A process and a system allow producing sodium hydrosulfite crystals. A suspension containing sodium hydrosulfite is provided. The sodium hydrosulfite crystals are separated from a remainder of the suspension. The separated sodium hydrosulfite crystals are cooled to a stable temperature. The suspension may be obtained by raising a pH and lowering a temperature of a solution containing sodium hydrosulfite. A partial precipitation of the sodium hydrosulfite to form the crystals may be facilitated by addition of a nucleating agent to the suspension.

A process and a system allow producing sodium hydrosulfite crystals. A suspension containing sodium hydrosulfite is provided. The sodium hydrosulfite crystals are separated from a remainder of the suspension. The separated sodium hydrosulfite crystals are cooled to a stable temperature. The suspension may be obtained by raising a pH and lowering a temperature of a solution containing sodium hydrosulfite. A partial precipitation of the sodium hydrosulfite to form the crystals may be facilitated by addition of a nucleating agent to the suspension.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S; Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO.sub.2 gas; Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, 2 or of between 0 and 2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S; Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO.sub.2 gas; Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, 2 or of between 0 and 2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps:

Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S;

Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate;

Step (2): providing SO.sub.2 gas;

Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5;

Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, ?2 or of between 0 and ?2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and

Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps:

Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S;

Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate;

Step (2): providing SO.sub.2 gas;

Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5;

Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, ?2 or of between 0 and ?2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and

Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S; Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO.sub.2 gas; Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, ?2 or of between 0 and ?2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S; Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO.sub.2 gas; Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, ?2 or of between 0 and ?2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S; Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO.sub.2 gas; Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, 2 or of between 0 and 2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S; Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO.sub.2 gas; Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, 2 or of between 0 and 2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.