\u00e3o resulta num acabamento superficial aprimorado no produto final.<\/p>\n<p>Quando o p\u00f3 de carv\u00e3o liberta mon\u00f3xido de carbono ao ser exposto ao ferro fundido, o mon\u00f3xido de carbono actua como um desgaseificador. Isto elimina contaminantes gasosos do interior da cavidade do molde que podem causar defeitos de fundi\u00e7\u00e3o e diminuir a porosidade do ferro. O p\u00f3 de carv\u00e3o tamb\u00e9m aumenta a colapsibilidade ou a capacidade de ser removido do metal solidificado da areia verde. O p\u00f3 de carv\u00e3o queima durante a fundi\u00e7\u00e3o e torna o molde muito mais f\u00e1cil de remover durante a remo\u00e7\u00e3o.<\/p>\n<p>Recomenda-se que o p\u00f3 de carv\u00e3o de fundi\u00e7\u00e3o contenha pelo menos 30% de mat\u00e9ria vol\u00e1til para obter um acabamento superficial desej\u00e1vel. O teor de cinzas n\u00e3o deve exceder 12% e o teor de enxofre nunca deve ser superior a 1% ou podem ocorrer defeitos de fundi\u00e7\u00e3o. O cloro tamb\u00e9m pode causar defeitos de fundi\u00e7\u00e3o que devem ser reduzidos ao m\u00ednimo.<\/p>\n<h3>Embalagem<\/h3>\n<p>Escolha a embalagem e o arranjo de envio que melhor atende \u00e0s suas necessidades, variamos de embalagens pequenas \u00e1 embalagens de tamanhos maiores, ou tamanhos personalizados feitos especialmente para voc\u00ea. Podemos acomodar praticamente qualquer tamanho, de uma tonelada m\u00e9trica a milhares. <\/p>\n<h3>Conveni\u00eancia<\/h3>\n<p>Mantemos pre\u00e7os competitivos em um esfor\u00e7o para conquistar e manter seus neg\u00f3cios pelo tempo que voc\u00ea precisar. Nosso objetivo \u00e9 atender \u00e0s necessidades de cada cliente, incluindo aqueles com solicita\u00e7\u00f5es especiais e cronogramas de produ\u00e7\u00e3o exigentes.<\/p>\n<p>Um retorno geral de 15 dias para a fabrica\u00e7\u00e3o nos permite entregar seus compostos o mais r\u00e1pido poss\u00edvel, para que voc\u00ea possa acompanhar as demandas de seus neg\u00f3cios. Pode nos contactar para que possamos te conectar com um distribuidor em sua \u00e1rea, caso n\u00e3o tenha tempo suficiente para esperar pelos materiais.<\/p>\n<p>Atualmente, fazemos entregas para 44 pa\u00edses em todo o mundo e estamos felizes em enviar para o seu tamb\u00e9m. Os canais de log\u00edstica confi\u00e1veis e profissionais que temos dispon\u00edveis facilitam a oferta de pre\u00e7os e servi\u00e7os excelentes, independentemente da sua localiza\u00e7\u00e3o. <\/p>\n<h3>African Pegmatite<\/h3>\n<p>Com 48 anos como profissionais em minera\u00e7\u00e3o e fabrica\u00e7\u00e3o, temos a vis\u00e3o, a rede e a experi\u00eancia para oferecer a voc\u00ea o melhor em qualidade, servi\u00e7o e efici\u00eancia. Somos credenciados pela ISO 9001 desde 2002 e, mais recentemente, atendemos ao padr\u00e3o de 2015.<\/p>\n<p>Nosso objetivo \u00e9 fornecer os melhores materiais dispon\u00edveis para os nossos clientes e nos tornar seu balc\u00e3o \u00fanico para corantes, minerais, compostos e muito mais. Visite a nossa p\u00e1gina geral de refrat\u00e1rios para ver todos os outros produtos refrat\u00e1rios e complementares que temos dispon\u00edveis.<\/p>\n<p>Se voc\u00ea deseja se tornar um distribuidor de produtos African Pegmatite, entre em contato para que possamos personalizar um acordo consigo.<\/p>\n\n","protected":false},"excerpt":{"rendered":"<p>P\u00f3 de Carv\u00e3o Iron Casting Application This fine, powdered coal has been used to improve the surface finish of iron and copper castings since the 1870s. Used in greensand and dry sand moulding, coal dust protects the mould surface against the action of molten metal. When the metal comes into contact with a mould surface&#8230;<\/p>\n","protected":false},"author":10,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"inline_featured_image":false,"footnotes":""},"categories":[6769],"tags":[],"class_list":["post-34541","page","type-page","status-publish","hentry","category-foundry-pt"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.1 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>P\u00f3 de Carv\u00e3o - African Pegmatite<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/mineralmilling.com\/foundry\/coal-dust\/\" \/>\n<meta property=\"og:locale\" content=\"pt_PT\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"P\u00f3 de Carv\u00e3o - African Pegmatite\" \/>\n<meta property=\"og:description\" content=\"P\u00f3 de Carv\u00e3o Iron Casting Application This fine, powdered coal has been used to improve the surface finish of iron and copper castings since the 1870s. Used in greensand and dry sand moulding, coal dust protects the mould surface against the action of molten metal. When the metal comes into contact with a mould surface...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/mineralmilling.com\/foundry\/coal-dust\/\" \/>\n<meta property=\"og:site_name\" content=\"African Pegmatite\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/AfricanPegmatite\/\" \/>\n<meta property=\"article:modified_time\" content=\"2022-03-28T08:23:02+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"6 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/mineralmilling.com\\\/foundry\\\/coal-dust\\\/\",\"url\":\"https:\\\/\\\/mineralmilling.com\\\/foundry\\\/coal-dust\\\/\",\"name\":\"P\u00f3 de Carv\u00e3o - African Pegmatite\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/mineralmilling.com\\\/#website\"},\"datePublished\":\"2022-02-07T12:50:55+00:00\",\"dateModified\":\"2022-03-28T08:23:02+00:00\",\"inLanguage\":\"pt\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/mineralmilling.com\\\/foundry\\\/coal-dust\\\/\"]}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/mineralmilling.com\\\/#website\",\"url\":\"https:\\\/\\\/mineralmilling.com\\\/\",\"name\":\"African Pegmatite\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\\\/\\\/mineralmilling.com\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/mineralmilling.com\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"pt\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/mineralmilling.com\\\/#organization\",\"name\":\"African Pegmatite\",\"url\":\"https:\\\/\\\/mineralmilling.com\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"pt\",\"@id\":\"https:\\\/\\\/mineralmilling.com\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/mineralmilling.com\\\/wp-content\\\/uploads\\\/2019\\\/05\\\/Alogo.png\",\"contentUrl\":\"https:\\\/\\\/mineralmilling.com\\\/wp-content\\\/uploads\\\/2019\\\/05\\\/Alogo.png\",\"width\":500,\"height\":132,\"caption\":\"African Pegmatite\"},\"image\":{\"@id\":\"https:\\\/\\\/mineralmilling.com\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.facebook.com\\\/AfricanPegmatite\\\/\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"P\u00f3 de Carv\u00e3o - African Pegmatite","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/mineralmilling.com\/foundry\/coal-dust\/","og_locale":"pt_PT","og_type":"article","og_title":"P\u00f3 de Carv\u00e3o - African Pegmatite","og_description":"P\u00f3 de Carv\u00e3o Iron Casting Application This fine, powdered coal has been used to improve the surface finish of iron and copper castings since the 1870s. Used in greensand and dry sand moulding, coal dust protects the mould surface against the action of molten metal. 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