Abstract: The present invention relates to a plant and to a process for producing a solid-state alkali metal cyanide product. In order to obtain a solid-state alkali metal cyanide product that has a good proportion by weight of alkali metal hydroxide, and in order to ensure that it remains as calm as possible in the plant during operation, it is proposed that the proportion by weight of alkali metal hydroxide in a suspension withdrawn from the crystallization vessel and sent to a solid-liquid separation device be increased before it enters the solid-liquid separation device.

Abstract: The invention relates to a method for producing alkali metal cyanides as solids, comprising the steps: i) an absorption step in the form of the absorption of hydrogen cyanide from a syngas containing hydrogen cyanide in an aqueous alkali metal hydroxide solution; ii) a preparation step for the waste gases containing cyanide that have accumulated in step i); iii) a crystallization step in the form of the introduction of the alkali metal cyanide solution into an evaporative crystallizer; iv) a condensation step for the vapour containing cyanide that has accumulated in step iii) to obtain a vapour condensate containing cyanide; v) a recirculation step, in which the vapour condensate containing cyanide that has been obtained in step iv) is used as an aqueous liquid in step ii).

Abstract: The invention relates to a process for the preparation of alkali metal cyanides as a solid substance, comprising the steps of: i) an absorption step in the form of an absorption of hydrogen cyanide from a hydrogen cyanide-containing synthesis gas in an aqueous alkali metal hydroxide solution; ii) a crystallization step in the form of introducing said alkali metal cyanide solution into an evaporative crystallizer; iii) a separation step; iv) a recycle step; v) a drying step.

Abstract: The invention relates to a process for the preparation of alkali metal cyanides as a solid substance, comprising the steps of: i) an absorption step in the form of an absorption of hydrogen cyanide from a hydrogen cyanide-containing synthesis gas in an aqueous alkali metal hydroxide solution; ii) a crystallization step in the form of introducing said alkali metal cyanide solution into an evaporative crystallizer; iii) a separation step; iv) a recycle step; v) a drying step.

Abstract: The invention provides an assay for identifying a bacterium capable of binding elemental heavy metal, comprising the following steps: cultivating a test bacterium in a suitable first culture medium; immersing at least a surface portion of a test tool into the first culture medium for a second predetermined period of time, said surface portion being coated by elemental heavy metal, respectively; removing said test tool from said first culture medium and optionally rinsing the test tool; contacting a second culture medium with the surface portion coated by elemental heavy metal of said test tool removed in the previous step; and identifying the test bacterium as being capable of binding elemental heavy metal from growth of the test bacterium in said second culture medium.

Abstract: The invention provides a process of isolating or enriching a heavy metal present in a suspension containing a particulate mineral ore containing a heavy metal, comprising the following steps: incubating a suspension containing (i) a particulate mineral ore containing a heavy metal and (ii) biomass comprising a bacterium capable of binding the heavy metal; separating the biomass having bound heavy metal from the suspension of the previous step; and isolating the heavy metal from the biomass separated in the previous step.

Abstract: The invention relates to a method for producing shaped inorganic cyanide bodies, especially made of alkaline metal cyanides and alkaline earth metal cyanides, by pressing particulate inorganic cyanide obtained by means of a crystallization method. According to the invention, a cyanide crystallate separated from a mother liquor by means of a solid-liquid separation device and containing 2-15 wt. % water is fed to a forming device without the addition of an auxiliary forming agent and placed under pressure and compressed to form shaped bodies containing 0.1-12 wt. % water. The amount of water contained by the shaped bodies is always less than that contained in the crystallates used for the production thereof. Preferably, the crystallite is pressed out of a rotary filter or a centrifuge at a temperature of more than 40° C. to form shaped bodies containing 0.2-6 wt. % residual water. The inventive method can be carried out in a more economical manner than previously known methods using dried cyanide.